Effect of agricultural production systems on the potato metabolome

Potato (Solanum tuberosum L.) cv. Santé was grown over 2 years under both conventional and organic fertiliser and crop protection regimes. The tuber metabolome was analysed using mass-spectrometry (MS) based approaches, principally liquid chromatography (LC)–MS and gas chromatography (GC)–MS. Data were analysed using Principal Components Analysis (PCA) and Analysis of Variance (ANOVA) to assess any differences between production practices. GC–MS analysis of non-polar metabolites did not detect any statistically significant differences, but GC–MS analysis of polar compounds identified 83 metabolites showing significant differences in the metabolome between the fertiliser treatments. Of the 62 metabolites that were less abundant in tuber samples from organic compared with conventionally fertilised crops, consistent year on year differences were dominated by free amino acids. The effect on free amino acids is associated with the lower nitrogen (N) content of the organically grown potatoes in this instance (50 % lower than for conventional production). LC–MS provided indications that levels of certain glycoalkaloids may be lower under the organic fertiliser regime in one growing season. Differences associated with the crop protection measures used were much less consistent, and relatively small, compared with the fertiliser effects found.     

Effects of agricultural production systems and their components on protein profiles of potato tubers

A range of studies have compared the level of nutritionally relevant compounds in crops from organic and nonorganic farming systems, but there is very limited information on the effect of farming systems and their key components on the protein composition of plants. We addressed this gap by quantifying the effects of different farming systems and key components of such systems on the protein profiles of potato tubers. Tuber samples were produced in the Nafferton factorial systems study, a group of long-term, replicated factorial field experiments designed to identify and quantify the effect of fertility management methods, crop protection practices and rotational designs used in organic, low input and conventional production systems. Protein profiles were determined by 2-DE and subsequent protein identification by HPLC-ESI-MS/MS. Principal component analysis of 2-DE data showed that only fertility management practices (organic matter vs. mineral fertiliser based) had a significant effect on protein composition. Quantitative differences were detected in 160 of the 1100 tuber proteins separated by 2-DE. Proteins identified by MS are involved in protein synthesis and turnover, carbon and energy metabolism and defence responses, suggesting that organic fertilisation leads to an increased stress response in potato tubers.     

A methodological approach to assess and compare the sustainability level of agricultural plant production systems

A large number of indicators have been developed, in order to assess agricultural sustainability. However, there is no unified theoretical basis for the creation of a scientifically substantiated system of indicators and especially for data collection, analysis, scale and final goal. This paper proposes a methodological approach to assess and to compare the sustainability level of agricultural plant production systems on regional scale combining the three pillars of sustainability environment, economy and society. The combination of 21 individual indicators expressed a unique indicator was realized using the Multiattribute Value Theory (MAVT). The proposed methodology was testified on two geographical regions in Greece, through an empirical study, utilizing questionnaires completed during interviews with farm managers. The questionnaire was designed to gather data on current agricultural practices applied in each particular region and was separated into three broad groups of questions concerning (a) crop management practices, (b) economic performance and (c) social characteristics of each farm. The results of our study demonstrate the overall status of the studied regions, regarding their level of agricultural sustainability. Finally, findings related to the acceptability of the proposed methodological framework were discussed.     

Restoration of biodiversity enhances agricultural production

Restoration of ecological communities is important to counteract global losses in biodiversity. However, restoration on agricultural land is perceived as being costly because of losses in agricultural production. We suggest the reported positive relationship between diversity and productivity means biodiversity could be used to enhance agricultural production. We examined this in hay meadow restoration experiments at seven sites across southern Britain. At each site two seed mixes ("species-poor" with 6–17 species and "species-rich" with 25–41 species) were applied in a randomised block experiment. Hay yield was higher in the species-rich treatment from the second year onward, by up to 60%. Comparing the two treatments in all sites, there was a simple linear relationship between the difference in species number and the amount of increase in hay production. Fodder quality was the same in both treatments. This suggests farmers can maximize high quality herbage production in re-sown grasslands by maximizing biodiversity.     

