assessment of environmental multifunctions of...

Assessment of Environmental Multifunctions

1

ASSESSMENT OF ENVIRONMENTAL MULTIFUNCTIONS OF PADDY FARMING IN CITARUM RIVER BASIN, WEST JAVA,

INDONESIA

MULTIFUNGSI LINGKUNGAN SISTEM PADI SAWAH DI DAS CITARUM, JAWA BARAT, INDONESIA

F. Agus1), R. L. Watung1), H. Suganda1), S. H. Tala’ohu1), Wahyunto, S. Sutono1), A. Setiyanto2), H. Mayrowani2), A. R. Nurmanaf2), and M. Kundarto3)

1) Soil Research Institute, Jl. Ir. H. Juanda 98, Bogor 16123, Indonesia 2), Center for Agricultural Socio-Economic Research, Bogor, Indonesia 3), UPN Veteran, Yogyakarta

ABSTRAK

Disamping berperan penting dalam menghasilkan produk yang dapat dipasarkan dan produk sampingan berupa fungsi lingkungan, alih fungsi lahan sawah ke penggunaan di luar pertanian tetap berlangsung disebabkan kurangnya penghargaan untuk sektor ini. Studi yang dilaksanakan tahun 2002 mengevaluasi: (i) peran multifungsi sistem pertanian lahan sawah di daerah aliran sungai Citarum menggunakan metode biaya pengganti (replacement cost method), (ii) erosi dari lahan sawah di Ungaran, Jawa Tengah dengan pengambilan contoh intensif dan analisis laboratorium, (iii) pengaruh limbah cair pabrik terhadap kualitas tanah dan produksi padi di daerah aliran sungai Citarum dengan metode survei. Hasil penelitian menunjukkan sistem pertanaman padi berkontribusi nyata dalam pengurangan banjir, konservasi sumber daya air, pencegahan erosi, pembuangan limbah, dan peredaman panas. Jumlah total biaya pengganti untuk fungsi lingkungan dari sistem pertanian padi mencapai 45% dari total harga produksi beras yang dihasilkan dari areal yang sama. Hal ini berarti bahwa petani menghasilkan jasa lingkungan secara cuma-cuma seharga 45% dari nilai produk padi. Erosi dari sawah bernilai negatif yang berarti bahwa sawah walaupun pada areal miring, mendepositkan sedimen, bukan menghasilkan sedimen. Hanya lahan sawah yang berdampingan dengan sungai menghasilkan sedimentasi sungai. Tanah di lahan sawah dekat pabrik tekstil (sepanjang 2 km ke arah hilir dan beberapa ratus meter di kiri kanan sungai) terkontaminasi oleh Cu, Zn, dan Co yang terindikasi oleh konsentrasi unsur tersebut di atas batas kritis. Konsentrasi Zn mencapai batas kritis 10 mg/kg pada padi yang dihasilkan dari sekitar pabrik. Dengan memperhatikan banyaknya jasa lingkungan dari sistem padi sawah dan pentingnya masalah ketahanan pangan di Indonesia, penelitian ini menghimbau diperlukannya formulasi kebijakan dalam upaya mengkontrol alih fungsi lahan sawah.

5

Prosiding Seminar Nasional Multifungsi dan Konversi Lahan PertanianPenyunting: Undang Kurnia, F. Agus, D. Setyorini, dan A. Setiyanto

ISBN 979-9474-20-

F. Agus et al.

ABSTRACT

Despite its strategic role in producing marketable products and environmental services, conversion of paddy field to non agricultural uses, because of lack of incentives in this farming sector, has been continuing. In this study, conducted in 2002, we evaluated (i) multifunctional roles of rice paddy system in the Citarum River Basin, West Java, using the replacement cost method, (ii) soil loss from paddy fields in Ungaran, Central Java, by intensive water sampling and laboratory analysis, and (iii) the effects of liquid wastes from factories on the quality of soil and rice products within the Citarum River Basin using a survey method. Results showed that paddy field system contribute significantly in flood mitigation, conservation of water resources, soil erosion prevention, waste disposal, and heat mitigation. The total replacement costs of environmental services from paddy farming for the indicators employed in this study was about 45% of the marketable rice products produced in the same area; meaning that the farmers have produced free services to the society around this area with the value of 45% of the marketable rice product. Net soil loss from paddy field is negative meaning that paddy fields, regardless of how steep its major slope, deposit rather than giving off sediment. Only those paddy fields located along the streams contribute to the stream sedimentation. Paddy field soil located near (within 2 km downstream and a few hundred meters along the stream) textile factories has been contaminated by at least Cu, Zn, and Co as indicated by their concentrations exceed the critical levels. Likewise Zn concentration reached the critical level of 10 mg/kg in rice produced in the factory’s vicinity. Considering the sizable environmental services paddy fields can offer and that attainment of a higher level of rice self sufficiency is important for Indonesia, this research results calls for formulation of measures to control paddy field conversion.

INTRODUCTION

Indonesian government has put food security as one of its highest agricultural development priorities and increasing the production of rice, corn and soybean absorbs substantial attention. Indonesian rice import has been increasing with time following the landmark self-sufficiency attainment in 1984 and recently it ranges between 1 and 3 million tons annually. With this level of import, Indonesia become the world largest rice importer. Provided that international rice supplies is uninterrupted and the country can secure enough foreign exchange, Indonesia can fulfill the country’s need from import. However, neither one of these two could fully be guaranteed. Reliance on importation may run the risk of interruption because of various unfavorable factors such as drought, flood, and war. Furthermore, with the sluggish economic recovery since the 1998 economic crises, the reserve of foreign exchange will remain low for some time. As such, Indonesia has to secure most of it’s own food stuff, especially rice.

2


Counter to increasing rice production efforts, conversion of paddy field and other agricultural lands to non agricultural uses is rampant. During the period of 1981 to 1999, one million ha paddy field in Java and 625,000 ha in the outer islands have been converted (Irawan et al., 2001) mostly to industrial and urban development (Agus et al., 2001). Although there have been 518,000 ha in Java and 2.7 million ha in the outer islands, new paddy fields developed during the same period, this does not solve Indonesian food insecurity problems, because the newly developed paddy fields are much less productive compared to the well developed (mostly with regulated irrigation facilities) ones. One of the major factors for conversion is that agriculture lacks incentives due to high cost of production and low rice price. Imported rice, while increasing rice stock to cover the need of all people, make farmers’ problems worse because it’s usually cheaper than the domestically produced rice. While the accelerating conversion trend is worried by a few stakeholders, but many have not been alarmed by such trend simply due to lack of understanding of social, economic and environmental consequences that may be resulted from the conversion.

