土壤学报2016，Vol.53Issue(1)：177-188,12.DOI:10.11766/trxb201503090072
长期不同施肥措施对雨养条件下陇东旱塬土壤氮素的影响
Effects of Long-term Fertilization on Soil Nitrogen under Rainfed Farming in Loess Plateau of East Gansu
摘要
Abstract
The Loess Plateau of East Gansu is a typical area where rainfed farming prevails. To understand effects of long-term fertilization on soil nitrogen in soil profile is something very meaningful to farmers in doing fertilization in this area and to researchers in enriching scientific knowledge of soil nitrogen nutrition as well. From wheat fields of a long-term fertilization experiment that started in 1978 and had six treatments,i.e.,no fertilizer(CK),nitrogen only(N),nitrogen and phosphorous(NP),nitrogen and phosphorous combined with straw return(SNP),manure only(M),nitrogen and phosphorous combined with manure(MNP),soil samples were collected during the booting and summer fallow stages of wheat in 2014 for analysis of soil total nitrogen(total-N),soil available nitrogen(ava-N),soil mineral nitrogen (min-N)and composition of min-N. Results showed that treatments M and MNP obviously improved soil nitrogen nutrition and were significantly higher than the other treatments in total-N,ava-N,min-N in the 0~40 cm soil layers. No big difference in soil total-N was found between the two treatments. They both increased soil total N by 26.2% on averagely in the 0~20 cm soil layer over the original value in the year of 1978 when the experiment started. Treatment SNP was higher in total-N and ava-N than CK but significantly lower than treatments M and MNP. However,total-N in treatment SNP remained almost the same as or was just slightly higher than the original value. Though treatment NP was quite low in total-N and ava-N,it was still higher than treatments N and CK. Treatments N and NP were 13.1% and 6.4%,respectively,lower than the original value in total-N of the 0~20 cm soil layer. The treatments did not vary much in absolute value of NH4+-N concentration in the soil profiles,but treatment N stood out in NO3--N concentration throughout the 0~100 cm soil profile,while the other treatments were higher in the topsoil and sub-topsoil layers than in the 40~100 cm or 60~100 cm soil layer. All the fertilization treatments,particularly treatments M and MNP, lowered NH4+-N/NO3--N ratio in the topsoil layer. Treatment SNP tended to increase the proportion of NH4+-N in soil total N and hence NH4+-N/NO3--N ratio in the middle and lower soil layers. The phenomenon was getting more significant with soil depth in the profile during the summer fallow season. To sum up,under rainfed farming in the Loess Plateau of East Gansu,the practices of applying NP in combination with organic manures are superior to the others in building up soil fertility. The application of N or NP only fails to maintain balance of total-N in the soil. The application of chemical nitrogen alone aggravates downward leaching of NO3--N, while the practices of manure,NP and NP plus manure application are proved to be able to reduce NO3--N leaching. However,NH4+-N is not much affected by fertilization practices. Fertilization changes composition of min-N,but the effects of manure application and straw incorporation differ quite sharply. It is,therefore, suggested that more efforts should be dedicated to the study on fate and transformation of soil nitrogen under rainfed farming in future.关键词
长期定位试验/不同施肥制度/土壤氮素特征/陇东旱塬Key words
Long-term experiment/Different fertilization practices/Soil nitrogen characteristic/Loess Plateau of East Gansu分类
农业科技引用本文复制引用
王婷,李利利,周海燕,丁宁平,车宗贤..长期不同施肥措施对雨养条件下陇东旱塬土壤氮素的影响[J].土壤学报,2016,53(1):177-188,12.基金项目
国家自然科学基金地区科学资金项目(31560584)和甘肃省农业科学院创新专项(2013GAAS12)"资助 Supported by the National Natural Science Foundation of China(No. 31560584)and the Special Fund Project of Gansu Academy of Agricultural Sciences(No. 2013GAAS12) （31560584）
