Grains and Oil Crops No-Tillage Grain Sorghum Response to Starter Nitrogen-Phosphorus Combinations

摘要

The use of starter fertilizers has become common in conservation-tillage corn (Zea mays L.) production systems, but little attention has been given to starter fertilizer nutrient ratios for no-tilled grain sorghum [Sorghum bicolor (L.) Moench]. The objective of this study was to evaluate the effect of N:P starter fertilizer ratios on no-tillage grain sorghum production at two planting dates. This field experiment was conducted from 1991 through 1993 at the North Central Kansas Experiment Field, located near Belleville, on a Crete silt loam soil (fine, montmorillioitic, mesic, Fachic, Argiustoll). Treatments included combinations of N and P to supply 0,10,30, or 90 Ib N/acre with or without 13 Ib P/acre. An unfertilized check plot and a broadcast treatment receiving 90 Ib N and 13 Ib P/acre (no-starter check) also were included. Planting dates were mid-May and mid-June each year. All starter treatments were applied 2 in. to the side and 1 in. below the seed at planting. Immediately after planting, broadcast surface applications were made to bring the total amount of fertilizer applied on all plots, except the unfertilized check, to 90 Ib N and 13 Ib P/acre. Only the treatments that included either 30 or 90 Ib N/acre with 13 ib P/acre (2.81:1 or 6.9