Earlier, government bias towards prioritizing industrial development at the expense of agricultural promotion have made it more difficult for agricultural sector to keep up with ever increasing food demand. Multifunctionality of agriculture i.e. agricultural roles other than producing agricultural products including flood mitigation, erosion reduction, rural amenity, food security, organic waste disposal, income generation, and employment have not been fully recognized and understood. Environmental degradation caused by land use conversion particularly from agriculture to industrial and urban development occur not only within the area under conversion, but also the surrounding areas as well as many aspects of human life. Hence, every stake holder, especially policy makers, should clearly understand agricultural multifunctionality, such that the positive externalities could be internalized in the form of agricultural development policies.

This paper explains the results of Year 2 Indonesian Case Study on Multifunctionality of Agriculture under the auspices of the project on the Evaluation of Multifunctionality of Paddy Field. Activities in Year 2 is an upscale and more in depth compared to that of Year 1 study as reported in Agus et al. (2001) and Agus et al. (2002b).

Year 1 (2001) study in Citarik Sub-watershed revealed that major land use conversions occurred from forest to agricultural lands and from various agricultural systems to housing/urban and industrial development areas (Wahyunto et al., 2001). There was also a trend that the rate of conversion increases with time. These conversions in general occurred from land use with a higher to a lower water buffering capacity and this means that with time the water buffering capacity of the studied

3

F. Agus et al.

catchments is decreasing which could be related to more frequent flood in the studied catchments.

Environmental evaluation as conducted in Year 1 was continued with economic assessment in the second year. Special attention was given for paddy field as one of the presumably most environmentally benign system as far as soil loss and thus soil loss. Measurement of erosion sediment input and output into and from paddy field system was adopted as a complementary activity. Threats to the sustainability of paddy field was also evaluated in terms of heavy metals contamination from manufactures located within productive paddy field areas in Citarum watershed.

OBJECTIVES

(i) To evaluate, using the economic terms, multifunctional roles of agriculture in the Citarum River Basin, West Java.

(ii) To quantify a year-round soil loss from paddy field. (iii) To evaluate the effects liquid wastes from factories on the sustainability of rice

production (the quality and quantity of rice products).

EXPECTED OUTPUTS

(i) Assessment of the replacement cost of restoring multifunctional roles of agriculture (paddy field) in Citarum River Basin had the roles disappear because of abandonment or conversion of paddy fields.

(ii) Analysis of soil loss from paddy field and its comparison with that of upland farming systems.

(iii) Analysis of the degree of damage on paddy field, in terms of yield reduction and heavy metal concentration in soil and plant as cause by industrial waste contamination.

MATERIALS AND METHODS

This research was conducted from October 2001 to September 2002. The case watershed was Citarum River Basin in West Java for addressing objectives (i) and (iii) and a series of terraced paddy fields in Ungaran, Central Java to address objective (ii). Therefore there were three activities included in this report:

1. Valuation of multifunctionality of paddy field using the replacement cost method,

2. Quantification of soil loss from paddy field, and

3. Evaluation of the effects of liquid wastes from factories on the sustainability of rice production (the quality and quantity of rice products).

4


Citarum river basin, with an area of 694,900 ha have three dams – Jatiluhur at the north, Cirata in the middle, and Saguling in the south (Figure 1). These dams have a very central role for industrial as well as agricultural developments and this justifies the selection of this study site. The three dams generate electric power for Java and Bali. Land use is variable and dominated by mixed farming (combination of annual and perennial tree crops), upland farming and paddy fields (Table 1).

Figure 1. Land use map of Citarum River Basin

5

F. Agus et al.

Table 1. Land use in Citarum river basin and in catchments filling into the dams of Saguling, Cirata, and Jatiluhur in 2001

Catchments/river basin area Land use

Saguling Cirata1) Jatiluhur1) Citarum1)

ha Pond and mangrove 0 0 0 9,685 Paddy field < 8% major slope 49,145 71,219 74,101 100,120 Paddy field > 8% major slope 27,033 44,955 47,739 57,518 Tea plantation 7,807 10,790 10,790 10,971 Rubber plantation 0 1,608 3,037 7,767 Annual upland 41,868 68,827 69,010 116,753 Mixed (multistrata) farming 42,453 96,287 111,427 201,898 Housing and industrial areas 24,633 27,092 27,355 46,159 Shrubs and under-utilized land 1,544 19,349 29,374 52,570 Forest 58,522 62,177 63,358 68,655 Protection forest 0 3,448 3,448 5,446 Dam (inundated areas) 4,581 9,937 17,356 17,356 Total 257,586 415,689 456,995 694,898 Source: Wahyunto et al. (2002). 1) Area of Cirata catchment include the entire area of Saguling catchment and so forth for Jatiluhur catchment and Citarum river

basin.

Valuation of multifunctionality of agriculture

This activity included the estimation of multi-functionality of agriculture using the replacement cost method (RCM) as explained by Yoshida (2001), and estimation of marketable values of agriculture using statistical data. Similar studies were conducted among others by Chen (2001) using the contingent valuation method (CVM) for Taiwan and by Eom and Kang (2001) for Korea emphasizing the environmental aspects and less of economic valuation. RCM is an indirect estimation of the costs for restoration of environmental services if certain forms of agricultural lands (in this case paddy fields) are abandoned or converted to other uses. In this current study we use the last two decade paddy field conversion rate as a basis to valuate the loss of environmental services.

Study by Wahyunto et al. (2001) for Citarik subwatershed as well as other studies revealed that most of paddy field conversion occurred near the urban or suburban areas and that the main successive land uses are housing or urban development and industrial areas. Sudaryanto (2002), based on data from the National Bureau of Statistics, stated that about 1 million ha of paddy field in Java has been converted to non agricultural uses between 1981 and 1999. This area is equivalent to

6


about 30% of paddy field area in Java. For this current study the last two decade’s scenario will be used as the basic assumptions:

1. Thirty percent of the paddy field in Citarum will decrease within the next two decades due to paddy field conversion.

2. The main successive land uses are urban and industrial areas as has been revealed by other studies.

3. Emphasis was given to positive environmental services (positive externalities) of paddy fields. The negative externalities are negligible based on an assumption that rice production in paddy field is managed properly, i.e. for example, agrochemicals are not used excessively that could otherwise cause negative residual effects to water bodies.

4. Methane and nitrous oxide gas emission is a potential negative externality from paddy fields, but valuation of its replacement cost is rather complicated and thus discounted from this report.

Summary of input data and method of estimation of replacement costs of

several environmental services that could be provided by paddy field is given in Table 2. Interpretation of each term in Table 1 is summarized as follows:

Flood mitigation function

Paddy fields surrounded by dikes temporarily store water at times of heavy rain, and discharge it gradually into downstream rivers and surrounding areas. In this way, their functioned as mini dams and thus prevent or mitigate the damage which might otherwise be caused by floods. Upland fields, on the other hand, store rainwater temporarily in porous soil layer as well as intercept rain water in its canopy. Some temporary ponding of water occur in the upland fields because of soil surface roughness. This role played by agricultural land is called the water retention function or flood mitigation function.

