Suppressive effects on weeds and dry matter yields of cover crops

Abstract: The objective of this work was to evaluate the dry matter yield of cover crops and their suppressive effects on weeds. The experiment was carried out during three years in a cerrado area of the state of Goiás, Brazil, and consisted of 16 treatments with fallow and cover crops cultivated in single cropping and intercropping. Fallow allowed high weed infestation. Cover crops affected the composition of weeds, which showed greater diversity in fallow, followed by the Pennisetum glaucum 'BRS 1501' and Cajanus cajan crops. In the average of the three experimental years, the highest dry matter yield was observed for the treatments Panicum maximum (10,857 kg ha-1), Urochloa brizantha 'Piatã' (11,437 kg ha-1), U. ruziziensis (9,463 kg ha-1), and U. ruziziensis intercropped with Crotalaria spectabilis (9,167 kg ha-1), which prevented weed infestation. Pennisetum glaucum 'BRS 1501' had a low dry matter yield (<5,000 kg ha-1) and did not suppress weeds. Panicum maximum, U. brizantha 'Piatã', U. ruziziensis, and U. ruziziensis intercropped with C. spectabilis provide high dry matter yield and suppress weed infestation in the cerrado area.

摘要：本研究旨在评估覆盖作物的干物质产量及其对杂草的抑制效果。实验于巴西戈亚斯州的塞拉多（cerrado）区域开展，历时三年，共设置16组处理，涵盖单作与间作模式下的休耕地及覆盖作物种植方案。休耕处理会引发严重的杂草侵染。覆盖作物会改变杂草群落组成，其中休耕地的杂草多样性最高，其次为珍珠粟（Pennisetum glaucum）‘BRS 1501’与木豆（Cajanus cajan）种植组。在三年实验的平均数据中，以下处理的干物质产量位居前列：大黍（Panicum maximum）（10857 kg·ha⁻¹）、布氏臂形草（Urochloa brizantha）‘Piatã’（11437 kg·ha⁻¹）、刚果臂形草（U. ruziziensis）（9463 kg·ha⁻¹），以及刚果臂形草与望江南（Crotalaria spectabilis）间作组合（9167 kg·ha⁻¹），上述处理均可有效抑制杂草侵染。珍珠粟‘BRS 1501’的干物质产量较低（<5000 kg·ha⁻¹），且无法起到杂草抑制作用。大黍、布氏臂形草‘Piatã’、刚果臂形草以及刚果臂形草与望江南间作组合，可在塞拉多区域实现较高干物质产量并抑制杂草侵染。