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）已对巴西农田系统的杂草综合防控造成阻碍。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能。试验采用完全随机区组设计，设置4次重复，采用6×5+1的因子排布方案。第一因子包含6种覆盖作物：御谷（Pennisetum glaucum）的ADR 7010与ADR 300品种、黄花野百合（Crotalaria ochroleuca）、鲁兹臂形草（Urochloa ruziziensis）、苦荞麦（Fagopyrum tataricum）以及海甘蓝（Crambe abyssinica）；第二因子为各覆盖作物的5个生物量水平：2 t·ha⁻¹、4 t·ha⁻¹、8 t·ha⁻¹、12 t·ha⁻¹与16 t·ha⁻¹，外加1组无土壤覆盖的对照处理。测定指标包括总出苗数、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，鲁兹臂形草可通过降低总出苗数、出苗速度指数、地上地下干生物量、根体积与叶面积，对蒺藜草的生长实现最优抑制效果。