EFFECT OF SHELTER TREES ON GROWTH AND YIELD OF PECHAI (BRASSICA CHINENSIS L.), MUNGBEAN (VIGNA RADIATA L.) AND MAIZE (ZEA MAYS L.)

Field experiments were conducted to determine how shading by shelter trees would influence shoot growth and yield of pechai (Brassica chinensis L.), mungbean (Vigna radiata L., cv. Fag asa 7) and maize (Zea mays L., cv. IPB var.1). Before sowing of crops, 3 treatments consisting of different relative light intensities (RLI; 100, 88.7 and 24.9%) were prepared without and with the use of shelter trees differing in density in a field at Bayog in Los Banos, the Philippines. Values of leaf number, leaf area, chlorophyll content, shoot dry matter and yield of the 3 crops at 24.9% RLI were significantly lower than those at 100 and 88.7% RLI. Values of specific leaf area (SLA) of the crops, on the other hand, increased significantly at 24.9% RLI. It was observed that there was a difference in yield components between mungbean and maize at 24.9% RLI. Yield of mungbean decreased due to the decrease in the pod number but not in the grain number per pod and grain weight, while that of maize decreased due to the decrease in both kernel number and kernel weight, suggesting that fertilization in maize was more affected by shading than in mungbean. In conclusion, solar radiation is necessary for proper growth and higher yield of crops intercropped with trees. It was suggested that mungbean became better adapted to shading than maize in terms of yield.