Intercropping pasture with grain crops provides a strategy for diversifying cropping systems and establishing a foundation for mixed crop-livestock farming systems. Investigating the effects of strip design and nitrogen (N) application on interspecific interaction, crop yield, N use efficiency (NUE), and land equivalent ratio (LER) in dryland wheat/alfalfa intercropping. We conducted a four-year field experiment, which tested three intercrops, namely, 2-row wheat with 1-row alfalfa (I21), 4-row wheat with 2-row alfalfa (I42), and 8-row wheat with 4-row alfalfa (I84), as well as sole wheat (SW) and alfalfa (SA). N rates of 150 (HN) and 75 kg ha (LN) were applied for wheat. Winter wheat exhibited earlier spring green-up than alfalfa and maintained dominance during co-growth. Over the four seasons, I21, I42, and I84 resulted in wheat yield (based on the wheat strip area) increases of 19.0%, 16.7%, and 24.0%, respectively, under HN, and 34.1%, 31.9%, and 43.4% under LN. Alfalfa growth was constrained during co-growth but recovered after the wheat harvest. Alfalfa in I42 and I84 maintained forage yield (based on the alfalfa strip area) as high as SA. Intercropping increased wheat NUE under both N conditions but did not significantly affect alfalfa NUE. I84 attained the highest LER of 1.01–1.14 and 1.11–1.25 under HN and LN respectively. Net revenue of I84 was lower than SA but three times higher than SW. Wide-strip wheat/alfalfa intercrop with low-N showed the best performance, which is promising in diversifying farming system and improving agricultural sustainability.

中文翻译：

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旱地小麦/苜蓿条带间作的种间相互作用和生产力

牧草与粮食作物间作提供了种植系统多样化的策略，并为混合种植业和畜牧业系统奠定了基础。研究旱地小麦/苜蓿间作中带状设计和施氮（N）对种间相互作用、作物产量、氮利用效率（NUE）和土地当量比（LER）的影响。我们进行了四年的田间试验，试验了三种间作，即2行小麦配1行苜蓿（I21）、4行小麦配2行苜蓿（I42）和8行小麦配4行苜蓿。行苜蓿 (I84)、以及独麦 (SW) 和苜蓿 (SA)。小麦施氮量为 150 kg ha (HN) 和 75 kg ha (LN)。冬小麦比苜蓿早春返青，并在共同生长过程中保持优势。四个季节中，I21、I42和I84导致小麦单产（以麦带面积计）分别比HN增加19.0%、16.7%和24.0%，在HN下分别增加34.1%、31.9%和43.4%在 LN 下。紫花苜蓿的生长在共生期间受到限制，但在小麦收获后恢复。 I42 和 I84 中的苜蓿保持了与 SA 一样高的草料产量（基于苜蓿条带面积）。间作在两种氮肥条件下均增加了小麦的 NUE，但并未显着影响苜蓿的 NUE。 I84 在 HN 和 LN 下分别达到最高的 LER 1.01-1.14 和 1.11-1.25。 I84的净收入低于SA，但高于SW的三倍。低氮宽条小麦/苜蓿间作表现最好，在农业体系多样化和提高农业可持续性方面具有广阔的前景。