OPTIFERT

Nutrient Leaching; Irrigation control; Soil Water Extractors; Irrigation; Soil

Moisture Probes

Introduction

• Cropnuts has been testing OPTIFERT at a flower farm in Thika farm from Feb 2014 till Sept 2014.

• OPTI-FERT is a two stage program with the objective of improving fertilizer use and reducing water waste through excessive irrigation:1. PHASE I: Monitoring of nutrient leaching down the profile

derived from the current practices, and2. PHASE II: Implementation of corrective management,

optimizing irrigation and fertilization• The method involves the use of Soil Water Extractors

(SWE) and a Soil Moisture Probe.

Methodology

• Soil Water Extractors (SWE)– Inert porous ceramic cup allows the soil solution to

freely permeate into & out of the instrument– SWE installed next to a drip line; Soil solution extracted

twice a week– 9 SWE were installed in 3 locations at 30, 60 & 90cm– The samples were analysed in the lab for drain water to

quantify nutrients (in particular Ca & NO3)

• Aquacheck Soil Moisture Probes– 8 sensors distributed every 10cm down to 80cm– One reading per sensor every 30min;– Data is stored & uploaded onto an online server every

2 hours and visualized using an online software

Results

• Phase I: irrigation of 40m3/ha/day in one event– Evidence of strong nutrient leaching in all sites

(highest levels of NO3 and Ca at 60 and 90 cm)• Phase II: irrigation volumes and events reduced

and regulated based on Aquacheck probe data– Reduction of nutrient leaching by 60%– Reduction of water consumption by 25%– Reduction of fertilizer input by 15%

Results – Leaching

• Average effect of improved water management:– 47% less nitrates in A60 and 52% less in A90– 34% less calcium in A60 and 61% less in A90

Results – Soil Moisture• Time span of graph: 10th June – 8th August– Moisture content (%) at 6 of the 8 levels

Root activity within top 20cm

Excessively wet profile allowed to dry: Increasing root activity in 30cm & 40cm

Results – Soil Moisture• Root zone graph– Moisture content (%) in the root zone

RAW (60% of AWC)

Lower management zone line (apply water now)

Upper management zone line (apply water to here) URAW

LRAW

VERY WET START OF MANAGINGPROFILE ALLOWED TO DRY

Aquacheck Soil Moisture Monitoring

• Aquacheck allows managing irrigation precisely, telling the management when & how much to irrigate

• Irrigate up to the URAW line and dry to the LRAW line before irrigating

• No more over-irrigation– Reduction of water wastage & leaching of fertilizer;– Increased soil aeration for healthier, deeper, roots

Conclusion• The SWE allowed to quantify the leaching of nutrients down the profile• Over-irrigation due to uncontrolled irrigation management has been

the cause of leaching• Reducing the irrigation (volumes & events) led to a reduction in

leaching• Irrigation management (and soil aeration) can be improved using

Aquacheck• It is believed that appropriate irrigation management will also lead to:– Improved crop quality (bud size, stem shelf life)– Improved general crop health– Hardiness of crop (due to deeper roots)– Reduced incidents of disease

OPTI-FERT

Thank You