Periods of coexistence of weeds with carrot grown with and without black oat straw

Abstract The objective of this work was to evaluate the effect of black oat (Avena strigosa) straw on the period prior to the interference (PPI) of weeds in the 'Alvorada' carrot (Daucus carota) crop. The experiment was carried out in a randomized complete block design, in a 2×5 factorial arrangement, with five replicates. The following two factors were evaluated in the 2016/2017 and 2017/2018 crop years: soil cover, with and without 10 Mg ha1 black oat straw; and periods of coexistence with weeds – 0, 15, 30, 60, and 120 days after emergence (DAE). To determine the PPI, a loss of 5% in the commercial yield of carrot roots was considered as acceptable. At the end of the crop cycle, straw reduced the total dry mass of weeds by 43.5 and 67.5%, respectively, in the first and second crop years. The PPI of the crops with and without straw was, respectively, 2.0 and 1.5 DAE in the first crop year and 17 and 6.0 DAE in the second. The use of black oat straw increases the PPI for the 'Alvorada' carrot crop.

摘要：本研究旨在探究黑燕麦（*Avena strigosa*）秸秆对‘阿尔沃拉达’（Alvorada）胡萝卜（*Daucus carota*）田杂草干扰前时期（period prior to the interference, PPI）的影响。试验采用完全随机区组设计，设置2×5析因组合，共5次重复。在2016/2017与2017/2018两个种植季中，共评估两类试验因素：其一为土壤覆盖处理，设置施加10 Mg·ha⁻¹黑燕麦秸秆与不施加秸秆两个水平；其二为杂草共存时长，即出苗后天数（days after emergence, DAE）分别为0、15、30、60和120天。本研究以胡萝卜商品根产量损失5%作为可接受阈值，以此计算PPI。在作物生育周期结束时，秸秆覆盖分别使两个种植季的杂草总干重降低43.5%与67.5%。施加与未施加秸秆的处理组，其PPI在首个种植季分别为2.0 DAE和1.5 DAE，在第二个种植季则分别为17 DAE和6.0 DAE。施用黑燕麦秸秆可延长‘阿尔沃拉达’胡萝卜田的杂草干扰前时期。