Evaluation of the replacement cost of water retention capacity of paddy fields is based on the cost of constructing a dam which would fulfill the same function of water control. The value of the temporary water retention capacity of porous soils is based on the replacement costs which may be incurred by a dam. In this calculation it is assumed that if paddy fields are converted, the succeeding land use will either be housing and industrial areas, and to a negligible extent, annual upland farming. Replacement cost for flood mitigation, RCF, if 30% of paddy field further decrease in the next two decades was calculated as: RCF = (Pipf – Pui) * A * CR * (Dc + Mc) …………………………… [1]

7

F. Agus et al.

Where: Pipf = Water retention capacity of paddy fields [m] Pui = Water retention capacity of urban and industrial areas [m] A = Area of paddy field in Citarum [m2] CR = The land conversion rate within the next two decades, which is

assumed equal to 0.3 for this case study Dc = Depreciation costs of a dam per unit of water stored [$ m-3 year-1] Mc = Maintenance cost of a dam per unit of water stored [$ m-3 year-1]

Function of conserving water resources

Based on water balance, schematically represented in Figure 2, paddy fields receive rainfall and irrigation water. The outputs from the paddy fields include direct runoff, evapo-transpiration and percolation. Part of the percolated water (in this case assumed 75%) reaches the rivers through underground flow and eventually reach dams. The rest of the percolated water recharge the ground water. Those water from paddy field recharging the ground water and reaching the dam as well as the runoff water that flows to the river and reach the dam is called the conserved water and the corresponding role of paddy field is called water conservation function. Valuation of water conservation function using the RCM is as follows:

WC(river) = (RO + LSS) *S* A * CR * (Dc + Mc) ……………… [2]

Where: WC(river) = Water conservation replacement cost of excess irrigation and rain

water received by paddy fields that eventually reaches the river and dam [$ year-1]

RO = Thickness of runoff coming from paddy field that end up in dams [m year-1]

LSS = Thickness of sub surface flow, i.e. a portion (assumed 75%) of water percolating from paddy field area that ends up in dam through lateral flow [m year-1]

S = Correction factor of runoff and subsurface flow of water that actually reaches the dam(s) in the downstream area

A = Area of paddy fields [m2] CR = The land conversion rate within the next two decades, which is

assumed equal to 0.3 for this case study Dc = Depreciation costs of a dam per unit of water stored [$ m-3 year-1] Mc = Maintenance cost of a dam per unit of water stored [$ m-3 year-1]

8


Rainfall=2500 mmIrrigation 1560 mm

ET=1460 mm RO=334 mm

Dam

Recycled via river to Dam = 1700 mm

Aquifer capacity

Percolation=2266 mm

Recharging ground water= 567 mm

Rainfall=2500 mmIrrigation 1560 mm

ET=1460 mm RO=334 mm

Dam

Recycled via river to Dam = 1700 mm

Aquifer capacity

Percolation=2266 mm

Recharging ground water= 567 mm

Figure 2. Schematic diagram of annual water balance for paddy field in Citarum

Pricing the water based on Dc and Mc is perhaps an under-estimation, because besides the costs for collecting water in the dam before distribution, the costs of irrigation networks should also be taken into consideration before the water can be reused for irrigation in the lower lying areas. Estimation of S, however is complicated and thus, while Equation 2 gives an understanding of the component of water conservation function, it is not operational in this study. Water conservation replacement cost (WCgw ) is calculated as follows:

WCgw = D * A * CR * Wp ………………………………………. [3]

Where: WCgw = Water conservation replacement cost of percolating water reaching

the ground water [$ year-1] D = Amount of water draining from paddy fields and recharging ground

water [in water thickness, m year-1] A = Area of paddy fields [m2] CR = The land conversion rate within the next two decades, which is

assumed equal to 0.3 for this case study Wp = Price of drinking water (difference between purchasing tap water

from well water) [$ m-3]

and total replacement cost for water conservation RCwc is calculated as: RCWC = WCr + WCgw …………………………………..………..[4]

9

F. Agus et al.

Table 2. Input data and sources/method of estimation for the study of environmental and economic valuation of multifunctional roles of agriculture for Citarum River Basin, West Java, Indonesia

Input data required Source/method of estimation

1. Flood prevention function 1.a. Effective water retention capacity of paddy fields Analysis of spatial land use data of

Citarum River Basin and calculation based on Agus et al. (2001)

1.b. Effective water retention capacity of urban and industrial areas

Idem

1.c. Dam annual depreciation and maintenance costs and dam capacity.

Survey at Saguling, Cirata and Jatiluhur Hydroelectric Power Plant (HEPP)

2. Conservation of water resources 2.a. Volume of irrigation water entering paddy field per

unit area Literature study, survey

2.b. Portion or volume of water entering agricultural land that eventually return to rivers

Field survey, literature studies

2.c. Volume of ground water utilized for agriculture Field survey and/or rough estimation 2.d. Maintenance and depreciation costs of irrigation

dams and irrigation canals Directorate General of Irrigation

3. Soil erosion prevention function 3.a. Volume of eroded soil under each major agricultural

system and under non agricultural systems Recalculation based on updated land use map.

3.b. Construction cost of a dam/check dams to retain the sediment

Survey at Saguling, Cirata and Jatiluhur Hydroelectric Power Plant (HEPP) and at district level forestry agencies.

4. Landslide prevention function 4.a. Number of landslide events when the land is used

for paddy field versus when the land is used for non agriculture

Field survey, secondary data at the Min. of Social Affairs, data at Directorate Bina Marga

4.b. Estimated cost of losses per landslide Idem 5. Function of organic waste disposal 5.a. Volume or tonnage of various forms of organic

wastes per year that potentially could be used for agriculture

Estimate of organic matter application

5.b. Estimate of disposal costs of such wastes Secondary data on transportation cost of waste disposal.

(Alternative to 5a and 5b) Retribution payment per year charged to each household for waste disposal by the town commission.

Local government

6. Rural amenity preservation function 6.a. Number and length of stay of tourists coming to

rural areas per year Estimate and/or secondary data at the case site, data from toll road company, and Min. of Tourism.

