Impact of conservation tillage under organic mulches on the reproductive efficacy and yield of quality protein maize

Abstract

The present study was carried out to evaluate the efficacy of conservation tillage under organic mulches on the reproductive developments and production potentials of Quality Protein Maize (QPM) cv. Pozarica during the period from November 2007 to April 2008. The study included tillage and zero tillage conditions and four indigenous mulches viz. water hyacinth, rice straw, rice husk and ash. All the mulches significantly modified microclimatic parameters in both tillage and zero tillage conditions. However, under non-tilth condition water hyacinth and rice straw mulches reduced the maximum soil temperature at 5 cm depth by 3.5-4.2°C and 2.4-2.7°C, respectively at 14:00 hrs and raised the minimum temperature by 1.5-2.3°C and 1.2-1.4°C at 06:00 hrs. The water retentive capacity of the mulched soil under zero tillage condition was higher at all the stages of plant growth and ranked in the order of water hyacinth>rice straw>rice husk>ash>control. The reproductive developments in mulched plants were advanced by about 1 to 10 days. Mulching practices also enhanced the number of ears plant-1 , ear height, length and diameter, tassel length, number of seed rows ear-1 and seeds row-1 , 1000-grains weight, weight of rachis ear-1 , grain yield and higher harvest index (HI). The grain yield of mulched plants notably water hyacinth was nearly double (8.73 t ha-1) than unmulched plants (4.93 t ha-1) under non-tilth condition. The indigenous mulches especially water hyacinth and rice straw, irrespective of tilth or non-tilth conditions, appeared to be great suppressants of weed growth allowing to produce less than one third of the total biomass compared to that of control. The residual mulching effect had little or no influence on physical properties of the soil under both conditions. However, the chemical properties were favourably influenced for the follow-up crops.