Abstract:

[Objective] This study aimed to clarify the effects of poplar-crop intercropping and fertilizer application on soil nutrients and plant growth. [Methods] A pot experiment was conducted to investigate soil nutrients and plant growth under three planting patterns: poplar (Populus deltoides) monoculture, wheat (Triticum aestivum)/soybean (Glycine max) monoculture, and poplar-wheat/soybean intercropping. Each planting pattern was subjected to three fertilizer application rates (10, 5, and 0 g of compound fertilizer per pot). [Results] Fertilizer application reduced soil pH by 0.1-0.4 units. Under the same planting pattern, the concentrations of soil nitrate nitrogen (NO₃⁻-N), available phosphorus (AP), and available potassium (AK) increased with increasing fertilizer application rate. In addition, at the same fertilizer application rate, soil AP and AK concentrations in the poplar monoculture and poplar-crop intercropping systems were more than 80% and 20% higher, respectively, than those in the wheat/soybean monoculture systems. In both monoculture and intercropping systems, crop yield and poplar growth were highest under the 10 g·pot⁻¹ fertilization treatment, followed by the 5 g·pot⁻¹ fertilization treatment, and lowest under the no-fertilization treatment. At the same fertilizer application rate, crop yield and poplar growth in the poplar-crop intercropping system were approximately 50% and 10% lower, respectively, than those in the corresponding crop and poplar monoculture systems. However, the land equivalent ratio of the poplar-crop intercropping system was greater than 1, indicating higher overall productivity than either poplar or crop monoculture. [Conclusion] Poplar planting promoted soil phosphorus activation and potassium release, thereby increasing soil AP and AK concentrations. Fertilizer application enhanced crop yield and poplar growth. The fertilizer requirement of the poplar-crop intercropping pattern was greater than that of either poplar or crop monoculture. Overall, poplar-crop intercropping was conducive to improving integrated land productivity.

Key words: agroforestry, poplar, intercropping, monoculture, fertilizer application, productivity

摘要：

【目的】为了解杨树与农作物复合经营以及施肥对土壤养分和植物生长的影响。【方法】采用盆栽控制试验研究了3种种植模式[杨树（Populus deltoides）单作、小麦（Triticum aestivum）/大豆（Glycine max）单作、杨农（杨树与小麦/杨树与大豆）间作]和3种施肥量（每盆分别施复合肥10、5、0 g）对土壤养分和植物生长的影响。【结果】施肥使土壤pH降低了0.1－0.4个单位；相同种植模式下的土壤硝态氮、有效磷和速效钾的质量分数均随施肥量的增加而增加；相同施肥量下，杨树单作和杨农间作的土壤有效磷和速效钾的质量分数比小麦/大豆单作分别提高了80%和20%以上。不论是单作还是间作，每盆施10 g肥料的作物产量和杨树生长量均最高，其次是每盆施5 g肥料，不施肥的最低；相同施肥量下，杨农间作的作物产量低于单作作物50%左右，杨农间作的杨树生长量低于单作杨树10%左右，但是杨农间作的土地当量比大于1，其综合生产力高于单作。【结论】种植杨树能促进土壤磷的活化和钾的释放，提高土壤有效磷和速效钾的质量分数，施肥能增加作物产量和杨树生长量，杨农间作对肥料的需求量大于杨树单作和作物单作，杨农间作有利于提高土地综合生产力。

关键词: 林农复合经营, 杨树, 间作, 单作, 施肥, 生产力