Study On The Characteristics Of Soil Water Change Of Interplanting Different Herbages For A Long Time In Apple Orchard In The Area Of Weibei Plateau

Interplanting herbages is a soil management mode commonly employed for orcharddevelopment in developed countries, and it has been promoted as measures of green fruitproducing in China since1998. Interplanting herbages makes positive effects on orchard grassmicroclimate, soil and fruit quality, however, negative effects are also existed，and thecompetition for soil moisture is outstanding in the arid and semi-arid region. The strength ofcompetition is the key of realizing high efficiency and sustainability in apple-grassintercropping system,and tend to be the main factor of restricting the promoting of grassplanting technology.The current research about effect of interplanting herbages on soilmoisture are mostly for short-tern, but the research about effect of interplanting herbages onsoil moisture for long-tern were seldom reported. In this paper, the variation characteristics ofperennial herbage towards soil moisture were analyzed by field investigation. This study wasaimed to providing scientific basis for its management of soil water. The main results are asfollows:1. Interplanting herbages increased the variation of soil moisture.The extent of variation fordifferent fields followed the sequence of Trifoliurn repens L.> Lotus corniculatus L.>Coronilla varia L.> Dactylis glomerata L.＞Clear tillage. The extent of variation in dry seasonwas greater than that in the rainy season;The vertical variation of soil moisture in the layer of0-200cm is analyzed based on coefficient variation method.The active layer is deeper in thefield of interplanting grass than that in clear tillage.And the thickness of active layer fordifferent fields followed the sequence of Trifoliurn repens L.> Lotus corniculatus L.>Coronilla varia L.> Dactylis glomerata L.＞Clear tillage.2. The seasonal change of soil water in the layer of0-200cm is analyzed by margin model tofind out that interplanting grass and clear tillage have the same variationcharacteristics:including two processes of soil water consumption and recovery,however thevalley and peak are different. With different types of yearly rainfall，the soil water storagediffered greatly．In a year of abundant rain，soil water storage of the orchard that planted grassincreased，while in a drought year，growing herbages in the orchard reduced the soil water storage．3. The soil water consumption ability order was: Trifoliurn repens L.> Coronilla varia L.>Lotus corniculatus L.> Dactylis glomerata L.＞Clear tillage.The water conpensation effectfrom stable layer to active layer was obvious in dry season. When the water in active layerdecreased, the water stored in the stable layer decreased as well. And the water conpensationeffect order was Trifoliurn repens L.＞then Dactylis glomerata L.＞Lotus corniculatu L.＞Coronilla varia L.＞Clear tillage.4.There is a significant dependence between the available rainfall and replenishment of thesoil water. When the rainfall increased, the water stored in the stable layer of0～200cm alsoincreased. And the order of water storage is Trifoliurn repens L.>Dactylis glomerata L.>Lotus corniculatu L.> Coronilla varia L.> Clear tillage.In the late autumn,the replenishmenteffect of active layer to stable layer is also existed.5. Compared with clear tillage, sod culture improved the water-retention capacity in theperiod from winter to early spring. The water consumption in dry season increased when thewater storage increased in early spring. The order of water-retention capacity was Trifoliurnrepens L.> Coronilla varia L.> Dactylis glomerata L.＞Lotus corniculatus L.>Clear tillage.