不同覆盖对圣女果秸秆简化静态堆肥与腐殖化进程的影响

    Effects of different coverings on the simplified static composting and humification process of cheery-tomato straw

    • 摘要: 热带圣女果种植分布广,产生的秸秆废弃物难收储。在热带高温多雨气候条件下,如何高效、简单、低成本实现圣女果秸秆的就地无害化与腐殖化还田,是热带圣女果秸秆废弃物处置利用面临的重要难题之一。该研究以构建秸秆简化、就地的静态堆肥工艺为目标,模拟了polytetrafluoroethylene(PTFE)分子膜、polyvinyl- chloride(PVC)塑料膜、无覆盖(即干秸秆原料)3种不同覆盖所形成的静态环境对堆肥理化性质与腐殖化进程的影响,结合冗余-相关性分析与二维相关傅立叶红外光谱阐明腐殖化的影响规律及其关键组分的分子结构演化机制。结果表明:3种覆盖下≥50℃高温期持续时间均超过5 d;促进产热-蓄热-保温能力上,由高到低顺序依次为:分子膜、无覆盖、塑料膜。秸秆堆肥过程中酸碱度、电导率、氮磷钾、容重升高,大颗粒破碎,小颗粒占比提高。覆盖塑料膜堆肥有效积温相对较低,有机碳损失相对较低,堆肥后有机碳降幅分别为20.12%(分子膜)、4.63%(塑料膜)与16.13%(无覆盖)。相比于无覆盖,分子膜覆盖可以显著加快堆肥腐殖化进程;塑料膜覆盖堆肥虽能实现一定程度腐殖化,但腐殖化率最低。3种处理下腐殖化指数分别为15.61%(分子膜)、9.95%(无覆盖)、6.17%(塑料膜)。二维相关光谱表明木质纤维素分解产生的醌、醛、酮、多酚类化合物与氨基聚合,多酚缩合可能是秸秆腐殖酸合成的主要途径。分子膜与塑料膜覆盖下,重点调控物料结构与养分,并提高温度,是提高腐殖化效果的关键。

       

      Abstract: Cherry tomatoes are widely distributed in the tropical region of China. However, tomato straw waste has been massively produced, due to the extreme difficulty in collection, detoxification, and reutilization. It is urgent to efficiently, simply, and low-costly detoxify and dispose of the tomato straw waste in the conditions of relatively high temperatures and frequent rain climates. An important issue can also be focused mainly on the recycling and reutilization of plant biomass resources. The aim of this study is to compare the variation of physicochemical properties and humification under three types of covering mode: PTFE membrane, PVC membrane, and dry straw (No cover). The redundancy-correlation analysis and two-dimensional correlated Fourier transform infrared spectroscopy (2D-COS-FTIR) were conducted to elucidate the humic impact factors and the key molecular structure evolution. The result indicated that three types of covering treatments fully meet the demand of harmless thermophilic time (≥50°C and ≥5 days). The heating generation, storage, and insulation were ranked in the effective order of PTFE, None, and PVC treatment. The pH, EC, total nitrogen, total phosphorus, total potassium, and unit weight increased, as the progress of composting. Massive large granular compost was shattered to gradually increase the proportion of the small granular. The loss of total organic carbon (TOC) was reduced under the treatment of PVC membrane. The reduction rates of TOC were 20.12%, 4.63%, and 16.13%, respectively, in the PTFE, PVC, and None treatments. The PTFE treatment shared the highest humification speed, while the PVC treatment also achieved partial humification, with their humification index (HI) were 15.61%(PFTE), 9.95%(None), and 6.17%(PVC), respectively. Compared with the None cover, the PFTE treatment performed best to accelerate the humification of tomato straw. The humification was observed in the PVC treatment, while there was the lowest humification rate. 2D-COS-FTIR showed that there were the quinones, aldehydes, ketones, and polyphenols that originated from the decomposition and transformation of lignocellulose in cherry tomato straw. The amino group (from urea) was then polymerized to form the humic acid (HA), according to the composition and components of composting raw material. Besides, the large synthesis in HA might be responsible for the self-condensation of polyphenols. The covering of the membrane was promoted to accelerate the humification process. The correlation showed that the humification can be expected to positively regulate the pile's physical structure, chemical nutrients, and temperature during composting under the condition of covering PTFE and PVC membrane. The humification of cheery-tomato straw under different covering treatments can be beneficial to the optimization and development of in-site rapid straw composting.

       

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