Microbial and biochemical soil quality indicators and their potential for differentiating areas under contrasting agricultural management regimes

The aim of this study was to examine interrelationships between functional biochemical and microbial indicators of soil quality, and their suitability to differentiate areas under contrasting agricultural management regimes. The study included five 0.8 ha areas on a sandy-loam soil which had received contrasting fertility and cropping regimes over a 5 year period. These were organically managed vegetable, vegetable -cereal and arable rotations, an organically managed grass clover ley, and a conventional cereal rotation. The organic areas had been converted from conventional cereal production 5 years prior to the start of the study. All of the biochemical analyses, including light fraction organic matter (LFOM) C and N, labile organic N (LON), dissolved organic N and water-soluble carbohydrates showed significant differences between the areas, although the nature of the relationships between the areas varied between the different parameters, and were not related to differences in total soil organic matter content. The clearest differences were seen in LFOM C and N and LON, which were higher in the organic arable area relative to the other areas. In the case of the biological parameters, there were differences between the areas for biomass-N, ATP, chitin content, and the ratios of ATP: biomass and basal respiration: biomass. For these parameters, the precise relationships between the areas varied. However, relative to the conventionally managed area, areas under organic management generally had lower biomass-N and higher ATP contents. Arbuscular mycorrhizal fungus colonization potential was extremely low in the conventional area relative to the organic areas. Further, metabolic diversity and microbial community level physiological profiles, determined by analysis of microbial community metabolism using Biolog GN plates and the activities of eight key nutrient cycling enzymes, grouped the organic areas together, but separated them from the conventional area. We conclude that microbial parameters are more effective and consistent indicators of management induced changes to soil quality than biochemical parameters, and that a variety of biochemical and microbial analyses should be used when considering the impact of management on soil quality. (C) 2004 Elsevier Ltd. All rights reserved.

Land use for England and Wales: evaluation of management options to support 'good ecological status' in surface freshwaters

This paper analyses historic records of agricultural land use and management for England and Wales from 1931 and 1991 and uses export coefficient modelling to hindcast the impact of these practices on the rates of diffuse nitrogen (N) and phosphorus (P) export to water bodies for each of the major geo-climatic regions of England and Wales. Key trends indicate the importance of animal agriculture as a contributor to the total diffuse agricultural nutrient loading on waters, and the need to bring these sources under control if conditions suitable for sustaining 'Good Ecological Status' under the Water Framework Directive are to be generated. The analysis highlights the importance of measuring changes in nutrient loading in relation to the catchment-specific baseline state for different water bodies. The approach is also used to forecast the likely impact of broad regional scale scenarios on nutrient export to waters and highlights the need to take sensitive land out of production, introduce ceilings on fertilizer use and stocking densities, and controls on agricultural practice in higher risk areas where intensive agriculture is combined with a low intrinsic nutrient retention capacity, although the uncertainties associated with the modelling applied at this scale should be taken into account in the interpretation of model output. The paper advocates the need for a two-tiered approach to nutrient management, combining broad regional policies with targeted management in high risk areas at the catchment and farm scale.

Nitrogen management is essential to prevent tropical oil palm plantations from causing ozone pollution

More than half the world's rainforest has been lost to agriculture since the Industrial Revolution. Among the most widespread tropical crops is oil palm (Elaeis guineensis): global production now exceeds 35 million tonnes per year. In Malaysia, for example, 13% of land area is now oil palm plantation, compared with 1% in 1974. There are enormous pressures to increase palm oil production for food, domestic products, and, especially, biofuels. Greater use of palm oil for biofuel production is predicated on the assumption that palm oil is an “environmentally friendly” fuel feedstock. Here we show, using measurements and models, that oil palm plantations in Malaysia directly emit more oxides of nitrogen and volatile organic compounds than rainforest. These compounds lead to the production of ground-level ozone (O3), an air pollutant that damages human health, plants, and materials, reduces crop productivity, and has effects on the Earth's climate. Our measurements show that, at present, O3 concentrations do not differ significantly over rainforest and adjacent oil palm plantation landscapes. However, our model calculations predict that if concentrations of oxides of nitrogen in Borneo are allowed to reach those currently seen over rural North America and Europe, ground-level O3 concentrations will reach 100 parts per billion (109) volume (ppbv) and exceed levels known to be harmful to human health. Our study provides an early warning of the urgent need to develop policies that manage nitrogen emissions if the detrimental effects of palm oil production on air quality and climate are to be avoided.

Influence of agricultural management, sward structure and food resources on grassland field use by birds in lowland England.

