Soil Fertility and on-Farm Research

Iowa State University of Science and Technology.

Type: Research Paper
Knowledge level: Advanced

Farm Table says:

The results up to this time show that no general recommendation is valid for all fields. The variability of soil nutrients is field-specific and, ideally, each field should be sampled and fertilized differently.

Using precision agriculture to improve management

Precision agriculture technologies have potential to improve soil fertility management and on-farm research or demonstrations.

This project is designed to address the expectation of many producers and agronomists in that grid sampling will adequately describe soil nutrient supplies better than the traditional “sampling by soil type” method and that variation in nutrient levels will explain much of the yield variability within a field.

What did the research involve?

Two major projects are being developed. One project focuses on the field-scale study of relationships between the phosphorus (P) and potassium (K) contents of soils and plants with grain yields and on the evaluation of soil sampling methods. No treatments are applied to the fields in this project.

The other project focuses on the evaluation of variable-rate fertilization and on adapting new technologies to traditional on-farm strip trials. In this project, treatments are applied to long strips replicated several times across the fields. Intensive grid soil sampling is conducted before and after applying the treatments. The treatments compared vary between fields and include fertilizer placements (starter, deep-banding), interactions of herbicides and fertilization, variable-rate fertilization or manuring, and others. In both projects, yields are measured with calibrated yield monitors and, in some strip trials, the yield monitors are checked by weighing the yield of each strip.

What were the key findings?

The results of sampling many fields show that the spatial variability of P and K and other nutrients in soils is complex and that variability patterns differ markedly among fields.

The impact of grid sampling and variable-rate fertilization on soil fertility management and the profitabilty of crop production depends on several factors.

Many producers believe that variation in nutrient levels will explain much of the yield variability within a field and that much can be learned from comparisons of several layers of information.

Results of many on-farm comparisons show that precision agriculture technologies can be successfully adapted to on-farm, field-scale evaluations of alternative management practices.

Final comment

Precision agriculture technologies can be used to evaluate and demonstrate alternative fertilization or other management practices on the basis of on-farm strip trials.  Precision agriculture technologies can be used to evaluate and demonstrate alternative fertilization or other management practices on the basis of on-farm strip trials.

 

1998 - United States - Iowa State University of Science and Technology.
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