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1.
The effect of different soil amendments and biological control agents on soil-borne root diseases that cause significant economic losses in organic and other soil-based tomato production systems (Pyrenochaeta lycopersici and Verticillium albo-atrum) was compared. Organic matter inputs (fresh Brassica tissue, household waste compost and composted cow manure) significantly reduced soil-borne disease severity (measured as increased root fresh weight) and/or increased tomato fruit yield, with some treatments also increasing fruit number and/or size. Soil biological activity also increased with increasing organic matter input levels and there were significant positive correlations between soil biological activity, root fresh weight and fruit yield. This indicates that one mechanism of soil-borne disease control by organic matter input may be increased competition by the soil biota. Chitin/chitosan products also significantly reduced soil-borne disease incidence and increased tomato fruit yield, number and/or size, but had no effect on soil biological activity. Biological control products based on Bacillus subtilis and Pythium oligandrum and commercial seaweed extract (Marinure) and fish emulsion (Nugro)-based liquid fertilisers had no positive effect on soil-borne disease incidence and fruit yield, number and size. The use of ‘suppressive’ organic matter inputs alone or in combination with chitin/chitosan soil amendments can therefore be recommended as methods to control soil-borne diseases in organic and other soil-based production systems.  相似文献   

2.
Liebman  & Davis 《Weed Research》2000,40(1):27-47
Greater adoption and refinement of low-external-input (LEI) farming systems have been proposed as ways to ameliorate economic, environmental and health problems associated with conventional farming systems. Organic soil amendments and crop diversification are basic components of LEI systems. Weed scientists can improve the use of these practices for weed management by improving knowledge of four relevant ecological mechanisms. First, multispecies crop rotations, intercrops and cover crops may reduce opportunities for weed growth and regeneration through resource competition and niche disruption. Secondly, weed species appear to be more susceptible to phytotoxic effects of crop residues and other organic soil amendments than crop species, possibly because of differences in seed mass. Thirdly, delayed patterns of N availability in LEI systems may favour large-seeded crops over small-seeded weeds. Finally, additions of organic materials can change the incidence and severity of soil-borne diseases affecting weeds and crops. Our research on LEI sweetcorn and potato production systems in central and northern Maine (USA) suggests that these mechanisms can reduce weed density and growth while maintaining crop yields. Low-external-input farming systems will advance most quickly through the application of interdisciplinary research focused on these and other ecological mechanisms.  相似文献   

3.
A. Grinstein 《Phytoparasitica》1992,20(Z1):S127-S131
Soil solarization is a non-chemical method for soil disinfestation. Theoretically, Israel is one of the ideal sites for the use of this technology. It has been shown that the introduction of soil solarization is highly crop-dependent and is inversely correlated with the availability of alternative soil disinfestation methods. Solarization has been easily introduced for crops with no reliable and recommended soil disinfestation methods or in organic farming and in cases where the technique is inexpensive. Its introduction into crops for which other soil disinfestation techniques are established, or to less intensive crops, has been much slower. Apart from objective reasons for not using solarization,e.g. plots which are in use during the suitable season or low efficacy against specific soilborne pests, there are problems that need to be solved. These are related to technology and technology diffusion, to the price of the plastic sheeting, and to the priority given by farmers to non-chemical methods.  相似文献   

4.
Soil salinity and sodicity are land degradation processes that strongly alter soil quality and consequently plant productivity. The reclamation of soils affected by salinity and/or sodicity is an important goal to maintain the sustainability of production. The objectives of this review were (1) to investigate the effectiveness of different organic amendments to reclaim saline/sodic soils and improve environmental quality and productivity of agro-ecosystems and (2) to provide useful information on the most appropriate waste management for minimizing any potential risks. To achieve these aims, recently published literature, related to field and laboratory studies, considering the effects of a wide range of organic amendments on main soil properties, was collected. Results of these studies underline that input of exogenous organic matter (manure, plant residues, by-product of farming or municipal activities, etc.) can be a feasible way to reclaim soils with serious problems of salinity and sodicity. Optimal rates (not greater than 50 t ha?1) of different organic amendments can improve physical (soil structure, permeability, water holding capacity, etc.) and chemical (pH, cation exchangeable capacity, etc.) soil properties, favoring plant growth and microbial activity, without any risks for the environment (subsoil and groundwater contamination). Of course, it is very important to characterize carefully the organic wastes before their use in agriculture and optimize their management, for avoiding further land degradation.  相似文献   

