Study On Temporal And Spatial Patterns Of Light And Soil Water Of Maize And Cabbage Intercroppings In Dry Land

To study on the mechanism of high efficiency of utilization of soil water, the experiment ofintercropped and monocropped models of maize and cabbage was conducted in dry land agricultureareas in Shouyang of Shanxi province. Precipitation, photosynthetically active radiation （PAR）, soilmoisture, the crop growth and yield were analyzed in monocultures and intercropping patterns.Theexperimental results were as follows.1. PAR of maize population in intercropped models was higher than that in monoculture, but PAR ofcabbage population in intercropped models was lower than that in monoculture. As rows of maize wereincreased, PAR of maize population was increased, while for cabbage population, it appeared anopposite tendency. PAR of outboard rows of maize population was higher than that of inside and itdecreased slowly from top canopy of maize population to the base. PAR of inside of maize populationdecreased quickly from top canopy of maize population to the height of50cm and decreased slowlyfrom height of50cm to0cm. PAR of maize population and cabbage population showed obviously dailyvariation and seasonal changes. The daily variation of PAR of maize population and cabbage populationshowed small difference in morning and afternoon, and large difference in the noon. The seasonalchanges of PAR of maize population and cabbage population showed small difference during the earlyand later of growing stage, and large difference during the middle of growing stage.The percentage oftransmitted PAR of maize population in intercropping was negative with LAI of maize population. PARof cabbge population was positive correlated with intercropping number rows of cabbage.2. Yield of maize was positive correlated with PAR of maize population, but it was negative withintercropping number rows of maize. Beacause of being shaded by maize, time of forming cabbage headin M1r‖C1rdelayed more than10days than that in M1r‖C2r, M_2r‖C_3r, M_3r‖C_4rand M_3r‖C_5randmonoculture of cabbage. But as rows of cabbage increased, shading fraction by maize decreased.Shading fraction was negative with intercropping number rows of cabbage. Yield of cabbage waspositive correlated with PAR and intercropping number rows of cabbage, but was negative with shadingfraction by maize.3. Water use by maize and cabbage intercrops in the growing season was lower than monocroppedmodel of maize and was higher than cabbage monoculture, which resulted in higher soil moisture inintercropped models than maize monoculture and lower than cabbage monoculture during the middleand later growing stage. For the intercropped models, as the rows of maize decreased (or the rows ofcabbage increased, its soil moisture increased gradually. The soil water contours were deepest andsuperficial in maize and cabbage monocultures respectively during the middle and later growing stage.Water use intensity of maize was higher than cabbage before mid-August and was lower afterwards.Intercropped models of maize and cabbage formed temporal and spatial complementary on using water,so it improved water use efficiency.4. Yield of maize increased in intercropping. The growing of cabbage in intercropped models was shaded by maize to different degrees, but the effect was weaker as the rows of cabbage increased, evendisappeared. When the cabbage rows in intercropped models were more than four （one time than maizeheight）, yield, output value and water use efficiency of maize and cabbage was higher thanmonocropped models. The conclusion was that when the cabbage rows in intercropped models weremore one time than maize height, the intercropped models were reasonable and better.