Evaluation of soil quality parameters in a tropical paddy soil amended with rice residues and tree litters   总被引：2，自引：0，他引：2  

B.K. Rajashekhara Rao  R. Siddaramappa 《European Journal of Soil Biology》2008,44(3):334-340

Laboratory and greenhouse experiments were conducted to study the effects of applications of rice residue and Pongamia pinnata and Azadirachta indica leaf litters on biochemical properties (extraction yield of humus, composition of humus, microbial biomass carbon, activities of urease and acid phosphatase) of a lowland rice soil under flooded conditions. Bulk soil sample collected from the Mandya paddy fields was used for the green house trials and the laboratory incubation studies. The organic materials were added at three rates – zero, 25.0 g carbon kg⁻¹ (2.5% C) and 50.0 g carbon kg⁻¹ dry soil (5.0% C). Results showed that tree leaf litter and rice residue at 5.0% C rate decreased instantaneous decay constant (k), there by retarded the rate of C mineralization. Carbon contents of HA increased with the rate of C added. Study of delta–log K values and C contents of humic acids revealed that greatest molecular weight of HA was in the pongamia litter treatment, followed by neem litter and rice residue. Grain and straw yields of rice crop in the pot culture study were statistically correlated to the soil quality parameters. Neem and pongamia tree litter incorporation at 2.5% C could be considered for improving soil health and crop yields of rice under flooded conditions; however, application at higher rates significantly (P ≤ 0.05) lowered total dry matter production in rice, despite favorable soil health parameters such as humic yields, microbial biomass – C content and acid phosphatase and urease activity. Among different soil health parameters, microbial quotient was found to be more sensitive indicator of decline in soil quality.  相似文献   

NBPT与DMPP不同剂量组合对尿素氮转化的影响   总被引：3，自引：0，他引：3  

XING Wei  陈利军  CHEN Zhen-hua  武志杰  JUAN Ying-hua  史云峰 《土壤通报》2008,39(4)

采用室内模拟试验的方法,探讨了脲酶抑制剂N-丁基硫代磷酰三胺(NBPT)和硝化抑制剂3,4-二甲基吡唑磷酸盐(DMPP)的不同浓度组合对尿素氮转化的影响。结果表明,NBPT与DMPP不同浓度组合均不同程度的延缓了尿素的水解,使尿素N水解产物更加以NH4+-N形态保持在土壤中;延缓了硝化作用进程并减少了硝酸盐在土壤累积,在此基础上增加了土壤有效态N含量。综合不同浓度组合对尿素水解的抑制、土壤NH4+-N和NO3--N含量变化、硝化作用抑制效果、土壤有效态N水平等指标并结合成本考虑,NBPT和DMPP分别为0.1%和0.5%施氮量时为最适宜的组合。  相似文献   

石榴果皮中抑菌活性物质提取工艺优化(简报)   总被引：2，自引：0，他引：2  

董周永  胡青霞  郭松年  赵国建  杜宝生  刘兴华 《农业工程学报》2008,24(3):274-277

为了研究石榴果皮中抑菌活性物质的提取工艺,以金黄色葡萄球菌做指示菌,以抑菌圈直径为活性追踪指标,在单因素试验的基础上通过二次回归正交旋转组合设计进行工艺参数优化.结果表明,对石榴果皮抑菌活性物质提取效果的影响大小顺序为:乙醇浓度、提取温度、液固比,提取时间;其最佳提取工艺条件为乙醇浓度60%,液固比10:1,提取温度60℃,提取时间4h.在此优化条件下,石榴果皮提取液抑菌圈直径为16.30 mm.  相似文献   

