Economics of tillage systems and herbicides in lowland rice production at Makurdi, southern guinea savanna, Nigeria

摘要

Two trials were conducted in 2008 and 2009 cropping season, with the principal objective of comparing the effects of tillage systems and herbicides on the yield as well as the economics of these systems in lowland rice production. The ten treatments used consist of nine (9) glyphosate at three levels (1.44, 2.16 and 2.88 kg a.i/ha) that was either followed by 2 4-D (360g/l), propanil (360g/l) or propanil (360 g/l) + 2,4-D (720 g/l) at – 3WAP and a control [conventional tillage + 2, 4-D {720 g/l) + propanil (360/l at 3 weeks after planting (WAP)]. The experiments were laid out in a Randomized Complete Block Design (RCBD) with four replications using a rice variety Faro 44 (SIPI 692033). Generally throughout the period of observation (3, 6 and 9 WAP) all the zero tillage treatment recorded lower weed cover score. However, crop vigour score was highest from conventional tillage system that was followed by a mixture of 2, 4-D and propanil 3 WAP. Rice stand at 4 WAP was not significantly affected by the tillage systems as comparable results were obtained from both the zero and conventional systems. The number of grains per panicle and grain yield increased as the amount of pre-plant herbicide increased. Conventional tillage recorded the highest number of grains per panicle (145.62) and grain yield (266.63 kg/ha) that was comparable to the zero tillage with glyphosate at the rate of 2.88 kg a.i/ha that was followed by a combination of 2,4-D and propanil both at the rate of 1.44 kg a.i/ha. The economics analysis (zero and conventional tillage systems) indicated that pre-plant glyphosate used at the rate of either 2.16 kg a.i/ha and 2.88 kg a.i/ha that was followed by either a mixture of 2, 4-D and propanil or used singly, gave benefit-cost ration of 4.55 – 4.75. The highest benefit-cost of 4.48 was obtained in the conventional tillage.