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11.
Effect of lime application on microbial community in acidic tea orchard soils
in comparison with those in wasteland and forest soils 总被引:1,自引:0,他引:1
Lime application is a conventional technology to control acidification in tea orchard soils. We investigated the e ect of lime
application on soil microbial community diversity in the soils of three tea orchards, wasteland and forest. The BIOLOG data showed
that both the average well color development of all carbon sources and the functional diversity index increased with the liming rate in
the tea orchards and the forest, but decreased in the wasteland. The phospholipid fatty acid (PLFA) analysis showed that the structural
diversity index of soil microbial community increased with the liming rate in all the tea orchards, the wasteland and the forest. Lime
application also increased the soil-bacterial PLFA content in all the soils. Soil fungal and actinomycete PLFAs in the tea orchards
showed an increasing trend from 0 to 3.2 g CaCO3/kg application and then a decreasing trend from 3.2 to 6.4 g CaCO3/kg application.
The principal component analysis of BIOLOG and PLFA data suggested that lime application had a significant e ect on soil microbial
community structure, and land use had a greater e ect on soil microbial community structure compared to lime application. 相似文献
12.
Nitrification potentials of Chinese tea orchard soils and their adjacent
wasteland and forest soils 总被引:1,自引:0,他引:1
To investigate the nitrifying activities of di erent soil types, soil samples collected from 8-, 50- and 90-year old tea orchards, the
adjacent wasteland, and 90-year old forest were measured for their nitrification potentials using the conventional soil incubation and the
liquid incubation method. Among di erent soil types, the nitrification potential of soil in tea orchards was higher than that of wasteland
and forest soils. The slurry shaken liquid incubation method was confirmed to be more accurate and have reliable results than the
soil incubation. Interestingly, experimental result revealed that the generally applied pH value of 7.2 for the liquid media was not the
optimal pH for these acid soils with a strong bu er capacity. This suggested that tea orchard soils may have nitrifiers requiring pHneutral
condition for the best activity. Our data also showed that treatment with the commonly used nitrogen fertilizer urea significantly
improved nitrification potential of the soils; such enhancement e ect was stronger on all of three tea orchard soils than on wasteland
and forest soils, and also stronger on the younger (8- and 50-year old) tea orchard soils than on the older one (90-year old). 相似文献
13.
水杨酸对梨叶感染轮纹菌后脂肪酸、叶绿素荧光参数和叶绿体超微结构的影响 总被引:1,自引:0,他引:1
用0.3 mmol L-1水杨酸预先处理梨叶片,3 d后接种轮纹病菌(Physalospora Piricola Nose),接种3 d后开始测定各种指标,随后每隔3 d测定1次,共5次.结果表明,经SA处理的梨叶片,感染轮纹病菌后不饱和脂肪酸含量(UFA)、不饱和脂肪酸指数(IUFA)、叶绿素含量、原初光能转换效率(Fv/Fm)、PSⅡ潜在活性(Fv/Fo)、光合电子传递量子效率(ΦPSⅡ)和光化学猝灭系数(qP)比未经SA处理的相应提高;非光化学猝灭系数(qN)比未经SA处理的相应下降.电镜观察表明,部分叶绿体膨大,变形;基粒片层弯曲、散开;淀粉粒数量减少;经SA处理后,症状减轻.图3表1参20 相似文献
14.
15.
三峡库区规模化顺坡沟垄果园氮、磷输出过程及流失负荷 总被引:4,自引:0,他引:4
通过对三峡库区顺坡垄沟构型的规模化柑橘园集水区次降雨过程径流氮、磷进行动态监测,分析典型降雨事件氮和磷流失负荷,并探讨了规模化柑橘种植对土壤氮磷流失及入库河流水环境的影响.结果表明:①顺坡沟垄柑橘园集水区径流氮和磷年流失负荷分别为13.43 kg·(hm2·a)-1和1.26 kg·(hm2·a)-1,春季施肥及强降雨冲刷是集水区污染物高负荷的主要原因;②集水区全年总氮(TN)和总磷(TP)的EMC为8.49 mg·L-1和0.87 mg·L-1,超过发生水体富营养化含量标准;③春季施肥后的2场典型降雨中,长历时暴雨径流硝态氮(NN)和溶解态磷(DP)负荷为4.94 kg·hm-2和0.28 kg·hm-2,分别占TN和TP流失负荷的92.90%和64.69%;短历时大雨径流NN和DP负荷为0.52 kg·hm-2和0.05 kg·hm-2,分别占TN和TP的65.92... 相似文献
16.
Background Frequent application of Bordeaux mixture, which includes copper, as a fungicide in fruit and grape orchards may lead to copper accumulation in the soil, especially when orchard age and application times increase. The objectives of this study were: (i) to investigate the copper content and its spatial distribution in orchard soils; (ii) to identify the copper fractionation in soil and its relationship with plant uptake; (iii) to understand the characteristics of copper contamination in orchard soils. Materials and Methods Soil profile samples were taken in apple orchards with ages of 0, 5, 10, 20, 30 years and pot experiments were also carried out to study the effects of external copper input on copper fractionation. All soil samples were air-dried, ground and extracted with 0.43 mol L1 HNO3 for the total absorbed copper. Fractionation determination was conducted following Tessier and Shuman sequential extraction methods, and copper was measured with AAS. Plant samples were first dry ashed, dissolved with 6 mol L1 HCl and then copper and other elements were measured with ICP-MS.Results and Discussion Soil total Cu was higher in the apple orchards than that in non-orchard fields and was seen to have increased with orchard age. Soil Cu increased substantially with the average annual copper increase, ranging from 2.5 to 9 mg Cu kg1. The distribution of copper in the soil profile was uneven, decreasing from surface to deeper layers, and the differences were significant, but the contents in every layer were also significantly correlated with those in the next layers.
