长期施肥对红壤性水稻土不同土层活性有机质及碳库管理指数的影响

【目的】研究基于长期定位试验,探索长期不同施肥下红壤性水稻土不同土层活性有机质(labile organic matter(LOM))和碳库管理指数(carbon pool management index,CPMI)变化特征,为红壤性水稻土碳库的合理管理提供依据。【方法】选取进贤红壤长期定位试验站4个典型施肥处理:(1)不施肥(CK);(2)单施化肥(NPK);(3)在NPK的基础上早稻施绿肥,晚稻施猪粪和稻草冬季还田(NPKSM);(4)在NPK的基础上早稻施绿肥,稻草冬季还田(NPKS),测定并分析0—10、10—20、20—40及40—60 cm土层土壤高活性有机质(HLOM)、中活性有机质(MLOM)、低活性有机质(LLOM)、非活性有机质(NLOM)含量以及CPMI变化特征。【结果】不同处理土壤有机质(SOM)含量均随土层加深而降低,施肥处理相对CK均明显提高了不同土层的SOM;在0—20 cm土层,SOM含量表现为NPKSM>NPKS>NPK>CK,且均以NPKSM处理最高,达到43.47g·kg^-1(10—20 cm)和45.09...

The Effects of Long-Term Fertilization on the Labile Organic Matter and Carbon Pool Management Index in Different Soil Layers in Red Soil

【Objective】This study was aimed to explore the characteristics of the labile organic matter (LOM) and carbon pool management index (CPMI) under different fertilization in different soil layers in red soil, so as to provide a theoretical basis for carbon pool management in red soil. 【Method】Based on the long-term experiment site located at Jinxian, Jiangxi province, four typical treatments were chosen as: (1) no fertilization (CK); (2) mineral nitrogen, phosphorus, potassium (NPK); (3) NPK combined with pig manure and straw (NPKSM); (4) NPK combined with straw (NPKS). The highly LOM (HLOM), moderately LOM (MLOM), lowly LOM (LLOM), non-LOM (NLOM) and CPMI in four soil depths (i.e. 0-10 cm, 10-20 cm, 20-40 cm and 40-60 cm) were measured and analyzed. 【Result】The results showed that the soil organic matter (SOM) content under each treatment was decreased with increasing of soil depths. Compared with CK treatment, the SOM was increased under the fertilization treatments. In 0-20 cm, the SOM content was ordered as NPKSM >NPKS >NPK >CK, with the highest value as 43.47 g·kg ^-1(10-20 cm) and 45.09 g·kg ^-1(0-10 cm) under NPKSM treatment. In 20-60 cm, the SOM content under NPKSM and NPKS was significantly higher than that under CK, while there was no different between NPKSM and NPKS. The dissolved organic carbon (DOC) content was decreased with soil depth under all treatments except NPK. The DOC content under NPKSM and NPKS was significantly higher than that under NPK and CK, and the highest value was 35.93 mg·kg ^-1under NPKSM treatment. The HLOM, MLOM, and LLOM content were increased under fertilization treatments compared with CK treatment. The LOM content was ordered as LLOM> MLOM> HLOM under the same treatment in same soil layer. All the LOM components content was significantly higher under NPKSM and NPKS treatments in all soil layers. The HLOM and MLOM content under all treatments were trended as first increased and then decreased with increasing of soil depth. The HLOM content was reached to peak in 20-40 cm under NPKSM (5.31 g·kg ^-1) and NPKS (5.49 g·kg ^-1). The highest MLOM content appeared in 10-20 cm under NPKSM treatment with 10.62 g·kg ^-1. The LLOM content under all treatments was decreased with soil depth. In 0-20 cm, the LLOM content was highest under NPKSM treatment with 18.52 g·kg ^-1(0-10 cm) and 15.93 g·kg ^-1(10-20 cm), respectively. The proportion of different LOM components and CPMI were increased under the fertilizer treatments. In 0-10 cm, compared with CK, the LOM content under NPKS and NPKSM was increased by 27.9%and 29.48%, respectively, MLOM proportion was increased by 7.21% and 7.72%, respectively, HLOM proportion was increased by 5.10% and 4.96%, respectively. The CPMI under fertilization treatment was higher than 100, and which was obviously higher under NPKSM and NPKS. In 0-20 cm, the different LOM components were extremely significantly positive correlation(P≤0.01), and they were significantly positive correlated with total SOM, total nitrogen, dissolved SOM and rice yield (P≤0.05). 【Conclusion】The SOM and LLOM content under all treatments were decreased with the increasing of soil depth. The SOM and all LOM components were significantly improved under NPKSM treatment, and HLOM and CPMI under NPKSM were the highest, followed by NPKS in 0-20 cm, while, which was the highest under NPKS in 20-60 cm.