Soil health in agricultural systems

Soil health is presented as an integrative property that reflects the capacity of soil to respond to agricultural intervention, so that it continues to support both the agricultural production and the provision of other ecosystem services. The major challenge within sustainable soil management is to conserve ecosystem service delivery while optimizing agricultural yields. It is proposed that soil health is dependent on the maintenance of four major functions: carbon transformations; nutrient cycles; soil structure maintenance; and the regulation of pests and diseases. Each of these functions is manifested as an aggregate of a variety of biological processes provided by a diversity of interacting soil organisms under the influence of the abiotic soil environment. Analysis of current models of the soil community under the impact of agricultural interventions (particularly those entailing substitution of biological processes with fossil fuel-derived energy or inputs) confirms the highly integrative pattern of interactions within each of these functions and leads to the conclusion that measurement of individual groups of organisms, processes or soil properties does not suffice to indicate the state of the soil health. A further conclusion is that quantifying the flow of energy and carbon between functions is an essential but non-trivial task for the assessment and management of soil health.     

Sustainable intensification in agricultural systems

BackgroundAgricultural systems are amended ecosystems with a variety of properties. Modern agroecosystems have tended towards high through-flow systems, with energy supplied by fossil fuels directed out of the system (either deliberately for harvests or accidentally through side effects). In the coming decades, resource constraints over water, soil, biodiversity and land will affect agricultural systems. Sustainable agroecosystems are those tending to have a positive impact on natural, social and human capital, while unsustainable systems feed back to deplete these assets, leaving fewer for the future. Sustainable intensification (SI) is defined as a process or system where agricultural yields are increased without adverse environmental impact and without the conversion of additional non-agricultural land. The concept does not articulate or privilege any particular vision or method of agricultural production. Rather, it emphasizes ends rather than means, and does not pre-determine technologies, species mix or particular design components. The combination of the terms ‘sustainable’ and ‘intensification’ is an attempt to indicate that desirable outcomes around both more food and improved environmental goods and services could be achieved by a variety of means. Nonetheless, it remains controversial to some.

Scope and Conclusions

This review analyses recent evidence of the impacts of SI in both developing and industrialized countries, and demonstrates that both yield and natural capital dividends can occur. The review begins with analysis of the emergence of combined agricultural–environmental systems, the environmental and social outcomes of recent agricultural revolutions, and analyses the challenges for food production this century as populations grow and consumption patterns change. Emergent criticisms are highlighted, and the positive impacts of SI on food outputs and renewable capital assets detailed. It concludes with observations on policies and incentives necessary for the wider adoption of SI, and indicates how SI could both promote transitions towards greener economies as well as benefit from progress in other sectors.     

Nitric oxide production in agricultural soils

Numerous papers on nitric oxide have been published covering various aspects ranging from its solution and gas-phase chemistry, biochemical and physiological functions and atmospheric processes. This review emphasizes recent developments in the literature relating to NO/NOx production in agricultural soils. We have tried to minimize overlap with other recent and relevant review articles. Emission measurements that have been made since 1992 are tabulated and discussed in terms of variability, fertilization effects, and advances made in monitoring fluxes. We describe attempts made by a number of authors to utilize ecological markers such as aeration, water, ammonium, nitrate content, etc. in order to distinguish between nitrification and denitrification as the primary source of production and/or consumption in natural field situations. This may allow a rational accounting for the high spatial and temporal variability observed, and the formulation of reliable predictive models. Factors such as diffusion, oxygen, water, and carbon (content and quality) that regulate or significantly influence production, consumption and emission are discussed. Finally some important implications of recent research relating to nitrification and denitrification is presented showing the chemical oxidation of NO which could occur when the acetylene inhibition technique is used.     

