Soil health improvements triggering better potato yields

This is branded content for Incitec Pivot.

Soil testing before planting is one way to understand and address the nutritional requirements of your potato crop. Improving soil health can also help balance crop nutrition, and humic substances are an effective way to do this.

Humic substances are made up of three distinct groups: humic acids, fulvic acids and humin. Humic acids can have beneficial effects on soil function such as improved biological activity, nutrient activity, cation exchange capacity, pH buffering, carbon sequestration, soil water relations (Schnitzer, 2000) and plant biomass (Nardi et al. 2002).

Increasing the humic content in soils has the potential to improve overall soil health resulting in healthier crops that are better able to withstand biotic and abiotic stress.

Humic substances are a mixture of organic materials, created by the decay of plant and animal residues. As organic materials, they are a good source of carbon and provide a food source for soil microorganisms, bacteria, algae, fungi and earthworms.

Trigger™, a new humic granule developed by Incitec Pivot Fertilisers, contains both humic and fulvic acid, addressing a key barrier to incorporating humic substances into a fertiliser program.

Traditionally, growers have been faced with an inability to incorporate humic substances into blends, resulting in additional costs to spread.

Trigger is s a hard granule, 2.4-2.6 mm in size, low in dust and air dried, helping it maintain the integrity of functional groups and making it ideal for blending with most custom-made blends.

Incitec Pivot Fertiliser Commercial Manager, Farming Services Phil Hoult believes the versatility of Trigger™ makes it an appealing option for growers across a range of crops.

"Long term soil health is key to consistent potato production, regardless of soil texture," Mr Hoult said.

"Building and maintaining carbon and structure over time in soils that are cultivated and cropped frequently is a major challenge for growers.

"Having a high quality, low dust, granulated humic product like Trigger™ allows growers to easily develop targeted custom blends for use at planting, specifically to suit their soil types and production needs without the cost of separate application."

In potatoes, Trigger™ is applied with the base planting blend at just 40kg/ha. It can pass through fertiliser equipment with relative ease, and can be broadcast, air seeded and banded at planting.

"We are seeing and hearing from growers that Trigger™ is helping deliver yield improvements in soils with lower than desired Cation Exchange capacity and Organic Carbon percentages," Mr Hoult said.

"Trigger™ granules themselves have a very high CEC and can provide 'localised' improvements in CEC or the ability to hold nutrient.

"Trigger™ also appears to give a localised buffering against alkalinity, helping the uptake of key nutrients like phosphorus, which is a key element for tuber set and yield in potatoes.

"In other crops we have also seen Trigger™ provide a buffering effect in saline soils, reducing chloride levels and EC.

"With some mainstream potato varieties being sensitive to high levels of chloride building up, we are looking to do more work in the future in these varieties."

A three-year experiment on potatoes grown in Idaho on low organic matter (1 per cent), calcareous soils (pH 8), demonstrated that incorporation of liquid humates at planting at a rate of 2.64 to 5.2 litres/ha resulted in increased petiole P uptake, increased tuber size, and an increased gross return per ha of $USD61.

In other crops, inclusion of humates has also shown to help improve yield and quality, boosting the bottom line for the grower.

References

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Davies P. (2010). The plant hormones: Their nature, occurrence, and functions. In: Davies P.J. (ed.): Plant Hormones: Biosyn-thesis, Signal Transduction and Action. 3rd Edition.

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Liu X.Q., K.Y. Ko, S.H. Kim and K.S. Lee. (2008). Effect of amino acid fertilization on nitrate assimilation of leafy radish and soil chemical properties in high nitrate soil. Communications in Soil Science and Plant Analysis, 39: 269-281.

Nardi, S., D. Pizzeghello, A. Muscolo, and A. Vianello. 2002. Physiological effects of humic substances on higher plants. Soil Biology and Biochemistry 34 (11):1527-36.

Schnitzer, M (2000) A lifetime perspective on the chemistry of soil organic matter. Adv Agron 68:358