人工影响天气在农业生产服务中的重要性及应用

我国是农业大国,农业是我国国民经济的基础,也是经济发展、社会安定、国家自立的基础。气象因素往往会对农业生产造成很大影响,给农民带来经济损失,不利于农业经济的发展。基于此,对人工影响天气在农业生产服务中的重要性及应用进行相关讨论,以提高我国气象为农服务水平,促进农业发展。     

人工湿地在农业面源污染治理中的应用探究

云南省拥有很多高原湖泊,其生态环境比较脆弱,且污染日益严重,所以有必要寻找有效的污染治理方法。就目前的湖泊污染治理经验来看,人工湿地在农业面源污染治理中的应用具有较好的效果,因此针对相关内容展开分析,旨在为实践提供指导。     

植物化感作用类型及其在农业中的应用

本文总结前人研究成果的基础上,对不同植物化感作用类型及其作用机制和在农业中的应用进行了探讨。植物化感作用包括化感偏害作用、自毒作用、自促作用和互惠作用。植物化感偏害作用是由植物根系分泌物介导下的植物与特异微生物共同作用的结果。利用植物化感偏害作用控制田间杂草是一项环境友好型的可持续农业技术,并已在水稻化感抑草研究方面取得了较突出的成果。植物化感自毒作用(作物连作障碍)是造成作物产量降低、生长状况变差、品质变差、病虫害频发的现象。药用植物,特别是以根部入药的药用植物中,连作障碍表现更为突出。近年来研究结果认为根系分泌物生态效应的间接作用及土壤微生物区系功能紊乱是导致植物连作障碍的主要因素。因此,改善土壤生长环境,恢复和修复根际土壤微生物结构平衡,增强生态系统机能是克服作物连作障碍的关键。植物化感自促作用(连作促进作用)是在植物根系分泌物促进下,根际土壤微生物之间此消彼长,有益微生物之间互利协作,土壤肥力和营养补给能力明显改善,从而增强植物根系抗性,促进植物生长发育,提高产量和品质的结果。牛膝的连作促进作用明显,有学者试图通过牛膝与其他不耐连作药用植物间作套种或轮作,实现药用植物生产的可持续发展。植物间的正相互作用(互惠作用)是作物间套种系统超产和养分等资源高效利用的重要机制,根系分泌物在介导根际微生物与植物的有利互作中起到重要作用。最后作者强调指出,存在于根际土壤的微生物群落的宏基因组组成是决定植物能否健康生长的关键。深入研究存在于土壤生态系统中的植物体外基因组的组成与演化机制,将成为借用现代合成生物学原理与技术,定向控制植物根际生物学过程,促进作物生产可持续发展的优先研究领域。     

植物化感作用及其在草地农业生态系统中的应用

植物化感作用作为一种自然的生态现象,在自然界中普遍存在.目前对植物化感作用的研究主要集中在化感物质的分离、鉴定、释放途径、作用机理及化感作用对农、林、牧等草地农业生态系统持续发展的应用潜力等方面.但化感作用在草地农业中的具体作用和应用还缺乏深入系统地概述.为探明化感作用在草地农业生态系统的作用,本文从植物化感作用的物质...     

农业机械化技术在乡镇农业生产中的推广及应用

我国作为农业大国,农业一直是国民经济发展的重要内容。随着经济和科学技术的飞速发展,农业已经逐渐步入了机械化的发展道路。农业机械化技术的推广应用,大大提高了乡镇的农作效率,增加了广大农民的收入。但是,当前乡镇的农业机械化技术在推广及应用方面存在一定的问题。基于此,简述了农业机械化技术对乡镇农业生产的积极影响,分析了农业机械化技术在推广及应用中存在的问题,并给出了相应的解决措施。     

计算机与PLC一体化控制技术在农业智能化生产中的应用探究

随着现代科学技术与农业生产的不断融合,农业智能化生产成为一种十分重要的农业新型生产模式,而计算机与PLC一体化控制技术作为新型农业智能化生产技术,其重要性逐渐突显出来.计算机与PLC一体化控制技术主要借助计算机控制系统和PLC控制设备以及其他配套设备来控制和调节作物生产所需环境条件,是一种新型农业生产模式,是农业摆脱自...     

蚯蚓粪肥在农业生产中的应用效果及研究进展

蚯蚓粪肥是将经蚯蚓消化有机废物产生的排泄物进行堆肥而制成的有机肥料,故含有丰富的营养物质和有益微生物.近年来,作物生产的应用效果表明,蚯蚓粪肥能改善土壤结构和微生物种群,促进作物生长、提高作物产量和农产品品质,还能增强植物抵抗病虫害能力,降低土壤中有毒重金属对植物危害.本文对蚯蚓粪肥的作用及相关研究进展进行综述,得出了...     

环保酵素的生物活性及在农业生产中的应用

为探究环保酵素在农业生产中的应用效果和方式,对环保酵素成分活性、在农业生产中的应用和所存在的问题进行总结和分析.发现环保酵素的代谢产物中富含多种有益微生物和活性物质,具备良好的生物活性,能够在种植业和养殖业发挥重要作用,合理利用环保酵素能够有效促进生态农业的建设和发展.     

