Influence of organic amendments on dissipation kinetics of two different pesticides in soil: a case study

A study was undertaken to investigate the remedial effect of some soil amendments (farmyard manure (FYM), press mud compost (PMC), cereal straw (CS) at 5 t ha^?1 and fresh cow dung slurry (FCD) @ 0.5 t ha^?1) on dissipation kinetics of imidacloprid and sulfosulfuron under laboratory conditions. Incorporation of CS or FCD was found to be most effective in degrading both the pesticides at faster rates. Dissipation of both the pesticides could be well accounted by two component (1 + 1) first order kinetics. The computed values of parameters revealed that use of organic amendments increased the dissipated fraction of imidacloprid and sulfosulfuron. Incorporation of CS or FCD in soil maintained relatively higher dissipation rate constants for both faster and slower dissipation processes of pesticides in comparison to control. Hence, eco-friendly practices of CS or FCD incorporation as soil amendment in soil can play a vital role in preventing soil and water pollution.     

不同种类有机物对污染农田土壤重金属活性的影响

为了解施用不同种类有机物对污染农田土壤重金属行为的影响,布设了田间小区试验,观察研究施用6种不同类型有机物对土壤水溶性重金属和农作物对重金属吸收等的影响。试验设7个处理,分别为对照(不施有机肥)、施新鲜水稻秸秆、新鲜鸡粪、鸡粪堆肥、新鲜猪粪、猪粪堆肥和商品有机肥,动态检测土壤中水溶性重金属含量、田面水中重金属浓度及收获水稻籽粒中重金属含量的变化。结果表明,与不施有机物的对照处理比较,施用各类有机物在试验前期均可明显提高土壤中水溶性重金属和田面水中重金属的含量,总体上以施用新鲜猪粪的最高,其次为新鲜鸡粪,施用商品有机肥的最低。土壤中水溶性重金属含量随试验时间增长逐渐下降。施用各类有机物对水稻籽粒中重金属的积累影响不明显。土壤中水溶性重金属及田面水中重金属含量均与相应的水溶性碳(DOC)浓度呈显著相关性,表明因有机物施用增加土壤中DOC浓度可能是土壤中水溶性重金属含量增加的主要原因;而不同有机物对土壤重金属活性影响的差异可能与有机物本身的分解程度及可释放DOC大小有关。但施用有机物引起的农田土壤水溶性重金属含量的增加是暂时的,对水稻生长后期籽粒中重金属积累的影响不明显。     

Reduction of soil heavy metal bioavailability by nanoparticles and cellulosic wastes improved the biomass of tree seedlings

The purpose of this study was to use zero‐valent iron nanoparticles (nZVI) and cellulosic wastes to reduce bioavailability of lead (Pb) and cadmium (Cd), and to establish Persian maple seedlings (Acer velutinum Bioss.) in contaminated soil. One‐year‐old seedlings were planted in pots filled with unpolluted soil. Lead [Pb(NO₃)₂] and Cd [Cd(NO₃)₂] were added with concentrations of 0 (Control), 100 (Pb100), 200 (Pb200), and 300 (Pb300) mg kg⁻¹ and 10 (Cd10), 20 (Cd20), and 30 (Cd30) mg kg⁻¹. Cellulosic wastes were mixed with soil at the same time of planting [four levels: 0, 10 (W1), 20 (W2), 30 (W3) g 100 g⁻¹ soil]. The nZVI was prepared by reducing Fe³⁺ to Fe⁰ and injected to pots [four levels: 0, 1 (N1), 2 (N2), and 3 (N3) mg kg⁻¹]. Height, diameter, biomass, tolerance index of seedlings, bioavailability of heavy metals in soil, and removal efficiency of amendments were measured. The highest values of seedling characteristics were observed in N3. The highest removal efficiency of Pb (Pb100: 81.95%, Pb200: 75.5%, Pb300: 69.9%) and Cd (Cd10: 92%, Cd20: 73.7%, Cd30: 68.5%) was also observed in N3. The use of nZVI and cellulosic waste could be a proper approach for seedling establishment in forests contaminated with heavy metals.     

