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

This project, initiated in 2011, witnessed the lowest precipitation of 15 mm in June 2013 at the A-site since initiation. Rainfall during July was only 24 mm. Such weather conditions had a negative effect on maize production. Grower’s fertilizer practice (GFP) and the Ecological Intensification (EI) management system for maize and soybean were compared at the A site. The GFP treatment 30-40 kg N-P/ha led to a maize yield of 4.44 t/ha in 2013. A reduction in the N application rate from 30 to 9 kg/ha caused a 9% yield loss. The maize yield of 4.73 t/ha was obtained in the EI treatment (85-70-40 kg N-P-K/ha) was a 7% increase over GFP. Again, a reduction in the N application rate from 85 to 17 kg N/ha caused a yield decline of 10%. The GFP treatment 20-40 kg N-P/ha gave soybean yield of 1.90 t/ha, and decreasing N rate from 20 to 9 kg/ha caused both a 12% yield loss and a decrease in grain protein content from 50 to 47%. In the EI treatment 30-45-30 kg N-P-K/ha, a soybean yield of 2.16 t/ha was obtained, which was a 14% increase over GFP. Again, decreasing the N application rate from 30 to 10 kg/ha caused a yield decline by 6% and the grain protein content decreased from 51 to 48%. The highest protein output (963 kg/ha) was obtained in the EI treatment.

Soil at the C-site was characterized by a high nitrate-N concentration of 15.9 ppm and very high levels of Olsen-P (17.5 ppm) and exchangeable K (354 ppm) in the 0 to 20 cm soil layer (obtained using weighted averages from data for 0 to 5, 5 to 10 and 10 to 20 cm layers). Maize followed winter wheat in the agri-enterprise field and had higher productivity when compared with the the A-site. The control treatment (i.e., no fertilizer applied) gave a maize yield of 4.78 t/ha and GFP (30 N 40 P) resulted in a 7% increase in yield over that obtained from the control treatment. The highest maize yield of 6.10 t/ha was attained in the treatment receiving ample NPK rates (100 N 80 P 60 K). This treatment gave a 28% increase in yield over the control treatment and 19% increase in yield over GFP. Decreasing the N application rate from 100 to 18 kg/ha resulted in a 9% yield loss. Omission of P and K decreased grain yields by 5 and 3%, respectively. Response to K fertilizer was, however, non-significant. These results corresponded well with the initial status of soil fertility.