Reducing soil erosion and the loss of soil fertility for environmentally-sustainable agricultural cropping and livestock production systems

My proposals for reducing soil erosion are based on my experience of assessing erosion, largely in Britain, both of cultivated land and of upland grazings. I have assessed the extent and rates of erosion in the field mostly by using easily‐ and rapidly‐used photographic and measurement techniques, rather than by using experimental plots set up either in the field or laboratory which overstate erosion. Policies which have governed the economics of agricultural production have also been examined. Much of the increase in occurrence of runoff and soil erosion in Britain is due to changes in land use and in intensity of use since the Agriculture Act was passed in 1947, and especially since joining the Common Market in 1973, with its even greater emphasis on paying for increased production. The increasing numbers of animals grazing the land, especially sheep, led to the initiation and erosion of bare soil in the uplands and to trampling and puddling of soils in lowland pastures. There is evidence that runoff from the land, and sedimentation of water courses have also increased. In the cultivated lowlands, the expansion in area of land drilled to winter cereals, the increase in area of land sown to maize or used to rear outdoor pigs, changes in farming techniques, and larger machines working in larger fields can explain much of the increase in erosion. Reversing some of these changes, for example by lowering the intensity of grazing and inserting grass (set‐aside) into the arable rotation will reduce the extent of erosion. Other techniques to reduce erosion are well‐known but need national and international agricultural policies that improve farmers' incomes to bring them into use. In developed countries, erosion need not reduce soil fertility, as nutrients removed from the soil by animals or crops can be affordably replaced. This may not be so in other parts of the world. Education of farmers also has a vital role to play in persuading them to use the land more sustainably, for many of the impacts of erosion such as flooding and pollution of water supplies bear on society as a whole, not just farmers who are themselves little affected. The principles devised to reduce erosion in developed countries are likely to be successful in developing countries. However, it may take many years for better and more sustainable agricultural policies at national and international level to be devised and brought into being.     

浅谈光合作用在农业生产上的应用

从以下８个方面对植物的光合作用在农业生产上的应用进行了概述,利用间作套种;增施二氧化碳”气肥”;延长光合作用时间;培育高光效作物品种;选育有利于光合作用进行了株型;避免或减轻农作物“午休”期间的影响;合理应用生长调节物质;利用不同色光改善光合产物品质。     

Cycling of nitrogen in modern agricultural systems

Summary Agro-ecosystems have developed from mixed- and multiple-cropping systems with relatively closed N cycles to intensively managed monocultures with large N inputs in the form of commercial fertilizers. Cultivation of increasingly larger areas of land has resulted in substantial losses of soil organic matter and N. Also, the move from slash and burn agriculture to intensively ploughed systems has resulted in losses through increased erosion.The use of N fertilizers has increased rapidly toca. 60 Tg N yr^–1 (1980/81), which is equivalent to at least 40% of the N fixed biologically in all terrestrial systems and 36% more than is fixed in all croplands. On a global scale, the major losses of N from agro-ecosystems are estimated to be: harvest, 30 Tg; leaching, 2 Tg; erosion, 2–20 Tg; denitrification 1–44 Tg; and ammonia volatilization, 13–23 Tg. However, the data base is very crude and several estimates may be wrong by as much as one order of magnitude.Additions of N fertilizers have both direct and indirect effects on soil microorganisms. The possible importance of such effects is briefly discussed and a specific example is given on long-term effects on soil microbial biomass and nitrification rates in 27-year-old cropping systems with different N additions: (i) 0 kg N ha^–1 yr^–1, (ii) 80 kg N ha^–1 yr^–1, (iii) farmyard manureca. 80 kg N ha^–1 yr^–1.Few detailed N budgets exist for agro-ecosystems, despite its major importance as a limiting plant nutrient and the large losses of N from such systems. In conclusion, preliminary nitrogen budgets for four cropping systems (barley receiving 0 or 120 kg N ha^–1 yr^–1; meadow fescue ley with 200 kg N ha^–1 yr^–1 and a lucerne ley) are presented, with special attention to N flow through the soil organisms.Keynote address     

Aerobiology of “closed” agricultural systems

In many, mostly temperate regions of the world, crops are cultivated in completely or partly closed environments. Problems concerning the dissemination of fungal spores or bacterial cells in these systems are comparable to those in open systems, but there are many supplementary problems, which have hardly been investigated up to now.