Nutrient uptake and residual effect of organic treatments applied to vegetable–rice system in an acid soil

Direct and residual effects of organic treatments and in combination with inorganic fertilizers applied to acid soils were studied in the okra–rice system. Among the treatments studied, vermicompost (V.C) and poultry manure improved soil pH and exhibited liming effect, whereas inorganic fertilizer decreased soil pH. Inorganic fertilizer contributed to 78% of net return in okra but the residual effect was observed in inorganic and V.C combination. Soil available nitrogen and potassium had increased at 100% recommended dose, compensated crop uptake at 75%, but depletion was observed at 50%. Uptake of nitrogen was higher for okra from inorganic fertilizer but higher phosphorus and potassium uptake from V.C was observed for rice. Organic treatments showed better correlation between soil pH and zinc (Zn) uptake by okra and significant residual effect on rice. But it reduced the solubility of iron (Fe) and its uptake by okra and indicated a negative correlation between pH and diethylene triamine penta acetic acid-extractable Fe²⁺.     

Organic amendments decomposability influences microbial activity in saline soils

Organic amendments with contrasting biochemical properties were investigated by conducting an incubation experiment in soils irrigated with different levels of saline water. Soil samples were taken from a long-term experimental field plots irrigated with normal water and saline water having electrical conductivity (EC) 6 and 12 dS m^?1, respectively. Finely ground biochar, rice straw (RS), farm yard manure (FYM) and glucose were added at two rates (1% and 2.5% carbon basis) and incubated for 8 weeks at 25°C. Cumulative respiration (CR), microbial biomass carbon and available nutrients (nitrogen and phosphorus) were negatively correlated with EC, irrespective of the source and amount of added carbon (C). Compared with non-saline soil, at EC 12, relative decrease in CR was lowest with glucose (21.0%) followed by RS (32.0%), FYM (46.0%) and biochar (55.0%). Dissolved organic carbon was positively correlated with salinity and its concentration was higher in treatments with higher rate of C addition (2.5% C). This study showed decomposability of organic amendments and their rate of addition determines microbial activity in saline soils. Further, lower nitrogen (N) release from amendments under saline conditions limits microbial ability to utilize available C for satisfying their energy needs.     

植物源氟对绵羊几种血清抗氧化酶的影响

以蒙古绵羊为试验动物,以乌梁素海高氟沉水水草龙须眼子菜(Potamogoton pectinatus)作为氟源,研究高氟水草对绵羊抗氧化系统及生产性能的影响。4组绵羊日粮水草氟水平分别为:0、50、100、150 mg/kg。连续饲喂5个月,观察绵羊中毒情况,测定绵羊15 d体质量增加量和血清抗氧化酶活性。结果表明,各试验组绵羊均未出现典型氟中毒症状;沉水水草与高丹草(Sorghum hybrid)对绵羊的体质量增加效果无明显差异(P0.05);血清超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活力均无显著变化(P0.05),血清总抗氧化能力(T-AOC)无显著变化(P0.05)。说明饲喂沉水水草后,绵羊生产性能未受到影响,机体的抗氧化系统未受到损害,没有发生氟中毒。     

茄子花培后代的观察与应用

对从长茄杂交种“牟尼卡”（编号06-1001）进行花药培养获得的花培品系二代（DH2）和三代（DH3）的主要植物学性状进行了观察与比较。结果表明,从同一接种材料可以获得不同类型的花培品系,其始花节位、果形指数和单果重变异幅度很大,15个二代品系中,有46.7%的品系始花节位与接种材料达到显著或极显著差异标准,有40.0%的品系果形指数与接种材料达到显著或极显著差异标准,有33.3%的品系单果重与接种材料达到显著或极显著差异标准。同一品系不同世代间始花节位、果实横径、果实纵径、果形指数和单果重能稳定遗传;品系内个体间始花节位、果实横径、果实纵径、果形指数和单果重变异系数较小(<10%),系内整齐一致。此外,初步选育的花培品系“06-139”和以花培品系为亲本的杂交组合“05-203”开始在农业生产中应用。     

橘子洲滨水景观处理艺术探讨

橘子洲滨水区的景观处理是整个橘子洲景区景观处理中的一个核心的组成部分之一,如何将滨水区域景观与城市、与人、与自然融为一体,构造生态式景区,营建动态景观,是我们探讨的方向。     

非洲菊切花品种引种试种研究

通过25个非洲菊切花品种的试种观察,就各品种的生育期、植物学性状、切花产量、抗病性、切花瓶插寿命、商品性及主要性状各月变化情况等方面进行了比较评价,据此推荐了11个综合性状较好的品种。