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1.
Behaviour of bentazon as influenced by water and tillage management in rice‐growing conditions
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Antonio López‐Piñeiro David Peña Ángel Albarrán Javier Sánchez‐Llerena José Manuel Rato‐Nunes María Ángeles Rozas 《Pest management science》2017,73(6):1067-1075
Bentazon is a widely used herbicide in rice agroecosystems that has commonly been found in water resources. To assess how tillage and water regimes affect sorption/desorption, dissipation and leaching of bentazon in Mediterranean rice‐growing conditions, field experiments were carried out using tillage and flooding (TF), tillage and sprinkler irrigation (TS), no‐tillage and sprinkler irrigation (NTS) and long‐term no‐tillage and sprinkler irrigation (NTS7). After 3 years, the Kd values in TS were 2.3, 1.6 and 1.7 times lower than the values in NTS7, NTS and TF respectively. Greater sorption of bentazon was related to higher contents in total organic carbon and, although to a lesser extent, in humic acids and dissolved organic carbon. The persistence of bentazon was significantly greater under anaerobic (half‐life DT50 = 94.1–135 days) than under aerobic (DT50 = 42.4–91.3 days) incubation conditions for all management regimes. Leaching losses of bentazon were reduced from 78 and 74% in TS and TF to 61 and 62% in NTS7 and NTS respectively. The mid‐ and long‐term implementation of sprinkler irrigation in combination with no‐tillage could be considered a management system that is effective at reducing water contamination by bentazon in Mediterranean rice‐growing agroecosystems. © 2017 Society of Chemical Industry 相似文献
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好氧堆肥过程常存在分层现象,对于发酵产物的均一性和整体质量存在影响。为探究好氧堆肥物料病原菌灭活的分层情况,该研究以不翻抛(T1)为对照组,设置3组好氧堆肥试验(T2高温期翻抛、T3降温期翻抛、T4高温期和降温期翻抛),对牛粪好氧堆肥过程中常规理化性质和病原菌去除效率等进行分析,并利用克里格法(KRIGING)对堆体不同位置的温度和含水率进行插值分析。结果表明,4个处理发酵温度均达到了《畜禽粪便堆肥技术规范》要求,高温期最长的处理为T3和T4,达到7 d,T4处理的病原菌去除率最高,达到97.15%;从分层规律来看,堆体含水率从高到低为上层、中层、下层;好氧堆肥物料病原菌去除效率顺序从高到低为中层、下层、上层,4个处理病原菌去除率均不低于95.56%。综合考虑,高温期和降温期翻抛(T4处理)更有利于牛粪和秸秆混合堆肥物料整体实现无害化。该研究可为牛粪好氧堆肥过程中病原菌杀灭和翻抛参数的优化提供技术指导。 相似文献
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污泥好氧堆肥过程中有机质含量的变化 总被引:3,自引:0,他引:3
【目的】研究污泥好氧堆肥过程中有机质含量的变化,为提高污泥堆肥质量及正确评价污泥堆肥的肥效提供参考依据。【方法】以城市污泥和小麦秸秆、玉米秸秆为堆肥原料,设置4个处理(处理1调理剂为小麦秸秆糠(d<5 mm),处理2调理剂为小麦秸秆段(3 cm相似文献
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为了考查磷素回收方法出水中的磷素残留量对后续生物脱氮系统的影响,选用序批式反应器(SBR),以畜禽养殖沼液为处理对象,探究水质磷素缺乏情况下对好氧颗粒污泥系统运行效果及稳定性的响应情况。结果表明,对于稳态的好氧颗粒污泥系统,在进水磷素缺乏和充足两种情况下MLVSS/MLSS比值分别为94%±4%和92%±2%,表明两个系统均具有较好的生物活性。但是磷缺乏会导致颗粒污泥的微生物聚集稳定性降低,在磷充足情况下Zeta电位为(-7.37±1.23)m V,在磷缺乏情况下Zeta电位为(-10.5±1.27)m V。此外,在进水磷素缺乏和充足两种情况下,系统的氨氮和化学需氧量(COD)的比降解速率分别为(110.03±0.48)、(132.23±0.31)mg NH+4-N·g~(-1)VSS·c~(-1)和(117.64±0.08)、(150.43±0.13)mg COD·g~(-1)VSS·c~(-1),即在磷充足的情况下颗粒化系统具有较好的有机污染物与氮素去除效果。由此可见,好氧颗粒污泥在处理畜禽养殖沼液时,化学除磷方法优化设定应考虑其出水磷素含量对后续生物法稳定性的作用影响,才可保证处理过程中集成工艺对有机质与氮素的处理效率及系统的稳定性。 相似文献
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袋栽香菇生长期间不同料层中木质纤维素的降解及有关酶活性的变化 总被引:4,自引:2,他引:2
本文研究了香菇生长过程菌袋中不同料层木质纤维素的降解及有关酶活性的变化。结果表明,在栽培结束时,菌袋中不同料层木质纤维素含量的差异不大;在整个栽培过程中,菌袋中不同料层羧甲基纤维素酶,半纤维素酶和漆酶活性的变化大致相同。就菌袋中不同料层木质纤维素的降解和利用而言,菌袋的中层和下层与上层相似。 相似文献
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Potato absorption and phytoavailability of Cd,Ni, Cu,Zn and Pb in sierozem soils amended with municipal sludge compost 总被引:1,自引:0,他引:1
Effects of sludge utilization on the mobility and phytoavailability of heavy metals in soil-plant systems have attracted broad attention in recent years. In this study, we analyzed the effects of municipal sludge compost(MSC) on the solubility and plant uptake of Cd, Ni, Cu, Zn and Pb in a soil-potato system to explore the mobility, potato plant uptake and enrichment of these five heavy metals in sierozem soils amended with MSC through a potato cultivation trial in Lanzhou University of China in 2014. Ridge regression analysis was conducted to investigate the phytoavailability of heavy metals in amended soils. Furthermore, CaCl_2, CH_3 COONH_4, CH_3COOH, diethylene triamine pentacetic acid(DTPA) and ethylene diamine tetraacetic acid(EDTA) were used to extract the labile fraction of heavy metals from the amended soils. The results show that the MSC could not only improve the fertility but also increase the dissolved organic carbon(DOC) content of sierozem soils. The total concentrations and labile fraction proportions of heavy metals increase with increasing MSC percentage in sierozem soils. In amended soils, Cd has the highest solubility and mobility while Ni has the lowest solubility and mobility among the five heavy metals. The MSC increases the concentrations of heavy metals in the root, stem, peel and tuber of the potato plant, with the concentrations being much higher in the stem and root than in the peel and tuber. Among the five heavy metals, the bioconcentration factor value of Cd is the highest, while that of Ni is the lowest. The complexing agent(DTPA and EDTA) extractable fractions of heavy metals are the highest in terms of phytoavailability. Soil properties(including organic matter, p H and DOC) have important impacts on the phytoavailability of heavy metals. Our results suggest that in soil-potato systems, although the MSC may improve soil fertility, it can also increase the risk of soils exposed to heavy metals. 相似文献