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除水分效果与发热量的影响。本试验采用随机完全区组设计，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×4个施药至收获间隔期）。
供试除草剂处理如下：两种不同剂量的草甘膦（glyphosate，1.92 kg 有效成分（a.i.）·公顷⁻¹与3.84 kg 有效成分（a.i.）·公顷⁻¹）、百草枯（paraquat，0.4 kg 有效成分（a.i.）·公顷⁻¹）、百草枯+敌草隆（paraquat + diuron）商品复配剂（0.6+0.3 kg 有效成分（a.i.）·公顷⁻¹）、草铵膦（glufosinate-ammonium，0.8 kg 有效成分（a.i.）·公顷⁻¹）以及空白对照（未施药处理）。
本次试验评估的施药至收获间隔期为脱干处理后7、14、21、28天（Days After Desiccation, 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）。
喷施百草枯及百草枯+敌草隆药剂可在施药后14天（DAD）产生脱叶效果。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，而仅草甘膦可降低茎秆含水率。各类除草剂均不会对生物质高粱的高位发热量产生影响。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备较高应用潜力。