Effects of rapeseed residue on lead and cadmium availability and uptake by rice plants in heavy metal contaminated paddy soil

Rapeseed (Brassica napus L.) has been cultivated for biodiesel production worldwide. Winter rapeseed is commonly grown in the southern part of Korea under a rice-rapeseed double cropping system. In this study, a greenhouse pot experiment was conducted to assess the effects of rapeseed residue applied as a green manure alone or in combinations with mineral N fertilizer on Cd and Pb speciation in the contaminated paddy soil and their availability to rice plant (Oryza sativa L.). The changes in soil chemical and biological properties in response to the addition of rapeseed residue were also evaluated. Specifically, the following four treatments were evaluated: 100% mineral N fertilizer (N100) as a control, 70% mineral N fertilizer + rapeseed residue (N70 + R), 30% mineral N fertilizer + rapeseed residue (N30 + R) and rapeseed residue alone (R). The electrical conductivity and exchangeable cations of the rice paddy soil subjected to the R treatment or in combinations with mineral N fertilizer treatment, N70 + R and N30 + R, were higher than those in soils subjected to the N100 treatment. However, the soil pH value with the R treatment (pH 6.3) was lower than that with N100 treatment (pH 6.9). Use of rapeseed residue as a green manure led to an increase in soil organic matter (SOM) and enhanced the microbial populations in the soil. Sequential extraction also revealed that the addition of rapeseed residue decreased the easily accessible fraction of Cd by 5-14% and Pb by 30-39% through the transformation into less accessible fractions, thereby reducing metal availability to the rice plant. Overall, the incorporation of rapeseed residue into the metal contaminated rice paddy soils may sustain SOM, improve the soil chemical and biological properties, and decrease the heavy metal phytoavailability.     

养猪业清洁生产途径与循环经济发展模式探讨

近年来,我国养猪业发展迅速,农村经济增长较快,农民收入和生活水平明显提高。同时,养猪业产生的猪粪便污染日趋严重,已严重影响当地居民生产生活和身体健康。为了彻底消除农村养猪场猪粪便污水和臭味污染,改善农村环境质量,促进农业经济发展,总结了长期从事清洁生产和循环经济发展研究的实践经验,提出了养猪业清洁生产途径和循环经济发展模式,意在从源头预防控制污染,大力推进养猪业清洁生产与农村经济可循环持续发展,并供关心我国养猪清洁生产与循环经济发展的同行借鉴参考。     

改进型升流式固体反应器处理猪粪污新工艺研究

对传统升流式固体反应器（USR）进行改进,反应器内设置专用搅拌器,搅拌器间歇开启,在保留USR各项优势的前提下,使料液与厌氧微生物接触更充分,反应温度更均匀,提高产气率,同时还解决了传统USR的“结壳”问题,提高了反应器的传质效率、甲烷产气率和COD去除效果。进料含固量在12.1%时,水利停留时间为17 d,反应器最高容积负荷达到4.9 kg COD/(m³·d),产气速率为2.55 m³/(m³·d),产气率达到0.359 m³/kg干猪粪。     

Size distributions of manure particles released under simulated rainfall

Manure and animal waste deposited on cropland and grazing lands serve as a source of microorganisms, some of which may be pathogenic. These microorganisms are released along with particles of dissolved manure during rainfall events. Relatively little if anything is known about the amounts and sizes of manure particles released during rainfall, that subsequently may serve as carriers, abode, and nutritional source for microorganisms. The objective of this work was to obtain and present the first experimental data on sizes of bovine manure particles released to runoff during simulated rainfall and leached through soil during subsequent infiltration. Experiments were conducted using 200 cm long boxes containing turfgrass soil sod; the boxes were designed so that rates of manure dissolution and subsequent infiltration and runoff could be monitored independently. Dairy manure was applied on the upper portion of boxes. Simulated rainfall (ca. 32.4 mm h(-1)) was applied for 90 min on boxes with stands of either live or dead grass. Electrical conductivity, turbidity, and particle size distributions obtained from laser diffractometry were determined in manure runoff and soil leachate samples. Turbidity of leachates and manure runoff samples decreased exponentially. Turbidity of manure runoff samples was on average 20% less than turbidity of soil leachate samples. Turbidity of leachate samples from boxes with dead grass was on average 30% less than from boxes with live grass. Particle size distributions in manure runoff and leachate suspensions remained remarkably stable after 15 min of runoff initiation, although the turbidity continued to decrease. Particles had the median diameter of 3.8 microm, and 90% of particles were between 0.6 and 17.8 microm. The particle size distributions were not affected by the grass status. Because manure particles are known to affect transport and retention of microbial pathogens in soil, more information needs to be collected about the concurrent release of pathogens and manure particles during rainfall events.     

