Improvement of Recommendations for Potash Fertilizer Use and Adjustment of Currently Used Soil Potassium Test Interpretation Classes in Intensive Cropping Systems

During the last 15 years in Russia, both nutrient rates and ratios were changed with a decline in the relative share of phosphate and potash fertilizers relative to N fertilizer. The adjustment of nutrient rates considering soil type, fertility status, and crop management factors has, thereby, high priority for research experiments in current cropping systems. With long-term removal of K exceeding K inputs negative K budgets are being observed in various agricultural zones of the country. Nevertheless, Russian agriculture has paid little attention to the optimization of K status in arable soils. Such an attitude towards K regime regulation in agricultural systems is largely due to the imperfect assessment of soil K fertility. Routine soil test K interpretation classes used in a practical work to develop potash fertilizer recommendations give some evaluation of soil K status. Unlike in some other countries, the current soil test K interpretation classes are not based on soil texture.
This new research project will be focus on optimization of potash fertilizer rates in current intensive cropping systems for crops with high response to K (sugar beet, maize, rape and soybean) and checking the measurement potential of routine soil test methods depending on the regional soil properties and adjusting the current interpretation classes based on results from short-term field experiments executed on large industrial farms located in Central Russia (Lipetskaya, Voronezhskaya, Belgorodskaya oblast) and South of Russia (Rostovskaya oblast).
The following goals will be addressed in growers cropping systems, i.e. in large agri enterprises and agri-holdings that use modern intensive crop management technologies:
1. Determine optimal potash fertilizer rates for major crops in crop rotation that have a high demand for potassium.
2. Evaluate the validity of currently used soil test potassium interpretation classes for proper assessment of plant potassium requirements.
3. Develop proposals to the Ministry of Agriculture on possible fine-tuning of current practice to develop K fertilizers recommendations and adjustment of currently used soil test potassium interpretation classes.

The first results from the project will due in December of 2013.