Research On Soil Water Recovery Ability Under Different Typical Mulching In The Hilly Loess Region

The dried soil layers can be found for artificial forest in the Hilly Loess Region and become aggravate with the increasing tree ages. This study aimed to analyze soil water recovery ability under different typical mulching and avoid to form the permanate dry soil layers in the Hilly Loess Region, we determined soil water during growth stage and beyond the growth stage by location monitoring and getting samples under large-scale earth pillar and mulching treatments in the field, indicating that natural recovery ability under typical mulching for artificial forest in the hilly regions. The results were as belows:1) Results showed that dried soil water content increased monthly influenced by the rainfall in the large-scale earth pillar during the jujube growth stage. However, the soil water increased differently under different mulching treatments and plastic film mulching >branches mulching>barren land >bluegrass planting treatment at the end of September. The soil water content for barren land was higher, compared with bluegrass planting treatment indicating that barren land is better to recover soil water in local areas. Increment accumulative soil water under three non-plants treatments have linear relations with the month change and plastic film mulching has close relationship with monthly accumulative rainfall, but accumulative storage soil water for bluegrass planting has non-liner relationship with rainfall. With the increasing soil layers, variable coefficient became smaller gradually, bluegrass and barren land reached stable below the depth of 200 cm; the stable depth for branches mulching and plastic film mulching were 240 cm and 340 cm separately.2) The soil water content change under typical mulching in the field has the same trends with soil water in the large-scale earth pillar: plastic film mulching >branches mulching>barren land >bluegrass planting treatment. But soil water content in the field was slightly lower than that in the earth pillar because of jujube water consumption in the field test. After the rainy season, the recovery depth for soil water in the field was shallow with 150 cm for bluegrass and barren land, 200 cm for branches mulching and 260 cm for plastic film mulching.3) The winter is the key time for soil water loss by determining earth pillar in the beyond the growth stage. The soil water for barren land reduced from 16.88% to 10.42% within the depth of 0-230 cm; bluegrass planting treatment reduced from 14.67% to 11.35% in the 0-220 cm depth; branches mulching reduced from 18.77% to 14.61% within 0-150 cm depth and film mulching decreased the soil water from 20.51% to 18.02% at the depth of 0-300 cm. the depths for soil water loss under for different treatments(barren land, bluegrass planting, branches mulching and plastic film mulching) were 230 cm, 220 cm, 150 cm and 300 cm separately. The soil water for barren land and bluegrass planting was hardly infiltrated to deeper, but the soil water under branches mulching and plastic film mulching treatment have obvious infiltration phenomena with the infiltration depths of 300 cm and 450 cm. the total soil water loss is 68.42 mm, 51.53 mm, 47.88 mm and 3.29 mm for barren land, bluegrass planting, branches mulching and plastic film mulching.Therefore, the influence for soil water content is different under four different mulching and the plastic film mulching treatment can effectively enhance soil water and has the better recovery ability to soil water. Besides, the winter is the most important time to consume soil water; we need focus more attention in the future study.