Soil solarization: a non-chemical approach for management of plant pathogens and pests

Soil solarization is a special mulching process which causes hydrothermal disinfestation and other physical and biological changes in soil which are beneficial to plant health and growth. Plastic film laid over moist soil during periods of high air temperature, usually for 1–2 months, can greatly reduce or eradicate a number of pathogens and pests including fungi, bacteria, nematodes, arthropods and weeds. Following soil solarization, growth of microflora beneficial to plant growth or antagonistic to pathogens and pests may slow the reinfestation of soil by these organisms for more than one growing season. Increased plant growth and yield of annual and perennial field, row, and nursery crops usually occur following soil solarization. In addition, the availability of increased mineral nutrients following solarization may reduce crop fertilization requirements. Soil solarization has been effective as a pre-plant and as a post-plant treatment, and has been compatible with chemical soil treatments and also biological soil amendments after solarization. Soil solarization is a significant advance in the non-chemical control of many pathogens and pests.     

Mapping soil micronutrients

Soils vary widely in their micronutrient content and in their ability to supply micronutrients in quantities sufficient for optimal crop growth. Soils deficient in their ability to supply micronutrients to crops are alarmingly widespread across the globe, and this problem is aggravated by the fact that many modern cultivars of major crops are highly sensitive to low micronutrient levels. Original geologic substrate and subsequent geochemical and pedogenic regimes determine total levels of micronutrients in soils. Total levels are rarely indicative of plant availability, however, because availability depends on soil pH, organic matter content, adsorptive surfaces, and other physical, chemical, and biological conditions in the rhizosphere. Micronutrient availability to plants can be measured in direct uptake experiments, or estimated with techniques that correlate quantities of micronutrients extracted chemically from soils to plant uptake and response to micronutrient fertilization. Rational management of micronutrient fertility and toxicity requires an understanding of how total and plant-available soil micronutrients vary across the land. A variety of approaches have been used to survey and map the geographic distribution of soil micronutrient content and availability at scales ranging from global to sites within single production fields. Soil micronutrient maps covering large areas improve our understanding of the nature and extent of micronutrient problems, and aid in determining their relationships with climate, soil properties, and soil genetic characteristics determined at similar scales, for example, Soil Taxonomy to the order, sub-order, or great group levels. Intermediate scale maps can be useful in delineating specific areas where deficiencies or toxicities are likely for agriculture, and in determining localized soil characteristics that may be associated with such problems. Highly detailed maps of soil micronutrient content and availability in individual fields are being developed for site-specific precision agriculture. Soil micronutrient maps have fostered discovery of relationships between soil micronutrient content and availability and some human and livestock health problems such as goiter, Keshan and Kaschin–Beck diseases, and cancer. Advances including the global positioning system (GPS), geographic information systems (GIS), inductively coupled plasma (ICP) spectrometry, geostatistics, and precision agriculture facilitate soil micronutrient mapping and provide quantitative support for decision and policy making to improve agricultural approaches to balanced micronutrient nutrition.     

根袋法获取木薯根际土壤及其细菌群落特征研究

为了获取木薯根际土壤并研究其细菌群落特征,加深对木薯根际微生态的认知,开展根袋试验,以粘土和砂质壤土根袋内不同土壤质量（100~500 g）为处理。结果表明,根袋内土质量影响株高,但不影响茎叶重。根袋内100 g土的速效养分受到根系强烈影响,其中铵态氮和速效钾显著高于根袋外。Illumina Hiseq高通量测序结果表明,细菌优势菌门包括变形菌门（31.272%）、放线菌门（25.753%）、酸杆菌门（12.761%）、绿弯菌门（8.799%）等。2种土壤根袋内细菌α多样性增加,粘土细菌丰度也增加。RDA分析表明,土壤速效磷与放线菌门和绿弯菌门正相关,与变形菌门负相关;速效氮、速效钾、铵态氮、硝态氮与芽单胞菌门、酸杆菌门、Parcubacteria等负相关,与厚壁菌门、蓝藻门、梭杆菌门、拟杆菌门正相关;从根袋内外土壤速效养分和土壤细菌多样性综合判定,根袋内100 g土壤时可视为根际土壤,且铵态氮和速效钾可作为判断是否根际土壤的指示指标。根际微生物多样性显著提高。鞘脂杆菌目是木薯品种SC205在不同土质下共同富集的根际细菌。发现了土壤速效养分与部分细菌门的相关性。     

Soil chemical properties,plant species composition,herbage quality,production and nutrient uptake of an alluvial meadow after 45 years of N,P and K application

