黄河流域五大灌区沿河耕地土壤肥力评价与改良措施

Soil fertility evaluation and improvement measures in five irrigated areas along the Yellow River basin

为了提高黄河流域农业可持续性,保障区域粮食安全,本文以宁夏(NX)、河套(HT)、汾河(FG)、关中(GZ)、华北平原(HB)五大引黄灌区耕层土壤为研究对象,测定其养分含量并进行土壤肥力评价。结果表明:五大灌区土壤pH均高于8.0,土壤有机质、全氮、碱解氮、全磷、速效磷、全钾、速效钾含量均值分别为16.43 g·kg^−1、0.96 g·kg^−1、79.71 mg·kg^−1、0.76 g·kg^−1、30.60 mg·kg^−1、16.85 g·kg^−1、228.73 mg·kg^−1,对应养分级别为四级、四级、四级、三级、二级、三级、一级;土壤微量元素有效态铁、锰、铜、锌含量均值为6.21 mg·kg^−1、5.94 mg·kg^−1、1.05 mg·kg^−1、5.10 mg·kg^−1,对应养分级别为三级、四级、一级、一级。黄河流域五大灌区沿河耕地土壤综合肥力指数由大到小的顺序为:NX>FG>HB>HT>GZ。各灌区应增加农田有机质,调整氮磷钾肥施加比例,重视微量元素供给,从而实现灌区种植的可持续发展。

Background,aim,and scope The Yellow River basin is one of the main agricultural production areas in China,which plays a crucial role in solving the problem of food security in China.However,with the continuous increase of irrigated area and fertilizer application amount,the problems of nutrient imbalance and low fertilizer utilization rate appear in the irrigated areas along the Yellow River.Although there have been some studies on soil quality evaluation in irrigated areas before,there are few reports on comprehensive evaluation of soil fertility in five irrigated areas along the Yellow River basin.In order to better realize the sustainable development of the irrigated areas and even the whole Yellow River Basin,our study aims to fully understand the characteristics of soil nutrient content in five major irrigated areas along the Yellow River.Materials and methods In this study,five irrigated areas in Ningxia(NX),Hetao(HT),Fenhe(FG),Guanzhong(GZ)and the North China Plain(HB)were selected as research objects.The nutrient contents of soil were measured and the soil fertility was evaluated.Results The results showed that the soil pH of the irrigated areas was higher than 8.0;The average contents of soil organic matter(SOM),total nitrogen(N),available nitrogen,total phosphorus(P),available phosphorus,total potassium(K)and available potassium were corresponding to four,four,four,three,two,three and one nutrient levels;The average contents of available Fe,Mn,Cu and Zn were corresponding to the three,four,one and one nutrient levels;The comprehensive fertility index of the five irrigated areas along the Yellow River basin is in the order of NX>FG>HB>HT>GZ.Discussion The differences of nutrient contents in five irrigated areas are related to fertilization,soil types,irrigation conditions and other factors.The contribution rate of organic matter and total nitrogen to soil comprehensive fertility was high in NX and HT.The reasons why the comprehensive index of soil fertility in GZ is low,in addition to the insufficient input of organic fertilizer,are the poor soil types,which mostly is tidal soil along the river.Conclusions The difference of soil comprehensive fertility caused by nutrient imbalance existed in five irrigated areas.Ningxia and Fenhe irrigated areas were of secondary fertility,while the rest were of tertiary fertility.Recommendations and perspectives The results indicate that we should strengthen the control of soil salinization,increase the organic matter of farmland,adjust the proportion of N,P,K and attach importance to the supply of trace elements,so as to change the current situation of soil nutrient imbalance between the five irrigated areas.