基于养分专家系统推荐施肥在东北玉米上的长期综合效应

为明确养分专家系统推荐施肥对东北玉米产量与收益、肥料利用率与土壤养分的长期综合效应，于2012-2020年开展了田间定位试验，共设置5处理：分别为1）不施肥（CK）；2）农民习惯施肥（FP）；3）养分专家系统推荐施肥（NE）；4）在NE基础上配施缓/控释氮肥（NER）；5）土壤测试推荐施肥（ST）。探究9 a 产量与收益、肥料利用率、土壤养分和养分平衡的变化规律。结果表明，NE和ST处理较FP处理显著降低了氮磷肥用量（P<0.05），显著增加了钾肥用量（P<0.05）。与FP处理相比，NE、NER和ST处理提高了玉米产量、收益及其稳定性。其中均以NE处理最高，之后依次为ST和NER处理。NE、NER和ST处理肥料平均回收利用率、农学利用率和偏生产力较FP处理分别提高了29.0%～40.1%（P<0.05）、31.3%～44.3%（P<0.05）和22.0%～31.7%（P<0.05），且均以NE处理最高。与FP处理相比，NE、NER和ST处理提高了0～30 cm土壤无机氮含量，降低了30～90 cm土壤无机氮和0～30 cm土壤有效磷含量，而不同施肥处理土壤速效钾含量差异未达显著水平（P>0.05），其中NE处理与试验起始养分含量最为接近。9 a养分平衡结果显示，FP、NE、NER和ST处理氮、磷均表现为盈余，而钾素表现为亏缺，且NE处理氮、磷盈余量和钾亏缺量均为最低。综上，与农民习惯施肥和土壤测试推荐施肥相比，养分专家系统推荐施肥不仅可提高玉米产量、收益和肥料利用效率，并可保持土壤养分稳定。因此，它是一种适用于中国东北玉米的推荐施肥方法。

Long-term comprehensive effects of recommended fertilization based on nutrient expert system of maize in Northeast China

A long-term site-specific experiment of fertilizer recommendation from 2012 to 2020 was conducted to evaluate the comprehensive effects of nutrient expert decision support system on yield, benefit, fertilizer use efficiency, and soil nutrient of spring maize in northeast China. Five treatments included no-fertilizer (CK) as the control, currently traditional farmers'' practices (FP), fertilizer recommended using a nutrient expert system (NE), slow/controlled-release nitrogen fertilizer using the same rate as NE treatment (NER), and conventional fertilizer recommendation using soil testing (ST). The current study also investigated the long-term changes of maize yield, benefit, fertilizer use efficiency, the contents of inorganic N, available P, and available K in the soil, as well as the balance of nutrient input/output during the nine-year period. The results showed that the maximum, minimum, or mean values of fertilizer inputs in NE, NER, and ST treatments were all significantly lower than that of FP treatment (P<0.05), respectively. In different nutrients, NE, NER and ST treatments significantly reduced the amounts of nitrogen (N) and phosphorus (P) fertilizers application (P<0.05), but significantly increased the amount of potassium (K) fertilizer application (P<0.05), compared with that of FP treatment, respectively. Compared with FP treatment, NE, NER, and ST treatments significantly improved the stability of maize yield and net income, where increased by 5.6%-11.0% and 8.3%-14.3%, respectively. The NE treatment achieved the highest value, followed by ST and NER treatment. The recovery efficiency, agronomic efficiency, and partial factor productivity in the NE, NER, and ST treatments were significantly higher than those in FP treatment, where increased by 29.0%-40.1%, 31.3%-44.3%, and 22.0%-31.7%, respectively. Specifically, the highest value was observed in NE treatment, followed by NER and ST treatments. Compared with FP treatment, NE, NER and ST treatments significantly improved the inorganic N content in 0-30 cm soil layer (P<0.05), but significantly reduced inorganic N content in 30-90 cm soil layer (P<0.05) and available P content in 0-30 cm soil layer (P<0.05). But the soil available K content wasn''t significantly different (P>0.05) among different fertilization treatments. The contents of soil inorganic N, available P, and available K in NE treatment were close to the initial testing values before planting. The nutrient input/output balance was obtained during the nine-year period, where the N and P balances were surplus under all fertilization treatments, whereas, the K balance was deficient. But the surplus of N, P, and the deficiency of K in NE treatment attained the lowest values, followed by NER and ST treatments. In conclusion, compared with farmers'' practices and the conventional fertilizer recommendation system, the NE fertilization recommendation system fully met the nutrient requirements of maize, with optimal fertilization rate, time, and ratio. Consequently, the NE fertilization recommendation system has the potential to improve maize yield, benefits, and fertilizer use efficiency, thereby maintaining the soil nutrient stability under the reduction of fertilizer application amount, compared with farmers'' practices. However, the simplified fertilization of slow/controlled-release nitrogen fertilizer in the NE fertilization recommendation system also obtained higher benefits, but reduced labor cost. Therefore, the NE system is an appropriate fertilizer recommendation for maize in northeast China.