磷影响下砷的根际效应及其对水稻生长的影响

通过水稻的生物量及含砷量、根际 p H值、根际有效砷的变化来研究磷影响下砷的根际效应及其对水稻生长的影响。结果表明 ,酸性紫色土中 ,无论单加砷还是磷、砷共存的处理 ,基本上 ,根际砷均高于非根际 ,砷在根际呈富集状态 ;但与单加砷相比 ,磷、砷共存的处理 ,根际 p H值下降 ,有效砷减少 ,水稻吸收砷量减少 ,生物量增加 ,水稻受砷毒害减轻 ,特别 P/As≥ 4时 ,磷减轻砷毒害的程度大于 P/As≤ 2时。因此 ,施加磷可减轻砷污染酸性紫色土上水稻砷毒害。选择最佳 P/As可使磷最大限度地减轻作物受砷的毒害。     

水溶性农药流失的影响因素及污染防治

根据实际室和田间试验结果，分析了水溶性农药稻田流失的影响因素，提出了对水稻生长前期的农药渗滤量、降雨径流量和排水流失量的估算。结果表明，仅渗滤与排水两项流失，占农药用量的１７．２８％～５９．３１％，调查表明，环境水体已受杀虫单的污染，最后提出了防治水溶性农药稻田流失的节水灌溉，控制排水等措施。     

EFFECT OF SYSTEM LAYOUT ON SUBSURFACE DRAINAGE COST IN FLAT IRRIGATED LAND1

ABSTRACT: The economic feasibility of large-scale subsurface drainage projects in irrigated land is affected by construction costs. This study was conducted to evaluate the effect of two different types of subsurface drainage system layout on construction costs for a 1000 ha pilot area located in the Nile Delta of Egypt. The two types of layout studied were the conventional layout currently used in Egypt and the modified layout that was developed for reducing water losses from rice fields. When compared to the conventional layout, the modified layout resulted in a reduction of 6.74 percent in construction costs (714,464 US$ versus 766,142 US$). This cost reduction is explained by the need for lesser lengths of large diameter collector pipes with the modified layout, which results from the smaller drainage area of subsurface drainage systems (average 23.7 versus 30.8 ha). We have found that the cost of subsurface drainage can be minimized by reducing the area drained by each subsurface drainage system.     

湘中某工业区农田重金属污染的初步研究

通过2年的定点调查,研究了湘中某工业区附近农田土壤、糙米中重金属含量状况;并对重金属在水稻植株中的含量分布,以及影响糙米中重金属含量的土壤因素进行了探讨。     

东太湖茭草资源的开发利用

本文论述了东太湖茭草资源的现状及对环境的影响,揭示其生态失调、利用价值下降的趋势,勾保护湖泊资源和水利功能,提出了开发治理对策。     

稻草秸秆发酵液对铜绿微囊藻生化参数影响

针对铜绿微囊藻在稻草秸秆（水稻分蘖枝）发酵液胁迫下的酶学特征及抗氧化能力、藻毒素和多糖含量等生化指标进行了检测分析，旨在为利用稻草秸秆抑藻提供进一步理论依据.结果表明：铜绿微囊藻在水稻分蘖枝发酵液胁迫下，其表征藻细胞代谢水平的酯酶活性显著降低，实验第5d，最高浓度组（0.65%V/V）99.9%的藻细胞内酯酶活性均被抑制，超氧化物歧化酶（SOD）与谷胱甘肽过氧化物酶（GSH-Px）活力分别下降至同期对照组的11.03%和8.47%；丙二醛（MDA）含量则与发酵液浓度以及作用时间呈显著正相关，pearson分析表明，所有浓度组和作用时间内r值均大于0.9，而P值均小于0.01，表明水稻分蘖枝发酵液可显著降低藻细胞的抗氧化水平；但高浓度水稻分蘖枝发酵液没有引起微囊藻毒素（MCs）升高，甚至显著降低MCs和多糖的含量，与对照组相比，P<0.01.因此，水稻分蘖枝发酵液可通过影响铜绿微囊藻的代谢过程，降低藻细胞抗氧化以及抵御对环境胁迫的能力，从而达到有效抑藻的目的.     