Little is known about the long-term effects of mineral N, P and K application on the nutritional status of mown alluvial grasslands. We asked how long-term fertilizer application affected soil chemical properties, plant species composition, herbage production, nutrient concentrations in soils and plants and balance of nutrients. Six treatments (control, PK, N50PK, N100PK, N150PK and N200PK) were investigated at the Černíkovice Experiment (Czech Republic) established in 1966 on an Alopecurus pratensis meadow, using annual application rates of 50, 100, 150 and 200 kg N, 40 kg P and 100 kg K ha⁻¹. Data were collected and analysed for 2007, 2008 and 2009. Although fertilizers had been applied over 45 years, differences in soil chemical properties between fertilization treatments were small. The legumes Lathyrus pratensis and Trifolium repens responded highly positively to PK application, and tall grasses, A. pratensis in particular, to NPK application. Herbage quality was high in terms of content of major nutrients, and its chemical properties varied considerably between treatments, cuts and years. Mean annual herbage yield ranged from 6·1 in the control to 9·7 t ha⁻¹ in the N200PK treatment. Herbage production was N-limited in 2007 and 2009, but not in 2008. Seasonal N agronomical efficiency ranged from 4·2 to 22·9 kg of DM herbage per kg of applied N. The herbage N:P and N:K ratios did not reflect the actual response of herbage production to N application. A negative balance between N applied and N removed in harvested herbage was recorded in all treatments. We concluded that in highly productive alluvial grasslands, mineral-rich soils can respond weakly to N, P and K application, fertilizer application modifies plant species composition and herbage production is not N-limited in all years. Nutrient ratios must be interpreted with caution for the estimation of nutrient limitation.     

接种菌剂条件下玉米秸秆还田对玉米产量、品质和土壤肥力的影响

通过田间试验研究接种菌剂条件下玉米秸秆还田对玉米产量、品质以及土壤肥力的影响。结果表明,除可溶性固形物、可溶性糖含量、植株磷含量和吸收量以外,施肥处理各项指标均优于对照。与单施化肥处理相比,化肥配施玉米秸秆直接还田导致玉米产量、农艺性状、品质和植株氮素与钾素含量下降,但接种菌剂能够改善农艺性状,降低减产幅度,而且能够改善玉米籽品质,提高植株氮素与钾素养分含量及吸收量。不同菌剂处理间以FSB2农艺性状较好,而品质和植株养分无明显差异。另外,化肥配施玉米秸秆直接还田能够增强土壤酶活性、提高土壤养分有效性,接种菌剂时效果更佳,在土壤养分方面以FSB2效果较好,而土壤酶无明显差异。说明接种降解菌剂有利于提高秸秆还田效果。     

茶要对修剪叶和不同氮肥对土壤pH和活性铝含量的影响

利用盆栽试验了茶树修剪叶和不同氮肥对土壤pH和活性铝含量的影响。结果表明,施用硫酸铵和茶树鲜叶,茶树干重显著增加。硫酸铵显著促进梢生长并提高氨基酸偏一,施茶树鲜叶显著促进茶树根系生长。施茶树鲜叶处理的土壤有机质含量显著提高,而且pH最高、活性铝含量很低。施用硫酸铵处理的土壤显著酸化。研究表明,茶园土壤酸化的主导因子是施用酸性化学肥料和茶树根系分泌的有机酸等,而并非茶树落叶和修剪叶还园。     

接种丛枝菌根真菌对土沉香和降香黄檀营养元素吸收的影响

为探究丛枝菌根真菌对珍贵树种植物 N、P、K 和土壤因子的影响，本文以土沉香（Aquilaria sinensis）和降香黄檀（Dalbergia odorifera）为研究对象，接种不同地区幼套近明球囊霉（Claroideoglomus etunicatum，CE1，CE2）和摩西斗管囊霉（Funneliformis mosseae，FM1，FM2）4 个菌株，苗木培养 4 个月后收获测定其根、茎、叶营养元素及栽种土壤的化学性质。结果表明：① 接菌提高土沉香和降香黄檀全株 N、P、K 含量吸收。接种 FM 菌株促进土沉香幼苗对 N 和 K 含量的吸收，表现为叶部>根部>茎部，P 含量在根茎叶分配差异均未达到显著差异；接种 CE 菌株促进降香黄檀幼苗对 N、P 含量的吸收，且主要体现在叶片的 N 含量上。② 接种 AM 真菌促进两种珍贵树种的土壤肥力，土沉香以接种 FM 菌株最佳，降香黄檀以接种 CE 菌株最佳。③ RDA 结果表明，土沉香和降香黄檀植物根茎叶 N、P、K 含量与土壤因子间呈显著的相关性。     

