Growth suppression of sandspur grass by cover crops1

ABSTRACTSandspur grass has hindered the integrated weed management in the Brazilian crop systems. This study aimed at evaluating the efficiency of biomass levels of different cover crops on the soil surface to control the sandspur grass. A complete randomized blocks design with four replications, in a 6 x 5 + 1 factorial arrangement, was used. The first factor consisted of six cover crops (Pennisetum glaucum-ADR 7010 and ADR 300 cultivars, Crotalaria ochroleuca, Urochloa ruziziensis, Fagopyrum tataricum and Crambe abyssinica) and the second one consisted of five biomass levels of each species (2 t ha-1, 4 t ha-1, 8 t ha-1, 12 t ha-1 and 16 t ha-1), plus a control treatment without soil cover. The variables analyzed were the total number of emerged plants, germination speed index, leaf area, root volume and shoot and root dry biomass. U. ruziziensis excelled in the suppression of C. echinatus growth by reducing the number of emerged plants, emergence speed index, shoot and root dry biomass, root volume and leaf area.

摘要：蒺藜草（sandspur grass）已成为巴西作物系统杂草综合管理的主要障碍。本研究旨在评估不同覆盖作物的地表生物量水平对蒺藜草的防控效果。实验采用完全随机区组设计，设置4次重复，采用6×5+1因子排列方案。第一因子包含6种覆盖作物：御谷（Pennisetum glaucum，品种ADR 7010与ADR 300）、浅黄猪屎豆（Crotalaria ochroleuca）、鲁兹臂形草（Urochloa ruziziensis）、鞑靼荞麦（Fagopyrum tataricum）以及阿比西尼亚荠蓝（Crambe abyssinica）；第二因子为各供试物种的5种生物量水平：2 t·ha⁻¹、4 t·ha⁻¹、8 t·ha⁻¹、12 t·ha⁻¹与16 t·ha⁻¹，另设1组无土壤覆盖的空白对照处理。本研究测定的指标包括总出苗株数、发芽速度指数、叶面积、根体积以及地上部与地下部干生物量。结果表明，鲁兹臂形草（Urochloa ruziziensis）对刺蒺藜草（C. echinatus）的生长抑制效果最优，可显著降低其出苗株数、出苗速度指数、地上部与地下部干生物量、根体积及叶面积。