天气预报在农业防灾减灾中的应用及提升对策探析

天气预报能够合理预测未来天气变化,对于农业防灾减灾工作的开展极为有利。在全球气候变暖的大背景下,我国气象灾害频繁出现,对农业生产的影响不断加重。因此,做好天气预报工作对于确保农业高产丰收极其重要。在简要概述天气预报种类的基础上,重点分析了天气预报在农业防灾减灾中的应用,给出了提升气象为农业防灾减灾的对策,以确保农业生产持续健康发展。     

聚-γ- 谷氨酸在农业中的应用及展望

聚-γ- 谷氨酸(γ-PGA)是一种主要由微生物生产的胞外高分子聚酰胺,仅由谷氨酸单体组成,具有阴离子特性、离子吸附性、螯合性、吸水性、生物可降解性和生物兼容性。在农业生产中用作肥料增效剂,能显著地促进作物生长、增加作物产量和提高肥料利用率,具有显著的增产节肥效应。γ-PGA 具备完全生物可降解性和生物兼容性,相较于其它肥料增效剂具有突出的生态和环保优势,未来在农业生产中具有广阔的应用前景。理解其增产节肥作用机制是应用和推广γ-PGA 新型肥料的理论基础,为进一步扩大和加深γ-PGA 在肥料产业和农业中的效果和贡献,未来应着重从土壤养分转化、植物营养和植物生理角度开展其增产节肥作用机制。同时,开展其对不同化肥的增效效果研究是靶向开发与应用新型聚氨酸肥料的理论基础和科学支撑。     

Uncomposted Sheep and Cow Manures as a Source of Commercial Humic Amendments: An Exploratory Study

Liquid humic amendments are widely used in many countries as an enhancer of crop production (particularly root growth). While leonardite is the main substrate for obtaining these products, there is growing concern about obtaining them from plant-derived residual materials, rich in lignin and polyphenolics, thus making possible a residue valorization. Composting is a necessary step for converting these residues into a source of humic substances. In arid countries, obtaining humic products from sources other than leonardite faces two main challenges: (i) often such countries are devoid of forested areas or tree crops capable of supplying lignin-rich residues in large amounts and (ii) water is scarce (or very expensive if obtained by desalination) and therefore composting on an industrial scale is very difficult. Thus it is essential to find alternative sources capable of yielding humic or humic-like compounds without any previous composting. Here we present the main results obtained using sheep and cow manure, two materials widely available in the Kingdom of Saudi Arabia (KSA). Both were extracted using potassium hydroxide (KOH) at a variety of concentrations (from 0.25 to 2 M), times (from 20 to 120 min), temperatures (from 100 to 150 °C), and pressures. Sheep manure, much easier to extract than cow manure, appears the more promising as a source of commercial humic amendments. No lengthy extraction times are needed to obtain alkaline extracts; 20 min yields only slightly less humic-like matter than 2 h. The relative abundance of humic-like substances in the extract tends to decrease with time, but some optical indicators of humification (E₄/E₆ ratio, absorption at 280 nm, ratios of absorption at 253/203 and 253/220 nm) tend to increase. Polysaccharides, the dominant form of organic matter in the original manure, strongly resist alkaline extraction: their prior hydrolysis may be necessary to increase the yields of humic-like matter from the studied manures.     

Humus Characterization of Humid Tropical Forest,Tea Garden,and Field Crop Soils of West Bengal,India: Chemical,Potentiometric, and Spectroscopic Methods

Humic acids (HA) and fulvic acids (FA) were extracted from tropical humid forest, tea garden, and field crop soils, and their chemical, potentiometric, and spectrophotometric properties were measured. There was less HA than FA in the cultivated soils. The HAs contained more carbon (C) and nitrogen (N) and had greater C/H ratios but lower O (oxygen)/H (hydrogen) ratios than FAs. Cultivated soils had greater total acidity than the forest soil generally because of both —COOH and phenolic-OH. Molecular weights of HA an FA, estimated from intrinsic viscosities, revealed that cultivation had reasonably reduced the molecular weights. The difference in pH (ΔpH) values, corresponding to three-fourths and one-fourth of the pH at final inflexion point showed that they were polyprotic. The longer time required for stability of greater pH of HAs was related to greater degree of stable coiling. The (E₄/E₆), in general, revealed a greater amount of aliphatic moiety rather than aromatic moiety.     

