Pattern of strip-planting under film mulching of millet-soybean and changes in photosynthesis and moisture

A new strip-planting pattern under plastic mulching of millet and soybean is developed by integration and optimization of alternate strip-planting technique of millet and soybean, spot-planting technique under film mulching of millet and strip-planting technique under film mulching of soybean. The new planting pattern is more advanced because not only photosynthesis, respiration and water utilization of millet and soybean are improved, but the yields are higher as well. Compared with the ordinary models of alternate strip-planting and monocropping millet, leaf photosynthetic rate (Pn) of millet in the new pattern increases by 19.2% and 32.4% respectively. Stomatal conductance of leaves (Cleaf) is higher by 6.3% and 42.2% respectively, while leaf transpiration rate (E) is similar to that in monocropping millet. For soybean, Pn under the new pattern is higher by 5.6% over that under ordinary alternate strip-planting; and by 56.1% over that under monocropping soybean. E increases by 3.1% and 46.1% respectively. Cleaf also increases by 31.3% and 148.9% respectively. Under the new pattern, water use efficiency (WUE) of millet and soybean are markedly enhanced, especially in millet where WUE exceeds 30% increment over the two old planting patterns. Total output is obviously higher than that in monocropping soybean, very close to that for monocropping millet. Yield increases by 17.7% compared with ordinary alternate strip-planting. Total economic benefit respectively increases by 1 413.75 yuan·hm^-2, 2 242.5 yuan·hm^-2 and 1 542.0 yuan·hm^-2 over monocropping millet and monocropping soybean, and alternate strip-planting system.