Effect of tillage practices on microclimate, soil fertility and moisture status and yield of corn (Zea mays L.) and mungbean (Vigna radiata (L.) Wilzeck) in an alley cropping system

Generally, tillage system did not result to significant differences in the height, leaf area index (LAI), dry weight production and yield of both crops. Although statistically insignificant, there was a general trend in that the growth of mungbean was more favorable with minimum tillage and zero tillage except for seed yield. LAI and height of mungbean were significantly different only at the late vegetative and filling stages, respectively. On the other hand, corn height was significantly affected by tillage system at the mature stage of growth. Corn grain yield was highest with zero tillage. Components of the crop microclimate, specifically relative humidity and air temperature, showed significant variations depending on the growth stage of the crops. Relative humidity varied significantly from the early vegetative to tasseling stage of corn while air temperature within and above the canopy varied significantly from dough to mature stage of corn. Soil temperature showed insignificant differences although the middle portion of the alleys had relatively higher temperature than those near the hedgerows. After harvest, tillage system showed significant effect on the soil properties. Zero tillage with flemingia prunings significantly had the highest organic matter content (5.44%), total nitrogen (0.27%) and an optimum pH level (5.92). The comparably higher organic matter content in zero tilled plot with mulch led to lesser soil compaction or lower bulk density (1.14 g/cc) as compared to the higher bulk densities obtained with conventional (1.33 g/cc) and minimum (1.54 g/cc) tillage. Available phosphorus (17.05 ppm) was significantly higher with conventional tillage that could probably be due to less weed population absorbing the said nutrient. Similarly, exchangeable potassium was significantly higher in the conventional tillage (4.49 me/100 g) as compared to the minimum (3.26 me/100 g) and zero (3.41 me/100 g) tillage plots. Partial analysis indicated that the minimum tillage and zero tillage with mulch had PhP1,938.00 and PhP1,562.00 net change in benefit, respectively. This is attributed to the higher sales of the intercrops harvested from the minimum tillage system. Generally, tillage system did not significantly affect growth and yield parameters of corn + mungbean but elicited a significant change (after land preparation vs. after harvest of the intercrops) in the soil properties. Similarly, the resulting (final) soil properties were significantly affected by tillage system