参与碳氮磷转化的水解酶对不同施肥响应的差异

本文旨在研究土壤水解酶对不同施肥的响应差异以及影响因素。通过在红壤中添加牛粪有机肥、化肥进行90d的室内土壤培养试验,采用微孔板荧光法动态分析5、30和90d参与碳氮磷转化的土壤水解酶(α-1,4-葡萄糖苷酶、β-1,4-葡萄糖苷酶、纤维素酶、木聚糖酶、亮氨酸氨基肽酶、β-1,4-N-乙酰氨基葡萄糖苷酶、磷酸酶)活性。与不施肥(对照)相比,在30 d后,化肥处理的总酶活性显著下降,对应的参与碳氮磷转化酶活性均有不同程度下降;而有机肥处理的总酶活性在培养期内均未发生显著变化,但是其α-1,4-葡萄糖苷酶显著增加,而磷酸酶活性显著降低。参与碳转化的4种水解酶中,只有α-1,4-葡萄糖苷酶活性对施肥的响应较强,且施加有机肥增加其活性而无机肥则降低其活性;对于参与氮转化的水解酶而言,化肥明显抑制了亮氨酸氨基肽酶活性,而有机肥增加了β-1,4-N-乙酰氨基葡萄糖苷酶活性;磷酸酶活性明显受到有机肥的抑制作用,而对化肥的响应总体不明显。不同水解酶对不同施肥的响应有明显差异,NMDS分析表明,α-1,4-葡萄糖苷酶和亮氨酸氨基肽酶响应最明显,其次为磷酸酶与木聚糖酶;相关和冗余分析显示,土壤p H、可溶...     

有机无机肥配施对旱地作物养分利用率及氮磷流失的影响

采用2年的田间小区试验,研究猪粪、猪粪堆肥或沼渣沼液与化肥配施对春玉米-小白菜轮作地氮磷径流损失与肥料利用率的影响.结果表明,有机无机肥配施可明显减少旱地氮素流失,NH+-N和NO3--N流失量占总氮流失的比例为49.08％～52.02％,且地表氮素径流损失量随着猪粪堆肥用量的增加而降低;与施纯化肥相比,以20％的猪粪堆肥N与80％化肥N配施可分别降低氮素径流损失28.95％,2年总氮肥利用率提高8.13％.以猪粪堆肥或沼渣沼液与化肥配施可明显降低磷素径流损失,并提高磷、钾肥利用率;与施纯化肥相比,以20％的猪粪堆肥氮或沼渣沼液氮与80％的化肥氮配施可分别减少磷素流失4.74％和2.76％,2年总磷肥利用率分别提高1.06％和2.75％,2年总钾肥利用率分别提高2.62％和11.48％.     

The Effect of Bat Guano Applied to the Soil in Different Forms and Doses on Some Plant Nutrient Contents

This research was conducted for the purpose of determining the effects of bat guano on plant nutrient contents in the soil and in lettuce (Lactuca sativa L.) during the spring of both 2014 and 2015 with three replications according to randomized blocks experiment design. Bat guano was applied to the soil in two different forms; According to the results organic matter, P, Cu and Mn amounts in the soil were found to be statistically significant and increased compared to the control. Likewise, in the application of bat guano dust, organic matter, P and Mn amounts in the soil were found to be statistically significant and increased compared to the control. In lettuce, N, K, Mg, Fe, Cu, Zn and Mn amounts in the application of bat guano powder and K, Ca, Mg, Fe, Zn and Mn amounts in the application of bat guano dust were found to be statistically significant.     

草甸草原土壤不同组分有机碳含量及化学结构对长期氮输入的响应

为探究长期氮输入对草甸草原土壤不同组分有机碳含量及化学结构影响，以内蒙古东北草甸草原为研究对象，于2010年设置0(CK)、30(N30)、50(N50)、100(N100)、150(N150)、200(N200)kg/(hm~2·a) 6个不同施氮水平处理，测定土壤不同组分有机碳含量及红外光谱特征。结果表明：(1)相比CK，长期氮输入条件下可提高土壤总有机碳(SOC)含量(增幅0.3%～13.6%)，且主要表现为颗粒有机碳(POC)含量的增加(9.22%～16.39%)，但降低土壤轻组有机碳(LOC)含量。(2)红外光谱主成分分析(PCA)结果表明，土壤LOC主要来源于脂肪碳、芳香碳、酚醇化合物，POC主要来源于芳香碳和酚醇化合物，矿物结合有机碳(MOC)主要来源于烷基碳和多糖。(3)相比CK，施氮处理凋落物和LOC官能团中烷氧碳(单糖+多糖)的相对强度降低，烷基碳、芳香碳相对强度增加；土壤POC和MOC官能团中烷氧碳、烷基碳及芳香碳相对强度增加，酚醇化合物相对强度降低；且施氮处理下凋落物及其不同土壤碳组分有机碳结构稳定性(芳香碳/脂肪碳)均高于CK。(4)结构方程模型(SEM)结果...     

Effects of Green Manures and Zinc Fertilizer Sources on DTPA-Extractable Zinc in Soil and Zinc Content in Basmati Rice Plants at Different Growth Stages

Rice is very sensitive to low zinc(Zn) supply in submerged paddy soils and Zn deficiency is one of the major limiting factors in determining rice production in India. A field experiment was conducted during the summer-rainy seasons of 2009 and 2010 at the research farm of the Indian Agricultural Research Institute, New Delhi, to determine the effects of summer green manure crops and Zn fertilizers on diethylenetriaminepentaacetic acid(DTPA)-extractable(available) Zn concentration in soil and total Zn content in Basmati rice cultivar Pusa Basmati 1 at periodic intervals. Summer green manure crops included Sesbania aculeata(Dhaincha),Crotalaria juncea(Sunhemp), and Vigna unguiculata(Cowpea) and the Zn fertilizers used were ethylenediaminetetraacetic acid(EDTA)-chelated Zn, ZnSO_4·7H_2O, ZnSO_4·H_2O, ZnO, and ZnSO_4·7H_2O + ZnO. Beneficial effects of summer green manure crops and Zn fertilizers on DTPA-extractable Zn concentration in soil and total Zn content in dry matter of Basmati rice at periodic intervals were observed, with significant increases in all the determined parameters, in comparison with those in the control(no Zn application or summer fallow). The rate of increase varied among summer green manure crops and Zn fertilizers during both years. Among the summer green manures, incorporation of S. aculeata led to a significant increase in mean Zn content in Basmati rice grain and straw when compared with C. juncea, V. unguiculata, and summer fallow treatments. Among the Zn fertilizers, significant increases in Zn content in Basmati rice dry matter and DTPA-extractable Zn concentration in soil during various growth stages of the plant were recorded with EDTA-chelated Zn application, followed by the application of ZnSO_4·7H_2O, ZnSO_4·H_2O, ZnSO_4·7H_2O + ZnO, ZnO,and no Zn. The highest mean Zn content in Basmati rice grain and straw was recorded with EDTA-chelated Zn application in 2009 and 2010, respectively. The application of ZnSO_4·7H_2O was the second best treatment after EDTA-chelated Zn; however, it was statistically inferior to EDTA-chelated Zn. The lowest values were recorded with the control(no Zn application) during both years of study. The amount of Zn concentration in soil was found to be significantly positively correlated with the Zn content in Basmati rice dry matter during both years. Significantly higher levels of residual fertility in soil after the harvest of Basmati rice were observed with application of EDTA-chelated Zn and incorporation of S. aculeata when compared with those of other Zn sources and summer green manures.