首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Soil and rhizosphere microbial communities in agroecosystems may be affected by soil, climate, plant species, and management. The management and environmental factors controlling microbial biomass and community structure were identified in a three-year field experiment. The experiment consisted of a tomato production agroecosystem with the following nine treatments: bare soil, black polyethylene mulch, white polyethylene mulch, vetch cover crop, vetch roots only, vetch shoots only, rye cover crop, rye roots only, and rye shoots only. The following hypotheses were tested: (1) Temperature and moisture differences between polyethylene-covered and cover-cropped treatments are partly responsible for treatment effects on soil microbial community composition, and (2) Different species of cover crops have unique root and shoot effects on soil microbial community composition. Microbial biomass and community composition were measured by phospholipid fatty acid analysis. Microbial biomass was increased by all cover crop treatments, including root only and shoot only. Cover cropping increased the absolute amount of all microbial groups, but Gram-positive bacteria decreased in proportion under cover crops. We attribute this decrease to increased readily available carbon under cover-cropped treatments, which favored other groups over Gram-positive bacteria. Higher soil temperatures under certain treatments also increased the proportion of Gram-positive bacteria. Vetch shoots increased the amount and proportion of Gram-negative bacteria, fungi, and arbuscular mycorrhizal fungi in the rhizosphere of tomato plants. The imposed treatments were much more significant than soil temperature, moisture, pH, and texture in controlling microbial biomass and community structure.  相似文献   

2.
设施农业不同种植模式系统生产力与土壤生物特性研究   总被引:5,自引:0,他引:5  
依据在陕西延安日光温室内的田间试验,对黄瓜与不同作物建立的种植模式系统生产力与土壤生物特性进行了研究。结果表明,冬春茬黄瓜收获后采用不同的种植模式,其系统生产力与土壤生物特性发生明显变化。由小青菜、豇豆与黄瓜组成种植模式的系统产品生产力和经济生产力最高,翻青玉米、四季豆与黄瓜组成的模式次之。豇豆作为前茬处理的土壤呼吸强度最高,翻青玉米、四季豆、翻青黑豆和CK处理的土壤呼吸强度次之,番茄和小青菜处理的土壤呼吸强度较低。黄瓜收获后利用夏季休闲3~4个月对降低土壤细菌和真菌数量的效果最好,其次是种植豇豆或与豆科作物轮作。  相似文献   

3.
Cover crops can improve soil properties, especially soil structure, through organic matter input and rooting activity. However, large variations exist among cover crops, which may lead to differences in the extent of these effects. In this study, cover crops with differing properties were compared regarding soil structure and subsequent sugar beet growth. Field experiments were conducted at two Luvisol sites in Central Germany. Four cover crops (oil radish, saia oat, spring vetch and winter rye) were compared with fallow. Cover crop effects on soil water, Nmin content, soil structure and subsequent early sugar beet growth were studied. Additionally, sugar beet received either no or optimal N fertilizer application. Rye and radish had the highest and vetch the lowest above- and belowground biomass. Soil water content was hardly affected by cover cropping, while topsoil Nmin contents in April were increased. Penetration resistance was lowered, and aggregate stability was increased by the cover crops, especially oil radish, while values after spring vetch were similar to those of fallow. Differences among the cover crops might be because of a differing root biomass. Independent of N fertilizer application, sugar beet biomass in May tended to be higher after all cover crops, in particular under oil radish. The higher aggregate stability and lower penetration resistance were found to be beneficial for early sugar beet growth. Thus, sugar beet can benefit from a 1-year cultivation of preceding cover crops. Modifications of this effect through cover crop root biomass and architecture as well as repeated cover cropping need to be investigated in further studies.  相似文献   

4.
Cover crops improve soil quality properties and thus land productivity. We compared soil chemical and biological changes influenced by hairy vetch (Vicia villosa Roth.) and cereal rye (Secale cereal) cover crops grown in Menfro silt loam (fine-silty, mixed, superactive, mesic Typic Hapludalfs), Mexico silt loam (fine, smectitic, mesic Vertic Epiaqualfs), or sand in the greenhouse. Cover crop biomass, soil β-glucosidase, β-glucosaminidase, and fluorescein diacetate (FDA) hydrolase activities, and soil chemical properties were measured at six, nine, and twelve weeks after planting. Cover crop biomass increased with highest (p < 0.0001) yields for hairy vetch and cereal rye in Menfro and Mexico soils, respectively. β-glucosaminidase, FDA, organic carbon (C), total nitrogen (N), and total phosphorus (P) contents significantly decreased in all soils for both cover crops. However, β-glucosidase activity significantly increased (p < 0.0001). Long-term field studies are needed to evaluate soil quality improvement under cover crops, especially for soils with marginal organic matter and fertility.  相似文献   