Environmental parameters affecting the species diversity along the Aliakmon River, North Greece

The annual distribution of aquatic and coastal macrophytes in five selected sites along the Aliakmon River was studied from January 2005 to December 2005 in Northern Greece. Soil and water chemical parameters in these sites were also evaluated. A total of 75 taxa were recorded belonging to 37 families and 53 genera. The majority of the macrophytes belonged to coastal plants (76%), whereas the rest of the macrophytes belonged to aquatic plants (24%). Species of the family Asteraceae were dominant among coastal plants, whereas species of the family Potamogetonaceae were dominant among aquatic plants. Soil samples from the site of Dam of Veria had higher pH and electric conductivity (80-100 cm depth), whereas CaCO3 contents were significantly higher in soil samples from the area of P. Prodromos (60-80 cm depth). Most physicochemical water parameters as well as selected soil nutrients and major ionic components showed an increase during the low charge period (fall) compared to with the high charge period (spring), especially in parameters associated with agricultural activity. Furthermore, there was an increase in most examined values moving towards the delta of the river.     

Different effects of earthworms and ants on soil properties of paddy fields in North-East Thailand

As soil engineers, earthworms and ants play major roles in soil functioning, especially in modifying soil physical and chemical properties. This study was conducted in a very constraining environment, i.e., paddy fields which have anoxic conditions (approximately four months per year), and which are affected by soil salinisation during the dry period (approximately eight months per year). This study points out that despite those very adverse conditions, soil invertebrates must be taken into account in the dynamic of soil organic and mineral properties in paddy fields. The effects of one earthworm species, Glyphodrillus sp., and an ant species, Epelysidris sp., on soil physical and chemical properties were determined through elemental soil physical and chemical properties (texture, pH, conductivity, C and N contents) and near infrared reflectance spectroscopy (NIRS) in order to evaluate their ability to influence soil organic matter quality. PCA processed with NIRS data clearly showed that biogenic structures (ant sheetings and earthworm casts) were separated from the control surrounding soil. Earthworms and ants affected differently soil properties. Glyphodrillus sp. increased the SOM content and decreased the pH on the surface of the soil. These effects were attributed to an increase in fine particle content (clay). Conversely, Epelysidris sp. only increased the content of coarse particles (sand) and did not influence either soil pH or SOM content. Soil conductivity was found to be very variable but was not significantly affected by soil invertebrates. These results show the potential of soil macro-fauna to create heterogeneity at small spatial scale and to modify the quality of surface soils even under adverse conditions like saline paddy fields.     

接种丛枝菌根真菌对土沉香和降香黄檀营养元素吸收的影响

为探究丛枝菌根真菌对珍贵树种植物 N、P、K 和土壤因子的影响，本文以土沉香（Aquilaria sinensis）和降香黄檀（Dalbergia odorifera）为研究对象，接种不同地区幼套近明球囊霉（Claroideoglomus etunicatum，CE1，CE2）和摩西斗管囊霉（Funneliformis mosseae，FM1，FM2）4 个菌株，苗木培养 4 个月后收获测定其根、茎、叶营养元素及栽种土壤的化学性质。结果表明：① 接菌提高土沉香和降香黄檀全株 N、P、K 含量吸收。接种 FM 菌株促进土沉香幼苗对 N 和 K 含量的吸收，表现为叶部>根部>茎部，P 含量在根茎叶分配差异均未达到显著差异；接种 CE 菌株促进降香黄檀幼苗对 N、P 含量的吸收，且主要体现在叶片的 N 含量上。② 接种 AM 真菌促进两种珍贵树种的土壤肥力，土沉香以接种 FM 菌株最佳，降香黄檀以接种 CE 菌株最佳。③ RDA 结果表明，土沉香和降香黄檀植物根茎叶 N、P、 K 含量与土壤因子间呈显著的相关性。     