Agricultural management of grassland in lowland Britain has changed fundamentally in the last 50 years, resulting in spatial and structural uniformity within the pastoral landscape. The full extent to which these changes may have reduced the suitability of grassland as foraging habitat for birds is unknown. This study investigated the mechanisms by which these changes have impacted on birds and their food supplies. We quantified field use by birds in summer and winter in two grassland areas of lowland England (Devon and Buckinghamshire) over 3 years, relating bird occurrence to the management, sward structure and seed and invertebrate food resources of individual fields. Management intensity was defined in terms of annual nitrogen input. There was no consistent effect of management intensity on total seed head production, although those of grasses generally increased with inputs while forbs were rare throughout. Relationships between management intensity and abundance of soil and epigeal invertebrates were complex. Soil beetle larvae were consistently lower in abundance, and surface-active beetle larvae counts consistently higher, in intensively managed fields. Foliar invertebrates showed more consistent negatively relationships with management intensity. Most bird species occurred at low densities. There were consistent relationships across regions and years between the occurrence of birds and measures of field management. In winter, there was a tendency towards higher occupancy of intensively managed fields by species feeding on soil invertebrates. In summer, there were few such relationships, although many species avoided fields with tall swards. Use of fields by birds was generally not related to measures of seed or invertebrate food abundance. While granivorous species were perhaps too rare to detect a relationship, in insectivores the strong negative relationships (in summer) with sward height suggested that access to food may be the critical factor. While it appears that intensification of grassland management has been deleterious to the summer food resources of insectivorous birds that use insects living within the grass sward, intensification may have been beneficial to several species in winter through the enhancement of soil invertebrates. Synthesis and applications. We suggest that attempts to restore habitat quality for birds in grassland landscapes need to create a range of management intensities and sward structures at the field and farm scales. A greater understanding of methods to enhance prey accessibility, as well as abundance, for insectivorous birds is required.

An application of life-cycle assessment for environmental planning and management: the potential environmental and human health impacts of growing genetically-modified herbicide-tolerant sugar beet

Life-Cycle Assessment (LCA) was used to assess the potential environmental and human health impacts of growing genetically-modified (GM), herbicide-tolerant sugar beet in the UK and Germany compared with conventional sugar beet varieties. The GM variety results in lower potential environmental impacts on global warming, airborne nutrification, ecotoxicity (of soil and water) and watercourse enrichment, and lower potential human health impacts in terms of production of toxic particulates, summer smog, carcinogens and ozone depletion. Although the overall contribution of GM sugar beet to reducing harmful emissions to the environment would be relatively small, the potential for GM crops to reduce pollution from agriculture, including diffuse water pollution, is highlighted.

Integrating woodland with pig production in the United Kingdom: an investigation of potential performance and interactions

Although silvopastoral systems involving pigs were once widespread in Britain, the practice has largely died out. However, recent changes in pig production techniques, consumer demands and the economic climate within which farmers operate, have led to renewed interest in both traditional and novel tree-pig systems. This paper describes a financial spreadsheet model (MAST) that was developed to: provide a means of determining financial performance of integrating finishing pigs with natural woodland; identify the likely importance of different as yet largely unresearched animal-tree interactions; and, determine which interactions warrant attention in research and management. Preliminary analysis suggests that the financial performance of this agroforestry enterprise could be superior to that of a pasture-based enterprise. The most important factors in determining incremental performance are identified as sales premia for ‘forest-reared’ pork, changes to feed conversion ratios arising from the provision of a heterogeneous microclimate, and the availability of cheaper land rents.

Integrating natural woodland with pig production in the United Kingdom: an investigation of potential performance and interactions

Although silvopastoral systems involving pigs were once widespread in Britain, the practice has largely died out. However, recent changes in pig production techniques, consumer demands and the economic climate within which farmers operate, have led to renewed interest in both traditional and novel tree-pig systems. This paper describes a financial spreadsheet model ( MAST) that was developed to: provide a means of determining financial performance of integrating finishing pigs with natural woodland; identify the likely importance of different as yet largely unresearched animal-tree interactions; and, determine which interactions warrant attention in research and management. Preliminary analysis suggests that the financial performance of this agroforestry enterprise could be superior to that of a pasture-based enterprise. The most important factors in determining incremental performance are identified as sales premia for 'forest-reared' pork, changes to feed conversion ratios arising from the provision of a heterogeneous microclimate, and the availability of cheaper land rents.