6.b. Cost of visiting the rural area per person. Transportation and accommodation cost per person per day

7. Estimation of economic value of marketable agricultural products

7.a. Annual production of each commodity Local statistics 7.b. Market price of each commodity Local statistics

10


Function of erosion prevention

Soil erosion under paddy field is negligible (comparable to that of forest land) regardless of the major (macro) slope of the land (Agus et al., 2002b). Other land uses, besides paddy field and forest, have a much higher soil loss. If paddy fields are converted to urban and industrial areas, it will create almost impermeable soil surface on areas used for building and paving and thus increase runoff and erosion on the exposed surface. In this calculation it was assumed that if paddy field is converted, soil loss increases to at least as high as that of upland farming areas. The difference in the volume of soil loss from the upland farming system with that of paddy field was estimated and given a monetary value based on the cost which would be incurred by constructing a dam to filter and retain sediments. Replacement cost for soil erosion prevention function (RCE) is calculated as follows:

RCE = (Eu – Epf) * A* CR * SDR * (Dc + Mc) …………………..…[5] Where: Eu = Estimated soil loss (erosion), in thickness unit, from upland

farming areas [m3 ha-1 year-1] Epf = Estimated soil loss from paddy field in unit thickness [m3 ha-1 year] A = Area of paddy field [ha] CR = The land conversion rate within the next two decades, which is

assumed equal to 0.3 for this case study SDR = Sediment Delivery Ratio, assumed equal to 0.1 Dc = Depreciation costs of a dam per unit of water stored [$ m-3 year-1] Mc = Maintenance cost of a dam per unit of water stored [$ m-3 year-1]

Function of landslide prevention

Yoshida (2001) explained that in the process of rice cultivation, paddy fields form shallow plates filled with water. Irrigation water constantly permeates into the soil, thereby maintaining a steady level of groundwater. However, if paddy fields are abandoned, the ground will crack, and the capacity to maintain a steady groundwater level will be reduced. The land, used for paddy fields, swamp land and fish ponds have the lowest potential for landslide although for some type of soils, such as volcanic soils, susceptibility to landslide may increase due to soil saturation by water. The estimated number of landslides that are prevented by continuous cultivation is valued based on the estimated cost of losses incurred by landslides. Replacement cost for landslide prevention (RCLS) is calculated as: RCLS = (LSoc - LSwc ) * A * CR * Cls …………………………….[6]

11

F. Agus et al.

Where: LSoc = Estimated number of landslides per year if cultivated fields are

abandoned LSwc = Estimated number of landslides with continuous cultivation A = Area of paddy field [ha] CR = The land conversion rate within the next two decades, which is

assumed equal to 0.3 for this case study Cls = Costs or losses per landslide per unit area [$ ha-1]

Function of organic waste disposal

Organic (biodegradable) wastes such as food residues and human wastes from non agricultural activities can be applied to agricultural lands such as paddy fields as compost or as fresh organic matter. This practice around agricultural areas lower the waste disposal costs compared to disposing biodegradable organic wastes to dumpsites. Organic materials returned to the fields to some extent can supply nutrients and increase soil organic matter content in the soil. Several assumptions applied for this practice:

• Separation of wastes into biodegradable and non biodegradable components has been adopted by the community.

• An institution for monitoring and evaluating the toxic components in the wastes such as heavy metals and recalcitrant toxic substances has been established and functioning.

The replacement cost for waste disposal (RCWD) could be calculated by either

one of at least the following two ways: 1. Reduction of transportation cost of wastes had been applied to agricultural areas

in the vicinity of wastes sources rather than transporting it to distanced dumpsites. RCWD = OW * TW * ROW * A * CR * TC …………………………. [7a]

Where: Ow = Proportion or percentage of biodegradable organic wastes from the

total city and domestic wastes. In this case assumed as high as 50%

Tw = Total city and domestic wastes produced annually [t year-1] Row = The rate of biodegradable wastes that could be applied to paddy

fields in such a way that will not cause negative detrimental effects such as nitrogen immobilization [t ha-1 year-1]

A = Paddy field area within the case study area [ha] TC = (Difference in) transportation cost of applying the wastes in paddy

fields near the sources versus dumping to dumpsites [$ t-1 year-1]

12


2. Retribution collected by the municipal government for waste disposal. Replacement cost for waste disposal (RCWD) is calculated as:

RCWD = OW * HH * Rw …………………………………..…… [7b] Where:

Ow = Proportion or percentage of biodegradable organic wastes from the total city and domestic wastes. In this case assumed as high as 50% [unit less]

HH = Number of household in the study area Rw = Annual retribution paid by each household to the municipal

government [$ hh-1 year-1]

Function of heat mitigation

Replacement cost for heat mitigation is calculated based on the fact that as paddy fields are converted to urban and industrial areas, there is an increase in air temperature. The loss of cooling effect of paddy field is replaced by the community by utilizing artificial cooling systems such as fan and air conditioner. Replacement cost for heat mitigation, (RCHM), is calculated as:

RCHM = {F* (Mf +Df) + AC (MAC+DAC)} * A * CR ………………[8] Where

F = Number of fan in the study area

Mf = Maintenance cost of a fan [$ year-1]

Df = Depreciation cost of a fan [$ year-1]

AC = Number of AC in the study area

MAC = Maintenance cost of an AC [$ year-1]

DAC = Depreciation cost of an AC [$ year-1] CR = The land conversion rate within the next two decades, which is

assumed equal to 0.3 for this case study

Function of preserving rural amenities for recreation and relaxation

Agricultural lands not only constitute beautiful agricultural landscape, but also create unique natural, cultural, and social environments attracting those living in urban areas to visit. The calculation of replacement cost of rural amenity is simply the sum of transportation and lodging costs of people visiting agricultural areas per unit of time.

13

F. Agus et al.

Air purification function

Paddy fields can potentially absorb SO2 and NO2 gases as much as 9.72 and 13.64 kg year-1, respectively (Yoshida, 2001). Paddy field also have some potential to sequester carbon from the atmosphere, but with C sequestration during the crop growth and emission during the off season, the time average of the C sequestration function may be negligible. Industrialized countries apply various measures for purifying gas if the concentration exceeds tolerable level. For Indonesia, there has not been any logical measures that can be referred for this study and thus this component was not estimated.

Estimation of marketable value of agriculture

This task was based on statistical data of agricultural products and multiplied by current market price of each product.

Quantification of soil and major nutrient losses from paddy field

This activity was conducted in connection with on-going research organized by the Management of Soil Erosion Consortium (MSEC). This MSEC project so far has ample data sets of the catchment-scale upland agriculture erosion and hydrology, but so far, little soil loss and chemical output evaluation has been done for the paddy field part of the catchment.

Several plots of paddy field were delineated and mapped. Water inlets and outlets were installed with V-notch weirs made of GI sheets. Water level at the inlets and outlets of each plot was recorded two times daily and rating curve for the relationship between water level and discharge was developed. During and after soil manipulation (plowing, puddling, transplanting, weeding, and fertilization) intensive water samples were taken and sediment and chemical (nitrate and phosphate) concentrations were determined using standard procedures. Less frequent (weekly) sampling was taken during the time when chemical and sediment concentrations are expected to be low. From sediment and chemical concentrations and water-discharge data, the sediment and chemical debits entering and leaving the paddy field were calculated.

