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How Variable Fertiliser Application Can Remove Variability in Crop Yields

How Variable Fertiliser Application Can Remove Variability in Crop Yields

28 March 2014

ANALYSIS - Variability of soil types in a field will produce variability right through the season and differences in biomass through the season will produce differences in yields.

Being able to track, understand and manage this variability and being able to control the in-puts into the soil will produce better yields.

In the past when fields were smaller, farmers were able to manage more accurately the soil types.

Nowadays, using a system of precision nutrient management can help to control the amounts of phosphorous, potassium, magnesium and nitrogen and the pH of the soil.

Knowledge of the soil types and conductivity scanning fields for the soil texture can also give the farmer information that will allow for variable seeding to get the optimum yields.

According to Ian Matts, an agronomist with fertiliser specialists Yara, analysing fields on a hectare grid basis for phosphorous and potash can help to reduce the variability of the crop over a seven year period.

And using the Yara system and testing the soil every four years can give information that will optimise yields and dictate the fertiliser application at the start of the season and the requirements for topping up on applications during the season.

Speaking at the recent Precision Farming event in the UK, Mr Matts said that using a system of variable rate nitrogen application with an N Sensor device can inform the farmer about the specific amounts of nitrogen that are needed and where to apply them.

“Sometimes the senor can give confidence to put no nitrogen on the field during the growing season, because it indicates there is sufficient,” he said.

“This technology relies on trust and belief.

“It helps to give confidence that it is doing what it should and by doing that gives us confidence as well.”

He said that increasing yields by applying the optimum nitrogen rate does not necessarily mean a uniform application rate.

“It puts more nitrogen where it measures less nitrogen in the soil and less where it measures more nitrogen in the crop in the field.”

Used for oil seed rape the sensor measures the nitrogen in the leaf canopy of the field and calibrates the requirements.

Because of variation in the soil mineral nitrogen efficiency in actually being taken up by the crop, the more accurate measurements are by taking the amount of nitrogen in the leaf canopy of the crop.

“It is not what in in the field that is important, but what the crop has been able to get hold of,” Mr Matts said.

He added that the technology now helps to make decisions that might not be made through instinct and farming knowledge.

Chris Harris

Chris Harris

Top image via Shutterstock

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