Cropping Systems and Soil Quality

SUMMARY

Cropping system refers to temporal and spatial arrangements of crops, and management of soil, water and vegetation in order to optimize the biomass/agronomic production per unit area, per unit time and per unit input. Soil quality refers to its intrinsic attributes that govern biomass productivity and environment moderating capacity. It is the ability of soil to perform specific functions of interest to humans. Three components of soil quality (e.g., physical, chemical and biological) are determined by inherent soil characteristics, some of which can be altered by management. Soil quality and soil resilience are inter-related but dissimilar attributes. Resilient soils, which have the ability to restore their quality following a perturbation, have high soil quality and vice versa. Decline in soil quality sets-in-motion degradative processes, which are also of three types, namely physical (e.g., compaction, erosion), chemical (e.g., acidification, salinization) and biological (e.g., depletion of soil organic matter content). Soil degradation, a biophysical process but driven by socioeconomic and political causes, adversely affects biomass productivity and environment quality. Determinants of soil quality are influenced by cropping systems and related components. Dramatic increases in crop yields during the 20th century are attributed to genetic improvements in crops, fertilizer use, and improved cropping systems. Dependence on fertilizers and other input, however, need to be reduced by adopting cropping systems to enhance biological nitrogen fixation and use efficiency of water and nutrients through conservation tillage, cover crops, and improved methods of soil structure and nutrient management.     

铜与锌对茶树生育特性及生理代谢的影响Ⅲ．施铜对茶树体内铜及其他矿质元素吸收的影响

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VA 菌根对茶树生长和矿质元素吸收的影响

采用盆栽法研究了 VA 菌根对茶树生长和矿质元素吸收的影响。结果表明,接种 VA 菌根真菌的茶树,无沦是地上部还是地下部的干重,都明显高于未接种的茶树,其中又以接种 VA 真菌同时施磷矿粉处理的茶树干重最大(较对照增加2.86倍);叶片含磷量较对照增加41%,特别是在施磷矿粉的条件下,叶片含磷量比对照增加87%,茶树整株的吸磷量是对照的3倍;叶片中 K、Cu、Fe 的含量增加,Zn、Mn、Ca、Mg、Na 的含量没有显著变动,但施磷处理使各处理茶树叶片中矿质元素含量的变动趋于复杂。研究还表明,随着水溶性磷     

不同品种香蕉种植地土壤微生物多样性及其对土壤理化性质的响应

本研究以广西不同品种香蕉种植地土壤微生物为研究对象,利用扩增子测序技术、Spearman相关性分析、RDA分析等方法对土壤微生物丰度与多样性进行测定分析,阐述了香蕉及种植地土壤理化性质对土壤微生物丰度与多样性的影响。结果表明：香蕉土壤细菌样品OTU总量与真菌样品OTU总量比率大约是2∶1;香蕉枯萎病病原菌所在属Fusarium占属水平丰度5.132%~55.132%;Spearman相关性分析显示Fusarium与土壤理化性质无显著相关;真菌的丰度与多样性比细菌更易受到土壤的理化性质与营养元素的影响,单一土壤理化性质无法显著影响土壤微生物的群落结构和物种组成;土壤真菌在一定程度上体现香蕉品种的抗病性程度。     

Soil and Plant Testing Programs as a Tool for Optimizing Fertilizer Strategies

Summary

Soil and plant testing programs are still based on ‘trial and error’ methods and lack scientific underpinning in terms of relevant soil chemical and plant nutritional processes, and are site-specific. The programs are valuable when the objective is to diagnose and predict deficiencies of plant nutrients. The programs are less valuable for refined fertilizer strategies, like Integrated Nutrient Management, which are essential in the near future to satisfy changing agricultural, environmental, economic and legislative boundary conditions. A more scientific approach to soil and plant testing programs appears desirable. To reduce undesirable side-effects of fertilization on the environment, more emphasis should be placed on fertilizer type and on timing and method of application.     

盐逆境下两个水稻品种根系Na+吸收及质膜ATP酶的作用

 以两个不同耐盐力水稻品种80-85 (耐盐) 和83-51(不耐盐)为材料进行研究。根系Na⁺总吸收随盐胁迫的加重而增高，耐盐品种始终具有较低的Na⁺总吸收和较高的整株K⁺／Na⁺比；在10 mmol／L NaCl浓度下显示出根系具有较低的Na⁺吸收速率和较强的对K⁺选择性，低盐浓度(0.2% NaCl) 对根质膜ATP酶活性略有提高；在高盐浓度(0.5% NaCl以上)下，质膜ATP酶活性受到明显抑制，而耐盐品种受抑程度更大．ATP酶活性的下降与根部Na⁺积累以及K⁺吸收的减少相伴随，推测根系K⁺、Na⁺吸收与质膜ATP酶有关     

