Evaluation of Yield and Yield Components of Common Millet and Soybean in Different Intercropping Ratios under Deficit Irrigation Levels in Hamden Region

Drought is one of the major abiotic stress limiting plants growth and productivity across the world. Intercropping increased the efficiency of water utilization. In arid and semi-arid regions, intercropping can improve water use efficiency and water conservation in soil. Because intercropped plants use water efficiently and caused increasing of water use efficiency. Intercropping of legumes and cereals compared with corresponding sole cropping is common and might be beneficial in semi-arid regions particularly in resource limiting conditions. Do and Goutan (1987) reported that millet can be planted in mixture with some plants such as cowpea, sorghum, peanut and soybean. The aim of the investigation was to study the impact of intercropping on the growth and yield of millet and soybean under deficit irrigation.

The experiment was carried out as a split-plot based on a randomized complete block design with three replications, at the Research Farm of Agricultural Faculty of Bu-Ali Sina University in 2015. The main factor included three levels of deficit irrigation (irrigation after 60 (well-watered), 90 (mild stress) and 120 (severe stress) mm by using of class A evaporation pan) and five levels of replacement intercropping consisted of monoculture of soybean, monoculture of millet, 67% soybean+ 33% millet (67S:33M), 50% soybean+ 50% millet (50S:50M) and 33% soybean+ 67% millet (33S:67M) as subplot.

Water stress decreased chlorophyll concentration of millet and soybean. In all intercropping ratios, the chlorophyll concentration of soybean was higher than its monoculture. The rate of increase in chlorophyll concentration in (67S:33M), (50S:50M), and (33S:67M) ratios compared to monoculture of soybean, were 8.43, 8.57 and 8.76 percent respectively. The highest total chlorophyll content of millet was obtained in (50S:50M) and (33S:67M) ratios, that was 12.34 and 12.09 percent higher than monoculture of millet, respectively. The highest number of panicles per plant of millet was obtained from (50S:50M) and (67S:33M) ratios under well-watered, and the lowest one was observed in monoculture of millet under severe water stress. The highest number of seed per panicles of millet was observed at intercropping of 33S:67M, 50S:50M and 67S:33M treatments under well-watered, and the lowest value was measured in monoculture of millet under sever water stress. Water stress decreased number of pods per plant, number of seeds per pod and 100-seed weight of soybean, compared to well-watered. Number of pods per plant, number of seeds per pod and 100-seed weight of soybean reduced in severe water stress were about 50.58, 33.68 and 26.09 percent, respectively, compared to well-watered. The number of pods per plant of soybean plants in all intercropping patterns was higher than monoculture of soybean. The rate of increase in number of pods per plant in (67S:33M), (50S:50M), and (33S:67M) ratios, were 6.38, 11.63 and 7.75 percent respectively, compared to monoculture of soybean. The highest seeds per pod of soybean was obtained in (50S:50M) ratio by 13.78 percent higher than monoculture of soybean. Water stress reduced grain yield of millet and soybean by 46.8 and 50.05 percent, respectively. Under well-watered condition, the highest yield of millet was obtained in (67S:33M) and (50S:50M) ratios. The highest actual yield of soybean was observed in (50S:50M) ratio by. Maximum value of LER (1.14) was achieved in (50S:50M) ratio intercropping in severe stress.

The best planting pattern to obtain maximum yield of millet and soybean was (50S:50M) ratio. The difference in rooting millet with soybean and better use of water in different soil depths could be reason to the high yield under water stress, the show millet and soybean intercropping were complementary