Evaluation of the effects of liquid wastes from factories on the sustainability of rice production

The Year 1 research showed progressive encroachment of factories and houses into paddy field areas. There is a strong indication of darkening of river water near industrial centers in Citarik River. Farmers living near the river reported disappearance of several fish species. Earlier report showed that there has been elevated concentrations of heavy metals in paddy field along the river. The next

14


question arising from that research is how wide is the spatial distribution of these toxic elements and how much they affect rice production and quality. This research results will present spatial distribution of concentration of a few heavy metal elements in the river receiving effluent from textile industries, as well as concentration of the respective elements in rice plants and in soil. Results of this research can reflect the environmental and sustainability threats of paddy field caused by factories in paddy field areas.

The research site extended from a major textile industrial plant to 2 km downstream area, and at least 0.5 km to the left and right sides of the river. Soil and plant samples were taken for a few heavy metal concentration analysis.

Table 3. Dam construction cost, life storage, life span, depreciation cost and maintenance cost and replacement cost of water buffering function in Citarum River Basin

Name of dam Properties Saguling Cirata Jatiluhur

Water retention capacity of paddy field average for the entire basin (m)

0.093

Water retention capacity of housing and industrial areas average for the entire basin (m)

0.02

Area of paddy field in Citarum river basin (m2)

1,999,850,000

Estimated conversion rate of paddy field till 2020

0.3

Dam construction cost ($) 191,112,669 250,423,497 935,596,371 Dam life storage (m3) 15,650,000 34,507,984 76,451,149

Dam life span (year) 46 50 270 Dam depreciation cost ($ m-3 year-1) 0.265 0.145 0.045 Average depreciation cost for the three dams ($ m-3 year-1) 0.152 Dam maintenance cost ($ m-3 year-1) 0.005 0.008 0.003 Average maintenance cost for the three dams ($ m-3 year-1) 0.005 RCF (replacement cost of flood mitigation function), using Equation [1], ($ year-1) 6,890,581

15

F. Agus et al.

0.000.020.040.060.080.100.120.140.16

Forest

Tea pl

antat

ion

Rubbe

r plan

tation

Shrub

Mixed c

roppin

g

Annua

l upla

nd

Paddy

field

<8% sl

ope

Paddy

field

>8% sl

ope

Housin

g and

indu

stry

Land use

Buf

ferin

g po

tent

ial (

m)

Interception storagePonding capacityPore absorption

Figure 3. Water buffering capacity (capacity of the system to hold water temporarily before runoff occur) of different land use system

0

50

100

150

200

250

Inlet 1 2 3 4 5 6 7 8 9 10 11

Plot Number

Sedi

men

t tra

nspo

rted

(kg)

Figure 4. Sediment lateral transport as measured at the inlet and outlets of plots 1 to 11

during tillage, in plots 3 to 6 on the first rice season (31 Oct. 2001 to 31 Jan 2002)

16


RESULTS AND DISCUSSION

Valuation of paddy field multi-functionality using the RCM Flood mitigation function

Flood prevention function was calculated using Equation [1] based on the difference in water buffering capacity of paddy field and that of housing and industrial areas. Buffering capacity calculation was exemplified by Agus et al. (2002) and calculation result is presented in Figure 3. A survey at the three dams gave the values of dam construction cost, life storage, and life span of the dams. From this number, dam depreciation and maintenance costs were calculated and results are presented in Table 3. Using Equation [1], data from Table 3 and Figure 3, the replacement cost of flood mitigation function is as high as US$ 6,891,000 per annum. This means that this amount will be spent in year 2020 for additional dam construction to mitigate flood if 30% of existing paddy field will have been converted.

Conservation of water resources

Values in Figure 2 was generated from calculation and estimation in Table 4. About 2034 mm (about 2.5 billion m3) of water from paddy fields is recycled back to river and dam, and about 567 mm (about 0.7 billion m3) recharges ground water annually. This amount could be valued, in economic term, using Equation [3] to have an estimate of water conservation function of paddy field and the result is presented in Table 5. As mentioned in Section 4.1.2, equation [2] is not operational and thus one component of water conservation function is missing in Table 5. With Equation [3] only, replacement cost of water conservation in Citarum for the 30% of paddy field area was estimated as high as $10 million per year. Table 4. Approximation of annual water balance in paddy field in Citarum River Basin

Item Rate Duration Amount mm day-1 day mm year-1

Water input: Irrigation (during the crop season) 13 120 1,560 Rainfall 2,500 Total input 4,060 Output: Percolation 10.3 220 2,266 • Eventually flow to river (75%) 1,700 • Recharging ground water (25%) 567 Runoff 334 Evapotranspiration 4 365 1,460 Total output 4,060

17

F. Agus et al.

Soil erosion prevention function

Predicted soil loss for different land uses in catchments within Citarum River basin varies and in general, annual upland farming contribute to the highest predicted soil loss while forest and paddy field areas had the lowest predicted soil loss (Table 6). Based on calculation using Equation [5], Table 7 shows that the replacement cost of paddy fields in Citarum in preventing erosion was about $10,317 per annum.

Table 5. Replacement cost of water conservation function for water recharging the ground water and potentially used for drinking water

Variable Value (Thickness) of drainage water recharging the aquiver (m year-1) 0.57

Paddy field area (m2) 1,999,850,000

Estimated conversion rate of paddy field till 2020 0.3

Price of tap water ($ m-3) 0.10

Estimated cost of pumping of well water ($ m-3) 0.07

Replacement cost for paddy field function in recharging ground water ($ year-1)

10,196,235

Table 6. Predicted soil loss of different land use systems in Citarum River Basin

Dam catchment Land use Saguling Cirata Jatiluhur Citarum Hilir

t ha-1 year-1

Forest 0,13 0,24 0,14 0,24 Mixed cropping 8,40 15,40 36,86 30,68 Rubber plantation - 8,85 11,39 40,75 Housing 0,03 0,02 0,15 0,02 Paddy field 0,33 0,40 1,45 1,13 Shrub 1,12 1,61 0,47 0,95 Annual upland field 22,02 61,31 40,05 35,66 Tea plantation 23,11 26,94 9,65 33,48

Source: Sutono et al., 2002b.

Landslide prevention function

There was difficulty in really making connection between land use and change, and its effects on landslide. Attempt was made by Wahyunto et al., (2002) for this, but it seems that this value is negligible.

18


Function of degradable waste disposal

Because of more reliable data for retribution cost of waste disposal, then equation 7b was used for this calculation. Note that currently separation of degradable from non degradable wastes is not yet a custom in the area, nor is the application of organic city and domestic wastes for agriculture. Calculation is merely based on the assumption that part of the wastes could potentially be used for agriculture.