猪粪和羊粪与麦秆不同配比中温厌氧发酵研究

研究了猪粪和羊粪分别与麦秆不同配比中温(35℃)厌氧发酵对产气量、消化时间和最优C/N值的影响。结果表明,猪粪与麦秆在中温厌氧发酵时,所需的最优C/N值为21,且经141 d就可充分发酵,最大干物质累积产气量可达369.53 mL/g。羊粪与麦秆中温厌氧发酵时,所需的最优C/N值为24,且经96 d就可充分发酵,最大干物质累积产气量可达209 mL/g。猪粪秸秆中温厌氧发酵时易发生酸化,发酵前应通过预处理来减少酸化可能;而羊粪麦秆不易发生酸化。     

宝应县畜禽养殖业的现状调研及污染防治对策

调查了宝应县畜禽养殖业的发展现状及分布情况,阐述了该县畜禽养殖业的污染防治状况,分析了污染防治中存在的主要问题,并提出了当地畜禽养殖业污染防治的基本思路和治理措施,对贯彻落实防治措施提出了建议。     

Atrazine is not readily mineralised in 24 temperate soils regardless of pre-exposure to triazine herbicides

Mineralisation of atrazine in soil has been shown to depend on previous exposure of the herbicide. In this study, 24 Danish soils were collected and screened for potential to mineralise atrazine. Six soils were chosen, because they had never been exposed to atrazine, whereas 18 soils were chosen because of their history of application of atrazine or the related compound terbuthylazine. None of the 24 soils revealed a mineralisation potential of more than 4% of the added atrazine within a 60 day timeframe. In an atrazine adapted French soil, we found 60% mineralisation of atrazine in 30 days. Cattle manure was applied in order to boost the microbial activity, and a 2-3% increase in the atrazine mineralisation was found in some of the temperate soils, while in the highly adapted French soil it caused a 5% reduction.     

辽西褐土施肥及养分循环再利用中长期试验 Ⅱ. 土壤养分收支

持续10a的田间试验结果表明,在保持农业系统养分循环再利用的基础上,根据土壤养分供给力设计化肥施用量,可以在实现作物高产的同时,平衡土壤养分收支,从而避免土壤中肥料养分（主要是氮）过剩而进入环境。     

不同配比农业废物堆肥过程中堆肥的阴阳离子和大分子对种子发芽的影响

为揭示不同配比农业废物堆肥过程中阴阳离子和大分子对植物毒性的影响机理，开展了以鸡粪和猪粪为主料，稻草秸秆为辅料的条垛堆肥试验，设置的试验处理包括：等质量的鸡粪+稻草秸秆+包菜（1∶1∶1）处理（T1）、鸡粪+稻草秸秆（1∶1）处理（T2）、大量猪粪+少量稻草秸秆（85∶15）处理（T3）.测定了各处理的堆温、堆肥的水溶性无机阴阳离子和有机大分子变化，以及对大白菜（Brassica rapa L.）和水堇（Lepidium sativum. L.）种子发芽指数（Germination Index， GI）等指标变化的影响.试验结果表明，T3处理堆肥的高温（>55 ℃）持续期最长，杀灭病原微生物和杂草种子的能力最好，且其堆肥的Cl^-、SO42-、K⁺、Na⁺、Ca²⁺和Mg²⁺浓度最低；T2处理堆肥的NH4+ 浓度最低.T1和T2处理堆肥过程中堆肥的脂肪烃可转化为稳定的芳香烃.T3处理堆肥对大白菜和水堇的种子发芽指数大于80%.堆肥中抑制种子发芽的阴阳离子及大分子浓度分别为：Ca²⁺浓度>0.98 mmol·L^-1，Mg²⁺浓度>0.92 mmol·L^-1，NH4+浓度均>5.75 mmol·L^-1，芳香C/多糖比值>0.33，羧基C/多糖比值>0.30.堆肥中脂肪族大分子增加、多糖类大分子减少可抑制种子发芽.综上所述，猪粪与稻草秸秆的质量配比为85∶15、初始C/N比为25、初始水分含量为60%、 堆肥期周为35 d是条垛式堆肥处理猪粪和稻草秸秆的最佳工艺参数.大白菜比水堇种子更能准确反映农业废物堆肥的植物毒性.本研究可为优化不同畜禽粪便与农作物秸秆的条垛堆肥工艺参数、减少土地利用的风险提供重要的决策支持.     

典型沼肥灌施农田重金属的时间多尺度特征分析

长期对农田进行沼肥灌施对土壤养分及重金属累积、迁移产生何种影响,尚缺乏系统的调查和研究。选取7—10年灌施沼肥的农田为研究对象,分析耕层土壤中Cu、Zn、Cr、Cd、Pb、Ni、Hg和As的全量及Cu、Zn各形态含量,并对污染水平及生态风险进行评价和预测。结果表明:持续灌施沼肥改变土壤的EC、pH等理化性质,造成P、K等营养元素和重金属Cu、Zn的显著累积。Cu、Zn平均积累速率分别为5.70~6.15、12.13~18.7 mg/(kg·年)。Cu和Zn含量之间具有显著相关性,表明它们同源。外源输入的稀释作用及形态转化使原土壤Cu、Zn赋存形态发生改变。综合污染指数法研究结果表明,养殖场土壤重金属均处于警戒水平。潜在生态风险指数法研究结果表明,养殖场土壤重金属危害程度整体表现为轻微生态危害。Cu、Zn年积累通量分别为10.26~11.07、21.83~33.66 kg/(hm²·年)。预测土壤中Cu、Zn浓度超出风险筛选值时间分别为10.19~11.01、9.16~14.14年。连续多年灌施沼肥将对土壤生态环境造成潜在风险。