5.
Soil Hydraulic Properties: Influence of Tillage and Cover Crops   总被引:1,自引:0,他引:1  
Understanding the effects of cover crops and tillage on soil physical properties is important for determining soil productivity. This study was conducted at Lincoln University's Freeman Center, USA to evaluate the effects of tillage and cover crop management on soil hydraulic properties. The field site included three replicate blocks in a randomized complete block design with each plot measuring 21.3 m in length and 12.2 m in width. Treatment factors were tillage at two levels(moldboard plow tillage vs. no tillage) and cover crop at two levels(cereal rye(Secale cereal) cover crop vs. no cover crop). Soil samples were collected in late spring/early summer from each treatment at 10-cm depth increments from the soil surface to a depth of 40 cm using cores(76.2-mm diameter and 76.2-mm length). Soil bulk density was 13% lower with tillage compared with no-tillage. Volumetric water content was significantly higher at 0.0 and -0.4 k Pa pressures with tillage compared with no tillage. Tillage increased the proportion of coarse mesopores by 32% compared with no tillage, resulting in 87% higher saturated hydraulic conductivity(K_(sat)). Cover crop increased the proportion of macropores by 24% compared with no cover crop; this can potentially increase water infiltration and reduce runoff. As a result of higher macroporosity, Ksat was higher under cover crop compared with no cover crop. This study demonstrated that tillage can benefit soil hydraulic properties in the short term, but these effects may not persist over time. Cover crops may slightly improve soil hydraulic properties, but longer term studies are needed to evaluate the long-term effects.  相似文献   

6.
Sandplain soils on the south coast of Western Australia have low inherent fertility, which is mainly due to poor nutrient retention caused by insufficient clay and organic colloidal material. Previous research has shown the benefits in nutrient levels and retention from adding clay to sandplain soils; however, there is almost no information on the addition of organic amendments. A field experiment was established at the Esperance Downs Research Station, Western Australian, in May 2010, to assess the effects of wheat straw (WS) and chicken manure (CM) biochars and compost with and without phosphorus (P) addition on soil properties and crop production over five growing seasons. The five seasons alternated between winter and summer crops.~The CM and WS biochar and compost treatments significantly increased crop yields and P uptake in 3, 2 and 1 of the five seasons, respectively. The yield increases $(P<0.05)$ were no more than 8\%. By the end of the third season, no differences in crop yields were found that could be attributed to the organic amendments. The addition of P increased crop yields in each winter cropping season. Phosphorus addition explained more than 30\% of the variation in crop yields. Despite marginal P levels and summer drought conditions, arbuscular mycorrhizal root colonisation was not affected by the organic amendments. There were no significant interactions between the organic amendments and P addition in terms of crop yields, P uptake or P uptake efficiency. We conclude that much of the effect of the organic amendments was due to direct nutrient addition which dissipated over time.  相似文献   

7.
Microbial community responses to alternative management may be indicative of soil quality change. In this study, soils were collected from research plots over 2 years and from commercial grower fields over 1 year. Treatments at the sites included 1-9 years of either winter cover cropping or winter fallow practices. Soils were assayed for microbial fatty acid methyl esters (FAMEs), direct count microscopy and Biolog substrate utilization potentials to assess management and environmental influences on soil communities. The strongest influence was season. Soils in early spring (prior to termination of the cover crop) utilized fewer carboxylic acids and generally were enriched in eukaryotic FAMEs, whereas proportionally more bacterial FAMEs were detected in soils at canopy closure and harvest of the summer vegetable crop. Within a season, community FAME and Biolog patterns were related to field properties. FAME profiles from grower fields in early spring and harvest were correlated significantly with soil texture, cation exchange capacity, and carbon content. Changes in community structure and Biolog potential occurred in some soils in response to winter cover crops, although effects were not observed until cover crop incorporation. Greater amounts of fungal and protozoan FAME markers were detected in some cover-cropped soils compared to winter fallow soils. Cover crop residues increased FAME diversity at one research station and Biolog diversity at two research stations and the grower fields. Although seasonal and field-dependent factors are major determinants of microbial community structure, shifts can occur as soil physical and chemical properties change in response to alternative practices, as demonstrated by this study.  相似文献   

