Optimization of Winter Wheat Nutrition

Response of winter wheat to foliar sprays with Potassium Nitrate is studied in field experiments conducted in drought-affected areas.


02 Jun 2018

2017 Annual Interpretive Summary

The 2016-2017 season was the second experimental season under this project. Field experiments with winter wheat were again conducted at two locations having different soil types: Southern Chernozem (Haplic Chernozem Pachic) and Light Chestnut soil (Haplic Kastanozem Chromic). Both soils had a heavy texture, high pH, moderate organic matter (OM) content (3.8% and 1.8%, respectively), high nitrate-nitrogen (N) levels (31 to 87 ppm), medium concentrations of available phosphorus (P) (18 to 19 ppm P2O5), and medium and ‘increased’ concentrations of available potassium (K) (255 to 370 ppm K2O) in the 0 to 20 cm soil layer. Available forms of P and K were extracted with ammonium carbonate solution.

The 2016-17 season had close to normal weather conditions. The best nutrient management practices in both locations included three sprays with potassium nitrate (PN): 1) 5% solution at tillering (2.4 kg N/ha and 8.1 kg K2O/ha); 2) 3% solution at stem elongation (1.4 kg N/ha and 4.9 kg K2O/ha); and 3) 3% solution at heading (1.4 kg N/ha and 4.9 kg K2O/ha).
    Both yield and quality of wheat grain were considerably improved compared to typical grower management practices for N, including ammonium nitrate (AN) topdressing in early spring at 34 kg N/ha. Grain yield was increased to 3.7 and 4.9 t/ha (Moisture content = 14%) or by 16 and 25% on the Chestnut soil and Chernozem, respectively. Grain protein concentration increased by 1% and gluten content improved by 2 to 3%. Grain quality thus matched the III class. A late-season application of urea at heading–flowering of 30 kg N/ha, in addition to AN topdressing in early spring, resulted in lower grain quality compared to foliar sprays with PN, especially without starter K fertilizer application on Southern Chernozem (4 N 16 P) were given at planting as monoammonium phosphate in 2016). Based on the two seasons of data available at this time, foliar fertilization with potassium nitrate seems to be a promising approach when growing winter wheat in Lower Volga. Nitrogen application is very minimal with these management practices.