The effects of Rottboellia cochinchinensis on the growth, development and yield of maize

Abstract

Pot and field studies were conducted to determine the effect of the duration of Rottboellia cochinchinensis [Lour.] W. D. Clayton presence or absence on the growth, development and yield of Z. mays L., and to establish the length of the critical period of weed interference. The crop was maintained weed‐free or weedinfested throughout the growth season or for periods of 0, 2, 4, 6, 8 and 10 weeks after emergence (w.a.e.), respectively. The crop and weed densities used were 55 000 plants/ha, and 55 plants/m², respectively. Regression models were fitted to the growth data and comparison of the relevant regression lines made. The results indicated that the presence or absence of the weed for the varying periods had no effect on the crop plant height, leaf area ratio (LAR), relative growth rate (RGR), net assimilation rate (NAR), and crop growth rate (CGR), but there was consistent trend of reduced LAI and shoot dry weight in the weed‐infested treatments. Increasing the periods of weed‐free treatments increased yields exponentially, while increasing the periods of the weed infestation decreased yields exponentially. The study demonstrated a critical period of R. cochinchinensis interference on Z. mays growth and development, and yield from 0 to 63 d.a.e., and suggests that the reduction in crop yield may be through non‐competitive interference by the weed on the crop.

Keywords:

• Critical period of competition
• growth analysis
• regression modelling
• weed interference

Notes

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