Toxicity interaction of metals (Ag, Cu, Hg, Zn) to urease and dehydrogenase activities in soils     

Sophie Chaperon 《Soil biology & biochemistry》2007,39(9):2329-2338

A study of the individual and mixture toxicities of the trace metals Ag, Cu, Hg, Zn to the soil enzymes dehydrogenase and urease was undertaken. An agricultural soil and a sandy forest soil were spiked with metal salts, individually and in combinations. The anion additions to the various treatments and controls were normalized for added anions using Ca salts. The soils were then left to equilibrate and leached to reduce the excess metals and anions. Total and dissolved metal concentrations were measured concurrently in order to consider the effect of soil chemistry on the enzyme activities. Dose-response relationships for total soil metals and soil solution metals were estimated for each metal separately following a log-logistic curve fitting. Ag and Hg were the most efficient metals to reduce soil enzyme activities. The Bliss independence model was used to predict the toxicity of metal combinations. The enzyme responses in relation to the total soil metal combinations were synergistic for the agricultural soil and antagonistic for the forest soil; possibly as a result of a higher organic matter content and higher pH in the latter soil. Enzyme activities expressed in relation to the dissolved metal concentrations were more variable than against the total metal contents and consequently we observed both synergistic and antagonistic interactions.  相似文献   

锐劲特与乙酰甲胺磷混配对水稻主要害虫的控制研究   总被引：1，自引：0，他引：1  

王德江  奚本贵  赵伟琚  王湘云  张桥  吴庭友 《安徽农业科学》2001,29(3):349-350,353

试验结果表明 ,锐劲特 5 %SC与乙酰甲胺磷 3 0 %EC混配防治水稻主要害虫稻纵卷叶螟、白背飞虱效果好 ,持效期长。锐劲特 5 %SC 2 40ml/hm2 +乙酰甲胺磷 3 0 %EC 12 0 0ml/hm2 对稻纵卷叶螟防效达 99.5 % ,持效期达 17d以上 ;对白背飞虱防效98.9% ,持效期达 14d以上 ,显著优于大面积使用的甲胺磷  相似文献   

西藏地区燕麦与箭筈豌豆不同混播比例对牧草产量和质量的影响   总被引：6，自引：1，他引：6  

李佶恺  孙涛  旺扎  李洪影  崔国文 《草地学报》2011,19(5):830-833

在西藏日喀则地区,将燕麦(Avena sativa L.)与箭筈豌豆(Vicia sativa L.)种子按不同比例进行混播试验,通过对混收牧草产量和品质的测定分析,研究适宜在当地生长的燕麦与箭筈豌豆的最佳混播比例,以期获得最大的生物产量和营养价值。结果表明:在燕麦播种量不变的情况下,随着箭筈豌豆混播比例的增加,粗蛋白质(CP)含量随之增加,而中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量降低。在49种混播组合中,混播播种量为燕麦210kg·hm^-2和箭筈豌豆75kg·hm^-2(G1)混播组合的干草产量和营养成分的综合指标最高,可在西藏日喀则地区推广应用。  相似文献   

黄河源区“黑土型”退化草地人工群落组分配置技术研究   总被引：1，自引：1，他引：1  

马玉寿  尚占环  施建军  董全民  龙瑞军 《西北农业学报》2007,16(5):1-6

在黄河源区的“黑土型”退化草地上,以6种多年生禾本科牧草的不同混播处理（A-垂穗披碱草;B-垂穗披碱草＋冷地早熟禾;C-垂穗披碱草＋冷地早熟禾＋中华羊茅;D-垂穗披碱草＋冷地早熟禾＋中华羊茅＋波伐早熟禾;E-垂穗披碱草＋冷地早熟禾＋中华羊茅＋波伐早熟禾＋西北羊茅;F-垂穗披碱草＋冷地早熟禾＋中华羊茅＋波伐早熟禾＋西北羊茅＋短芒老芒麦）进行了连续3 a的群落学试验研究。结果表明,不同混播群落的牧草产量差异极显著（P〈0.01）,建植的当年,混播群落牧草产量、草层高度和群落盖度等指标主要受垂穗披碱草和短芒老芒麦等高禾草控制;垂穗披碱草单播群落牧草产量显著高于混播群落（P〈0.01）,第2年各群落生长趋势与建植当年基本一致,但混播群落的生长优势已开始显现。第3年,6种牧草混播处理的牧草产量显著高于单播群落（P〈0.01）。不同高、矮禾草的合理配置可有效地优化人工植被的群落结构,遏制单一种建植的快速退化现象,几种多年生禾本科牧草的合理混播配置可能是“黑土型”退化草地进行人工建植恢复的关键技术,是一项快速稳定恢复“黑土型”退化草地植被的重要措施。  相似文献   

复方中药合剂对肉仔鸡疫苗免疫抗体效价的影响          下载免费PDF全文

靳双星  张桂枝  李新正 《西北农业学报》2014,23(2):26-29

为探讨自拟复方中药合剂对疫苗免疫后抗体效价的影响。以AA肉仔鸡为研究对象,重点考察复方中药合剂分别与新城疫(ND)Clone-30疫苗、ND油乳剂灭活苗和传染性法氏囊病(IBD)冻干苗联用后,肉仔鸡血清中ND、IBD抗体效价的变化规律。结果显示,试验组鸡血清中的ND和IBD抗体效价均高于对照组。说明,该复方中药合剂可增强肉仔鸡的疫苗免疫效果,具有显著的免疫增强作用。  相似文献