Table 7. Calculation of soil erosion reduction function of paddy field based on land use in 2000 within the Citarum River Basin

Dam catchment Land use Saguling Cirata Jatiluhur Citarum Hilir

Predicted average soil loss for upland areas, excluding forest (t ha-1 year-1)

5.7 16.5 14.2 16.1

Area of upland excluding forest (ha) 118,305 105,648 27,040 27,040 Weighted average of upland field soil loss (t ha-1 year-1)

11.6

Predicted soil loss from paddy field (t ha-1 year-1)

0.33 0.4 1.45 1.13

Paddy field area (ha) 76,178 39,996 5,666 78,145 Weighted average of paddy field soil loss (t ha-1 year-1)

0.7

Total paddy field area (ha) 199,985 Estimated conversion rate of paddy field till 2020

0.3

DAM depreciation cost ($ m-3 year-1) 0.152 DAM maintenance cost ($ m-3 year-1) 0.005 Replacement cost for erosion control 10,317

Table 8. Replacement costs of waste disposal based on household retribution in Citarum

Number of Yearly Replacement City/district Household Population retribution cost

$ hh-1 $ year-1

Bandung municipal 595,425 2,141,837 3.00 893,138 Bandung district 832,030 3,557,665 1.80 748,827 Purwakarta district 159,785 639,832 1.20 95,871 Total 6,339,334 1,737,836 Estimated Citarum population 13,000,000 Annual retribution for degradable waste disposal in Citarum 3,563,759 Proportion of paddy field area to total land area of Citarum 0.286 Land conversion rate 0.30 Replacement cost for waste disposal for 30% of paddy field area in Citarum 306,124

19

F. Agus et al.

Rural amenity preservation function

Attempts were made by Setiyanto et al. (2002) to estimate the value of rural amenity. In their calculation, replacement cost of rural amenity was estimated using the equation:

RCr = (Tn*Tr*Ct*Et) + (Ht*Hr*Ch*Eh) …………………………….. [9]

The definition and calculation using Equation [9] is given in Table 9 and according to this estimate the replacement cost for the 30% paddy field area is about $5.5 million per year.

Table 9. Value of rural amenity and relaxation of paddy field in Citarum River Basin

Code Item Unit Value Tn Total number of tourist Person year-1 1,943,370 Tr Proportion of tourits visiting rural area % 27

Ct Correction coefficient of tourist that truly visit Agricultural areas % 21

Et Expenses for the visit $ person-1 year-1 156 Ht Number of home coming people Person 422,217 Hr Proportion of home coming people to rural areas % 16 Ch Correction coefficient of A % 14 Eh Expenses required for homecoming $ person-1 year-1 120.64 RCr Replacement cost for rural amenities $ year-1 18,232,623

Replacement cost for expected 30% of converted area

$ year-1 5,469,787

Adapted from Setiyanto et al. (2002) Heat mitigation

Measurement of air temperature in three districts at similar elevation, but different land uses showed that day (afternoon) temperature was the highest at urban centers and the coolest in areas with mixed (multistrata) farming. Paddy field area is about 2oC cooler than the urban areas (Table 10). The use of air conditioner (AC) and/or fan could be partially related to temperature increase in the urban areas; i.e. because of forgone benefits of cooling of air temperature that could be offered by paddy field, the community restore the benefit by utilizing the artificial cooling systems. Some other people, however, use AC and/or fan because of high original temperature due to latitudinal and elevation positions of their houses. Using equation [8], replacement cost of heat mitigation function was calculated and presented in Table 11. This estimation shows that about $1,618,406 will be spent annually for

20


cooling off of air temperature and this amount was attributed to the heating up due to agricultural land conversion.

Table 10. Average air temperature at urban, paddy fields and mixed garden areas in Citarum River Basin

Average temperature (oC) from 11:00 am to 3:00 pm Location Uban area Paddy field Mixed garden Bandung 34 32 Na Cianjur 34 31 28.5 Purwakarta 35 34 29.5

Source: Sutono et al. 2002a

Table 11. Calculation of replacement cost for heat mitigation function of agriculture in Citarum River Basin

Sets of Maintenance cost Total replacement costs1)City/district House hold

AC Fan AC Fan AC Fan

Set Set $ unit-1 year-1 $ year-1

Bandung municipal 595,425 66,985 357,255 72.00 0.25 3,667,446 1,786,275

Bandung district 832,030 41,602 332,812 72.00 0.25 2,277,682 1,664,060Purwakarta district 159,785 32 6,391 6.00 0.15 1,750 31,957Cianjur district 8,035 2 402 6.00 0.15 88 2,009TOTAL 1,595,275 108,620 696,860 5,946,966 3,484,301

Total replacement cost ($ year-1) 9,431,266With number of household about twice as many in Citarum watershed compared to selected location (above), total replacement cost for heat mitigation become ($ year-1) 18,862,533Proportion of paddy field area to total land area of Citarum 0.286Land conversion rate 0.30Corrected replacement cost for heat mitigation function of 30% of the current paddy field ($ year-1)

1,618,406

Note: Maintenance cost for AC ($ unit-1) = 72Maintenance cost for fan ($ unit-1) = 6Depreciation cost of AC, assuming a unit last for 8 years ($ set-1 year-1) = 38Depreciation cost of fan, assuming a unit lasts for 5 years ($ unit-1 year-1) = 41) Assuming 50% of hh use AC and fan due to heat increase resulted from agricultural land conversion.

Estimation of economic value of marketable agricultural products

Marketable economic values of agriculture in Citarum River Basin, based on statistical data from the Central Bureau of Statistics, was analyzed and presented by Mayrowani et al. (2002). The estimated sum of marketable values of agricultural

21

F. Agus et al.

products was about $442 million annually and that of paddy field alone was about $181 million. If 30% of existing paddy field areas are converted to non agricultural uses, the reduction in revenue from paddy field will be as high as $54,402,800 (Table 12). In addition, there will be about $24.5 million loss in the forms of environmental services if the paddy fields are converted. With this figure, the total replacement costs of environmental services from paddy field is about 45% of the marketable rice products. This translates to society’s enjoyment at no cost of environmental services at the value of about 45% of revenue from rice produced in the same area. Based on this figure, it is justifiable to increase incentives to the mostly poor paddy farmers. While increasing rice prices will potentially cause social and political coercion, internalizing these positive external benefits perhaps is a wiser approach. With better incentive to farmers the rate of paddy field conversion is expected to slow down.

