ABSTRACT

The objective of this project was to investigate if integrating cover crops into the lettuce (Lactuca sativa L.) production can control weeds and improve various components of soil health. A two-year field study was conducted at the research farm of the University of Mohaghegh Ardabili, Ardabil, Iran, during the 2017 and 2018 growing seasons. In this study, we used monoculture, two-way, and a three-way mixture of barley, chickling pea, and buckwheat cover crops and no cover crop (local weeds). Sole barley cover crop produced the highest biomass in both growing seasons. The barley and buckwheat mixture in 2017 and barley and chickling pea in 2018 were most efficient in suppressing weeds. The dominant weeds included lambsquarters, redwood pigweed, and charlock mustard. Although the number of earthworms was more in the sole barley plots, the microbial population was highest in the three-way cover crop mixture. Soil carbon improved in the three-way cover crops by 12%; however, the differences amongst cover crop treatments were not statistically significant. Bulk density was reduced by 13% and water infiltration rate reduced by half averaged across cover crop treatments compared to no cover crop. Lettuce fresh weight increased in all cover crop treatments; however, a mixture of chickling pea and buckwheat cover crop improved the yield of lettuce by 17.8%, compared with the no cover crop.

摘要

该项目的目的是研究是否将覆盖作物整合到生菜中（Lactuca sativaL.）生产可以控制杂草并改善土壤健康的各个组成部分。在2017年和2018年生长季节，在伊朗阿尔达比勒的Mohaghegh Ardabili大学的研究农场进行了为期两年的实地研究。在本研究中，我们使用了大麦，鹰嘴豆和荞麦覆盖作物而没有覆盖作物（当地杂草）的单向，双向和三向混合物。大麦覆盖作物在两个生长季节中产生的生物量最高。2017年的大麦和荞麦混合物以及2018年的大麦和雏豌豆对抑制杂草最有效。优势杂草包括羊腿，红木杂草和夏洛克芥末。尽管在唯一的大麦田中worm的数量更多，但在三向覆盖作物混合物中微生物种群最高。三元覆盖作物的土壤碳含量提高了12％；然而，覆盖作物处理之间的差异在统计学上并不显着。与无遮盖作物相比，遮盖作物处理的平均容重降低了13％，水分渗透率平均降低了一半。在所有覆盖作物处理中，生菜鲜重增加；然而，与无盖作物相比，鹰嘴豆和荞麦覆盖作物的混合物使生菜的产量提高了17.8％。