Andrew Olley

National Agronomy Services Manager

Controlled Release Fertiliser in Horticulture

AusVeg May 2013

Nutrient delivery via fertilisers into Horticultural crops is often poorly converted through to crop yield and quality

A number of factors have influence over nutrient efficiency such as

-Loss Mechanisms after application

-Timing applications

-Labour and capital constraints for delivery

-Weather events

-Antagonism between competing nutrients

-Choice of nutrient form

Science and field experience of growers / advisors have developed fertiliser strategies to supply crops with their nutrient needs with improved efficiencies.

Such practices include:

-Spilt applications of granular products

-Nutrient delivered through irrigation “Fertigation”

-Foliar and liquid soil applications

-Nutrient formulation changes

-Monitoring nutrient status SAP, Leaf, Solute testing

These advances have greatly improved the supply of nutrient to crops.

However this is most often achieved by excess nutrient supply to try ensure the crop is not yield limited by nutrient.

In many instances 100 % or greater of key nutrients over the actual crop requirements are applied with the following effects

-Increased spend on fertiliser

-Capital intensive delivery systems

-Labour intensive management systems

-High cost nutrient formulations

Field crop production operation at tighter margins and high risk has not allowed the uptake of technologies in nutrient delivery used in higher value plant production systems.

Amenity Horticulture “Nursery & Turf Industries” with higher margins have been able to develop sophisticated nutrient products

-Slow Release chemistry

Protected Cropping industry reliance on high density production which comes at a higher capital costs developed exact nutrient delivery systems

- Hydroponic nutrient formulation

Slow Release fertiliser products offer the potential to field producers however limitations to commercial adoption have been:

-High manufacturing cost per kg nutrient supplied

-Freight costs to import from overseas

-Fixed N:P:K analysis not suited to local conditions

-Nutrient release rate dominated by soil temperature hence complex process to select right product and release rate through the year

-Low availability in the market from supply companies

Impact fertilisers were contacted by Everris BV in early 2012 to distribute a commercially available nutrient delivery technology that has been extensively used commercial agriculture.

Investigation of the technology on offer and its use in overseas fertiliser markets revealed a solution to increase fertiliser use efficiency for crop production in Australia was available.

Polymer coatingElemental sulphur coating

Urea, MOP, SOPcore

Controlled Release Granule Technology

N 39 Urea K 43 MOP

Immersed in water for 10 weeks

“Slow Release Coatings”

Laboratory Data, Everris BV. Netherlands

Laboratory Data, Everris BV. Netherlands

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38:0:0:13 Agrocote N 38

Controlled Release Technology

Polymer coating

Elemental sulphur coating

Urea, MOP, SOPcore

Technology

•Crystalline 8 member ring •Brittle at room temperature •Forms cracks permeable to moisture •Release less temperature sensitive 

Agrocote N39 Release Curve

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. . Total N release kgs N release kgs per day

Return HomeAgrocote N39 Release Curve

200 kgs - 78 kgs N

80 %

90 %

Agrocote N38 Release Curve

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. . Total N Release kgs kgs N per day

Return HomeAgrocote N38 Release Curve

200 kgs - 76 kgs N

50 %

65 %

80 %

Agrocote Blend Release CurvesNitrogen 100 kgs / ha

- Custom Nitrogen release curves can be created with blends

30 % Agrocote N

70 % Urea N

50 % Agrocote N

50 % Urea N

70 % Agrocote N

30 % Urea N

CompatibilitiesHighly compatible with existing fertiliser components

MAP DAP ZincStar MES10

Urea SOA Compounds

MOP SOP HiMag (MgS04) MgO

TSP SSP

Zinc Copper Boron

Conventional Potato Fertiliser Program

Nitr

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e Nitrogen Applications Crop Daily N

N Applied

Controlled Release Potato Fertiliser Program

Nitr

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e Nitrogen Applications Crop Daily N

Conv N Applied

Nitrogen Losses in Crops• VolatilizationUrea ammonia gas losses from surface application

• DenitrificationNitrogen losses in water-logged soils

• LeachingNutrient movement of Nitrate below the crop root zone

The three main losses of applied N & K to the crop are greatly reduced

Agrocote only losses N & K while conditions favoring loss occur.

The proportion of Total N & K loss is small.

Hence the efficiency of nutrient uptake by the crop is greatly improved.

Polymer and Sulphur coating control N release rate

Volatilization

Leaching

De Nitrification

Potassium ProductsMOP and SOP available

Controlled release greatly decreases the Salt Index of MOP and hence can be used on higher EC soils and Irrigation water.

High seed safety due to coating on MOP

Potassium releases over a 4 month period

Conductivity of MOP versus Agrocote MOP

Agrocote in PotatoesConventional Fertiliser Program:

Planting Blend: 10:6:12:15 at 1000 kg/ha

Side-dress 1: 23:0:20: 10 at 150 kg/ha

Side-dress 2: 23: 0:20:10 at 150 kg/ha

Side-dress 3: 18:0:25:12 at 150 kg/ha

Side-dress 4: 12:0:30:15 at 150 kg/ha

Total Nutrient Applied kgs/haN 210 P 60 K 266

Agrocote in PotatoesAgrocote Fertiliser Program:

Agrocote Planting Blend: 14: 6:19:9 at 950 kgs / ha

36 % total N as CR Nitrogen50 % total K as CR Potassium

Total Nutrient Applied kgs/haN 153 P 60 K 178

Equivalent Nutrient Program(based on Agrocote efficiency 0.5)N 209 P 60 K 267

• Conventional: 400 kg N, 50 kg P, 546 kg K /ha/yr

Agromaster: 200 kg N, 27 kg P, 243 kg K

• Reduced N and K rates to 50% and 44%, respectively • Reduced from 12 to 3 applications per year

Overseas ExperienceBananas Central America

Overseas ExperiencePineapple Central America

•Conventional: –Monthly N&K side dressed for 3 months –Foliar NPK for 8 months

–Total rate 780 kg N, 27 kg P, 530 kg K/ha

•Agromaster: –Single Agromaster 2wks after planting (100% coated N&K)

–Replaces 3 side-dressings and 1 foliar application

–Rate reduction:•55% of first 4 applications

•85% of N and K overall

Summary Key Advantages to growers & industry

-Improved nutrient use efficiency

-Less freight, handling and application costs

-Reduces potential nutrient gaps in crop growth

-Increased quality through consistent crop nutrition

-Greatly reduced nutrient losses on and off farm

-Addition to all common fertiliser blends as a component

-Nitrogen and Potassium Controlled Release

-Negates the need for high capital delivery systems

-Commercially available, trained resellers