Table 12. The value of multi-functional roles of agriculture in Citarum River Basin, West Java based on calculation using the replacement cost method and its comparison with marketable values

Function Value $ year-1

Marketable/tangible values Estimated total marketable value of agriculture in Citarum 442,087,716 Estimated total marketable value of paddy field in Citarum 181,342,667 Reduced revenue from paddy filed had 30% paddy fields are converted 54,402,800 Non Marketable/intangible values 1. Flood mitigation function 6,890,581 2. Conservation of water resources 10,196,235 3. Soil erosion prevention function 10,317 4. Landslide prevention function Not estimated/

negligible 5. Function of organic waste disposal 306,124 6. Air purification Not estimated/

negligible 7. Rural amenity preservation function 5,469,794 8. Heat mitigation 1,618,400 Total non marketable value 24,491,451 Total forgone benefits if 15% paddy field are converted 78,894,251

Soil loss from paddy field

Soil loss and nutrient transport measurement was conducted on 18 terraces (plots) of paddy fields, each having an area ranging from 12 m2 to 360 m2 and the total

22


area of 2515 m2. The macro slope of these terraces is 22%. The dike height of each plot is 10 to 15 cm and its width is 28 cm. Average elevation difference between plot is 73 cm.

Summary of the measurement of sediment transport is given in Table 13. The two seasons data shows that there was net sediment gain in paddy field as high as 2 t ha-1 in the first season and 5.4 t/ha-1 in the second season. Sediment output from the plot is relatively high during the plowing and puddling period but the sediment transported from one plot mostly deposited in the next plots and thus the net output at the end of the terraces is very low (about 2.2 t ha-1 year-1 during the two seasons). In comparison, sediment output was about 10 to 20 t ha-1 year-1 from a 1.1 ha catchment planted to annual upland crops at the same location (Agus et al., 2002a and 2003).

Table 13. Summary of observation of sediment transport into and out of 18 rice terraces having a total area of 2515 m2 during two seasons rice crops

Rice crop Observation First season Second season

Duration of observation (days) 1 Nov’01- 31 Jan’02

16 Mar- 30 June 02

Sediment transport Total sediment entering the system with irrigation water

864 kg (3.4 t ha-1)

1567 kg (6.2 t ha-1)

Total sediment leaving the system 347 kg (1.4 t ha-1)

210 kg (0.85 t ha-1)

Sediment net gain 517 kg (2 t ha-1)

1357 kg (5.4 t ha-1)

Sediment leaving the system during soil tillage (part of total sediment leaving the system)

181 kg (0.72 t ha-1)

165 kg (0.65 t ha-1)

Source: Kundarto et al. (2002).

Effects of liquid wastes from factories on the sustainability of rice production

This study was conducted at an important rice production center that coincides with industrial (mainly textile industry) in Bandung and Sumedang districts in Rancaekek, West Java, stretching between 6o56’20” – 7o00’45” S and 107o45’19” - 107o49’34” E. Around 42 textile industries exist in Rancaekek area and their liquid wastes, after processing in purification tanks are discarded into nearby rivers and thus potentially affect irrigation water.

Analysis on water samples in domestic drinking water wells and river water did not show any elevation in the chemical concentration, although the nearby farmers claim that

23

F. Agus et al.

from time to time the color of irrigation and river water change from clear to blackish or reddish. Decline in the diversity of fish species in the river has also been claimed by people around the industrial area and they attributed this decline to toxic effluent from the industries. This claim from the people may be, at least, partially true because the concentration of Cu, Zn and Co in the paddy filed soil in the suspected areas reached the critical level (Table 14). Despite the relatively high level of these three metals, the concentration in plant sample in general are still below the critical level except for Zn that have reached the level considered unsafe for human and animal consumptions (Table 15). With this sign of elevated heavy metal in rice, it is necessary to further delineate the area with high heavy metal concentration for remedial actions.

Table 14. Soil heavy metal concentration at the surveyed area Heavy metal Average concentration Critical level mg kg-1

Cu Zn Pb Cd Co Cr Ni

43 57

8 0.05

14 0.8 14

83 137 23

0.19 27 25 21

60-125 70-400

100-400 3-8

25-50 75-100

- Source: Suganda et al. (2002)

Table 15. Range of heavy metals concentration in rice straw and milled rice Range of concentration Heavy metal Straw Mill rice

Critical level in plant

mg kg-1

Cu Zn Pb Cd Co Cr Ni

2-13 17-64

0.971-5.384 0.029-0.351 0.108-5.917 0.673-4.521

0.437-15.864

2-7 14-23

0.092-0.918 0.026-0.180 0.111-4.157

0.985-17.110 0.609-43.072

20-100 10-400 50-300 5-30

15-30 -

5-30 Source: Suganda et al. (2002)

24


CONCLUSIONS

1. Agricultural multifunctionality valuation using the replacement cost method shows that paddy field system contribute significantly for flood mitigation, conservation of water resources, soil erosion prevention, waste disposal, and heat mitigation.

2. The total replacement costs of environmental services from paddy farming in Citarum river basin is about 45% of the marketable rice products and this amount could be considered as farmers’ free environmental services to the community. For this level of service, farmers deserve some reward in the form of incentives to make paddy farming a little more attractive such that land conversion rate could be controlled and these services could continually be enjoyed by the community.

3. Net soil loss from paddy field is negative meaning that paddy fields deposit sediment. Only those paddy fields located along the streams contribute to the stream sedimentation. Sediment from paddy field far from the water body is deposited in the next lower few terraces and unlikely reach water bodies in years.

4. Despite the seemingly low concentration of heavy metal in rivers near textile factories in West Java, Cu, Zn, and Co concentrations in paddy soils adjacent to the factories exceed the critical level, likewise Zn concentration reached the critical level of 10 mg/kg in rice. This calls for further study of delineating the area potential for heavy metal contamination in this area.

REFERENCES

Agus, F., Wahyunto, Sutono, S.H. Tala’ohu and Rozani Nurmanaf. 2001. Environmental and economic functions of paddy field (sawah) in case watersheds in Java. Presented at fourth group Meeting on Interchange of Agricultural Tecnology Information between ASEAN Member Countries and Japan and Working group Meeting of the ASEAN Japan Project on Multifunctionality of Paddy Farming and its Effect in Asean member Countries. Bali, Indonesia. 12-16 Februari 2001. (Unpublished)

Agus, F., T. Vadari, Sukristiyonubowo, B. Hermianto, J.P. Bricquet, and A. Maglinao. 2002a. Catchment Size and Land Management Systems Affect Water and Sediment Yields. pp. 469-475. In Proceedings of 12th ISCO Conference, Beijing, China. 26-30 May 2002,

25

F. Agus et al.

Agus, F., Wahyunto, and S. H. Tala’ohu. 2002b. Multifunctional roles of paddy fields in case watersheds in Java, Indonesia. Presented at the Working Group Meeting of the ASEAN-Japan Project on Multifunctionality of Paddy Farming and Its Effects in ASEAN Countries. Kuala Lumpur, Malaysia, 27 February-1 March 2002. (Unpublished)

Agus, F, T. Vadari, R. L. Watung, Sukristiyonubowo C. Valentin, R. Ilao, T. Duc Toan, and A. Boonsaner. 2003. Effects of Catchment Size and Land Management Systems on Water and Sediment Yield: A Case Study from Several Micro Catchments in Southeast Asia. Proceedings 7th MSEC Assembly held in Vientiane, Lao PDR, 3-7 Dec. 2002. International Water Management Institute, Colombo. (In press).

