河南省小麦玉米秸秆资源测算与养分还田利用潜力分析

Spatial distribution of wheat and maize straw resources and nutrient utilization potential under straw return in Henan Province

河南省为我国小麦和玉米主产区,明晰其主粮作物秸秆资源的市域尺度空间分布格局及秸秆还田情景下的化肥可替代量,可为秸秆综合利用政策制定及农田养分管理方案优化提供参考依据。本研究基于2018—2020年河南省18个地级市的小麦、玉米播种面积和产量,根据文献调研获得的作物草谷比及秸秆养分含量等参数,测算各地级市小麦、玉米秸秆产量和单位面积可收集量,并分析秸秆还田替代化肥的潜力。结果表明:2018—2020年河南省小麦和玉米秸秆年均产量分别为4168.5万t和1944.3万t,在市级尺度上,小麦秸秆产量较高的地市依次为周口(611.3万t)、驻马店(579.2万t)、商丘(493.7万t)和南阳(470.6万t),其总占比为51.7%;四市的玉米秸秆产量也居于前列,分别为284.0万、216.9万、235.3万t和196.6万t,总占比为48.0%。郑州、鹤壁、三门峡、济源的小麦和玉米秸秆产量均较低,四市的总占比分别仅为5.0%和7.1%。河南省小麦秸秆N、P2O5、K2O养分年均资源量分别为19.8万、7.3万、72.5万t,玉米秸秆N、P2O5、K2O养分资源量分别为14.4万、5.7万、31.6万t。小麦秸秆还田当季的N、P2O5、K2O养分可替代量分别为17.8、8.3、118.3 kg·hm^(-2),玉米秸秆还田当季养分可替代量分别为23.7、11.0、77.7 kg·hm^(-2)。研究表明,河南省小麦、玉米秸秆资源丰富,但空间分布不均衡,应以秸秆主产市为重点,高质高效推进秸秆全量化利用,秸秆养分还田具有可观的化肥替代潜力,可通过秸秆科学还田实现化肥合理减量。

Henan is the main wheat and maize production province in China.Clarifying the spatial distribution pattern of straw resources from staple crops at the municipal level and evaluating the potential of replacing chemical fertilizer under straw return could offer important references for the optimization of comprehensive straw utilization policies and farmland nutrient management measures.Based on the sown area and yield of wheat and maize of 18 cities in the Henan Province from 2018 to 2020,the quantity of major crops straw resources,collectable straw per unit sown area,and chemical fertilizer reduction potential under straw return were estimated using straw/grain ratio and nutrients content of straw collected from relevant literature.The annual outputs of wheat and maize straw were 41.685 millions and 19.443 million tons in the Henan Province during 2018—2020,respectively.At the municipal level,the wheat and maize straw resources were mainly distributed in Zhoukou(6.113 million and 2.840 million tons),Zhumadian(5.792 million and 2.169 million tons),Shangqiu(4.937 million and 2.353 million tons),and Nanyang(4.706 million and 1.966 million tons).The wheat and maize straw yields of these cities accounted for 51.7%and 48.0%,respectively.However,the total proportions of wheat and maize straw outputs from Zhengzhou,Hebi,Sanmenxia,and Jiyuan were only 5.0%and 7.1%,respectively.The amounts of nutrients from wheat straw were 0.198 million tons of N,0.073 million tons of P2O5,and 0.725 million tons of K2O in the Henan Province.The outputs of nutrients from maize straw were 0.144 million tons of N,0.057 million tons of P2O5,and 0.316 million tons of K2O.The substituting potentials of N,P2O5,and K2O through wheat straw return in the Henan Province was 17.8,8.3 kg·hm^(-2),and 118.3 kg·hm^(-2),respectively.Moreover,maize straw incorporation could substitute synthetic fertilizers of N 23.7,P2O511.0 kg·hm^(-2),and K2O 77.7 kg·hm^(-2)theoretically.The results indicate that wheat and maize straw resources are abundant in the Henan Province;however,the spatial distribution of straws is unbalanced at the city scale.The main straw-producing cities should be emphasized to promote the full quantitative utilization of straws with high quality and efficiency.Moreover,returning wheat and maize straw to the field could provide a feasible pathway for rational replacement and reduction of chemical fertilizer usage.