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| Biochar Effects on Organic Carbon and Nitrogen in Soil Aggregates in Semiarid Farmland |
| Received:January 30, 2015 |
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| KeyWord:biochar;water-stable aggregate;soil organic carbon;total nitrogen |
| Author Name | Affiliation | E-mail | | MI Hui-zhen | State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Northwest A&F University, Yangling 712100, China
College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China | | | ZHU Li-xia | College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China | | | SHEN Yu-fang | State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Northwest A&F University, Yangling 712100, China
College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, China | shenyufang@nwsuaf.edu.cn | | LI Shi-qing | State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Northwest A&F University, Yangling 712100, China | |
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| Abstract: |
| Biochars have many benefits to soil, including increasing soil carbon, enhancing soil water and nutrient retention, and improving soil aggregates. In the present study, the effects of biochar amendments on the distribution of soil organic carbon(SOC) and total nitrogen(TN) in soil aggregates in semiarid farmland were investigated. Soil samples from different depths(0~10 cm、 10~20 cm and 20~30 cm) in a field experiment with four biochar application rates:0 t·hm-2(CK), 10 t·hm-2(C1), 20 t·hm-2(C2) and 30 t·hm-2(C3) were collected. The soil samples were fractionated into different sized aggregates(> 2 mm, 2~0.25 mm, 0.25~0.053 mm and < 0.053 mm) using wet sieving method, and then SOC and TN in each aggregate fraction were measured. Compared with the control, two-year amendments of biochar trended to increase the content of > 0.25 mm water-stable macro-aggregates in the 0~10 cm and 10~20 cm soil layers. At the rate of 30 t·hm-2, the percentages of 0.25~0.053 mm micro-aggregates in the 10~20 cm and 20~30 cm soil layers were also significantly increased. Biochar additions significantly increased the SOC and TN content in different aggregates both in the 0~10 cm and 10~20 cm soil layers with C3> C2> C1> CK. In the 0~10 cm soil layer, the contribution rates of SOC and TN in the 2~0.25 mm aggregate to the whole soil were the greatest among all the water-stable aggregates. The contribution rates of SOC and TN in the < 0.053 mm aggregates increased with soil depth. In 0~30 cm soil, the average contribution rates of SOC and TN in the 2~0.25 mm and 0.25~0.053 mm aggregates increased with biochar amounts. |
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