| Due to the fragile ecological environment and harsh natural environment,the development of surrounding cities in the sandy area of southern Xinjiang is seriously restricted.The implementation of ecological protection projects of mountains,rivers,forests,fields,lakes and sands based on scientific ecological protection means is conducive to the construction of ecological civilization in China.In this paper,the windbreak and sand-fixing forest of Atriplex canescens introduced and planted in the wind-sand frontier area of the eleventh regiment of the first division in Aksu area of Xinjiang is taken as the object.The characteristics of ecological protection,soil improvement,plant restoration,biomass and nutrient content of sand-fixing forests with different forest ages and planting methods were studied.Evaluate the ecological benefits.The aim is to protect the fragile ecosystem in the sandy area;develop the rich desert resources in the Taklimakan Desert.The main results are as follows:(1)The planting of Atriplex canescens can significantly reduce the wind speed,wind erosion and sediment transport in the forest.The windbreak efficiency of 2-year-old,4-year-old and intercropping plots was 44.86%,48.67%and 55.87%,respectively.The amount of wind erosion and sediment transport in the1-year-old,2-year-old,4-year-old and intercropping plots were 2.45 mm/10d,3.20 mm/10d,3.16 mm/10d,2.90 mm/10d and 50.40 g/(d dm~2),52.24 g/(d dm~2),52.04 g/(d dm~2),51.90 g/(d dm~2)lower than those in the bare land,respectively.And with the increase of forest age,windbreak efficiency increased,wind erosion and sediment transport decreased.(2)The atmospheric temperature and relative humidity in the forest of Atriplex canescens with different years and planting patterns were 15.26-31.02°C and 20.36-28.91%,respectively.At the same time,the diurnal variation of atmospheric temperature increased first and then decreased,and the diurnal variation of relative humidity decreased first and then increased.Compared with bare land,the planting of Atriplex can play a role in cooling and humidifying as a whole,and is most obvious in summer.In addition,it has a certain thermal insulation effect in the morning and evening of spring and autumn.(3)The soil aggregate structure in the study area is poor.After planting Atriplex canescens.With the increase of forest age,With the increase of forest age,soil water content,porosity,organic matter,total nitrogen,total phosphorus,available nitrogen,available phosphorus and available potassium content increased,soil bulk density and p H increased first and then decreased,and total salt content showed a trend of’down-up-down’.Under different planting patterns,the contents of soil organic matter,total nitrogen and total phosphorus were higher than those of bare land,and the total potassium content was lower.In addition,with the increase of soil layer,the soil water content of each forest age gradually increased,the soil organic matter,total nitrogen and available nitrogen content gradually decreased,and the surface aggregation was obvious.(4)There were 13 species of plants belonging to 6 families in Atriplex canescens plantation,3 species of plants belonging to 3 families in bare land,8 species of plants belonging to 5 families in 1-year-old,11species of plants belonging to 6 families in 2-year-old,and 10 species of plants belonging to 5 families in 4-year-old.The Margalef index,Simpson index,Shannon-Wiener index and Pielou index of each forest age were 2 years old>4 years old>1 year old>bare land.(5)In spring,the biomass proportion of each organ was stem>root>leaf.In summer and autumn,the proportion of stem and root decreased,and the proportion of fruit and leaf increased.The carbon content of plant organs in each planting pattern was higher in roots,while the contents of nitrogen,phosphorus and potassium in leaves and fruits were higher than those in branches and roots.(6)The soil conservation value per hectare per year of one-year-old pure forest,two-year-old pure forest,four-year-old pure forest and four-year-old Atriplex canescens intercropping macrophyte forest reached 246.1 thousand yuan,282.7 thousand yuan,272.1 thousand yuan and 253.5 thousand yuan respectively.The value of ecological products per hectare per year of 2-year-old pure forest,4-year-old pure forest,4-year-old Atriplex canescens intercropping with Pennisetum giganteum forest and 4-year-old inoculated Cistanche deserticola pure forest were 990.48 yuan,3716.51 yuan,2666.60 yuan and 121131.94yuan,respectively.The nutrient retention value of forest trees was 384.89 yuan,963.05 yuan,856.34 yuan and 622.67 yuan,respectively.The value of carbon oxygen release was 9599.42 yuan,24088.15 yuan,22569.37 yuan and 14274.96 yuan,respectively.In addition,the cost of afforestation at the initial planting was 3950 yuan/hm~2,the cost of afforestation with Cistanche deserticola was 21950 yuan/hm~2,and the cost of tending was 4050 yuan/hm~2.In terms of ecological benefits,the 4-year-old pure forest was the highest,reaching 297 200 yuan/hm~2;in terms of economic benefits,Cistanche inoculation had the highest phosphorus,with an average of 67,800 yuan/hm~2.After planting Atriplex canescens in the wind-sand frontier area,it has obvious ecological benefits.In terms of windbreak and sand fixation and microclimate,it can significantly reduce wind speed,wind erosion,sediment transport,air temperature and increase air humidity in the forest;In terms of soil improvement,Atriplex can improve soil water content,porosity,organic matter,total nitrogen,total phosphorus,available nitrogen,available phosphorus and available potassium content;It can improve plant diversity in plant restoration. |
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