Effects of irrigation and green manure on corn (Zea mays l.) biomass and grain yield

Abstract

The effect of green manure on the growth of irrigated corn (Zea mays L. cv Cisko) was investigated under different drip irrigation rates on a clay soil in Greece. A feed pea (Pisum sativum L. cv Olympus) crop was established in autumn and incorporated into the soil in spring, about 3 weeks before the sowing of the subsequent corn. During the growing period, the growth stages and yield of corn were assessed under three drip irrigation levels I1 (33% low), I2 (66% moderate) and I3 (100% full of actual evapotranspiration, ETm) and two cultivation practices a) application of green manure and b) experiment without previous green manuring. The positive effects of green manuring were greater in the moderately and fully irrigated plots. Drip irrigation was applied to minimize nitrate leaching which requires low volume of water. In plots receiving moderate or full irrigation, biomass, leaf area index (LAI) and seed yield were much higher in comparison to stressed plants (33% ETm). Increased yield and dry biomass obtained in the plots after incorporation of feed pea residues, may be attributed mainly to the elevated amount of soil organic matter (SOM). The increased yield exceeds the overall cost for green manure application, and this economic incentive is expected to be even more significant taking into account the continuous improvement of soil conditions.