N and P impact on the yield of maize in a long-term trial

In order to elaborate site-specific, environmentally sound fertiliser recommendations aimed at achieving an economic yield level in maize, the N and P supplies of the soil, the N and P effects detectable in the yield, and the limit values for N and P supply levels were investigated in a ten-year mineral fertilisation experiment set up on chernozem meadow soil.Over the average of ten years, this chernozem meadow soil, which had a humus content of 2.8–3.2%, gave a grain yield of 6.10 t ha −1 without N fertiliser, the relative yield was 79% and N fertilisation gave a yield surplus of 1.35 t ha −1 . The economic yield level was achieved when the NO 3 -N content of the upper 0–60 cm soil layer was 100–110 kg ha −1 prior to sowing. The mineral N content of the soil is a better indicator of the soil N supply level and of the N fertiliser requirements of maize than the humus content. On this acidic, clay loam soil, which had a P supply level of 120–160 mg kg −1 AL-P 2 O 5 without P fertilisation, the relative yield was 93%, averaged over 10 years, and the yield surplus 0.2 t ha −1 . A P effect was only detected in approximately 50% of the years, when the economic yield level was achieved at an AL-P 2 O 5 supply level of 130–170 mg kg −1 . On this acidic, clay loam, chernozem meadow soil, a limit value of 120–170 mg kg −1 AL-P 2 O 5 represented a good supply level

Effect of Fertilization System and NO3-N Distribution on Corn Yield

The objectives of the study have been to determine the effects of winter precipitation, NO3-N distribution in the soil profile and their interaction on corn yield in different fertilization systems. Corn yield varied across fertilization systems and winter rainfall in the investigated years (2001-2004). Significantly higher yields were found in variants with manure application in diculture (DC-M-NPK - 12.11 t ha(-1)) and in monoculture (MC-M-NPK - 9.25 t ha-1). Path coefficients showed that the highest direct positive effects on corn yields were exhibited by NO3-N amounts at soil depths 30-60 cm and 60-90 cm (p = 0.4336** and p = 0.2346**, respectively). Winter precipitation had a direct negative effect on the yield performance (p = -0.1159), however, the downward movement of NO3-N from topsoil (0-30 cm) to deeper soil layers (30-60 and 60-90 cm), whose N levels were directly positively correlated with yield, made the indirect effect of winter precipitation on yield positive