玉米秸秆还田对土壤理化性状与小麦生长发育和产量的影响研究进展

为给玉米秸秆还田技术的机理研究和推广应用提供参考,总结和分析了该技术的研究进展。秸秆还田对土壤物理性状、土壤水分含量、土壤有机质和矿质营养含量、土壤微生物和土壤酶活性,以及下茬小麦生长发育、产量及其构成因素、籽粒品质及麦田病虫害均有影响。未来该技术应增强增产机理、量化技术及配套技术方面的研究。     

不同木薯种质资源主要矿物质元素差异性分析

为了解不同木薯种质资源矿物质元素含量,优选含量丰富的品种,为木薯的综合利用提供数据支撑,本文采用马弗炉法、原子吸收和原子荧光法分别对113份木薯种质资源灰分与矿物质元素含量进行测定,结果表明：矿物质元素Cr、Cu、Se含量均低于1 mg/kg（干重）,Ca、Fe、K、Mg、Mn、Na、Zn含量分别为66.39~1609.81 mg/kg、4.35~ 38.93 mg/kg、1954.56~8762.78 mg/kg、149.04~1143.73 mg/kg、4.48~37.40 mg/kg、36.80~530.40 mg/kg、6.35~24.83 mg/kg。利用概率分级法将113份木薯种质资源灰分及矿物质元素含量分为5级,即极高、高、中、低和极低,并推荐极高品系作为基础亲本材料。在相关性分析中,灰分与Fe、Mg、Na、Zn含量具有较为显著的相关性,Ca含量与K、Mn含量呈极显著正相关,Ca含量与Mg、Na含量呈极显著负相关,Fe含量与Mg、Na、Zn含量成极显著正相关,K含量与Mn含量呈极显著正相关,与Na含量呈极显著负相关,Mg含量与Na、Zn含量呈极显著正相关,Zn含量与Mn、Na含量呈极显著正相关。Zn与各矿物质元素的吸收有较强的相互促进作用,Fe含量与Mg、Na含量有较强的相互促进作用,Ca含量与K、Mn的吸收有较强的促进作用,而Ca、K、Mn与Fe、Mg、Na的吸收可能存在一定的拮抗作用。结合主成分分析、聚类分析对不同木薯种质资源矿物质元素含量进行综合评价,得到特征值大于1的主成分2个,累计方差贡献率达61.707%。聚类分析可将113个木薯种质资源分为3类,根据矿物质元素含量差异可将不同木薯品种分为Na、Mg、Zn、Fe含量较高和Mn、Ca、K、Zn含量较高两大类,主成分综合评价中‘274'‘50'‘571'‘521'‘417'等木薯种质资源得分较高。     

Effects of cement kiln dust on soil and potato crop quality

Cement kiln dust is a potential source of K and Ca for crops on acidic soils in Eastern Canada. The objective of this study was to assess the effect of cement kiln dust on soil chemical properties and potato (Solanum tuberosum L. cv. Superior) yield and quality on two Spodosols. Four rates of cement kiln dust, commercial K fertilizers, and lime were yearly applied and arranged in a randomized complete block design with four replicates. Soil extractable K and Ca increased rapidly after cement kiln dust applications and were comparable to commercial fertilizers or lime treatments. Heavy metal soil contents and plant uptake were not influenced by treatments. Soil metal contents decreased from to initial soil levels and were lower than recommended maximal norms. Tuber yields increased with rates of cement kiln dust and commercial fertilizers but decreased with lime rates. Yields were positively correlated to soil extractable K and partially with extractable Mg. The K and Mg plant uptake increased with cement kiln dust and commercial fertilizers rates but was significantly reduced by liming. Tuber specific gravity decreased with the highest commercial fertilizers and cement kiln dust rates. These results showed that cement kiln dust is an effective source of K and Ca for potato production without short term loss in tuber quality or soil contamination by metals.     

不同树龄橡胶林土壤养分变化特征及对细根的影响

通过用根钻法对幼树期（5a）、初产期（9a）和旺产期（16a）3个树龄橡胶林土壤养分变化特征及对橡胶树细根影响的研究。结果表明：在橡胶林0~60cm土层的土壤中,5a橡胶林土壤肥力相对比9a、16a橡胶林的高,9a橡胶林肥力相对较低,土壤养分随着土层增加而减少,不同土层养分含量各有差异。不同树龄橡胶树细根生物量,与土壤养分有不同程度的相关性。典型相关分析表明,除了受树龄影响外,橡胶树细根生物量主要还受以有机质、全氮、速效磷等养分为代表的土壤肥力的影响,在一定的条件下,创造合适的土壤肥力条件是确保橡胶树细根高生长量、高吸收效率和养分循环的基本保证。