Soda Wannipa, Noble Andrew D, Suzuki Shinji, Simmons Robert, Sindhusen La-Ait, Bhuthorndharaj Suwannee
International Water Management Institute (IWMI), Southeast Asia Regional Office, c/o WorldFish P.O Box 500 GPO, 10670 Penang, Malaysia.
J Environ Qual. 2006 Oct 27;35(6):2293-301. doi: 10.2134/jeq2005.0455. Print 2006 Nov-Dec.
Acid waste bentonite is a byproduct from vegetable oil bleaching that is acidic (pH < 3.0) and hydrophobic. These materials are currently disposed of in landfills and could potentially have a negative impact on the effective function of microbes that are intolerant of acidic conditions. A study was undertaken using three different sources of acid waste bentonites, namely soybean oil bentonite (SB), palm oil bentonite (PB), and rice bran oil bentonite (RB). These materials were co-composted with rice husk, rice husk ash, and chicken litter to eliminate their acid reactivity and hydrophobic nature. The organic carbon (OC) content, pH, exchangeable cations, and cation exchange capacity (CEC) of the acid-activated bentonites increased significantly after the co-composting phase. In addition, the hydrophobic nature of these materials as measured using the water drop penetration time (WDPT) decreased from >10 800 s to 16 to 80 s after composting. Furthermore, these composted materials showed positive impacts on soil physical attributes including specific surface area, bulk density, and available water content for crop growth. Highly significant increases in maize biomass (Zea mays L.) production over two consecutive cropping cycles was observed in treatments receiving co-composted bentonite. The study clearly demonstrates the potential for converting an environmentally hazardous material into a high-quality soil conditioner using readily available agricultural byproducts. It is envisaged that the application of these composted acid waste bentonites to degraded soils will increase productivity and on-farm income, thus contributing toward food security and poverty alleviation.
酸性废膨润土是植物油漂白产生的副产品，呈酸性（pH < 3.0）且具有疏水性。这些材料目前被填埋处理，可能会对不耐酸性条件的微生物的有效功能产生负面影响。本研究使用了三种不同来源的酸性废膨润土，即大豆油膨润土（SB）、棕榈油膨润土（PB）和米糠油膨润土（RB）。这些材料与稻壳、稻壳灰和鸡粪一起进行共堆肥处理，以消除其酸反应性和疏水性。共堆肥阶段后，酸活化膨润土的有机碳（OC）含量、pH值、可交换阳离子和阳离子交换容量（CEC）显著增加。此外，使用水滴渗透时间（WDPT）测量，这些材料的疏水性在堆肥后从>10800秒降至16至80秒。此外，这些堆肥材料对土壤物理属性产生了积极影响，包括比表面积、容重和作物生长的有效含水量。在接受共堆肥膨润土处理的试验中，连续两个种植周期的玉米生物量（Zea mays L.）产量显著增加。该研究清楚地表明了利用现成的农业副产品将环境有害物质转化为优质土壤改良剂的潜力。预计将这些堆肥后的酸性废膨润土应用于退化土壤将提高生产力和农场收入，从而有助于粮食安全和减贫。
