Irrigation and tillage practices for fodder maize (Zea mays L) in rice fallows

Abstract

A field experiment was conducted at the College of Horticulture, Vellanikkara during 2012-13 summer season to study the response of fodder maize (Zea mays L.) to different irrigation practices and tillage methods. The treatments consisted of four levels of irrigation (irrigation at IW/CPE ratios of 0.4, 0.8 and 1.0 and no irrigation) and three tillage methods (herbicide based zero tillage, minimum tillage and conventional tillage). The experiment was laid out in split plot design with three replications. The study revealed that fodder maize responded well to frequent irrigations and herbicide based zero tillage. Biometric characters such as plant height, number of leaves/plant, leaf area, leaf area index and shoot: root ratio were higher in frequently irrigated plots with herbicide based zero tillage whereas leaf: stem ratio was lesser in frequently irrigated plots. Stem dry matter, total dry matter production and fresh forage yield were higher in frequently irrigated, herbicide based zero tillage plots. There was no significant difference between levels of irrigation or tillage methods with respect to per cent content of phosphorus, potassium, calcium and magnesium. However, nitrogen and crude protein contents decreased with increased levels of irrigation. Leaf crude fibre increased with increased levels of irrigation but no differences in stem crude fibre was noticed among treatments. Uptake of nutrients was higher in herbicide based zero tillage plots receiving more number of irrigations. Consumptive use, field water use efficiency and crop water use efficiency were higher in frequently irrigated plots (IW/CPE= 1.0 and 0.7). Frequently irrigated plots extracted more water from the top layers. In general, fodder maize extracted 61-79 per cent of the total water use from the top 30 cm soil layer. Among the irrigation schedules IW/CPE=1.0 recorded the highest gross returns, net returns and B: C ratio followed by IW/CPE=0.7. Among the different tillage methods herbicide based zero tillage resulted in the highest net returns and B: C ratio. It can be concluded that fodder maize cultivation with 40 mm irrigation scheduled at IW/CPE ratio 1.0 with herbicide based zero tillage is superior with respect to fodder yield and net returns, and hence suited for summer rice fallows where water for irrigation is available. Depending on mean daily evaporation values in Kerala, this translates to irrigation with 40 mm water (40 L/m2) at an interval of 6-9 days.