5.
有机改良剂在防治植物土传病害中的应用   总被引：22，自引：0，他引：22  
 本文综述了有机改良剂的类型及其在防治作物土传病害的应用情况,包括壳质粗粉、植物残体、绿肥、饼肥、堆肥和粪肥;概括了有机改良剂的防病机制,如直接的抑菌作用、对土壤微生物区系的调节、诱导抗病性、改良土壤结构和促进植物生长等;讨论了当前有机改良剂防治作物土传病害研究存在的一些问题及今后应重点研究的课题,并对有机改良剂防治植物病害在未来的发展前景提出了自己的看法。  相似文献   

6.
Experiments were conducted in laboratory bioreactors and in field plots to test effects of certain cultivated members of the grass family (Poaceae = Gramineae), including wheat (Triticum aestivum cv. Yolo), barley (Hordeum vulgare cv. UC337), oats (Avena sativa cv. Montezuma), triticale (X Triticosecale), and a sorghum-sudangrass hybrid (Sorghum bicolor x S. sudanense = “sudex”, cv. Green Grazer V) for soil disinfestation potential. Soilborne pest organisms tested for effects on survival and activity included the phytopathogens Sclerotium rolfsii, Pythium ultimum and Meloidogyne incognita, and a variety of weed taxa. Following soil amendment, bioreactors were incubated for 7 days at ambient (23°C) or elevated, but sublethal (38°C day/27°C night), soil heating regimens. Addition of each of the poaceous amendments to soil at 23°C resulted in inconsistently reduced tomato root galling (49–97%) by M. incognita, or reduced recovery of S. rolfsii and P. ultimum (0–100%) fungi in soil, after 7 days’ incubation (P ≤ 0.05). When the organisms were exposed to the poaceous soil amendments at the 38o/27o temperature regimen, nematode galling and recovery of active fungi were consistently and significantly reduced by 98–100%. These results demonstrated feasibility of soil disinfestation (“biofumigation”) by activity of poaceous amendments, further aided by combining plant residues with soil heating (e.g. solarization). Results from three field experiments with sudex cover crops, conducted throughout the growing season, demonstrated biocidal activity on a range of weedy plants, including Amaranthus retroflexus, Calandrinia ciliata, Cerastium arvense, Digitaria sanguinalis, Echinochloa crus-galli and Poa annua. Both shoots and roots of sudex provided allelopathic weed biomass reductions of 35–100%, and for at least 106 days after shredding. Deleterious activity of shredded residues incorporated in soil was less persistent. These properties in poaceous crops can be useful for soil disinfestation; however, harmful phytotoxicity to subsequent crops may also result. In order to take full advantage of these low-input measures for controlling soilborne diseases and pests, further understanding of their properties must be gained, and user guidelines developed.  相似文献   

7.
Fusarium wilt of strawberry, caused by Fusarium oxysporum f. sp. fragariae, is a disease of primary concern for strawberry production in many countries. Crop rotation and anaerobic soil disinfestation (ASD) have gained recent interest for their potential to contribute to management of this disease. Both techniques involve incorporation of organic matter into soil, which may be utilized by strains of Fusarium that are competitive saprophytes. We show that F. oxysporum f. sp. fragariae can colonize strawberry, lettuce, raspberry, and broccoli leaf tissues, which are sources of organic matter generated during crop rotation. This pathogen increased in soil population density during ASD treatments that did not become anaerobic, possibly as a result of growth on the organic amendment. However, significant population decreases were observed after ASD treatment when at least 100,000 cumulative reduced mV hours occurred in a 14-day experiment. Post-ASD abundance of F. oxysporum f. sp. fragariae in soil was negatively correlated with cumulative reduced mV hours. The only treatment that consistently caused disinfestation was exposed to a maximum temperature of 22 °C, which indicates there is potential for developing effective ASD treatments in the cool climates where strawberries are grown. Awareness that F. oxysporum f. sp. fragariae can act as a competitive soil saprophyte should be further investigated for its potential to alter disease outcomes where organic amendments are applied.  相似文献   

