秸秆和有机肥配合替代部分化肥提高作物水分利用率减少土壤硝态氮残留

赵凯男; 吴金芝; 李俊红; 田文仲; 张洁; 李芳; 侯园泉; 张振旺; 姚宇卿; 吕军杰; 黄明; 李友军

doi:10.11674/zwyf.2022051

秸秆和有机肥配合替代部分化肥提高作物水分利用率减少土壤硝态氮残留

Effects of combined straw and organic fertilizer application as partial replacement for chemical fertilizers on water use efficiency and soil nitrate residue

摘要

摘要:
目的研究长期秸秆和有机肥配合替代部分化肥对小麦玉米一年两熟种植制度下农田生产力及氮肥残留的影响，为改善旱地土壤肥力，提高作物产量，降低环境风险提供科学依据。
方法依托中国农业科学院洛阳旱农试验基地始于2007年的长期定位培肥试验，选取不施肥对照 (CK)、常规氮磷钾化肥 (NPK)、秸秆和有机肥配合替代1/3的氮磷钾养分 (SOR) 3个处理。调查了2015—2020年度夏玉米、冬小麦及周年产量、生育期耗水量、水分利用效率；分析了2020年冬小麦收获期0—60 cm土层土壤养分含量，以及硝态氮在0—380 cm土层剖面的分布积累量。
结果与2007年试验开始时相比，2020年CK处理0—20 cm土层土壤养分(除速效钾外)含量显著下降，而NPK和SOR处理不同程度地提高了土壤养分含量。与NPK处理相比，SOR处理0—60 cm土层土壤有机质含量显著提高了10.4%～16.4%，0—40 cm土层全氮含量显著提高了16.7%～20.0%，0—20 cm土层土壤速效磷和速效钾含量分别显著提高了12.9%和15.4%。与NPK处理相比，SOR处理夏玉米产量在干旱年 (2015和2017年) 及5年平均分别显著提高了35.3%和10.1%，水分利用效率在干旱年、平水年 (2016年) 及5年均值分别显著提高了42.7%、12.3%和18.5%，周年产量和水分利用效率在干旱年分别显著提高了20.5%和23.5%；冬小麦产量在不同降水年型下均未显著降低，但水分利用效率在平水年 (2015—2016、2016—2017、2019—2020) 及5年均值较NPK处理分别显著降低了9.8%和7.9%。NPK处理的硝态氮总累积量为732 kg/hm²，其中68.2%积累在100—230 cm土层；SOR处理的硝态氮总累积量为833 kg/hm²，其中74.8%积累在80—200 cm土层。与NPK处理相比，SOR处理显著降低了200—380 cm土层土壤硝态氮积累量，在200—230、260—290、320—350和350—380 cm土层分别显著降低了54.9%、21.1%、25.0%、57.9%。
结论无论降雨多寡，秸秆和有机肥配合替代1/3氮磷钾肥均未降低冬小麦产量，但显著提高了干旱年夏玉米及周年产量及水分利用效率，并提高了0—60 cm土层土壤有机质和全氮含量，提高了0—20 cm土层土壤速效磷和速效钾含量，同时较常规氮磷钾处理显著降低了200—380 cm土层土壤硝态氮积累量，是旱作麦玉两熟区兼顾产量、效率和环境的施肥模式。

Abstract:
Objectives We studied the effects of combined straw and organic fertilizer application as replacement for partial chemical fertilizer on crop yield, water use efficiency and soil NO₃^––N residue to improve soil fertility and reducing environmental risks in dryland.
Methods A long-term field experiment was conducted at the Luoyang Dry Farming Experimental Station of Chinese Academy of Agricultural Sciences, Henan Province, since 2007. The tested treatments included no fertilizer control (CK), NPK fertilizer (NPK), and replacing 1/3 of NPK input with straw and organic fertilizer (SOR). The yield, water consumption of winter wheat and summer maize were investigated from 2015 to 2020. The soil nutrient content in the 0–60 cm soil layer and nitrate-N content in the 0–380 cm soil profile were analyzed after the harvest of winter wheat in 2020.
Results Compared to 2007, CK treatment significantly decreased 0–20 cm soil nutrient content, except readily available K, while NPK and SOR treatments improved soil nutrient content in 2020. Compared to NPK, SOR treatment increased organic matter content in 0–60 cm soil layer by 10.4%–16.4%, total N in 0–40 cm soil layer by 16.7%–20.0%, available P and readily available K in 0–20 cm soil layer by 12.9% and 15.4%, respectively (P<0.05). Compared to NPK, SOR treatment increased maize yield by 35.3% in drought years (2015 and 2017) and by 10.1% on average of 5-years; enhanced maize water use efficiency by 42.7%, 12.3% and 18.5% in dry years, normal year (2016) and 5-year on average; and increased the annual yield and water use efficiency by 20.5% and 23.5% in the dry years on average. However, SOR treatment did not significantly change the yield of winter wheat across the 5-years, but significantly reduced the water use efficiency by 9.8% in the normal years (2015—2016, 2016—2017, 2019—2020) and by 7.9% on average of 5-years. The NO₃^––N residue in NPK treatment was 732 kg/hm² and 68.2% was retained in 100–230 cm soil profile, while the NO₃^––N residue in SOR treatment was 833 kg/hm² and 74.8% stayed in 80–200 cm soil profile. Compared with NPK, SOR treatment decreased NO₃^––N residue by 54.9% in 200–230 cm, by 21.1% in 260–290 cm, by 25.0% in 320–350 cm, and by 57.9% in 350–380 cm soil layer.
Conclusions Replacing 1/3 of NPK fertilizer by combined straw and organic fertilizer application did not impact the yield of winter wheat, but significantly increased the yield and water use efficiency of summer maize, and thus increased the annual yield and water use efficiencies. Straw and organic fertilizer application together enhanced the soil organic matter and total N in the 0–60 cm layer, available P and readily available K in 0–20 cm layer, significantly decreased the nitrate-N residue in 200–380 cm soil layer.

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