有机物料还田和减施氮肥对麦-玉周年农田碳氮水足迹及经济效益的影响

为研究不同有机物料还田与减施氮肥处理对农田碳氮水足迹及经济效益的影响，本试验以单施化肥处理（CK，纯氮270kg·hm^-2）为对照，设置了秸秆（J）、秸秆+牛粪（JF）、秸秆+菌渣（JZ）3种有机物料还田方式，耦合减施氮肥10%（N1，243 kg·hm^-2）、20%（N2，216 kg·hm^-2）、30%（N3，189 kg·hm^-2）3个施氮水平，共计10个处理。结果表明：与单施化肥相比，有机物料还田与减施氮肥处理能够显著提高作物产量及农田经济效益，且JZN1、JN2和JFN3处理对农田经济效益的提高效果最显著；JN1、JN2、JFN2、JFN3和JZN3处理均可以有效增加农田的净碳值及碳效率，降低农田的生产氮足迹，增加其输出氮足迹，提高氮投入有效利用水平，同时降低农田水足迹。其中JFN3处理可以在保证农田经济效益的同时，显著提高其碳效率、降低生产氮足迹、提高氮投入有效利用水平、降低农田的水足迹。因此建议豫北地区采用秸秆+牛粪还田、配施纯氮189 kg·hm^-2的施肥方式。

Effects of organic material returning and nitrogen fertilizer reduction on the economic yields and carbon, nitrogen, and water footprints of wheat-maize annual farmland in China

The aim of the present study was to investigate the effects of returning different organic materials to agricultural fields and reducing nitrogen fertilizer application on the carbon, nitrogen, water footprints and economic yields of farmland in northern Henan, China. Conventional single nitrogen fertilizer was used as control (270 kg·hm^-2), and three types of organic materials (straw, straw+manure, straw+ mushroom dregs) were used to amend fields under various nitrogen fertilizer regimes (90%, 80%, or 70% of the control treatment). Compared with a single application of chemical fertilizer, returning organic materials to the field and reducing the amount of nitrogen fertilizer significantly improved crop yield and economic benefits, with the straw+mushroom dregs+90% fertilizer, straw+80% fertilizer, and straw+ manure+70% fertilizer treatment providing the greatest economic benefits. The net carbon value, carbon efficiency, nitrogen output, and nitrogen input efficiency were increased significantly by the straw+90% fertilizer, straw+80% fertilizer, straw+manure+80% fertilizer, straw+ manure+70% fertilizer and straw+mushroom dregs+70% fertilizer treatments, whereas the nitrogen and water footprints were reduced. Because the straw+manure+70% fertilizer treatment significantly improved both carbon and nitrogen input efficiency and reduced the production nitrogen and water footprints of the experimental farmland while also optimizing economic yield, the results of present study suggest that straw and cattle manure should be returned to farmland in northern Henan and that nitrogen fertilizer application should be simultaneously reduced by 30%.