ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Effect of N fertilizer rate and nitrapyrin on leaf chlorophyll, leaf N concentration and yield of three irrigated maize hybrids in Nebraska.

Lohry, R. O.;

Dissertation Abstracts International. B, Sciences and Engineering Year: 1990 Vol: 50 Issue: 12 Pages: 5387B

1990

บทคัดย่อ

In 1986 to 1988 on a Crete silt loam soil (fine, montmorillonitic, mesic Pachic Argiustolls) 3 Pioneer brand maize hybrids (3377, 3475, 3551) were used to examine the effects of increasing N rates (0, 75, 150, 300 kg/ha), a nitrification inhibitor (nitrapyrin at 0.56 kg/ha) and tillage on leaf N, leaf chlorophyll, DM production, N uptake, N leaching and yield. Chlorophyll and leaf N concn were correlated in 1987, but chlorophyll varied significantly with environmental conditions in other years. Laminar leaf punch N concn was linearly related to midseason stover N concn. Leaf N concn was not consistently correlated with grain yield, although a significant association was observed in 1987. Midseason DM production, N uptake and N concn increased with applied N in every year. Grain yields were not influenced by tillage practice. Grain yields in 1986 were not increased by N applications beyond 75 kg N/ha due to residual N effects. Plots incurred hail damage in 1987 but yields were better than 1986 with max. yields (12 t/ha) occurring near the 150 kg N rate. Because of heat stress, 1988 grain yields were 30% lower than 1987, but DM production, N uptake and N concn in the stover at harvest were all increased. Grain N removal was near the amount applied at rates below 150 kg N. Nitrapyrin decreased leaf N concn in 1987, but did not affect yield. Nitrapyrin increased preanthesis inorganic soil N in all years. Postharvest soil samples exhibited significantly higher amounts of inorganic N at the highest rate indicating that N not used by the crop is subject to leaching.