三峡库区柑橘园不同土壤管理方式对土壤温度的影响

Effects of different soil managements on soil temperatures of citrus orchard in Three Gorges Reservoir area

【目的】研究土壤管理方式对土壤土层温度的影响,为三峡库区柑橘园冬季保温越冬、高温伏旱期降温抗旱提供理论依据。【方法】在重庆市忠县新立镇选取一典型库区坡地柑橘园,采用覆盖、生草、清耕和中耕4种土壤管理方式,用土壤温湿度自动记录仪测定10、30、60 cm土层温度,并用自动空气温湿度仪和自动雨量计分别测定试验点空气温湿度、降雨过程及降雨量,对测定数据进行统计分析。【结果】重庆忠县4—8月的气温高于土壤温度,土壤温度10 cm土层>30 cm土层>60 cm土层,中耕>清耕>生草>覆盖,日均最高温时,覆盖10、30、60 cm土壤温度分别比生草低0.51℃、0.02℃和0.10℃,分别比清耕低2.52℃、2.00℃和1.23℃,分别比中耕低4.67℃、3.64℃和1.42℃;9月至翌年3月的气温低于土壤温度,土壤温度60 cm土层>30 cm土层>10 cm土层,覆盖>生草>清耕>中耕,日均最低温时,覆盖10、30、60 cm土壤温度分别比生草高0.02℃、0.39℃和1.02℃,分别比清耕高1.80℃、1.98℃和1.46℃,分别比中耕高1.94℃、2.05℃和1.92℃。3月是土壤温度从低温向高温转换的过渡时期,土壤温度随土层的加深逐渐降低;9月是土壤温度从高温向低温转换的过渡时期,土壤温度随土层的加深逐渐升高。【结论】覆盖和生草有利于缓和土壤温度变化,具有低温增温和高温降温双层效用,并有利于柑橘产量和品质的提高;中耕和清耕不利于土壤温度的稳定和柑橘产量、品质的提高,尤其是中耕。

【Objective】 The aim of the study was to provide the reference to stabilizing temperature in winter, reducing temperature in Summer and Autumn and improving the yield and quality in citrus orchards located in the Three Gorges Reservoir Area, the annual variations of soil temperatures at 10 cm, 30 cm and 60 cm soil layers were studied under four soil management methods(straw mulching, sod cultivation,clean tillage and inter tillage). 【Method】 One typical citrus orchard was selected in Zhongxian County,Chongqing city, and four methods of soil management as mentioned above were conducted, and then the soil temperatures at 10 cm, 30 cm and 60 cm soil layers were recorded by automatic temperature recorders. Meanwhile, the air temperature, air relative humidity and rainfall were also recorded. 【Result】The results showed that the air temperature was higher than the soil temperature from April to August in Zhongxian County, Chongqing city. The soil temperatures at different soil layers were 10 cm >30cm>60 cm, and the soil temperatures under different soil managements were inter tillage>clean tillage>sod cultivation>straw mulching. On the day of annual average daily maximum air temperature, the average daily soil temperatures of 10 cm, 30 cm and 60 cm soil layer mulched by straws were 0.51 ℃, 0.02 ℃ and0.10 ℃ lower than those of sod cultivation, respectively, 2.52 ℃, 2.00 ℃ and 1.23 ℃ lower than those of clean tillage, respectively, and 4.67 ℃, 3.64 ℃ and 1.42 ℃ lower than those of inter tillage, respectively.While from September to the following March, the air temperature was lower than the soil temperature, as a result the soil temperatures at different soil layers were 10 cm<30 cm<60 cm, and the soil temperatures under different soil managements were inter tillage<clean tillage<sod cultivation<straw mulching. On the day of annual average daily minimum air temperature, the soil temperatures of 10 cm, 30 cm and 60 cm soil layer mulched by straws were 0.02 ℃, 0.39 ℃ and 1.02 ℃ higher than those of sod cultivation, respectively, 1.80 ℃, 1.98 ℃ and 1.46 ℃ higher than those of clean tillage, respectively, and 1.94 ℃,2.05 ℃ and 1.92 ℃ higher than those of inter tillage, respectively. March was the transition period of soil temperature from low to high, and the soil temperature gradually decreased with the increase of soil depth.On the contrary, September was the transition period of soil temperature from high to low, and the soil temperature was gradually increased with the increase of soil depth. 【Conclusion】 Both straw mulching and sod cultivation in citrus orchard were beneficial to buffer fluctuation of soil temperature and to the improvement of citrus yield and quality. Straw mulching and sod cultivation reduced soil temperatures in summer and autumn seasons, however, they increased soil temperatures in winter and early spring. Compared with straw mulching and sod cultivation, inter tillage and clean tillage were not good for stabilization of soil temperature and improvement of citrus production and quality, especially for the inter tillage soil management.