8.
Cover crops are important components of a sustainable crop production system. They can be planted with plantation crops such as cacao, coffee, banana, rubber, and oil palm or in rotation with cash crops. Their use in a cropping system is mainly beneficial for soil and water conservation, recycling of nutrients, control of pests and improved microbiological activities. However, beneficial effects depend on the selection of appropriate cover crops and their management. Hence, understanding their agronomy and physiology is fundamental for their use in sustainable cropping systems. Growth and development of a crop (physiological aspects) is determined genetically as well as influenced by environmental variables. This information can be useful in improving production of these crops and, consequently, their incorporation in farming systems, wherever it is possible. There are hundreds of tropical cover crops and, therefore, it is not possible to include all of them in one article. Hence, selected cereals and legumes are included.  相似文献   

9.
《Applied soil ecology》2008,38(3):247-255
Soil microbial community structure and crop yield was investigated in field tomato production systems that compared black polyethylene mulch to hairy vetch mulch and inorganic N to organic N. The following hypotheses were tested: (1) hairy vetch cover cropping increases crop yield and significantly affects soil microbial community structure when compared to the standard plastic mulch and synthetic fertilizer-based system; (2) within plastic mulch systems, organic amendments will increase crop yield and significantly affect soil microbial community structure when compared to synthetic fertilizer; (3) crop yields and microbial community structure will be similar in the hairy vetch cover cropping and the organic amended plasticulture systems. Treatments consisted of ammonium nitrate (control), hairy vetch cover crop, hairy vetch cover crop and poultry manure compost (10 Mg/ha), three levels of poultry manure compost (5, 10, and 20 Mg/ha), and two levels of poultry manure (2.5 and 5 Mg/ha). Black polyethylene mulch was used in all treatments without hairy vetch. Fatty acid analysis was used to characterize the total soil microbial community structure, while two substrate utilization assays were used to investigate the community structure of culturable bacteria and fungi. Crop yield was not significantly increased by hairy vetch cover cropping when compared to black polyethylene mulch, although microbial community structure was significantly affected by cover cropping. Under black polyethylene mulch, crop yields were significantly increased by the highest levels of compost and manure when compared to inorganic fertilizer, but there was no detectable effect on soil microbial community structure. When cover cropping was compared to organic amended plasticulture systems, crop yields were similar one year but dissimilar the next. However, hairy vetch cover cropping and organic amendments under black plastic mulch produced significantly different soil microbial community structure.  相似文献   

10.
Cover crops have traditionally been used to reduce soil erosion and build soil quality, but more recently cover crops are being used as an effective tool in organic weed management. Many studies have demonstrated microbial community response to individual cover crop species, but the effects of mixed species cover crop communities have received less attention. Moreover, the relationship between arable weeds and soil microbial communities is not well understood. The objective of this study was to determine the relative influence of cover crop diversity, early-season weed communities, and tillage on soil microbial community structure in an organic cropping system through the extraction of fatty acid methyl esters (FAMEs). A field experiment was conducted between 2009 and 2011 near Mead, NE where spring-sown mixtures of zero (control), two, and eight cover crop species were included in a sunflower–soybean–corn crop rotation. A mixture of four weed species was planted in all experimental units (excluding the no-cover control), and also included as an individual treatment. Cover crops and weeds were planted in late-March, then terminated in late-May using a field disk or sweep plow undercutter, and main crops were planted within one week of termination. Three (2009) or four (2010–11) soil cores were taken to a depth of 20 cm in all experimental units at 45, 32, and 25 days following cover crop termination in 2009, 2010, and 2011, respectively. Total FAMEs pooled across 2009 and 2010 were greatest in the two species mixture–undercutter treatment combination (140.8 ± 3.9 nmol g−1) followed by the eight species mixture–undercutter treatment combination (132.4 ± 3.9 nmol g−1). Abundance of five (2009 and 2010) and seventeen (2011) FAME biomarkers was reduced in the weedy treatment relative to both cover-cropped treatments and the no-cover control. In 2009 and 2010, termination with the undercutter reduced abundance of most actinomycete biomarkers while termination with the field disk reduced abundance of C18:1(cis11) and iC16:0. Canonical discriminant analysis of the microbial community successfully segregated most cover crop mixture by termination method treatment combinations in 2009 and 2010. Microbial communities were most strongly influenced by the presence and type of early-spring plant communities, as weeds exerted a strong negative influence on abundance of many key microbial biomarkers, including the AMF markers C16:1(cis11) and C18:1(cis11). Weeds may alter soil microbial community structure as a means of increasing competitive success in arable soils, but this relationship requires further investigation.  相似文献   

