| Since serious soil and water loss, soil impoverishment and water resources shortage,apple product had been inhibited to sustained and healthy development in the loess hill andgully area of Northern Shaanxi. How to reduce soil erosion, increase soil moisture and soilnutrient, and improve the ecological environment of apple were the primary task to hillsideorchard development. Application of super absorbent polymer materials could reduce runoffand sediment, conserve fertilizer in rainy season, and have water conservation and droughtresistance effects during the dry season, which can be used as the chemical control measure toreduce soil and water loss. This paper took soil conditioner PAM, BJ2101-L and Wote superabsorbent as tested materials, the effects of three kinds of polymer materials on soil moisture,runoff and sediment, soil nutrient loss and the growth of apple trees in the loess hill and gullyarea of Northern Shaanxi were conducted, and had the following results:1. Polymer materials obviously improved soil moisture content, but they have a certainperiod of effectiveness. The main soil layers that polymer materials effected on soil moisturewere0~50cm soil depth, during the apple growing period, the soil moisture of0~50cm soildepth at different stages were as follows: rainy season＞after rainy season＞before droughtseason＞drought season. PAM、BJ2101-L and Wote super absorbent respectively increased0~50cm soil moisture by0.75%,0.33%and0.67%compared with the CK in drought season,and did not show significant difference；respectively increased9.57%、3.59%、4.32%in rainyseason, and PAM had significantly higher than CK at0.05levels; respectively increased9.70%,16.67%,5.92%after rainy season，and BJ2101-L had significantly higher than CK at0.01levels. PAM promoted the water infiltration in rainy season, and improved the water moisture below50cm soil depth. In all the treatments, the effect of PAM treatment was moreobvious. The application of polymer materials should be centralized before rainy season.2. Polymer materials significantly decreased runoff amount. Runoff of slope orchard wasclosely related to precipitation characteristics in the loess hill and gully area of NorthernShaanxi. The runoff amount of different treatment increased with precipitation amount andprecipitation intensity, and the relationships followed power function and linear function,respectively. There were no significant effects between runoff amount of slope orchard andprecipitation duration, precipitation interval. Among the precipitation factors, precipitationintensity had the greateat effects on the runoff amount. The relationships between orchardrunoff amount and precipitation amount, precipitation intensity as follows:CK=-0.02+0.03P+0.16E R2=0.91; PAM=-0.09+0.02P+0.12E R2=0.89;BJ2101-L=-0.05+0.02P+0.13E R2=0.88; Wote=-0.03+0.02P+0.14E R2=0.90.Compared with the CK, the orchard runoff amount of PAM, BJ2101-L and Wote superabsorbent were decreased by22.19%,16.9%and12.7%, respectively, in which the effect ofPAM treatment was more obvious.3. Polymer materials significantly decreased erosion amount. Soil erosion of hillsideorchard was closely related to precipitation characteristics in loess hill and gully area ofNorthern Shaanxi. The erosion amount of different treatment increased with precipitationamount and precipitation intensity, and the relationships followed linear function and powerfunction, respectively. There were no significant effects between erosion amount of slopeorchard and precipitation duration, precipitation interval. Among the precipitation factors,precipitation intensity had the greateat efrects on the erosion amount. Relationships betweenorchard erosion amount and precipitation amount, precipitation intensity as follows:CK=-49.63+0.30P+16.37E R2=0.86; PAM=-36.83+0.04P+12.57E R2=0.86;BJ2101-L=-40.77+0.13P+13.54E R2=0.86; Wote=-43.88+0.19P+14.44E R2=0.86.Compared with the CK, the orchard erosion amount of PAM, BJ2101-L and Wote superabsorbent were decreased by27.50%,20.63%and14.27%, respectively, in which the effect ofPAM treatment was more obvious. 4. Polymer materials could effectively decrease soil nutrient loss. Compared with the CK,annual nitrogen loss amount of PAM, BJ2101-L and Wote super absorbent were decreased by44.02%,53.30%,42.55%, respectively; annual phosphorus loss amount decreased by38.74%,47.01%,31.60%, respectively; annual potassium loss amount decreased by36.97%,41.14%,25.44%, respectively; annual organic matter loss amount decreased by28.21%,30.50%,22.93%, respectively. All the polymer materials treatments decreased the annual nutrient lossamount, in which of them BJ2101-L has a comparatively better effect. Under fieldprecipitation condition, nitrogen, phosphorus, potassium and organic matter loss amount withsediment forms account for83.24%~93.31%,99.66%~99.87%and99.54%~99.59%of thetatal, respectively. Sediment was mainly approach of nutrient loss. Improving soil effectivelyand reducing soil and water loss was the key to prevent and control of soil nutrient loss.5. Polymer materials could improve the growth of apple trees, but had no significanteffects on fruit quality. Different treatments had no significant effect on the height and crownof apple trees, had no significant effect on the soluble solids, soluble sugar, organic acid,firmness, vitamin C, fruit shape index of apple fruit，but significantly increased new shootslength, new shoots thickness and stem diameter, apple yields, apple economic value, and hada more significant effects along with the time. Compared with the CK, economic value ofPAM, BJ2101-L and Wote super absorbent were increased by12.5%,22.11%,19.23%,respectively. All the treatments improved economic value in2012, in which of BJ2101-L wasthe highest, and that of PAM was the lowest. |
PDF Full Text Request