Now the application of chemicals in agriculture is strongly discussed worldwide, it will be of the utmost importance to know more about the aerobiological principles of spore dissemination in closed, more or less conditioned environments, to be able to create better disease management programs for plant diseases on crops cultivated in those conditioned environments.

In this paper problems concerning the dissemination phase of the fungal infection cycle developing in “closed” spaces will be discussed.     

Integrated assessment of agricultural production practices to enhance sustainable development in agricultural landscapes

This study presents an integrated assessment approach for the sustainable development of agricultural landscapes. The approach evaluates single agricultural production practices by means of environmental, economic and social indicators. To implement the approach, a mixed method was employed that combines modelling techniques and survey methods. The economic and environmental indicators were implemented within the bio-economic modelling system MODAM (Multi-Objective Decision support system for Agro-ecosystem Management) in order to assess economic performance and the effects on the abiotic and biotic environments. The modelling approach was applied to a case study in a region of north-eastern Germany, within the state of Brandenburg. In addition, the acceptance by farmers of different production alternatives that are known to have environmental benefits was examined in the case study. To allow for a direct comparison between different indicators, the results of the assessment are dimensionless index values that indicate the suitability of certain agricultural production practices with respect to an indicator. The indicator-related indices are then aggregated into an overall index of sustainability differentiating between ‘strong’ and ‘weak’ sustainability. Results are presented for exemplarily chosen production practices for sugar beet, potato and winter rape production and set aside. Depending on the underlying concept of sustainability (‘weak’ vs. ‘strong’), different production practices were identified as the most suitable ones in a given situation. This integrated assessment enables determination of positive and negative correlations between indicators. The approach allows for the identification of production alternatives that are assessed to be economically and environmentally beneficial as well as socially accepted, although at different levels.     

Impact assessment for LCAs involving agricultural production

LCA has been developed primarily for industrial production systems. Application to agricultural systems requires systematic application of existing methodology and new methodological developments. Conventional approaches can obscure potential options for improving the environmental performance of systems involving agricultural production due to use of restricted system boundaries, incomplete assessment of impacts, and exclusion of ancillaries from the analysis. For use of nutrients such as phosphorus, it is proposed that Impact Assessment should be based on the quantity dispersed after use rather than on the input to the productive system. Eventually, the impacts associated with depletion should be based on technological or thermodynamic assessment of concentration for reuse, but this approach requires further theoretical development.     

The role of molybdenum in agricultural plant production

BACKGROUND: The importance of molybdenum for plant growth is disproportionate with respect to the absolute amounts required by most plants. Apart from Cu, Mo is the least abundant essential micronutrient found in most plant tissues and is often set as the base from which all other nutrients are compared and measured. Molybdenum is utilized by selected enzymes to carry out redox reactions. Enzymes that require molybdenum for activity include nitrate reductase, xanthine dehydrogenase, aldehyde oxidase and sulfite oxidase. SCOPE: Loss of Mo-dependent enzyme activity (directly or indirectly through low internal molybdenum levels) impacts upon plant development, in particular, those processes involving nitrogen metabolism and the synthesis of the phytohormones abscisic acid and indole-3 butyric acid. Currently, there is little information on how plants access molybdate from the soil solution and redistribute it within the plant. In this review, the role of molybdenum in plants is discussed, focusing on its current constraints in some agricultural situations and where increased molybdenum nutrition may aid in agricultural plant development and yields. CONCLUSIONS: Molybdenum deficiencies are considered rare in most agricultural cropping areas; however, the phenotype is often misdiagnosed and attributed to other downstream effects associated with its role in various enzymatic redox reactions. Molybdenum fertilization through foliar sprays can effectively supplement internal molybdenum deficiencies and rescue the activity of molybdoenzymes. The current understanding on how plants access molybdate from the soil solution or later redistribute it once in the plant is still unclear; however, plants have similar physiological molybdenum transport phenotypes to those found in prokaryotic systems. Thus, careful analysis of existing prokaryotic molybdate transport mechanisms, as well as a re-examination of know anion transport mechanisms present in plants, will help to resolve how this important trace element is accumulated.     

