ABSTRACT

Field experiments were conducted from May-September 2015 and April-August 2016 cropping seasons at Eastern farm of the Michael Okpara University of Agriculture Umudike, Abia State to determine the effect of population density and time of planting on the growth and yield of mungbean-maize intercropping system. Each experiment was laid out in a randomized complete block design (RCBD) replicated three times. Treatments included three different population density of mungbean (125,000 plants/ha, 200,000 plants/ha and 250,000 plants/ha) and three different times of introduction of maize at 0, 2 and 4 weeks after sowing mungbean. The result obtained showed that mungbean population density and time of introduction of maize significantly influenced yield and yield component in both mungbean and maize. Results showed that among the intercrops and time of introduction, the highest mean plant height of 50.2cm and 50.2cm at 8 WAP were recorded at mungbean 200,000 plants/ha and mungbean with maize introduced 2 WAP in 2015 season. In 2016 cropping season, the highest plant height of 53.7cm was recorded in mungbean with maize introduction 2 WAP mungbean at the final harvest. The interaction of mungbean at125, 000 plants/ha with maize introduced 2 WAP and 4 WAP recorded the highest plant height of 55.9cm and 55.5cm at final harvest in the two cropping seasons. The highest number of leaves (16.1) was produced by sole mungbean at 200,000 plants/ha at the final harvest. The interaction of mungbean at 125, 000 plants/ha with maize introduced 4 WAP gave the highest number of leaves, 15.3 in 2016 cropping season at 8 WAP. The highest number of mungbean pods, 40.3 was recorded in sole mungbean at 250,000 plants/ha in 2016 cropping season. The highest sole mungbean seed yield of 721 and 863 kg/ha were obtained at mungbean 200,000 and 250,000 plants/ha respectively in both cropping seasons. Under the intercrop system, the highest seed yield of 483 and 581 kg/ha were recorded in mungbean at 250,000 plants/ha with maize sown the same day and when maize was introduced 2 WAP mungbean in the two cropping seasons. Similarly, the interaction of mungbean at 250,000 and 200,000 plants/ha with maize 4 WAP mungbean gave the maximum mungbean seed yield of 515 and 720 kg/ha respectively in two cropping seasons. The highest maize plant height of 128cm and 136 cm were recorded in sole maize and maize intercrop with mungbean at 200,000 plants/ha at 8 WAP in the two cropping seasons. The highest maize grain yield of 6,154 and 5,895 kg/ha among the intercrops was recorded in maize crops sown with mungbean at 250,000 plants/ha in the two seasons. Based on the time of introduction of maize, the result showed that maize sown the same day with mungbean gave the maximum grain yield of 6,216 and 5,976 kg/ha in the two seasons. Also, the interaction of mungbean at 125,000 plants/ha sown the same day with maize gave the maximum maize grain yield of 7,722 and 6,945 kg/ha in the two cropping seasons. The maximum value of total land equivalent ratio, land equivalent coefficient and total gross monetary return of 2.1, 1.1 and N6.5m was obtained in mungbean sown the same day with maize in the 2015 season. The interaction of mungbean  at 125,000 plants/ha with maize  2 WAP mungbean gave the maximum total land equivalent ratio and land equivalent coefficient of 2.3, and 1.2 while the highest total monetary return of N7.9m was recorded in mungbean at 125,000 plants/ha sown the same day with maize in  2015 cropping season. In 2016 cropping season, the maximum total land equivalent ratio, land equivalent coefficient and total gross monetary return of 2.1, 1.0 and N6.1m was obtained in mungbean intercrop the same day with maize. The result on interaction showed that the maximum total land equivalent ratio, and land equivalent coefficient of 2.4 and 1.4 was recorded at mungbean at 125,000 plants/ha with maize introduced 4 WAP mungbean while the maximum total gross monetary return of N710, 700 was obtained at mungbean at 125,000 plants/ha sown the same day with maize in the 2016 cropping season. These results indicated that population density and time of planting are important factors determining the productivity of mungbean-maize intercropping system. The crops must be intercropped and sown simultaneously to obtain adequate yield.