The Influence of Preceding Crops and Intercropping Maize with Cowpea on Productivity and Associated Weeds

TWO FIELD experiments were carried out at Mallawi Agric. Res. St. (Middle Egypt) during the two summer seasons of 2008 and 2009. The objectives of this study were to investigate the effect of preceding crops and intercropping maize with cowpea on productivity and associated weeds. A randomized complete block design (RCBD) in a split plot arrangement with three replications was used in both seasons. The main plots were devoted to the three preceding winter crops (wheat, faba bean and berseem) while sub plots were allocated for three solid planting namely solid maize, solid cowpea cut two months (forage) and solid cowpea left without cutting (seeds), as well as two intercropping treatments namely: maize + cowpea cut after two months (forage) and maize + cowpea left without cutting (seeds).
The results showed that maize preceded by faba bean was superior in most studied characters while the lowest values were observed when it grew after wheat. The weed density in maize sequenced by legume crops was less than this grown in maize sequenced by wheat.The yield and yield components of maize were decreased under intercropping conditions. The lowest values were observed when cowpea (forage) was preceded by wheat. The reduction in maize grain yield when intercropping with cowpea was 4.7% (combination of the two seasons). The reduction in weed weight was 72.8% when intercropped cowpea was forage and 72.0% when cowpea was seeds compared with solid planting.
The forage and seeds yield of cowpea were more decreased under intercropping condition. The reduction in forage and seeds yield were 52.2 and 74.3% compared with solid planting, respectively.
The highest values of land equivalent ratio (LER) (1.46), area time equivalent ratio (ATAR) (1.19) and monetary advantage index (MAI) (1874.66) were observed when sequenced by berseem and intercropped cowpea with cut after two months.