Chen, M. 2001. Evaluation of environmental services of Agriculture in Taiwan. Paper presented at International Seminar on Multi-functionality of Agriculture, Tsukuba, Japan, 16-20 October 2001. (Unpublished)

Eom, K.C., and K.K. Kang. 2001. Assessment of Environmental Multifunctions of Rice Paddy and Upland Farming in the Republic of Korea. p. 37-48.

Irawan, B, S. Friyatno, A. Supriyatna, I.S. Anugrah, N.A. Kitom, B. Rachman, dan B. Wiryono, 2001. Perumusan Modal Kelembagaan Konservasi Lahan Pertanian. Pusat Penelitian Sosial Ekonomi Pertanian, Bogor.

Kundarto, M., F. Agus, A. Maas, and B.H. Sunarminto. 2003. Water balance, soil erosion, and lateral transport of NPK in rice field system of Sub Watershed Kalibabon, Semarang. hlm. 223-238. dalam Prosiding Seminar Nasional Multifungsi dan Konversi Lahan Pertanian. Bogor, 2 Oktober dan Jakarta, 25 Oktober 2002. Pusat Penelitian dan Pengembangan Tanah dan Agrokliamat, Badan Penelitian dan Pengembangan Pertanian, Departemen Pertanian. (In Indonesian)

Mayrowani, H., S.K. Darmuredjo, A.R. Nurmanaf, Y. Sulaeman, and A. Setyanu. 2003. Marketable product value of agriculture system in Citarum watershed. hlm. 193-202. dalam Prosiding Seminar Nasional Multifungsi dan Konversi Lahan Pertanian. Bogor, 2 Oktober dan Jakarta, 25 Oktober 2002. Pusat Penelitian dan Pengembangan Tanah dan Agrokliamat, Badan Penelitian dan Pengembangan Pertanian, Departemen Pertanian. (In Indonesian)

Setiyanto, A., A.R. Nurmanaf, Y. Sulaeman, H. Mayrowani, and S.K. Dermuredjo. 2003. Paddy field role for rural amenities. hlm. 179-187 dalam Prosiding Seminar Nasional Multifungsi dan Konversi Lahan Pertanian. Bogor, 2 Oktober dan Jakarta, 25 Oktober 2002. Pusat Penelitian dan Pengembangan Tanah dan Agrokliamat, Badan Penelitian dan Pengembangan Pertanian, Departemen Pertanian. (In Indonesian)

26


Sudaryanto, T. 2003. Konversi lahan dan produksi pangan nasional (Land conversion and national food production). hlm. 57-65 dalam Prosiding Seminar Nasional Multifungsi dan Konversi Lahan Pertanian. Bogor, 2 Oktober dan Jakarta, 25 Oktober 2002. Pusat Penelitian dan Pengembangan Tanah dan Agrokliamat, Badan Penelitian dan Pengembangan Pertanian, Departemen Pertanian. (In Indonesian)

Suganda, H. D. Setyorini, H. Kusnadi, I. Saripin, and U. Kurnia. 2003. Evaluation of the pollution of liquid wastes textile industry on the sustainability of rice field. hlm. 203-221. dalam Prosiding Seminar Nasional Multifungsi dan Konversi Lahan Pertanian. Bogor, 2 Oktober dan Jakarta, 25 Oktober 2002. Pusat Penelitian dan Pengembangan Tanah dan Agrokliamat, Badan Penelitian dan Pengembangan Pertanian, Departemen Pertanian. (In Indonesian)

Sutono, S., S.H. Tala’ohu, and F. Agus. 2003a. The role of paddy field in mitigation air temperature in Citarum river basin. hlm. 159-170 dalam Prosiding Seminar Nasional Multifungsi dan Konversi Lahan Pertanian. Bogor, 2 Oktober dan Jakarta, 25 Oktober 2002. Pusat Penelitian dan Pengembangan Tanah dan Agrokliamat, Badan Penelitian dan Pengembangan Pertanian, Departemen Pertanian. (In Indonesian)

Sutono, S., S.H. Tala’ohu, O. Sopandi, and F. Agus. 2003b. Soil loss as affected by different land uses in Citarum river basin, West Java. hlm. 113-133 dalam Prosiding Seminar Nasional Multifungsi dan Konversi Lahan Pertanian. Bogor, 2 Oktober dan Jakarta, 25 Oktober 2002. Pusat Penelitian dan Pengembangan Tanah dan Agrokliamat, Badan Penelitian dan Pengembangan Pertanian, Departemen Pertanian. (In Indonesian)

Wahyunto, H. Sastramihardja, W. Supriatna, W. Wahdini, and Sunaryo. 2003. Landslide susceptibility of agricultural areas in Citarum Watershed, West Java. hlm. 99-112 dalam Prosiding Seminar Nasional Multifungsi dan Konversi Lahan Pertanian. Bogor, 2 Oktober dan Jakarta, 25 Oktober 2002. Pusat Penelitian dan Pengembangan Tanah dan Agrokliamat, Badan Penelitian dan Pengembangan Pertanian, Departemen Pertanian. (In Indonesian)

Wahyunto, Zainal Abidin, M., Priyono, A., and Sunaryo. 2001. Studi perubahan penggunaan lahan di Sub DAS Citarik, Jawa Barat dan DAS Kaligarang, Jawa Tengah (A Study on land use changes in Citarik Subwatershed, West Java and Kaligarang Watershed, Central Java). pp. 39-63 In Prosiding Seminar Nasional Multifungsi Lahan Sawah, Bogor, 1 Mei 2001. Pusat Penelitian dan Pengembangan Tanah dan Agroklimat, Bogor. (In Indonesian)

27

F. Agus et al.

Watung, R.L., S.H. Tala’ohu, and F. Agus. 2003. Paddy field role in preserving water resources. hlm. 149-157 dalam Prosiding Seminar Nasional Multifungsi dan Konversi Lahan Pertanian. Bogor, 2 Oktober dan Jakarta, 25 Oktober 2002. Pusat Penelitian dan Pengembangan Tanah dan Agrokliamat, Badan Penelitian dan Pengembangan Pertanian, Departemen Pertanian. (In Indonesian)

Yoshida, K. 2001. An economic evaluation of the multifunctional roles of agriculture and rural areas in Japan. Technical Bulletin 154, August 2001. Food & Fertilizer Technology Center (FFTC), Taipei.

28

assessment of environmental multifunctions of...

Documents