International public goods through integrated natural resources management research in CGIAR partnerships

The CGIAR System conducts research to produce international public goods (IPG) that are of wide applicability creating a scientific base which speeds and broadens local adaptive development. Integrated natural resources management (INRM) research is sometimes seen to be very location specific and consequently does not lend itself readily to the production of IPGs. In this paper we analyse ways in which strategic approaches to INRM research can have broad international applicability and serve as useful foundations for the development of locally adapted technologies. The paper describes the evolution of the IPG concept within the CGIAR and elaborates on five major types of IPGs that have been generated from a varied set of recent INRM research efforts. CGIAR networks have both strengths and weaknesses in INRM research and application, with enormous differences in relative research and development capacities, responsibilities and data access of its partners, making programme process evolution critical to acceptance and participation. Many of the lessons learnt regarding challenges and corresponding IPG research approaches are relevant to designing and managing future multi-scale, multi-locational, coordinated INRM programmes involving broad-based partnerships to address complex environmental and livelihood problems for development.

Animal health and welfare in organic livestock production in Europe: Current state and future challenges

Existing data on animal health and welfare in organic livestock production systems in the European Community countries are reviewed in the light of the demands and challenges of the recently implemented EU regulation on organic livestock production. The main conclusions and recommendations of a three-year networking project on organic livestock production are summarised and the future challenges to organic livestock production in terms of welfare and health management are discussed. The authors conclude that, whilst the available data are limited and the implementation of the EC regulation is relatively recent, there is little evidence to suggest that organic livestock management causes major threats to animal health and welfare in comparison with conventional systems. There are, however, some well-identified areas, like parasite control and balanced ration formulation, where efforts are needed to find solutions that meet with organic standard requirements and guarantee high levels of health and welfare. It is suggested that, whilst organic standards offer an implicit framework for animal health and welfare management, there is a need to solve apparent conflicts between the organic farming objectives in regard to environment, public health, farmer income and animal health and welfare. The key challenges for the future of organic livestock production in Europe are related to the feasibility of implementing improved husbandry inputs and the development of evidence-based decision support systems for health and feeding management.

Estimation of milk production from smallholder dairy cattle in the coastal lowlands of Kenya

A study was carried out on 92 smallholder farms in Kwale district in Coast Province of Kenya to estimate the milk yield. The effect of concentrate feed supplementation on milk yield was also evaluated. Data were collected during a one-year observational longitudinal study. Analysis was done for 371 observations following 63 calving events. The mean annual milk offtake was estimated at 2021 kg/cow. Forty-nine (77.8%) of the lactating cows were supplemented with concentrate feeds at varying rates of 0.5-3.0 kg/cow per day. Supplementary feeding of lactating cows led to a significantly higher mean daily milk yield compared to non-supplemented cows throughout the year (p<0.05). The mean annual milk offtake from supplemented cows (2195 kg/cow) was 18.6% more than offtake from non-supplemented cows, a difference that was statistically significant (p<0.05). Therefore, supplementary feeding of commercial feed concentrates was a rational management practice. It was also concluded that milk production from smallholder dairy cows in the coastal lowlands of Kenya was comparable to that from similar production systems but lower than national targets.

Rice versus fish revisited: On the integrated management of floodplain resources in Bangladesh

Disproportionately little attention has been paid to the dry season trade-off between rice and (inland capture) fish production on the floodplains of Bangladesh, compared to the same trade-off during the flood season. As the rural economy grows increasingly dominated by dry-season irrigated rice production, and floodplain land and water come under ever-increasing pressure during the dry winter months, there is an urgent need to focus attention on these dry months that are so critical to the survival and propagation of the floodplain resident fish, and to the poor people that depend on these fish for their livelihood. This article examines three important dry-season natural resource constraints to floodplain livelihoods in Bangladesh, and finds a common factor at the heart of all three: rice cultivation on lands at low and very low elevations. The article articulates the system interlinkages that bind these constraints and the long-run trend towards irrigated rice cropping on lower-lying lands, and suggests a management approach based on locally tailored strategies to arrest this trend. Apart from its direct relevance to the floodplains of Bangladesh, which support more than 100 million people, these lessons have relevance for river floodplain systems elsewhere in the developing world, notably the Mekong Delta.

Economic analysis of integrated weed management in field bean (Phaseolus vulgaris L.)

Field experiments were conducted in field bean in the north-eastern part of the Republic of Croatia to compare weed control and crop response under different management practices within the critical period of field bean production. The practices consisted in broadcast application of labelled rate of preemergence herbicide (PRE) and postemergence herbicide application: (POST) broadcast, band application over the rows, and band application combined with mechanical cultivation using of different herbicide doses recommended by the manufacturer (2x, 1x, 1/2x, 1/4x, 1/8x). In 1999, weed control with PRE application of pendimethalin was superior to POST bentazone application due to late emergence of weeds and lack of residual herbicide control. In 2000 bentazone combined with cycloxydim controlled weeds in field bean better than PRE herbicide application. Based on the results of this research, single PRE or POST application of herbicide did not control a broad spectrum of weeds and did not provide the commercially acceptable full season control. Reduced rates of herbicide are not advisable tinder high weed pressure.