11.
Abstract

Cover crops play an important role in improving productivity of subsequent row crops by improving soil physical, chemical, and biological properties. The objective of this article is to review recent advances in cover crops practice, in the context of potential benefits and drawbacks for annual crop production and sustained soil quality. Desirable attributes of a cover crop are the ability to establish rapidly under less than ideal conditions, provide sufficient dry matter or soil cover, fix atmospheric nitrogen (N), establish a deep root system to facilitate nutrient uptake from lower soil depths, produce organic matter with low‐residue carbon/nitrogen (C/N) ratio, and absence of phytoxic or allelopathic effects on subsequent crops. Cover crops can be leguminous or nonleguminous. Leguminous cover crops provide a substantial amount of biologically fixed N to the primary crop, as well as ease of decomposition due to their low C/N ratio. Legume cover crops also possess a strong ability to absorb low available nutrients in the soil profile and can help in increasing concentration of plant nutrients in the surface layers of soil. Some nonleguminous cover crops having high N scavenger capacity compared with leguminous crops and sometimes, the growth of these scavenging grass cover crops is limited by N deficiency, growing grass/legume mixtures appears to be the best strategy in obtaining maximum benefits from cover crops.  相似文献   

12.
覆盖作物的种植是一种可实现农业可持续发展的保护性耕作措施,对维护农业生产的可持续性具有积极意义。目前,对覆盖作物的研究主要侧重于覆盖作物对土壤和后茬作物的影响评价,包括对土壤有机碳、氮的固存,对杂草和病虫害的抑制、对土壤理化性质的改良和对土壤微生物活性的影响等方面。然而,覆盖作物的效益因覆盖作物类型、地理位置和覆盖时间不同而存在差异。另外,覆盖作物的选择、设置方法、终止方法、经济效益等充满了不确定性,这限制了其在农田中的大面积推广。该研究基于当前国内外的研究进展简要介绍了覆盖作物的种植管理现状,总结了覆盖作物提供的多种生态系统服务功能,讨论了限制覆盖作物在农作物种植系统中广泛应用的关键因素,提出了覆盖作物合理选择的建议。同时,基于覆盖作物在农学、生态环境上的经济和生态效益,对覆盖作物的贡献以及面临的瓶颈进行了思考。发现良种培育、覆盖作物-土壤微生物-土壤养分-作物之间的协同机制仍是今后需要突破的重点课题,以期为覆盖作物的合理选择及大面积推广提供依据。  相似文献   

13.
Soil food webs cycle nutrients and regulate parasites and pathogens, services essential for both agricultural productivity and ecosystem health. Nematodes provide useful indicators of soil food web dynamics. This study was conducted to determine if nematode soil food web indicators and crop yield can be enhanced by combinations of cover crops in a conservation tillage system. The effects of three cover crop treatments (vetch/pea, oat/wheat and oat/wheat/pea/vetch) with low, medium and high C:N and a bare fallow control were investigated in Davis, CA. Nematode fauna, soil properties and plant productivity were measured. Soil food web indices, including the Enrichment Index (EI), Structure Index (SI), Basal Index (BI), and Channel Index (CI), based on the composition of nematode assemblages, were calculated to infer soil food web condition. Cover cropped tomato/corn rotations had twice the number of enrichment opportunist bacterial feeding nematodes, active participants in nitrogen mineralization, than fallowed tomato/corn rotations (opportunist bacterial feeders = 163 versus 98). In winter fallowed plots food webs were basal, common in disturbed, nutrient-poor conditions (BI = 37). Total number of enrichment opportunist nematodes, soil NH4-N levels, and inferred nitrogen mineralization, were higher in cover crop treatments with low to mid C:N ratios. Omnivore and predator nematodes were scarce, averaging less than 6 nematodes 100 g?1 in all treatments. In year one, plant productivity was highest after fallow. In contrast, in year two productivity was highest after cover crops with high nitrogen content and productivity significantly correlated with the structure of the soil fauna. Monitoring the abundance of enrichment opportunists may provide managers with a new tool to evaluate soil food web nitrogen mineralization and plant productivity.  相似文献   