Effect of Fe,Mn or Al Compounds on Humification of Three Types of Plant Residues during Thermal Incubation

The effect of three inorganic minerals on the humification of three types of plant residues was determined by employing a model thermal incubation experiment. The plant residues consisiting of rice (Oryza sativa) straw, broadleaf tree (a mixture of oak/beech, Quercus serrata, Q. dentata, Q. acutissima etc.) sawdust and Japanese cedar (Cryptomeria japonica) sawdust were each mixed with Fe, Mn and Al in the form of hydroxides, oxides and sulfates. Humic materials were extracted after incubation and their composition was analyzed using a mixed solution of 0.02 M Na₄P₂O₇ and 0.1 M NaOH. The pH values of the samples after a longer duration of the incubation period were all less than 5.0, with the lowest value of 2.16 for a sample incubated with Al₂(SO₄)₃, except for the values of the samples incubated with MnO₂, which ranged from 4.75 to 6.0. The ΔlogK values decreased with the increase of the duration of the incubation period, whereas the RF values increased, as well as the amount of humus extracted (HE) and percentage of humic acid (PQ). Whereas most of the samples were identified as Type B and Type Rp humic acids, Type A humic acid was formed in all the plant residues incubated with Al₂(SO₄)₃, FeO(OH) and MnO₂ after ?180 d of incubation period. Moreover, the degree of humification of the plant residues was observed in the order of broadleaf tree > rice straw > Japanese cedar. It can be concluded that the inorganic compounds Al₂(SO₄)₃, FeO(OH) and MnO₂ contributed to the acceleration of the humification process of plant residues during the thermal incubation. The effect of Al₂(SO₄)₃ may be associated with the increase in the reactivity with other components in the system due to its high solubility, whereas FeO(OH) and MnO₂ may be involved in a reduction-oxidation reaction during the incubation. The browning and/or blackening of the plant residues were similar to the production of melanoidin which led us to consider that the mechanism involved in the study was similar to that of the Maillard reaction.     

Are humic substances soil microbial residues or unique synthesized compounds?A perspective on their distinctiveness

Humic substances(HS),which are defined as a series of highly acidic,relatively high-molecular-weight,and yellow to black colored substances formed during the decay and transformation of plant and microbial remains,ubiquitously occur in nature.Humic substances represent the largest stable organic carbon pool in terrestrial environments and are the central characteristic of the soil.However,the validity of the HS concept and the justification of their extraction procedure have been recently debated.Here,we argue that the traditional humic paradigm is still relevant.Humic substances are distinctive and complex because the extracted HS formed during the humification are chemically distinct from their precursors and are heterogeneous among soils.By reviewing the concept,formation pathways,and stabilization of HS,we propose that the key question facing soil scientists is whether HS are soil microbial residues or unique synthesized compounds.Without revealing the distinctiveness of HS,it is impossible to address this question,as the structure,composition,and reactivity of HS are still poorly known owing to the heterogeneity and geographical variability of HS and the limits of the currently available analytical techniques.In our view,the distinctiveness of HS is fundamental to the soil,and thus further studies should be focused on revealing the distinctiveness of HS and explaining why HS hold this distinctiveness.     

Bacteriological studies on the mineralization of soil organic nitrogen in paddy soils

Anaerobes were isolated from both disrupted and undisrupted soil samples incubated under submerged condition. All isolates were divided into 9 groups based on their gram stain and morphological characteristics. Correlation coefficients between the amount of nitrogen mineralized and the number of each group were calculated. A significant correlation was observed only between the amount of nitrogen mineralized and the number of gram positive-rod shaped anaerobic microorganisms (r=0.768 at P=0.05). This result indicates that in this study system, sorne particular anaerobes may play an important role in the mineralization of soil organic nitrogen.     

有机物料对不同作物根系土壤腐殖质组成和结构的影响

为探讨施用有机物料后不同作物根系土壤腐殖质各组分含量和胡敏酸元素组成的变化情况,以吉林农业大学试验田培肥2a的黑土为研究对象,试验选取3种作物(玉米、大豆、白菜),每种作物设4种施肥处理,包括化肥(CK)、玉米秸秆配施化肥、树叶配施化肥和鸡粪配施化肥。采用腐殖质修改法提取水溶性物质(WSS)、胡敏酸(HA)、富里酸(FA)、胡敏素(HM),利用重铬酸钾外加热法测定腐殖质各组分有机碳含量,采用分光光度计法测定HA和FA的光学性质,通过光密度E_4/E_6值和元素组成分析HA的结构变化。结果表明:土壤总有机碳(TOC)和腐殖质各组分有机碳含量均表现为白菜玉米大豆。相比CK,配施有机物料后作物根系土壤TOC、WSS、HA含量分别显著增加5%~8%,34%~55%,8%~20%,FA含量变化不明显。相比树叶和鸡粪,秸秆可显著提高TOC含量;WSS在各物料之间差异不明显;HM含量表现为秸秆树叶鸡粪CK。有机物料对PQ值的影响因作物而异,秸秆和鸡粪对玉米、大豆根系土壤PQ值(HA占腐殖酸的比率)的影响相似,而鸡粪对白菜根系土壤PQ值的影响显著高于玉米秸秆。施用有机物料后HA的E_4/E_6未发生明显改变,FA的E_4/E_6显著提高。有机物料使根系土壤HA缩合度升高,分子结构更加复杂,且有利于HA含氮基团的形成,以秸秆处理作用最好。由此可见,有机物料具有良好的培肥效果,其中鸡粪对白菜根系土壤培肥效果最显著,秸秆与鸡粪对玉米、大豆根系土壤培肥效果相似,均显著高于化肥。