| Due to the severe soil water depletion existed in forest land in the semi-arid Loess Plateau, select similar aspect and slope position level terraces in the 11year-old mountain dwarf jujube plant. Setting straw mulching treatment, film mulching treatment, gravel mulching treatment and bare land treatment in each level terrace. The soil water content under four different mulching patterns in jujube land and meteorological datas were measured during 2012~2016. The objective of this study was to investigate and evaluate the effects of mulching patterns on soil water balance in jujube land during the whole growth period. This study can provide more acurrate breakthrough point for the soil water restoration measures in jujube plant as well as the development of dry farming jujube in semi-arid areas, and provide theoretical and techmical support for establishing benign soil water ecological environment. The preliminary conclusions are as follows:1) Through analyzing the dynamic soil water change of different mulching patterns in jujube plant from 2012.3. to 2016.4., indicates that the soil water is at rising stage in growth period influnced by rainfall(April-October), and at declining stage in dormancy period(October-the next year on April). Dormancy period is the serious period of soil water depletion.2)The dynamic soil water storage change can be devided into three stages in different mulching patters of non-growth period. The first stage is from October to December. In this period, the soil water decreased. The second stage is from December to the next Janurary. In this period, the soil water increased. The third stage is from Janurary to April. In this period, the soil water decreased, too. Overall, film mulching, gravel mulching, the straw mulching, and bare land patter soil water storage were lower 61.6 mm, 75.8 mm, 87.2 mm and 113.4 mm respectively in dormancy period, which is equivalent to synchronization rainfall 1.36 times, 1.67 times,1.92 times and 2.50 times. The results indicate that the soil water lost most seriouly in bare land patter and taking mulching measures can keep soil water effect in different degrees.3)Rainfall infiltration and redistribution is a process from shallow to deep, and evapotranspiration process shows the characteristic of whole moviation. The maximum rainfall infiltration depth of film mulching, gravel mulching, straw mulching and non-mulching pattern is 440 cm, 340 cm, 320 cm and 260 cm. And the maximum rainfall infiltration depth is 380 cm, 300 cm, 280 cm and 260 cm respectively.4)The soil water vertical section can be roughly divided int two sections in early and late non-growth period in jujube plant. They are the easy and difficult recovery areas of soil water respectively. In easy recovery area, the soil water changed markelly, but relatively stable in difficult recovery area. Compared with non-growth mulching patter, the film mulching,gravel mulching pattern and straw mulching can improve the depth of soil water is 320 cm, 280 cm, 240 cm respectively after the non-growth period.5)According to the soil water balance of three anniversary change of soil water balance, it can be divided into three different types. In a wet year, the soil water recharge rate is larger than expenditure rate. In a scanty precipitation year, the soil water changed a little. And in a dry year, the soil water recharge rate is lower than expenditure rate.6)In a wet year, the ratio of evaporation and the synchronization rainfall is all lower than 1, which indicates that the soil water storage is at rising stage, and in a scanty precipitation year, the ratio of that is nearly at 1. And in a dry year, it is lager than 1, indicating that the soil water storage is an deceasing stage. Because the amounts of scanty precipitation year account for 56% of the total year, it may have an adverse effect on the formation of dried soil layer in this area. |
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