应用~(13)C核磁共振技术研究土壤有机质化学结构进展   总被引：11，自引：1，他引：10  

李娜  盛明  尤孟阳  韩晓增 《土壤学报》2019,56(4):796-812

土壤有机质化学结构对准确评价土壤有机质的稳定性及其在土壤中的功能具有重要意义。土壤有机质化学结构的研究方法中,固态~(13)C核磁共振波谱技术(Solid-state ~(13)C-NMR spectroscopy)具有独特优势,对土壤有机质化学结构的解析更贴近真实状态,近年来已取得诸多新进展和新突破。综述了近年来应用~(13)C-NMR测定土壤全土、团聚体和密度组分、腐殖质组分的有机碳化学结构特征,分析了影响化学结构变化的因素。不同气候条件、植被类型、土地利用管理方式、土壤类型、土壤有机碳含量的全土中有机碳化学结构比较相似,均表现为烷氧碳比例最高,其次为烷基碳和芳香碳,羧基羰基碳比例最低。土壤有机碳主要来源于外源植物残体,植物残体化学结构的相似性可能是导致土壤有机碳化学结构相似的主要原因,环境条件、土壤自身属性和微生物活性的差异使土壤有机碳化学结构产生微小差异。土壤颗粒及化学组分间的有机碳分子结构差异较大,大颗粒有机碳中烷氧碳比例最高,小粒径及与矿物颗粒结合的有机碳中烷基碳和羧基羰基碳比例更高,粉黏粒和腐殖酸组分的有机碳化学结构在土壤类型间差异较大。今后的研究重点应更多地关注土壤有机质来源的定量化分析、土壤微生物对土壤有机碳组分和结构稳定性的贡献及调控机制、土壤有机碳稳定性的生物物理化学保护机制、空间大尺度环境因子/土壤生态过程与微观尺度的有机碳化学分子结构的耦合作用机制、跨学科的多种土壤有机碳化学分子结构测定辨识技术等方面的研究。  相似文献   

发芽过程中大豆活性物质、抗营养因子及抗氧化活性变化的综述     

高春霞  王凤忠  袁莉 《核农学报》2019,33(5):962-968

大豆是一种优质的蛋白质资源。大豆种子发芽过程中大豆多肽、大豆异黄酮、大豆皂苷、γ-氨基丁酸及维生素C等活性物质含量增加,大豆胰蛋白酶抑制剂、血球凝集素、脂肪氧化酶和植酸等抗营养因子含量下降。随着发芽时间的延长,大豆DPPH自由基清除能力和铁还原力等抗氧化能力增强。因此,发芽可作为提高大豆及其制品的营养价值、消化性、适口性及生物利用性的重要手段。本文对发芽期间大豆中生物活性物质、抗营养因子及抗氧化活性的变化进行综述,并展望了发芽大豆的综合性应用,以期明确大豆发芽过程中各活性物质变化规律,为发芽大豆在食品中的应用提供科学依据。  相似文献   

生化抑制剂组合与施肥模式对黄泥田稻季田面水及 渗漏液氮素动态变化的影响   总被引：4，自引：0，他引：4  

周旋  吴良欢  戴锋  董春华 《土壤》2019,51(3):434-441

采用二因素随机区组设计,研究生化抑制剂组合(N-丁基硫代磷酰三胺(NBPT)、N-丙基硫代磷酰三胺(NPPT)和2-氯-6-(三氯甲基)吡啶(CP))与施肥模式(一次性施肥和分次施肥)互作对黄泥田稻季田面水和渗漏液氮(N)素浓度动态变化特征的影响。结果表明,黄泥田稻季田面水和渗漏液中N素形态分别以NH4+-N和NO–3-N为主。基肥施用后,稻田田面水中NH4+-N和总氮(TN)浓度于第1天达到峰值后降低,第6天分别降为峰值的57.9%～69.1%、41.9%～59.0%(一次性施肥)和29.9%～60.7%、60.9%～69.7%(分次施肥);稻田渗漏液中NO–3-N和TN浓度于第1～3天达到峰值后降低,第6天分别降为峰值的51.4%～56.5%、56.6%～61.6%(一次性施肥)和45.3%～57.5%、51.1%～59.6%(分次施肥)。不同施肥模式下,硝化抑制剂CP会提高田面水NH4+-N浓度,而脲酶抑制剂NBPT/NPPT或配施CP有效抑制脲酶活性,降低田面水NH4+-N峰值;CP显著降低渗漏液NO–3-N浓度,且CP或配施NBPT/NPPT有效抑制硝化作用,降低渗漏液NO–3-N峰值。新型脲酶抑制剂NPPT单独施用及与CP配施的稻田田面水和渗漏液N素浓度动态变化特征与NBPT相似。总之,生化抑制剂与适宜的氮肥运筹相结合更能有效延缓黄泥田中尿素水解,抑制硝化作用,减少N素径流和渗漏损失。  相似文献   

