Experimental Study On Crop Water Regulation Of Ridge-Furrow Irrigated Intercropping System

Intercropping system is one of the most effective practices to preserve and enchance thesustainability of grain yield in worldwide. There are many precious studies on intercroppingsystems, which have improved grain yield greatly, but those practices would do harm to thesustainable utilization of water resources, which have affected the the stabilization ofagricultural production system. Based on the problem discussed above, we cooperatedintercropping models into furrow irrigation and proposed a new plant technique called ridgeand furrow irrigated intercropping（RFII） system. Field experiments （using maize and soybeanas indicator crops） were conducted in the experimental station of Institute of Water-savingAgriculture in Arid Areas of China（IWSA）, Northwest A＆F University（108°04ˊE,34°20ˊN） during the spring planted crop growth duration （from April toSuptember,2010） and summer planted crop growth duration （from July to November,2010）.In order to investigate the effects of RFII system, the experiment comprised soil waterdynamics, crop water consumption, eco-physiological characteristics and the yield and wateruse efficiency under two experimental factors, which are irrigation quato and plant model,respectively. The irrigation quato was set three levels which are405mm （W1）,270mm（W2）and135mm（W3） in spring planted crop growth duration and180mm （W1）,90mm（W2） and0（W3） in summer planted crop growth duration, respectively. The plant models wereconventional flat practice including sole maize（SM）, sole soybean（SS） and traditional maizeand soybean intercropping system （TI）, and ridge and furrow planting system includingRF105, RF90, RF75and RF60（furrow width was all60cm and ridge width was105cm,90cm,75cm and60cm respectively）. The main results showed as follows:1)RFII system decreased soil water content compared with that of conventional practice（TI, SM and SS） in0⁴0cm soil layer before the maize jointing stage/soybean flower buddifferentiation stage. In maize flowering stage/soybean podding and blossom stage, soil watercontent has a larger amplitude of decrease in RFII system compared with that in conventionalflat practice in spring planted crop growth duration. RFII system was helpful to soil water reservation in summer planted crop growth duration.2)Different soil surface management and cultivation significantly affected the soil moistureuniformity between soil moisture of different soil layers. Soil moisture uniformity in RFIIsystem increased with the decrease of irrigation quato. Soil moisture uniformity in RF75wasthe highest at the same irrigation level, which was helpful for the external water infiltrationand soil moisture conservation.3)Irrigation quato has significant effects on total crop water consumption, plant models,however, has little effect. With the decrease of irrigation quato, total water consumptiondecreased and the ratios of precipitation and soil water consumption to total crop waterconsumption increased significantly. RFII under W2irrigation quato in spring planted cropduration and W3n summer planted crop duration could reduce yield loss ceused by watershortage as far as possible by making full use of the soil moisture.The ratio of soilevaporation to evaportraspiration（E/ET） decreased with the decrease of irrigation quota. E/ETin RFII system decrease by7.14%,7.35and11.83%compared with that in TI under W1, W2and W3respectively. RFII system could decrease E/ET in the later of crop growth duration,especially for RF90and RF75, which could increase the valibility of field water consumption.4)Mean leaf instantaneous WUE under W2increased by9.37%and2.82%, comparedwith that under W1and W3, respectively. Leaf instantaneous WUE of RF75under W1, RF90under W2and RF75under W3was the largest in the corresponding irrigation amount, whichincreased by15.66%,27.46%and21.77%compared with that of TI1, respectively. Leafinstantaneous WUE was also increased by intercropping system. Leaf instantaneous WUE ofRF90and RF75under W2and W3was obviously higher than that of TI. Under W1, leafinstantaneous WUE in RFII system even declined.5)Irrigation and plant models effected crop yield in interopping system significantly. Inspring planted and summer planted, mean crop yield in W2and W3was the largest,respectively. Total yield in intercropping system decreased compared with that in SM andincreased significantly compared with that in SS. RF75was the best treatment because of thesmallest yield decrease amplitude and the largest yield increase amplitude. Proper RFIIsystem could increase LER siggnificantly, especially for RF75, yield increasing effect was themost significant. Correlation analysis between LER and ridge width showed that the yieldincreasing effects was the largest when ridge width was85.07cm,75.87cm and72.71cm inspring planted crop growth duration and95.63cm,74.91cm and71.5cm in summer plantedcrop growth duration under W1, W2and W3, respectively.6) For spring planted crops, water use efficiency（WUE） in intercropping system was9.95kg·hm^-2·mm^-1,12.93kg·hm^-2·mm^-1and14.34kg·hm^-2·mm^-1which decreased by28.26%, 23.67%and28.18%compared with that in SM and increased by239.43%,168.38%and189.02%compared with that in SS, under W1, W2and W3, respectively. For summer plantedcrops, mean WUE in intercropping system decreased by13.87%,13.95%and-4.83%compared with that in SM and increased by234.73%,189.36%and185.15%compared withthat in SS, under W1, W2and W3, respectively. RF75was the best treatment because of thesmallest WUE decrease amplitude compared with that of SM and the largest WUE increaseamplitude compared with that of SS. Correlation analysis between LER and ridge widthshowed that WUE was the highest when ridge width was85.17cm,77.16cm and79.33cmunder W1, W2and W3, respectively.