8.
Biological soil disinfestation (BSD), or reductive soil disinfestation, achieved by amendment with organic materials such as wheat bran followed by flooding and covering the soil surface, has been used to control some soilborne diseases including Fusarium wilt and bacterial wilt of tomato. During a BSD treatment, accumulation of acetic acid and/or butyric acid was detected with high-performance liquid chromatography. Survival of Fusarium oxysporum f. sp. lycopersici or Ralstonia solanacearum was suppressed by these organic acids. Amendment of these organic acids into soil suppressed the survival of R. solanacearum at lower concentrations than the maximum detected in BSD treatment, indicating that production of these organic acids is one of the mechanisms of control. However, F. oxysporum f. sp. lycopersici in soil survived with the maximum concentrations of these organic acids achieved by BSD; thus, involvement of factors other than organic acids may be involved.  相似文献   

9.
In organic potato production adequate plant nutrition and plant protection have to be achieved by long term and preventive management strategies. Late blight, caused by Phytophthora infestans Mont. De Bary is one of the most important diseases in organic potatoes and besides varietal resistance its management in Germany relies mainly on the limited use of protective copper based fungicides. The currently allowed amounts of copper of 3?kg?ha?1 and year are more than necessary for plant nutrition and thus are in contrast to the aim of sustainability of organic farming. The results of the presented studies show that it is usually possible to achieve good disease control with only 1–1.5?kg?Cu?ha?1 even under high disease pressure with the help of the forecasting model BioPhyto-PRE which was developed for organic farming. To increase the efficiency of less effective fungicides such as plant extracts in organic farming, disease pressure has to be reduced as much as possible by management approaches. Four on-farm experiments showed that strip intercropping of potatoes does reduce disease pressure in 12–16?m wide strips with neighbour spring wheat or carrots. A cost-benefit analysis using the prices of the year 2004 showed that growing potatoes without treatment in most cases was the most lucrative option with slightly increased benefits by strip cropping the potatoes. Multiple stepwise regressions show that in organic farming the yield loss relationships between late blight and potatoes can only be determined when N-uptake is integrated into the model. Overall, only very limited yield benefits are achieved by the application of copper fungicides, in most cases due to the limited nutrient supply in organic systems. It is concluded that an integrated forecasting model for late blight management in organic farming will have to include data on growth stage dependent plant nutrient uptake and variety specific properties to allow for efficient and minimised fungicide applications.  相似文献   

10.
The addition of organic materials to soil has been used in managing plant-parasitic nematodes and has resulted in increased crop yield. Research on the utilization of waste materials such as oilseed cakes, chitin, compost, livestock and poultry manures, and cellulosic wastes appears promising for reducing populations of plant-parasitic nematodes. Nitrogen based amendments, plant phenolics, nematotoxic chemicals, development of predators and parasites of nematodes and microorganism stimulation have been considered to be promising agents for nematode management. In addition, organic amendments change the physical as well as the trophic structure of soil, which affects the pathogen development and overall plant growth performance. Mechanisms of action of organic soil amendments in relation to nematode management are yet to be fully explored.Plant Protection Division, Institute of Agriculture  相似文献   

11.
The application of organic amendments followed by solarization is a promising alternative to chemical disinfestation for the control of soilborne pathogens in protected crops. We assessed the effectiveness of the application of sugar beet vinasse, alone and in combination with fresh sheep manure, followed by solarization on (i) disease incidence of Meloidogyne incognita in protected pepper crops of southeast Spain and (ii) soil properties with potential as indicators of soil quality. When treatments were applied in summer, a 97% and 87% reduction in the galling index and percentage of galled plants, respectively, was observed in vinasse-amendment plots at the end of the crop season, compared with untreated controls. Treatments led to higher values of soil organic C, total N, total P and extractable K+, and lower values of soil pH. Values of enzyme activities (dehydrogenase, β-glucosidase, acid and alkaline phosphatase, arylsulfatase, urease), microbial biomass C, potentially mineralizable N, water soluble organic C and microbial functional diversity were higher in treated versus untreated soils. Positive correlations were found between enzyme activities and microbial biomass C. In general, no differences were observed between vinasse and vinasse+manure treatments. It was concluded that the application of sugar beet vinasse followed by solarization is a good alternative to methyl bromide for the control of M. incognita in protected pepper crops of southeast Spain, especially, but not exclusively, when carried out in summer. Additionally, treatments resulted in an improvement in soil quality, as reflected by the higher values of microbial biomass, activity and functional diversity.  相似文献   