14.
The dry matter yields of the main and second product in the years 2001–2010 and organic C content in 2007–2010 were used to evaluate the productivity of two rather different crop rotations, a 9-year crop rotation and an alternate growing of spring wheat and sugar beet in long-term field experiments in Prague. A comparative effect of farmyard manure and cattle slurry plus straw in combination with mineral fertilization was also evaluated. Crop rotation positively affected dry matter yields in the non-fertilized variants. The alternate growing of spring wheat and sugar beet was more dependent on external mineral nutrients input in order to reach yields comparable with crop rotation. There was no substantial difference in the effect of crop rotation on the organic C content in the topsoil. Mineral fertilizers significantly increased the organic C content in the topsoil compared with non-fertilized plots. The effect of mineral nitrogen fertilizers on simplified carbon balance was strongly positive, whereas its effect on nitrogen balance was slightly positive. There was no significant difference between the effects of farmyard manure and cattle slurry plus straw on the dry matter yields of crops.  相似文献   

15.
A field experiment was conducted in split plot design to examine the energy efficiency, productivity, and profitability of 6 rice based cropping systems for selected conservation agricultural (SCA) and the conventional (CNV) practices during the years 2010 to 2012. Results revealed that rice crop grown in wet season with SCA resulted in higher net energy, energy output: input ratio, energy productivity, and net returns as compared to CNV. Also, in the dry season, higher yield, net return, net energy and the net economic water productivity (NEWP) were noted for the SCA. Among the dry season crops, sunflower recorded highest net energy (57.2 GJ ha?1) followed by horsegram and cabbage. The NEWP was highest for babycorn (US $ 0.198 m?3), followed by cabbage and sweetcorn. However, the per cent increase in net return, net energy and the NEWP for SCA as compared to the CNV was highest for horsegram followed by sunflower. Despite having low system productivity, rice-sunflower and rice-horsegram cropping systems were more energy efficient with high net energy of 194.4 and 169.4 GJ ha?1, respectively. These two systems were low water demanding and helped in buildup of soil organic carbon, nitrogen (N), phosphorus (P) and potassium (K).  相似文献   

16.
Grasses as well as leguminous and non-leguminous broadleaves are the major categories of commonly grown cover crops worldwide. This review focuses on the contribution of cover crops to soil properties. The review first considers the single and mixed cover crops and shows that grass species are desirable for their decay and ability to provide substantial soil cover, broadleaf species are used for their quick decomposition and capacity of releasing residues into the soil, while the leguminous species are used for their ability to fix atmospheric nitrogen. Secondly, the impacts of cover crops on soil health are reviewed. Integrating cover crops into conventional cropping systems may reduce soil bulk density, improve soil structure and hydraulic properties to facilitate increased water infiltration and storage. Crop residue additions from cover crops may enhance soil organic C and N accretion as well as increase availability of P, K, Ca, Fe and Mg in some soil types under certain climatic conditions. Further, cover crops may provide a better condition for microbial activity, abundance, and diversity. Finally, the review shows that through proper management, cover crops may be utilized as an essential component of soil conservation practices for enhanced soil health. Still, further investigation is necessary to determine cover crop effects in additional cropping systems and climatic zones as well as the long-term effects of cover crops on soil properties, subsequent crop yield, and overall cropping system profitability. This review is an important source of information for crop growers, crop management institutions, universities, and crop consultants for sustainable agricultural production.  相似文献   