秦家镇绿色水稻产地水质分布GIS模拟

利用2002年水质监测数据,基于ARCGIS8.3平台,运用Geostastical Analyst分析模块,模拟秦家镇绿色水稻产地灌溉用水水质的分布.结果表明,秦家镇西北部水质最为清洁,Nemerow综合污染指数＜0.35,由北向西南水质下降,秦家镇附近水质最差,综合污染指数为0.499,接近警戒级(0.5);全镇灌溉用水清洁,属一等安全级,各污染物的单项污染指数均＜1,综合污染指数均＜0.5,适宜发展AA级绿色食品水稻基地.     

Potential of rice husk ash in atrazine removal

An experimental study was carried out to explore the possibility of using a prepared microporous material, Rice Husk Ash (RHA) as an alternative to the commercial Powdered Activated Carbon (PAC), to remove atrazine (ATZ) pesticide from aqueous solution. The effects of contact time and pH on the adsorption were studied using the batch technique. Based on Hückel model calculations, the zwitterion behaviour of atrazine molecule was proved to be related to the pH of zero charge point of adsorbents (6.8 for RHA and 8.2 for PAC). The results showed that the Pseudo Second Order model is applicable to both adsorbents, suggesting that chemisorption is the rate-limiting step. The equilibrium data fitted well with the Langmuir model in the case of RHA, whereas the Freundlich model better fitted the equilibrium data in the PAC case, suggesting the existence of multi-layer adsorption of atrazine. The adsorption for RHA was found to be feasible and spontaneous, with a removal capacity of atrazine of more than 7?mg?g^?1. With regard to the BET surface, this removal capacity (50.5?µg_ATZ / m²_RHA) was 25% better than that PAC (37.75µg_ATZ / m²_PAC).     

两种淹水模式下施用钝化材料对镉污染农田水稻安全生产的影响

为实现镉(Cd)污染农田稻米安全生产,以中度Cd污染农田为研究对象,通过连续2 a的大田试验,对比分析了间歇性淹水和全生育期淹水2种淹水模式下,玉石粉、生物炭和粉煤灰这3种钝化材料施用后对土壤pH,有效Cd和稻米Cd含量的影响.结果 表明:①单一淹水处理下,全生育期淹水和间歇性淹水处理均可提高土壤pH,土壤有效Cd降低...     

污灌区稻田汞污染特征及健康风险评价

选择天津北排污河灌区作为研究区域,调查了土壤和水稻总汞和甲基汞的含量及分布特征,评估污灌区稻米食用汞暴露风险,并对污灌区土壤-稻米甲基汞的影响因素进行了初步分析.结果表明,1.调查的29个污灌区稻田,土壤总汞含量为(367.04 ± 129.36) μg/kg,显著高于区域土壤Hg背景值73 μg/kg,甲基汞含量为(0.87 ± 0.77) μg/kg;水稻各部位总汞含量依次为稻叶 > 稻根 > 稻茎 > 稻米,稻米总汞含量为(12.80 ± 5.14) μg/kg,甲基汞含量依次为稻米 > 稻根 > 稻茎 > 稻叶,稻米对甲基汞具有很强的富集能力,甲基汞含量为(2.09 ± 1.20) μg/kg,甲基化率均值超过10%.污灌区稻米总汞每周摄入量为0.068~1.25μg/(kg·bw),甲基汞每周摄入量为0.0095~0.49μg/(kg·bw),污灌区稻米总汞及甲基汞暴露对居民健康风险总体仍在安全阈值内,但个别汞污染较严重地块甲基汞暴露风险值得高度关注.土壤甲基汞含量仅与土壤总汞含量及黏粒含量的相关性达到显著性水平,稻米甲基汞含量与土壤总汞含量、土壤甲基汞含量、稻米总汞含量及黏粒含量的相关性达到显著性水平.