Effects of agricultural cropping systems on micronutrients transformation

Summary The effect of cropping systems of wheat-maize (WM), wheat-rice (WR), wheat-groundnut (WG), gram-bajra (GrB), potato-guara (PGu), and raya-mash (RaMa) in combination with treatments of dummy (uncultivated area) and applied Zn 0.0 (Zn₀), 2.8 (Zn₁), 5.6 (Zn₂) 11.2 (Zn₃) kg/ha was studied on the transformation of labile Zn fractions: exchangeable (Exch.), adsorbed (TAd) [weakly (WAd), moderately (MAd), strongly (SAd)], and organic matter (OM) in different layers of sandy loam soil. The added Zn stayed largely in the 0–30 cm layer and was associated with the WAd- and OM-Zn fractions. About 70% of the total labile Zn (PAv) remained in the WAd- and OM-Zn, that is, 33 and 39% in 0–15 cm layer, and 33–39% and 31–36% in 16–150 cm layer. All the Zn fractions in 0–15 cm layer, and only of WAd in 16–30 cm layer, significantly increased with rates of Zn addition. These were also significantly higher in Zn_1–3 than Zn₀ and dummy treatments because of the residual Zn. Diverse effects of cropping systems on soil properties, residual Zn, and labile Zn fractions were found. The influence was strong in 0–15 cm layer decreasing gradually with soil depth due largely to differences in Zn requirement, crop intake of various Zn fractions and the cultural practices of the systems. All the crops and rotations appreciabilly responded to Zn application. Uptake of Zn by crops markedly and successively increased with increasing rates of Zn application. The WR caused a significant increase in soil organic matter whereas WR and WM in CaCO₃. The WR, WM and GrB resulted in a decrease in pH while WG and GrB in CaCO₃. The RaMa and PGu maintained much higher residual Zn than other systems. The systems which caused the maximum decrease in Zn fractions were: cereal-cereal (WM) in Exch. legume-millet (GrB) in all the adsorbed, PAv and the Zn associated with CaCO₃, vegetable-legume (PGu) also in MAd and SAd; and cereal-legume (WG) in OM and PAv. Hence GrB, WG and WM in that order will cause the deficiency of Zn much earlier than the other systems due to greater use and or transformation of WAd- andOM-Zn. Such effects were least under RaMa because it increased the WAd-, MAd- and OM-Zn.     

Biodiversity of soil microbial communities in agricultural systems

The productivity and health of agricultural systems depend greatly upon the functional processes carried out by soil microorganisms and soil microbial communities. The biodiversity of the soil microbial communities and the effect of diversity on the stability of the agricultural system, is unknown. Taxonomic approaches to estimating biodiversity of soil microbial communities are limited by difficulties in defining suitable taxonomic units and the apparent non-culturability of the majority of the microbial species present in the soil. Analysis of functional diversity may be a more meaningful approach but is also limited by the need to culture organisms. Approaches which do not rely on culturing organisms such as fatty acid analysis and 16S/18S rRNA analysis have provided an insight into the extent of genetic diversity within communities and may be useful in the analysis of community structure. Scale effects, including successional processes associated with organic matter decomposition, local effects associated with abiotic soil factors, and regional effects including the effect of agricultural management practices, on the diversity of microbial communities are considered. Their impact is important in relation to the minimum biodiversity required to maintain system function.