17.
A field experiment was conducted in the semi arid tropics to study the effects of soil structural modification on cropping systems. The aim was to improve crop production and land resource protection using innovative soil management practices. Tillage, mulch and perennial/annual rotational based systems were compared for 5 years in an Alfisol at ICRISAT in India. Crop yield parameters, including grain and biomass yield, leaf area index, crop cover, and plant height were measured. Results indicate significant benefits to annual crop yield (maize, sorghum) from improved water supply due to mulching with farmyard manure or and rice straw, and due to rotation with prior-perennial crops. Grain yields were 16 to 59% higher in mulched treatments compared to unmulched treatments, with similar increases for fodder yields. Annual crop yields after 4 years of perennials were 14 to 81% higher than unmulched treatments, except for low fertility maize grown after buffel grass. The interaction with chemical fertility was less clear than for water supply. The results have implications for soil management throughout the semi-arid tropics.  相似文献   

18.
The field experiments were carried out at Indian Agricultural Research Institute, New Delhi during three crop cycles from 1996-97 to 1998-99 to study the effect of incorporation of wheat and rice residues with and without a culture of cellulolytic fungi Trichrus spiralis on grain and straw yields and NPK uptake of rice-wheat cropping system and organic C, available P and available K content of soil. Incorporation of residue of wheat, rice or both had no significant effect on individual grain and straw yields and N and P uptake of rice and wheat, but significantly increased total grain and straw yields and N and P uptake of rice-wheat cropping system. Cellulolytic culture had no additional advantage over crop residues. Incorporation of residue of wheat, rice or both significantly increased K uptake of both rice and wheat as this practice resulted in recycling of 90% of total K uptake by rice and wheat crops. Incorporation of crop residue also resulted in building up of organic C, available P and available K content in soil.  相似文献   

19.
Cover crops are increasingly being used in agriculture, primarily for weed or erosion management. The addition of cover crops increases the primary productivity of the system and diversifies basal resources for higher trophic levels. How increases in the quality and quantity of basal resources affect bottom-up and top-down control remains a key question in soil food web ecology. We evaluated the response of the nematode community to the introduction of cover crops between rows of a banana plantation. We measured changes in nematode food web structure and inferred the prevalence of bottom-up and top-down effects on the abundance of phytophagous nematodes (i.e., plant-feeding and root-hair-feeding species) 1.5 years after plots with cover crops (Poaceae or Fabaceae species) or bare soil were established. The addition of a cover crop greatly affected the structure and the abundance of the soil nematode community 1.5 years after planting. The abundance of all trophic groups except for plant-feeding nematodes tended to increase with the addition of cover crops. The Shannon–Weaver diversity index and the enrichment index increased with the addition of cover crops, indicating that opportunistic, bacterivorous and fungivorous nematodes benefited from the added resources. Plant-feeding nematodes were least abundant in plots with Poaceae cover crops, while bacterivorous, omnivorous, and root-hair-feeding nematodes were more abundant with Fabaceae cover crops than with bare soil, indicating that cover crop identity or quality greatly affected soil food web structure. Bottom-up effects on all trophic groups other than plant-feeding nematodes were evident with Poaceae cover crops, suggesting an top-down control of plant-feeding nematodes by omnivorous nematodes. Conversely, plant-feeding nematodes were evidently not suppressed in Fabaceae cover crops, perhaps because bottom-up effects on omnivorous nematodes were weaker (hence, top-down control by omnivorous nematodes was weaker), and because Fabaceae cover crops probably served as good hosts for some plant-feeding nematodes.  相似文献   

20.
Abstract

Field experiments were conducted on an Entisol from 1984 to 1987 at Bidhan Chandra Agricultural University, West Bengal, India, to study the residual effects of N, P, and K on productivity of mung bean (Vigna radiatus Roxb.) and sesame (Sesamum indicum L.) in irrigated multiple cropping with rice‐potato‐mung bean and rice‐potato‐sesame cropping systems. The crops were grown with or without application of farmyard manure or incorporation of crop residues. Different quantities of inorganic fertilizers based on locally recommended practices for fertilization were applied to rice and potato and their residual effects on succeeding mung bean or sesame crops were assessed. Application of fertilizers at a higher rate than the recommended amounts to rice and potato in the system showed no significant residual effect on yields of succeeding mung bean or sesame compared to the yields obtained with the application of N, P, and K at 100% of the recommended rate or 75% of the recommended rate with manure or residues. Any reduction in the application of recommended amounts of fertilizers to rice or potato without compensating amounts coming from other organic sources resulted in lower productivity of succeeding mung bean and sesame.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号