Effect of green manuring on the yield of sweet corn

Abstract - Experiments were conducted on a clay soil to assess the effects of green manuring of three annual legumes and nitrogen fertilization on sweet corn (Zea mays var. saccharata Sturt.), during three growing seasons (2001-2003). The green manuring legumes were field pea (Pisum sativum L.), common vetch (Vicia sativa L.) and faba bean (Vicia faba L.) N fertilization ranged from 0 to 360 kg ha^-1. On a three-year average, field pea (3 065 kg ha^-1) and common vetch (2 647 kg ha^-1) consistently had higher aboveground dry matter yields than faba bean (1307 kg ha^-1). Field pea and common vetch had N contents of 68.7 and 54.0 kg ha^-1, respectively, in aboveground dry matter in the spring. The average N content of faba bean was only 30.0 kg ha^-1. Green manuring treatments and N fertilization had different effects on yield components of sweet corn. Average ear yields of corn were significantly greater in plots receiving green manuring (15 127 kg ha^-1) than those without green manuring (13 826 kg ha^-1). The ear yields following green manuring legumes were 33-39% higher compared with fallow under unfertilized conditions. Ear yield of corn generally increased with an increasing rate of N fertilizer. Although the combined use of green manuring and 240 and 360 kg ha^-1 N fertilization produced high ear yields, there were no statistically significant increases beyond 120 kg ha^-1 N.