12.
土壤厌氧消毒(anaerobic soil disinfestation,ASD)技术作为一种环境友好的非化学土壤消毒技术能有效防治真菌、细菌、线虫和杂草等引起的土传病害。该技术已在多个国家广泛应用并被证实可显著增加作物产量。ASD技术基本流程为向土壤中添加适量有机碳源、补充足够水分和用塑料薄膜覆膜密闭2～15周。ASD技术对土传病害防控的作用机理为有机碳源分解产生的挥发性有机物对土传病原菌有抑制作用,土壤理化指标的改变(如pH降低、有机质增加等)能提升土壤质量,从而提高作物抗逆能力,土壤厌氧条件促进土壤微生物群落结构及多样性的改变,通过生物竞争和结构重建改善土壤微生态环境,降低土传病害发生风险。ASD技术对土传病害的防治效果也因有机碳源类别、土壤理化性质及覆盖薄膜的不同而存在差异。因此,优化ASD技术试验条件、深入探索ASD技术作用机理、挖掘更多有灭菌活性的挥发性物质或有益生防菌是未来ASD技术的研究重点。同时,ASD技术与其他土壤消毒技术结合使用,有助于提高其防治效果,扩大应用范围。  相似文献   

13.
Strawberry (Fragaria?×?ananassa) is one of the most important berry crops worldwide. Fusarium wilt poses a serious threat to commercial strawberry production worldwide and causes severe economic losses. Our previous surveys suggested that soil pH, soil amendment with organic matter and/or crop rotation could offer opportunities for improved management of strawberry disease. Studies were conducted for the first time to determine the effects of soil pH, soil amendments with manure compost and crop residue, and crop rotation on the severity and impact of Fusarium wilt on strawberry. At soil pH 6.7, plants showed the least severe disease and the lowest reductions in shoot and root dry weight (DW) of plants from disease, significantly lower than those of plants in acidic soil at pH 5.2 or 5.8. In soil amendment with manure compost at 5.0?%, plants showed the least severe disease and the lowest reductions in shoot and root DW of plants from disease, significantly lower than those of plants in the other three levels of manure compost. In soil amendment with crop residue at 2.5?% or 5.0?%, shoot and root disease of plants and reductions in shoot and root DW of plants from disease were significantly lower than those of plants in soil without crop residue or excessive crop residue amendment at 10.0?%. Plants in soil rotated with tomato not only showed the least severe disease but also showed the lowest reductions in shoot and root DW of plants from disease, significantly lower than those of plants in soil continuously planted with strawberry without rotation or rotated with capsicum. Soil pH, soil amendment with manure compost or crop residue, and crop rotation, all significantly reduced the severity and impact of Fusarium wilt on strawberry. There is great potential for manipulating soil pH, adding soil organic amendments and utilizing crop rotation, not only to successfully manage Fusarium wilt on strawberry, but to do so in a sustainable way without current reliance upon chemical fumigants.  相似文献   

