Evaluation of the Potassium Status of Arable Soils in Ukraine on the Basis of Modern Soil Diagnostic Techniques and Development of Recommendations for the Rational and Efficient Application of Potassium Fertilizers.

The project has the following objectives a) provide an accurate assessment of K status of arable soils, b) determine the demand for K fertilizers, c) establish the efficiency of K fertilizers in the soils of the main soil-climatic zones, and d) work out fertilizer recommendations for maize, wheat and sugar beet grown on chernozems. The data of the automatized informational database on Ukraine and CIS countries containing information on soil properties will be summarized and supplemented. The data of soil survey, Ukraine Agrochemical Service experiments and geographic network of long-term experiments will be analyzed and generalized.

IPNI-2011-UKR-1

27 Mar 2014

2013 Annual Interpretive Summary


The project was initiated with the objectives to provide an accurate assessment of K status of arable soils, determine the response to K fertilizers, estimate the efficiency of K fertilizers in the soils of the main climatic zones, and work out fertilizer recommendations for K application in maize, wheat and sugar beet grown in rotation on leached chernozems. The project summarized the database containing information on crop response to K fertilizer applications in field trials conducted in Ukraine during the last 40 years. Some of the major factors that determine the efficiency of K fertilizers in different climatic zones of Ukraine were the amount of precipitation and temperature during the growing season, and adequate plant-available K in the soil. The mathematical relationships between soil K concentrations and agronomic efficiency of K fertilizer, as well as between hydrothermal coefficient and agronomic efficiency of K fertilizer for winter wheat, grain maize and sugar beet were determined. Efficiency of K fertilizer use tends to decline from West to East and in Southeast provinces, mainly due to decrease in precipitation.

Assessment of K status of arable soils by a new diagnostic approach (new soil test methods and soil K interpretation classes) showed that the majority of arable soils in Ukraine have medium content of extractable K. The comparison of plant-available K contents obtained by different extraction methods showed that the Chirikov method (0.5 M CH3COOH) overestimated the K supply of chernozems. The minimum requirement for K fertilizers in Ukraine, as calculated from the average data for K removal by main agricultural crops during harvest, has been estimated to be 1.8 million t K2O/year.

A 3-year field experiment on the efficiency of four different K fertilizer rates with two combinations of NP in crop rotation typical for the steep-forest zone of Ukraine (forage maize-wheat-sugar beet) was conducted. High efficiency and economic benefit resulted from applying K fertilizers to all three crops. Optimization of the N and P supply contributed to the increase on the economic return from K fertilizer. The highest economic benefit for the maize crop was obtained at the 90-90-40 kg N-P-К/ha application rate. Banded application of K fertilizer (before preplant cultivation) significantly increased the yield of maize green mass (14 to 18%) compared with broadcast application. Due to adverse weather conditions during the growing season, the yields of wheat (1.7 to 2.4 t/ha) and sugar beet (24 to 35 t/ha) were lower than expected. In the situation of summer drought, K fertilizers contributed up to 10% of the yield increase in plots with optimized NP fertilization.