Pre-harvest desiccation in biomass sorghum with herbicides

ABSTRACT The purpose of this study was to assess the effect of different herbicide treatments on moisture removal and calorific power of biomass sorghum for co-generation of electric energy through burning. The experiment was conducted in randomized complete block design with four replicates per treatment and a 6x4 factorial scheme (six herbicide treatments x four intervals between spraying and harvesting). The herbicide treatments were: two different doses of glyphosate (1.92 kg a.i. ha-1 and 3.84 Kg a.i. ha-1), paraquat (0.4 Kg a.i. ha-1), a commercial mixture of paraquat + diuron (0.6 + 0.3 Kg a.i. ha-1), glufosinate-ammonium (0.8 Kg a.i. ha-1) and control (unsprayed). The intervals between spraying and harvesting assessed were 7, 14, 21 and 28 days after desiccation (DAD). It was assessed: the number of leaves per plant, moisture content of leaves, panicles, culm and whole ground plants and Superior Calorific Power (SCP). The herbicides paraquat and paraquat + diuron promotes defoliation, after 14 DAD. Glyphosate, paraquat, paraquat + diuron and glufosinate-ammonium reduce leaf and panicle moisture, despite only glyphosate reduces moisture in the culm. The herbicides do not affect the SCP of biomass sorghum. Therefore, the herbicides, especially glyphosate, have high potential for pre-harvest desiccation in biomass sorghum.

摘要 本研究旨在评估不同除草剂处理对用于燃烧发电联产的生物质高粱的脱水性与发热量的影响。本实验采用完全随机区组设计，每个处理设置4次重复，采用6×4因子试验方案（6种除草剂处理×喷施与收获间的4个间隔期）。供试除草剂处理包括：两种不同剂量的草甘膦（glyphosate，1.92 kg a.i.·ha⁻¹与3.84 kg a.i.·ha⁻¹）、百草枯（paraquat，0.4 kg a.i.·ha⁻¹）、百草枯+敌草隆（paraquat + diuron）商品复配剂（0.6+0.3 kg a.i.·ha⁻¹）、草铵膦（glufosinate-ammonium，0.8 kg a.i.·ha⁻¹）以及空白对照（未喷施）。本研究考察的喷施至收获间隔期为脱干处理后7、14、21、28天（DAD）。测定指标包括单株叶片数、叶片含水率、穗部含水率、茎秆含水率及整株植株含水率，以及高位发热量（Superior Calorific Power，SCP）。喷施百草枯与百草枯+敌草隆复配剂，可在脱干处理后14天诱导植株脱叶。草甘膦、百草枯、百草枯+敌草隆及草铵膦均可降低叶片与穗部的含水率，仅草甘膦可降低茎秆含水率。各类除草剂均不影响生物质高粱的高位发热量。综上，各类除草剂尤其是草甘膦，在生物质高粱收获前脱干处理中具有较高应用潜力。