Study on the yield response of IR54 and the competitive ability of Echinocloa crusgali as influenced by the levels of nitrogen

Abstract

This study was conducted from September 16 to December 7, 1982 at the experimental field of the College of Agriculture, Central Philippine University. This aimed to find out (1) the number of E. crusgalli which could be tolerated by the IR54 rice variety at certain level of nitrogen; 2) what level of nitrogen can support both the crop and a certain number of E. crusgalli and 3) the yield reduction at different weed density and level of nitrogen.

The experimental treatments were arranged in a split plot in randomized complete block design replicated three times. The main plots were varying numbers of E. crusgalli, namely 0, 3, 6 and 9 planted per square meter. The subplots were the levels of nitrogen 0, 60, 90 and 120 kg N/ha.