For all copper fractions, the organically bound, crystalline Mn oxide bound, and amorphous Fe bound fractions extracted with the Shuman method were much higher than the exchangeable and residual fractions. Using the Tessier method, organically bound, carbonate bound and Fe-Mn oxide bound fractions were much higher. With an increase in external copper input, the organically bound, crystalline Mn oxide bound and amorphous Fe bound fractions in the Shuman method and organically bound, carbonate bound and Fe-Mn oxide bound fractions in the Tessier method all increased significantly, while the changes in other fractions were not significant.
Soil total copper and copper fractions were found to have good correlations with apple tree uptake. Copper in fruit flesh had significant correlations with soil total content in the 010 cm layer, all the copper fractions in the 05 cm layer, and some fractions in the deeper layers. Conclusion Copper content in orchard soils increased significantly with intensive application of Bordeaux mixtures and orchard age. Copper content decreased sharply from the topsoil to deeper soil layers. The copper contents in different layers also significantly correlated with those in the next layers. Dominant fractions of the copper in soil were mainly associated with organic matter, iron and manganese oxides and carbonates. A close relationship was found between the copper content in soils and in apple tree organs (which contained 8.9 to 66mg kg1 Cu). Recommendation and Perspective Though most copper in the soil was specifically adsorbed or immobilized, and copper was mainly distributed in topsoil, which was essentially devoid of roots, the copper concentration of fruit still had significantly positive correlations with soil copper and most copper fractions. Therefore, measures must be taken to control copper accumulation in orchard soils and to make the apple fruit production sustainable. 相似文献
17.
18.
苹果园土壤呼吸的变化及生物和非生物因素的影响 总被引:1,自引:1,他引:0
了解果园土壤呼吸变化及其影响因素,有利于深入理解退耕还果条件下黄土高原地区土壤碳源汇功能.在长武农田生态系统国家野外站,以盛产期果园(2000年建成)为对象,利用土壤碳通量测量系统(Li-COR,Lincoln,NE,USA)于2011、2012年监测了果树冠幅下距树干不同距离处土壤呼吸、土壤水分和温度变化,分析了土壤呼吸的时空变化及其影响因素.结果表明:①土壤呼吸速率随着距树干距离延长而降低.与2 m处相比,0.5 m处土壤累积呼吸量2011年提高20%,2012年提高31%;0.5 m和2 m处土壤呼吸的温度敏感性(Q10)2011年相应依次为1.79和1.56,2012年依次为1.79和1.38.②距树干2 m处温度和水分稍高于0.5 m处,但差异不显著(P>0.05).土壤呼吸与土壤温度均呈显著的指数关系,而与土壤水分的相关性不显著.温度变化可解释土壤呼吸的季节性变化,但并不能解释距离树干不同处的差异.③距离树干不同位置处的根系密度差异是影响果园土壤呼吸空间变化及其温度敏感性的重要生物因素;④冠幅下土壤呼吸的变异系数为23%~31%.估算果园土壤呼吸需考虑其距离树干的空间差异性. 相似文献
19.
有机肥替代作为一种减肥增效和多元化肥替代技术在农业生产中被大力推广.然而,目前尚缺乏对于有机肥在果园N2 O和NO排放方面的影响综合评估.采用静态暗箱-气相色谱法,周年观测桃园种植过程中N2 O和NO的排放,比较了单施化肥和有机肥部分替代化肥处理对桃园氮氧化物排放的影响.结果表明,有机肥部分替代化肥分别降低桃园N2 O和NO排放总量15.0 %和9.4 %,同时 N2 O和NO排放系数降低21.3 %和21.1 %.有机肥处理土壤的矿质氮含量低于单施化肥处理.有机肥处理提高了硝化作用中AOA的贡献,降低AOB的贡献,从而减少了硝化作用产生的N2 O.此外,双同位素混合模型[δ18O(N2 O/H2 O)vs.δ15NSP]结果表明,硝化细菌反硝化/细菌反硝化(bD/nD)是桃园土壤N2 O排放的主要途径.施用有机肥增强了土壤反硝化作用,导致更多的N2 O和NO被还原.因此,有机肥部分替代可以缓解果园氮氧化物排放,是实现农业绿色低碳的可行措施. 相似文献
20.
Based on growth level and peroxidase activity, a comparative study and paried-samples t test were made between vires-free Zaosu pear seedlings and the seedlings inoculated with apple stem grooving virus(ASGV). The results showed : ( 1 )virus-free Zaosu pear seedlings grew better than inoculated ones. Of the seedlings the height, diameter, branches and autumn braches differed statistically significantly; (2)the peroxidase activity of inoculated seedlings was higher than that of virus-free ones, and the peak of peroxidase activity occurred on about d 7 and d 24 after inoculation. Fig 1, Tab 1, Ref 9 相似文献