Evaluation of Two Products Recently Introduced as Nitrification Inhibitors     

R. Jay Goos 《Communications in Soil Science and Plant Analysis》2019,50(5):503-511

This study compared the relative effectiveness of two products recently introduced as nitrification inhibitors with other materials used to inhibit nitrification. Four soils were treated with 0, 0.2, 1, 5, and 25 mg kg^?1 of nitrapyrin (NP), a new microencapsulated nitrapyrin product (ENP), dicyandiamide (DCD), a new maleic-itaconic polymer product (MIP), and ammonium thiosulfate (ATS). The soils were also treated with 200 mg N kg^?1 as urea, and percent inhibition of nitrification determined after 2 or 4 weeks of incubation. After 4 weeks, similar levels of nitrification inhibition were provided by 1 mg kg^?1 of NP (72%), 5 mg kg^?1 of ENP (79%), and 25 mg kg^?1 of DCD (73%), averaged across soil. After 4 weeks with a sandy soil, the highest rate of MIP and ATS provided 15 and 36% inhibition, respectively. MIP and ATS were ineffective at inhibiting nitrification when added to the other three soils.

Abbreviations: ATS: ammonium thiosulfate; DCD: dicyandiamide; ENP: encapsulated nitrapyrin; MIP: maleic-itaconic polymer; NP: nitrapyrin; UAN: urea-ammonium nitrate liquid fertilizer  相似文献   

The effect of biostimulators on the content of crude oil and total protein in winter oilseed rape (Brassica napus L.) seeds     

Marek Gugała  Krystyna Zarzecka  Krzysztof Kapela  Iwona Mystkowska 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2019,69(2):121-125

The objective of the study was to determine the effect of the experimental factors on the seed quality of three winter oilseed rape cultivars. The following factors were studied: I-three winter oilseed rape morphotypes: population, hybrid restored characterised by a semi-dwarf growth pattern, hybrid restored characterised by a conventional growth pattern; II-two sowing methods: a spacing of 22.5?cm, a spacing of 45.0?cm; III-four types of biostimulants: control-no biostimulants, the biostimulant Tytanit^®, Asahi^®SL, Silvit^®. Seed samples were subjected to chemical analysis to determine: crude oil, total protein and crude fibre. Natural stimulants of plant growth and development contributed to an increase in crude oil ranging from 7.4 to 9.5?g?kg^–1 d.m., on average, compared with control. The biostimulants applied did not affect total protein content which was, however, affected by meteorological conditions in individual study years as well as the genetic factor. Biostimulants increased crude fibre content compared with control.  相似文献   

干旱胁迫对垂柳生理特性的影响   总被引：1，自引：0，他引：1  

石峰 《陕西林业科技》2019,(2):6-10

试验在田间条件下研究了干旱对垂柳2年生苗生理特性的影响规律,结果表明:随着干旱时间的延长,垂柳叶片内叶绿素a、叶绿素b、总叶绿素含量均有所降低,6月9日,干旱处理与对照相比分别降低了1.45、0.30、1.45mg·g^-1;干旱胁迫提高了保护酶活性,其中POD、SOD、CAT活性分别比对照提高了14.30、17.42、9.67U·g^-1;渗透物质含量在干旱持续时间超过25d后显著升高,其中可溶性蛋白、可溶性糖、游离脯氨酸含量与对照相比分别提高了40.10%、25.33%、69.46%;电导率在干旱持续15d后显著升高,MDA含量在干旱持续10d后显著升高,试验结束时分别比对照提高了21.47%、35.62%。综合分析认为,浇水25d后垂柳生理特性会发生显著变化。  相似文献   

铅胁迫对马铃薯幼苗生长形态及内源激素的影响     

宋洁  郭华春  李俊  张光海  思玲超 《西北农业学报》2019,28(11):1830-1835

以高富集马铃薯品种‘青薯9号’和低富集马铃薯品种‘丽薯6号’为试验材料,研究不同质量浓度Pb处理对供试马铃薯幼苗生长形态和内源激素的影响。结果显示,Pb处理质量浓度小于250 mg/L时对供试马铃薯幼苗的生物量有促进作用,当质量浓度大于500 mg/L时对供试马铃薯幼苗的生物量有抑制作用,不同程度Pb处理,重金属低富集型‘丽薯6号’脱落酸(ABA)和水杨酸(SA)质量分数高于重金属高富集型‘青薯9号’,生长素浓度为26.47～38.29 pmol/L,处于促进根系生长的最适浓度。低质量浓度Pb对马铃薯幼苗生长有促进作用,高质量浓度Pb对马铃薯幼苗生长有抑制作用,不同质量浓度Pb处理下马铃薯幼苗内源激素变化是一个比较复杂的过程, ABA、SA、乙烯、生长素、玉米素和赤霉素共同参与马铃薯在重金属胁迫下的协调机制。  相似文献