Improvement of Maize and Soybean (Chickpea) Mineral Nutrition on a Calcareous Common Chernozem

Farmer fertilizer practice (FP) and the Ecological Intensification (EI) management system are compared at the A-site. Two different maize hybrids were grown in 2016 under these crop management systems including Krasnodarskiy 291 (FAO = 290) and P9175 (FAO = 330) under FP and EI, respectively. The 2016 season had good weather conditions. FP produced a maize yield of 8.3 t/ha and the omission of nitrogen (N) (decreasing N from 30 to 9 kg/ha) caused a yield loss of only 3%. Maize yield of 9.0 t/ha was obtained in the EI treatment giving a significant increase over FP (by 8%). The omission of N from the EI system (decreasing N from 85 to 17 kg/ha) caused a statistically significant yield decline to 8.5 t/ha.

FP gave chickpea a yield of 2.3 t/ha while the addition of N (increasing N from 6 to 24 kg/ha) caused a considerable yield increase by 13%. Seed yield of 3.0 t/ha was obtained with a moderate N rate in the EI treatment giving a huge improvement over FP (by 29%). The omission of N in the EI system (decreasing N from 24 to 12 kg/ha) caused a statistically significant yield decline to 2.8 t/ha.

Soil at the C-site prior to planting had a medium NO₃-N concentration of 11 ppm (NH₄-N concentration of 16 ppm), high concentration of Olsen Phosphorus (P) (13 ppm) and a very high concentration of exchangeable potassium (K) (356 ppm) in the 0 to 20 cm layer. Maize treatments at the C-site in 2016 included: 1) Control; 2) N₃₀P₄₀ (FP); 3) N₄₀P₈₀К₆₀; 4) N₆₀P₈₀К₆₀; 5) N₈₀P₈₀К₆₀; 6) N₁₀₀P₈₀К₆₀; 7) N₁₀₀P₈₀К₆₀S₁₉; and 8) N₁₀₀P₈₀К₃₀. Seed coating with zinc (Zn) was done in Treatments 3-8. Fertilizers were applied before planting excepting K in Treatment 8 which was applied at planting.

A N application rate of 80 kg/ha was found to be agronomically optimum, but the response to increasing N rates was quite low. A maize grain yield of 7.2 t/ha was obtained in the Control and FP resulted in a statistically significant yield increase of 5%. The highest grain yield of 8.5 t/ha was achieved with ample nutrient rates (100 kg N/ha, 80 kg P₂O₅/ha, 60 kg K₂O/ha, and 19 kg S/ha) giving a significant increase over the Control and FP (by 19% and 13%, respectively). Broadcasting of K at 60 kg K₂O/ha had practically the same effectiveness as a starter application at 30 kg K₂O/ha. Sulfur source broadcasting had somewhat low effectiveness for improving yields.