14.
强还原处理所使用有机物料与其杀菌效果的相互关系   总被引：3，自引：0，他引：3  
创造土壤厌氧环境并添加大量有机物料的强还原处理(reductive soil disinfestation,RSD)是一种有效的土壤消毒方法,但对于RSD过程中添加不同有机物料与其杀菌效果间的相互关系研究甚少。本试验采集两种连作土壤,分别进行添加稻壳(RSD1)、麦麸(RSD2)和芦苇(RSD3);甘蔗渣(RSD4)、葡萄糖(RSD5)和纤维素(RSD6)的RSD处理,采用荧光定量PCR、变性梯度凝胶电泳等方法研究物料理化性质与杀菌效果的相互关系。结果表明:RSD处理显著地降低了土壤中的NO-3-N含量和电导率Ec,增加了NH+4-N含量;稻壳、麦麸和芦苇RSD处理的杀菌效果分别为88.60%、90.76%和85.91%,甘蔗渣、葡萄糖和纤维素RSD处理的杀菌效果分别为72.30%、85.87%和30.65%;有机物料中的总有机碳(total organic carbon,TOC)、易氧化有机碳(easily oxidized organic carbon,EOC)和总氮(total nitrogen,TN)与杀菌效果及细菌数量都呈显著正相关(P0.05),土壤中添加有机物料初始C/N与杀菌效果呈显著负相关,与细菌数量显著正相关。综上所述,添加高EOC和TN及低C/N的有机物料的RSD处理杀菌效果更好。  相似文献   

15.
The olive industry generates residues which can be applied as amendments to soils in their original form (olive cake) or after composting or vermicomposting processes. The addition, fresh or incubated, of these amendments to soil and of their different organic fractions was studied in relation to the sorption/desorption of three sulfonylurea herbicides, bensulfuron‐methyl, chlorsulfuron and prosulfuron. Herbicide sorption was low or very low, slightly promoted by the addition of the agricultural by‐products, especially olive cake, and mainly affected by pH of the soil solution, with the organic carbon content having no significant effect on herbicide retention. Desorption was only reduced when fresh olive cake was added. The incubation of soil and amendments for 3 months did not modify herbicide sorption, but made desorption reversible except for olive cake. The transformation of the organic matter of the amendments due to humification and maturity processes are likely to be responsible for this behaviour. Different organic fractions were removed to assess the influence of each fraction on sulfonylurea sorption. Only the removal of all studied organic fractions increased herbicide sorption, revealing the role of humin and mineral fractions in this process. Therefore, the use of organic amendments is not useful for reducing the risk of movement of ionisable molecules in soil.  相似文献   

16.
近10年来, 随着人们对环境的关注, 绿色发展成为农业生产的主流。在土传病害的防治中, 要尽可能减少对环境和生态的影响, 同时保证取得更好的经济效益。因而, 一些环境友好的防治技术受到重视。农业防治技术如抗性品种利用和嫁接、阻截传播、深翻、轮作和无土栽培; 生物防治技术如生物熏蒸、厌氧消毒、生物防治制剂等; 物理防治技术如太阳能消毒、火焰消毒、微波消毒、电消毒、射频消毒也在不断地创新; 化学防治技术主要依赖土壤熏蒸剂, 一些新型的环境友好的熏蒸剂如异硫氰酸烯丙酯、二甲基二硫、乙二腈、乙蒜素等也在不断发展。熏蒸剂新剂型、新的施药机械也在不断创新。土壤熏蒸剂在防治土传病害时, 也会对土壤中的微生态造成不同程度的影响。此外, 我们也应该清醒地认识到任何技术都有两面性, 并正视不同防治技术中的不足。土传病害作为一类难以防治的病害, 也面临着巨大的挑战, 高传染性要求有高质量的种苗和高效的防治和阻隔技术, 土传病害的定量检测技术, 土壤中的病原菌数量与发病的关系、土壤微生态对发病的影响都是亟待研究和解决的问题。在防控土传病害时, 如何减少温室气体的排放、减少防治投入以及塑料薄膜的污染均为面临的环境和经济学挑战。  相似文献   

17.
The genus Verticillium includes several species that attack economically important crops throughout the world. The control of Verticillium spp. becomes especially difficult when they form microsclerotia that can survive in the field soil for several years. It has been common practice to fumigate soil with chemicals such as methyl bromide and/or chloropicrin to control soil‐borne fungal pathogens. Other chemicals that are used against Verticillium spp. are the antifungal antibiotic aureofungin, the fungicides benomyl, captan, carbendazim, thiram, azoxystrobin and trifloxystrobin and the plant defence activator acibenzolar‐S‐methyl. However, the potential risks involved in applying phytochemicals to crop plants for both the environment and human health, together with their limited efficacy for controlling Verticillium‐induced diseases, support the need to find alternatives to replace their use or improve their efficacy. Soil amendment with animal or plant organic debris is a cultural practice that has long been used to control Verticillium spp. However, today the organic farming industry is becoming a significant player in the global agricultural production scene. In this review, some of the main results concerning the efficacy of several soil amendments as plant protectors against Verticillium spp. are covered, and the limitations and future perspectives of such products are discussed in terms of the control of plant diseases. Copyright © 2009 Society of Chemical Industry  相似文献   

