安徽省县域麦稻玉米秸秆时空分异特征与还田养分输入量测算

安徽省是国家重要商品粮生产基地，作为农业大省其粮食作物秸秆产量居于全国前列。明晰全省产粮大县主要粮食作物秸秆理论资源量和可收集资源量时空分布特征，并准确测算秸秆就地还田对土壤养分输入的贡献，可为秸秆全量化差异化利用策略优化及秸秆还田情景下的农田养分平衡调控提供决策依据。研究表明，2011-2019年安徽省产粮大县三大粮食作物秸秆资源总量呈现出稳步增长的态势，而不同作物秸秆产量年际变化趋势各异：小麦秸秆先升后稳，水稻秸秆波动不大，玉米秸秆逐年递增。2019年安徽省产粮大县三大粮食作物秸秆理论资源量为3 878万t，其中小麦、水稻和玉米秸秆所占比例分别为47.3%、36.3%和16.4%。淮北区为小麦和玉米秸秆资源集中分布区，占比分别为73.0%和88.3%，水稻秸秆主要产自江淮区（41.7%）、皖西区（21.3%）及沿江区（19.7%）。主要粮食作物秸秆资源总量分布表现为淮北区（52.5%）?江淮区（24.3%）?皖西区（10.5%）?沿江区（9.1%）?皖南区（3.6%）。2019年全省产粮大县小麦、水稻和玉米秸秆可收集资源量分别为1 338万、1 041万和542万t，淮北区单位播种面积小麦和玉米秸秆可收集资源量分别为4 505～6 310和4 171～5 395 kg/hm2，江淮区、皖西区和沿江区单位播种面积水稻秸秆可收集资源量分别为4 487～5 326、4 570～5 028和4 329～5 778 kg/hm2。2019年安徽省产粮大县三大粮食作物秸秆氮（N）、磷（P2O5）和钾（K2O）养分资源总量分别为25.3万、10.9万和90.1万t。在秸秆就地全量还田情景下，小麦玉米主产区（淮北区）小麦秸秆还田的氮（N）、磷（P2O5）和钾（K2O）养分输入量分别为35.8～50.1、14.1～19.8和139.8～195.8 kg/hm2，玉米秸秆还田的养分输入量分别为42.7～55.2、16.9～21.8和93.4～120.9 kg/hm2；水稻主产区（江淮区、皖西区和沿江区）水稻秸秆还田的养分输入量分别为38.0～50.8、18.8～25.0和151.6～202.3 kg/hm2。研究结果对进一步提升安徽省产粮大县秸秆资源综合利用效率及推动农业绿色高质量发展具有重要的现实意义。

Spatio-temporal variations of wheat, rice and maize straw in major grain-producing counties of Anhui Province and utilization potential of straw nutrient returning to field

Abstract: Abstract: Anhui Province of China is one of the most important agricultural production bases with abundant grain crop straw resources. It is necessary to clarify the temporal and regional characteristics of theoretical and crop residues for the differentiated development of fully quantitative utilization in straw sources in major grain-producing counties. Accurate evaluation of utilization potential to straw nutrient resources can essentially contribute to balancing the regulation of soil nutrients under straw returning. In this study, a systematic investigation was made on the spatiotemporal variation of wheat, rice and maize straw in major grain-producing counties of Anhui Province and utilization potential of a straw nutrient return to the field. The result showed that the total output of straw resources presented a slowly rising trend from 2011 to 2019. However, the straw production during 2011-2019 presented significant differences among three major grain crops, where the wheat straw firstly increased and then remained stable, while the rice straw was relatively stable with small fluctuation, and the maize straw showed an outstanding ascending. The theoretical amount of three main grain crop straws were 38.78 million tons in 2019, among which the wheat, rice, and maize straws accounted for 47.3%, 36.3%, and 16.4%, respectively. The wheat straw (73.0%) and maize straw (88.3%) were mainly concentrated in the North area of the Huai River. The rice straw was mainly distributed in the area between the Yangtze and the Huai River (41.7%), Western Anhui Province (21.3%), and the edge area of the Yangtze River (19.7%). The distribution of total straw yields from the three main grain crops in different agricultural areas was ranked as follows: North area of the Huai River (52.5%) ? Area between the Yangtze and the Huai River (24.3%) ? Western Anhui Province (10.5%) ? Edge area of the Yangtze River (9.1%) ? Southern Anhui Province (3.6%). The straw resources in 2019 were 13.38, 10.41, and 5.42 million tons for wheat, rice, and maize, respectively. The straw resources per unit sown area in the north area of the Huai River of Anhui Province were 4 505-6 310 and 4 171-5 395 kg/hm2 for wheat and maize, respectively. The rice straw per unit sown area were 4 487-5 326, 4 570-5 028, and 4 329-5 778 kg/hm2 for the Area between the Yangtze and the Huai River, Western Anhui Province and the Edge area of the Yangtze River, respectively. Furthermore, the contents of N, P2O5, and K2O were 0.253, 0.109, and 0.901 million tons, respectively, for the main grain crop straws in 2019. In the North area of Huai River of Anhui province, the nutrient inputs by wheat straw incorporation were N 35.8-50.1, P2O5 14.1-19.8, and K2O 139.8-195.8 kg/hm2, respectively, and the nutrient inputs under maize straw return scenario were N 42.7-55.2, P2O5 16.9-21.8 and K2O 93.4-120.9 kg/hm2, respectively. In the primary rice-growing regions (Area between the Yangtze and the Huai River, Western Anhui Province, and Edge area of the Yangtze River), the soil nutrient inputs from rice straw incorporation were N 38.0-50.8, P2O5 18.8-25.0, and K2O 151.6-202.3 kg/hm2, respectively. The finding can offer a great practical significance to improve the comprehensive utilization rate of straw resources, and further promote the green and high-quality development of agriculture for major grain-producing counties in Anhui Province of China.