Zhang Kai-Li, Hao Qing-Ju, Feng Di, Shi Jiang-Lai, Shi Xiao-Jun, Jiang Chang-Sheng
Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, College of Resources and Environment, Southwest University, Chongqing 400716, China.
National Monitoring Station of Soil Fertility and Fertilizer Efficiency on Purple Soils, Chongqing 400716, China.
Huan Jing Ke Xue. 2017 Aug 8;38(8):3451-3462. doi: 10.13227/j.hjkx.201701002.
Using the static opaque chamber method and choosing a chili-radish cropping system, a field experiment, located in the Key Field Station for Monitoring of Eco-Environment of Purple Soil of the Ministry of Agriculture of China in the farm of Southwest University in Chongqing, was conducted for one year. Mulching and non-mulching treatments were set in the field, and the seasonal variation of CH flux and CH concentrations in the soil profile and the seasonal changes in soil moisture and temperature were observed for different treatments to explore the effect of plastic film mulching on soil moisture and temperature. The results showed that plastic film mulching can significantly improve the surface soil temperature during the pepper growing season in spring and summer (<0.01), but no significant difference was seen during the radish growing season in autumn and winter (>0.05). The soil moisture of the plastic film mulching treatment was significantly higher than that of no mulching in the radish growing season (<0.05), but no significant difference was observed for the pepper growing season (>0.05). During the whole observation period and under the condition of plastic film mulching and conventional planting, the CH flux from soil had no significant seasonal variation under all treatments, and the mean CH fluxes were -7.64 μg·(m·h) and -9.00 μg·(m·h), respectively. The cumulative CH emissions for plastic film mulching and conventional planting were -0.54 kg·hm and -0.64 kg·hm, respectively, in the whole observation period, and all the treatments showed a net absorption of CH for the whole observation period. The results showed that the plastic film mulching could weaken the ability of CH as a sink of the CH for the whole observation period. The CH concentrations in different soil profiles were in the order 10 cm>20 cm>30 cm, and the concentrations of CH change patterns in different soil layers were almost identical during the whole observation period. The CH concentrations at the depths of 20 cm and 30 cm under the plastic film mulching soil were significantly lower than those under no mulching soil (<0.05), but no significant difference was observed for the depth of 10 cm (>0.05). Correlation analysis showed that, under the plastic film mulching conditions, CH flux and the 5 cm geothermal showed significant positive correlation (<0.05), but CH flux and soil moisture showed significant negative correlation (<0.05). However, under the conventional cultivation conditions, there were no correlations between CH flux and the 5 cm geothermal or soil moisture. There was also significant positive correlation between CH concentration in the 10 cm and 20 cm depth soil layers with the CH concentration in surface soil (<0.01), and the CH concentration in the 30 cm depth soil layer had significant positive correlation with the surface soil temperatures and the 5 cm geothermal. There was no significant correlation between soil CH concentration and soil water content.
采用静态暗箱法，选取辣椒 - 萝卜种植系统，在中国农业农村部紫色土生态环境重点野外科学观测试验站（位于重庆西南大学农场）进行了为期一年的田间试验。试验设置了覆膜和不覆膜处理，观测不同处理下土壤剖面中CH通量和CH浓度的季节变化以及土壤水分和温度的季节变化，以探究地膜覆盖对土壤水分和温度的影响。结果表明，地膜覆盖能显著提高春夏季辣椒生长季的表层土壤温度（<0.01），但在秋冬季萝卜生长季差异不显著（>0.05）。地膜覆盖处理的土壤水分在萝卜生长季显著高于不覆膜处理（<0.05），但在辣椒生长季差异不显著（>0.05）。在整个观测期内，地膜覆盖和常规种植条件下，各处理土壤CH通量均无显著季节变化，平均CH通量分别为-7.64 μg·(m²·h)和-9.00 μg·(m²·h)。整个观测期内地膜覆盖和常规种植的CH累积排放量分别为-0.54 kg·hm²和-0.64 kg·hm²，所有处理在整个观测期内均表现为CH净吸收。结果表明，地膜覆盖在整个观测期内会削弱土壤作为CH汇的能力。不同土壤剖面的CH浓度顺序为10 cm>20 cm>30 cm，整个观测期内不同土层CH浓度变化模式基本一致。地膜覆盖土壤20 cm和30 cm深度处的CH浓度显著低于不覆膜土壤（<0.05），但10 cm深度处差异不显著（>0.05）。相关性分析表明，在地膜覆盖条件下，CH通量与5 cm地温呈显著正相关（<0.05），但CH通量与土壤水分呈显著负相关（<0.05）。然而，在常规种植条件下，CH通量与5 cm地温或土壤水分之间无相关性。10 cm和20 cm深度土层的CH浓度与表层土壤CH浓度也呈显著正相关（<0.01），30 cm深度土层的CH浓度与表层土壤温度和5 cm地温呈显著正相关。土壤CH浓度与土壤含水量无显著相关性。
