摘要
摘要:利用长期施肥定位试验开展土壤-作物系统的可持续性评价，可为农田合理施肥和管理提供理论支撑。在黄土丘陵区栗褐土农田进行了26年长期肥料定位试验，设置8个处理，分别是不施肥（CK）、单施氮肥[120.0 kg（N）·hm^-2，N]、氮[120.0 kg（N）·hm^-2]和磷[75 kg（P₂O₅）·hm^-2]肥配施（NP）、单施低量有机肥（22 500 kg·hm^-2，M₁）、低量有机肥与氮肥配合施用（M₁N）、低量有机肥与氮磷肥配合施用（M₁NP）、高量有机肥（45 000 kg·hm^-2）与氮肥配合施用（M₂N）和高量有机肥与氮磷肥配合施用（M₂NP）。测定了19项指标，根据三角性面积法计算了土壤养分指数、土壤微生物指数、作物指数和可持续性指数，分析讨论了长期施肥对栗褐土区土壤-作物系统可持续性的影响。结果表明：1）N、M₁处理的可持续性指数较CK分别提高27.1%、141.7%，但较临界值（1.30）低53.1%和10.8%；NP处理的可持续性指数虽然较N处理提高62.3%，但仍比临界值（1.30）低23.8%。说明长期单施氮肥、低量有机肥和氮磷配施下土壤-作物系统均不可持续。2）施用无机肥处理（N和NP）的土壤养分指数、土壤微生物指数和作物指数较CK提高7.1%和46.4%、-6.0%和25.4%、40.0%和60.0%；单施低量有机肥（M₁）的土壤养分指数、土壤微生物指数和作物指数较CK提高98.2%、41.8%和31.7%。说明施用无机肥有利于作物指数的提升，而施用有机肥有利于土壤养分指数和土壤微生物指数的提升。3）M₁N处理的土壤养分指数（1.06）、土壤微生物指数（1.04）、作物指数（1.00）和可持续性指数（1.38）均超过或等于临界值，使土壤-作物系统具有较好的可持续性。4）M₁NP、M₂N、M₂NP处理的土壤养分指数较M₁N处理分别提高21.7%、37.7%和72.6%，土壤微生物指数较M₁N处理分别提高15.4%、7.7%和18.3%，作物指数与M₁N处理相比差异很小，可持续性指数较M₁N处理分别提高28.3%、32.6%和68.1%。说明在M₁N基础上再增施磷肥或有机肥，可持续性指数可进一步提升是由于土壤养分指数和土壤微生物指数提高的缘故，同时也增加了潜在的环境风险。适量有机肥与无机氮配合施用（M₁N）是实现栗褐土区土壤-作物系统可持续生产的较佳施肥模式。
关键词:土壤-作物系统/
长期施肥/
栗褐土/
可持续性指数/
土壤养分指数/
土壤微生物指数/
作物指数
Abstract:The sustainability of soil-crop systems was evaluated based on a long-term fertilization experiment to provide theoretical support for farmland fertilization and management. The long-term fertilizer experiment consisting of 8 treatments and a CK was carried out in the Chestnut Cinnamon soil of loess hilly-gully region for 26 years. The treatments included:non-fertilization (CK), 120.0 kg(N)·hm^-2 urea (N), 120.0 kg(N)·hm^-2 urea + 75 kg(P₂O₅)·hm^-2 calcium superphosphate (NP), 22 500 kg·hm^-2 organic fertilizer (M₁), M₁ + N (M₁N), M₁ + NP (M₁NP), 45 000 kg·hm^-2 organic fertilizer + 120.0 kg(N)·hm^-2 urea (M₂N) and M₂ + NP (M₂NP). A total of 19 indicators of the soil-crop system were measured, and soil nutrient index, soil microbial index, crop index and sustainability index were calculated by the triangle area method. The effects of long-term fertilization on the sustainability of soil-crop systems in the Chestnut Cinnamon soil region were discussed. The results indicated that:1) the sustainability indexes of N and M₁ treatments increased respectively by 27.1% and 141.7% compared with CK, but were 53.1% and 10.8% lower than the critical value (1.30). Although the sustainability index of NP treatment was 62.3% higher than N treatment, it was 23.8% lower than the critical value (1.30). This indicated that soil-crop systems under long-term application of single nitrogen, or low organic fertilizer or nitrogen and phosphorus were all unsustainable. 2) Nutrient index, microbial index and crop index of inorganic fertilizer (N, NP) treatments increased respectively by 7.1% and 46.4%, -6.0% and 25.4%, 40.0% and 60.0% compared with CK. Nutrient index, microbial index and crop index of single application of organic fertilizer (M₁) were respectively 98.2%, 41.8% and 31.7% higher than those of CK, showing inorganic fertilizer application improved crop index, organic fertilizer application improved nutrient index and microbial index. 3) Soil nutrient index (1.06), soil microbial index (1.04), crop index (1.00) and sustainability index (1.38) of M₁N all exceeded or equaled the critical value, which was good for the sustainability of soil-crop systems. 4) Soil nutrient indexes of M₁NP, M₂N and M₂NP increased respectively by 21.7%, 37.7% and 72.6% compared with M₁N, and the corresponding soil microbial index increased by 15.4%, 7.7% and 18.3% over M₁N. There were small differences in crop indexes of the above treatments, compared with M₁N. Sustainability indexes of the above treatments increased respectively by 28.3%, 32.6% and 68.1% compared with M₁N. The results indicated that increasing application of phosphorus or organic fertilizer over M₁N further enhanced sustainability index because of enhanced soil nutrient index and microbial index, but also increased potential environmental risk. A combination of moderate amounts of organic and inorganic N application (M₁N) was a comparatively better fertilization model, which ensured sustainable production of soil-crop systems in Chestnut Cinnamon soil region.
Key words:Soil-crop system/
Long-term fertilization/
Chestnut Cinnamon soil/
Sustainability index/
Soil nutrient index/
Soil microbial index/
Crop index



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