| 摘要: |
| 【目的】我国亚热带地区为典型的双季稻种植区，水分管理多采用长期淹水和间歇灌溉两种方式，灌溉方式的不同会导致土壤水分含量的差异，其势必会影响土壤酸碱性的改变，此方面的研究还较少。生物质炭添加可改变土壤孔隙度即土壤性质，稻田间歇灌溉条件下添加生物质炭，如何影响对双季稻田土壤水分及酸碱性的影响尚不清楚，需要大量田间试验进行验证。【方法】采用田间小区试验，于2012年早稻季、晚稻季及休闲季研究水分管理方式（长期淹水（CF）和间歇灌溉（IF））及生物质炭施用量（0、24 t hm-2（LB+IF）和48 t hm-2（HB+IF））对亚热带双季稻田土壤含水率及pH的影响。【结果】与长期淹水相比，早稻季和晚稻季间歇灌溉的土壤含水率并没有显著降低，这主要是由于烤田期间降雨造成的。生物质炭添加并未显著影响早稻季和晚稻季土壤含水率，但在休闲季生物质炭处理对土壤含水率有一定的降低作用，这可能是由质地较细的生物质炭占据了土壤大孔隙，降低了土壤孔隙率所致。研究期间，CF、IF、LB+IF和HB+IF处理的土壤含水率周年均值分别为0.47、0.40、0.37和0.39，与长期淹水相比，间歇灌溉降低了全年的土壤含水率，降幅达16.41%，而生物质炭对间歇灌溉稻田土壤含水率影响不大。与长期淹水相比，早稻季和晚稻季间歇灌溉处理的土壤pH分别显著降低了0.22和0.57个单位，休闲季不同水分管理方式之间的土壤pH差异不显著。由于生物质炭本身呈碱性，添加到土壤后可增加土壤pH，且随着生物质炭添加量的增加而增加。与IF处理相比，早稻季和晚稻季生物质炭处理的pH分别增加了0.23~0.68个单位和0.17~0.60个单位。【结论】水分管理可影响双季稻田土壤含水率和pH。间歇灌溉降低了亚热带地区双季稻酸性土壤的pH。生物质炭添加，尤其是高量生物质炭添加，可在一定程度上缓解间歇灌溉对酸性土壤pH的降低作用。 |
| 关键词: 水分管理;生物质炭;双季稻田;土壤含水率;土壤pH |
| DOI： |
| 分类号:X172 |
| 基金项目: |
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| Effects of Water Management and Biochar Amendment on Soil Water Content and pH in Double Rice Cropping Field in Subtropical China |
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Liu Jie-yun1, Zhang Wenzheng1, Shen Jian-lin2, Tang Hong3, Wang Cong4, Qiu Hu-sen5
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1.Farmland Irrigation Research Institute,Chinese Academy of Agricultural Sciences;2.Key Laboratory of Agro-ecological Processes in Subtropical Region,Institute of Subtropical Agriculture,Chinese Academy of Sciences;3.College of Environment and Life Science,Kaili University;4.Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management,Guangdong Institute of Eco-environmental Science and Technology;5.Suzhou University
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| Abstract: |
| 【Background】 Rice is one of three main crops in China. Meanwhile, paddy field is the main water user. The traditional flooding irrigation wasted plenty of water resource, and caused water pollution. Double rice cropping system is the typical planting patterns in subtropical China. The soil in subtropical area is acid. How to irrigate reasonably to reduce water waste and reduce soil acidity is a difficult problem in subtropical China.【Objective】Double rice cropping system is the typical planting patterns in subtropical China. Flooding and intermittent irrigation were the main water management methods in double rice cropping system. Biochar amendment can increase soil water holding capacity and neutralize soil acidity. While, the effects of different water management and biochar amendment on soil water content and soil pH in subtropical area were not clear, and plenty of field study is needed.【Method】A field plot experiment was conducted to study the influences of water management and biochar amendment on soil water content and pH in double rice cropping field during the early rice, late rice and fallow season in subtropical area. Water management types were continuous flooding (CF) and intermittent irrigation (IF). Three biochar application rates were arranged in intermittent irrigation method: no biochar treatment (IF), added 24 t hm-2 biochar treatment (LB+IF) and added 48 t hm-2 biochar treatment (HB+IF) .【Result】In comparison with CF treatment, soil water content with IF treatment was not significantly decreased in the early rice and late rice seasons, which may result from the precipitation during drainage period. Biochar amendment did not change soil water contents during the early rice season and late rice season, but reduced soil water content during the fallow season, which may attributed to that fine textured biochar occupied soil pore space and reduced soil porosity. The annual average soil water content of CF, IF, LB+IF and HB+IF treatments were 0.47, 0.40, 0.37 and 0.39, respectively. Intermittent irrigation reduced annual average soil water contents compared to continuous flooding, but biochar amendment did not significantly affect annual average soil water contents. IF treatment reduced soil pH by 0.22 and 0.57 during the early rice season and late rice season as compared to CF treatment. While, no difference of soil pH was observed between IF and CF treatments during the fallow season. Due to the alkalinity, biochar amendment can increase soil pH, and soil pH increased with the increasing of biochar application rates. Compared to IF treatment, biocahar treatments increased soil pH by 0.23~0.68 in the early rice season and 0.17~0.60 during in the early rice season and late rice season.【Conclusion】From above, water management can affects soil water contents and pH. Intermittent irrigation reduced soil pH. Biochar amendment, especially the high rate biochar amendment, can increase soil pH and neutralize the pH reduction of with intermittent irrigation in acid soil. The results of this study can supply the theoretical support for the intermittent irrigation and biochar amendment in double rice cropping system in subtropical China. |
| Key words: water management; biochar; double rice cropping field; soil water content; soil pH |