18.
Weed control is one of the most important crop protection activities undertaken in both intensive and low-input farming systems. However, even under intensive systems, crop protection which is less dependent on pesticides may require that weeds be managed to obtain a balance between crop and non-crop vegetation to encourage an increase in natural enemies of crop pests. In the low-input farming systems which sustain much of the rural population of Africa, weed control is usually done by hand and clean weeding is often beyond the labour resources of the farming family. The vegetational diversity of peasant agriculture in Africa to which weeds make their contribution, helps to decrease the risk of disease and pest epidemics. In addition to the pest control benefits of a diverse agroecosystem, weeds contribute to the resource base of the rural community, providing a source of secondary foods, medicines and insecticides. Weed control within an integrated crop protection system appropriate to the needs of the resource-poor farmer, requires that weeds are managed in such a way that their biodiversity is maintained and the more useful species retained within the field or field margin. Those weeds with high food potential or which have pesticidal or medicinal properties might be deliberately encouraged within the crop or field margins. Certain weed species may harbour important pests or diseases of local crops and therefore should be selectively removed. The paper reviews and discusses the literature on the beneficial and deleterious effects of weeds and argues for a weed management strategy which balances the effects of weed competition on crop production with the ethnobotanical and pest control attributes of individual weed species and weed communities.  相似文献   

19.
Anaerobic soil disinfestation (ASD) is a cultural technique primarily targeted for control of soilborne plant pathogens, but can also impact weed propagules. A repeated pot study was conducted to evaluate ASD treatment impact on sprouting and growth of introduced Cyperus esculentus (yellow nutsedge) tubers using dry molasses‐based and wheat bran‐based amendment mixtures at four carbon‐to‐nitrogen (C:N) ratios (from 10:1 to 40:1) and compared with a non‐amended control. The mean percentage of sprouted tubers recovered after ASD treatment was lower for wheat bran‐based (42%) than dry molasses‐based (65%) amendments, and tuber production was 1.6‐fold higher in dry molasses‐based than wheat bran‐based treatments. The highest percentage of sprouted tubers (79%) and the highest mean production of large tubers (threefold higher than wheat bran‐based and 1.7‐fold higher than molasses‐based amendments) were observed for the non‐amended control. Tuber sprouting was significantly lower from all ASD treatments (regardless of amendment C:N ratio) compared with the non‐amended control at a 15 cm burial depth. New tuber production was lowest at C:N ratios of 10:1 and 20:1 and more than twofold higher in the non‐amended control. Wheat bran‐based amendments reduced above‐ground C. esculentus biomass compared with the non‐amended control and ASD treatments with molasses‐based amendments, and reduced below‐ground biomass compared with molasses‐based amendments. Above‐ground biomass was highest at amendment C:N ratio of 10:1, and below‐ground biomass was highest at amendment C:N ratio of 40:1 and the non‐amended control. ASD treatment with wheat bran‐based amendments at lower C:N ratios reduced tuber sprouting and reproduction compared with the non‐amended control, but not at rates high enough to use as a primary weed management tactic.  相似文献   

20.
The markets for organic produce offer the opportunity for smallholders in Africa (and elsewhere) to increase their income through access to the price premiums paid in Europe and North America. Facing declining soil fertility, the high cost of off-farm inputs and the collapse of state or para-statal input credit schemes, organic farming offers a sustainable solution for resource-poor farming communities, quite apart from the lure of price premiums. The use of purchased inputs is already at a low level in the smallholder sector in Africa and this may allow farm produce to immediately meet organic standards. The principles of IPM can be applied to organic agriculture to achieve adequate pest and disease control with the restricted use of pesticides that is required for farm produce to meet organic standards. The paper describes some of the problems facing smallholders wishing to access organic markets and describes the IPM options available, which meet the standards of organic certification.  相似文献   

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