不同施肥处理对红壤丘陵区水稻土养分状况的影响

研究依托千烟洲生态站,利用1998年建立的红壤稻田长期定位施肥试验,研究不同施肥处理对水稻土土壤碳及养分的影响。结果表明:①施用有机肥有利于提高土壤碳、 氮、 磷含量,土壤总有机碳(SOC)含量达到16.8 g·kg^-1,全氮(TN)含量达到1.5 g·kg^-1,速效氮(AN)含量达到153.8 mg·kg^-1,速效磷(AP)含量达到43.3 mg·kg^-1,而土壤速效钾(AK)含量仅达到23.0 mg·kg^-1,低于施用化肥的各个处理;②施用氮、 磷、 钾肥减缓了红壤水稻土酸化趋势,显著增加土壤AP(12.3~47.1 mg·kg^-1)、 AK(22.3~54.5 mg·kg^-1)含量;③秸秆还田可以提高稻田红壤SOC(10.8 g·kg^-1)、 TN(1.1 g·kg^-1)含量。因此,建议在红壤稻田施入适量有机肥,提倡秸秆还田,提高土壤碳含量,同时配合施用钾肥,满足作物对养分的需求;化肥、 有机肥施用量需要考虑其对水体氮、 磷污染的潜在风险。

Effects of Different Fertilization Treatment on Paddy Soil Nutrients in Red Soil Hilly Region

Supported by Qianyanzhou Ecological Experiment Station, this study aimed to discuss the effects of different fertilizer treatments on paddy soil elements including carbon and other nutrients by using the long-term fertilization trial on paddy soil established in 1998. The results showed as follows: 1) Application of organic manure was beneficial to increase the contents of soil carbon, nitrogen and phosphorus. Specifically, the content of soil organic carbon (SOC) reached 16.8 g·kg^-1, total nitrogen (TN) reached 1.5 g·kg^-1, available nitrogen (AN) reached 153.8 mg·kg^-1, available phosphorus (AP) reached 43.3 mg·kg^-1, while the content of available potassium (AK) was only 23.0 mg·kg^-1 which was lower than the chemical fertilizer treatments. 2) The application of chemical fertilizer could alleviate soil acidification tendency to some extent in red paddy soil and significantly increase the contents of AP (12.3-47.1mg·kg^-1) and AK (22.3-54.5 mg·kg^-1). 3) Application of straw returning enhanced the content of SOC (10.8 g·kg^-1) and TN (1.1 g·kg^-1). 4) In conclusion, it was recommended to apply the organic manure and straw returning with K fertilizer to increase the soil carbon and satisfy the nutrient demand of rice. Meanwhile, the application rate of organic manure and chemical fertilizer should consider the potential risk of nitrogen and phosphorus pollution.