The goal of this study was to evaluate the effects of thinning eucalyptus trees on yield and nutritive value of corn for silage and palisadegrass in a crop–livestock–forest integrated system and to evaluate the total aboveground biomass yield in systems with and without trees. Plant variables, as well as the incidence of photosynthetically active radiation (PAR) and soil moisture, were evaluated between October 2016 and March 2018 in São Carlos, Brazil, in a crop–livestock–forest and a crop–livestock system. In the crop–livestock–forest system, eucalyptus trees (Eucalyptus urograndis clone GG100) were planted in April 2011, in single rows, with 15 × 2 m spacing. In 2016, the trees were thinned, and the spacing was changed to 15 × 4 m. The treatments comprised measurements at 0.00, 3.75, 7.50, and 11.25 m from the trees of the North row in the integrated crop–livestock–forest (iCLF) system and integrated crop–livestock (iCL) system. Palisadegrass (Urochloa brizantha) was sown after harvesting the corn. Corn yields were similar between treatments, with an average of 13.6 Mg ha−1. Corn for silage presented a higher percentage of grain in total biomass in the crop–livestock–forest positions (41.4 and 42.1%) than in the crop–livestock system (35.6%). No differences in forage accumulation were observed. Crude protein content in corn for silage and palisadegrass was higher in the crop–livestock–forest treatments than in the crop–livestock system. Such results indicate that thinning was favorable to production in the crop–livestock–forest system. Total aboveground biomass yield was higher in the iCLF system, indicating better land use for this type of integrated system.

中文翻译：

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通过疏伐桉树来减少作物-牲畜-森林综合系统中的竞争

本研究的目的是评估在作物-牲畜-森林综合系统中桉树间伐对青贮和栅栏草的玉米产量和营养价值的影响，并评估有树和无树系统的地上总生物量产量。2016 年 10 月至 2018 年 3 月期间，在巴西圣卡洛斯的作物-牲畜-森林和作物-牲畜系统中评估了植物变量以及光合有效辐射 (PAR) 和土壤水分的发生率。在农牧林系统中，桉树（桉树GG100 克隆）于 2011 年 4 月种植，单行，行距 15 × 2 m。2016年树木间伐，间距改为15×4米。处理包括在作物-牲畜-森林综合 (iCLF) 系统和作物-牲畜综合 (iCL) 系统中距离北行树木 0.00、3.75、7.50 和 11.25 m 处的测量值。栅栏草 (牛尾草) 是在收获玉米后播种的。处理之间的玉米产量相似，平均为 13.6 毫克/公顷-1. 用于青贮的玉米在作物-牲畜-森林位置（41.4% 和 42.1%）中的谷物占总生物量的百分比高于作物-牲畜系统（35.6%）。没有观察到草料积累的差异。作物-牲畜-森林处理中用于青贮饲料和栅栏草的玉米粗蛋白含量高于作物-牲畜系统。这些结果表明间伐有利于作物-牲畜-森林系统的生产。iCLF 系统的地上总生物量产量较高，表明这种集成系统的土地利用更好。