Effect of neem fertilizer rates and weed control methods on the growth and yield of soybeans (Glycine max (L.) merrill) in north Central Nigeria

Abstract

Two field experiments were conducted at the Research Farm of the Ibrahim Badamasi Babangida University, Lapai, Niger State during the 2018 and 2019 rainy seasons to determine the effect of neem fertilizer rates and weed control methods on the growth and yields of soybeans. The experimental treatments were made up of four neem fertilizer rates (0, 50, 100 and 150 kg ha^-1) and six weed control methods (pendimethalin at 1.5 kg a.i ha^-1 followed by one hoe weeding, pendimethalin at 2.0 kg a.i. ha^-1 followed by diuron at 1.5 kg a.i ha^-1, weeding once at 3 WAS, weeding twice at 3 and 6 WAS, weed free and weedy check. The experiment was a 3 × 3 factorial experiment laid out in a Randomize complete block design replicated three times. TGX 1448 – 2E variety of soybean was used for the study. Result showed that weed control efficiency was better with the use of 150 kg ha^-1 of neem fertilizer, while decrease in weed dry matter was obtained at 50 kg ha^-1. Increase in number of leaves and leaf area were encouraged with 150 kg ha-1 of neem fertilizer. Weed free treatments recorded the highest grain yield and 100 seed weight of soybean. Pendimethalin at 1.5 or 2.0 kg a.i ha^-1 supplemented with one hoe weeding or diuron at 1.5 kg a.i ha^-1 respectively can be an alternative for better control of weeds to obtain greater yield of soybean in the study area.