Optimizing the application of dairy farm effluent and manure to mitigate gas emission

Journal of Soils and Sediments - The impact of dairy farm effluent and manure applications upon gas emissions from soil is of concern for agronomic, ecological, and environmental reasons. Yet it...     

Microbial activity and metabolic quotient of microbes in soils amended with biochar and contaminated with atrazine and paraquat

The study was conducted to determine how biochar as a soil amendment maintained the microbial community in pesticide contaminated soils. Alfisol (Adenta series – Typic Kandiustalf) and Vertisol (Akuse series – Typic Calciustert) were amended with biochar (0 t/ha biochar, 10 t/ha cocoa husk biochar (CHB), 10 t/ha rice husk biochar (RHB)) and pesticides (atrazine and paraquat at two rates each namely 0 kg/ha pesticide and 10 times the normal recommended rate of pesticide) were applied. The CHB-amended soils stimulated microbial activities such as ammonia and nitrate release more than the RHB-amended soils. Basal respiration was significantly higher in the atrazine polluted soils than in paraquat polluted soil. Significant interaction occurred between soil type and biochar and high microbial biomass carbon was recorded for vertisol amended with CHB. Metabolic quotient was lower in soils amended with biochar and polluted with atrazine than in the un-amended soil. The use of CHB in soil of high clay content (47.5%, i.e. the vertisol) was a more effective management tool in maintaining the microbial community in a pesticide-polluted environment than in soil of lower clay content (22.5%). Soils of high clay content amended with biochar can sustain the soil microbial community even in a disturbed environment.     

菲和Cu2+在黑垆土上的吸附及其交互影响

采用批平衡法,研究了菲和Cu2+在黑垆土上的吸附及其交互影响。结果表明,菲和Cu2+在黑垆土上的吸附动力学曲线较好符合一级动力学方程,菲在黑垆土上的吸附主要通过分配作用,其吸附等温曲线符合线性Henry方程,Cu2+的存在抑制菲在黑垆土上的吸附;而Cu2+在黑垆土上的吸附主要通过表面吸附和专性吸附作用,其吸附等温曲线符合Freundlich方程,菲的存在促进了Cu2+的吸附;对菲和Cu2+来说,pH均是影响黑垆土吸附的主要因素,黑垆土对Cu2+的吸附量随着土壤溶液pH值的增加而增加,而对菲的吸附量随着pH增加而降低。