The future of lucerne in British agriculture: an economic assessment

With its potential for high yields and high animal output, lucerne appears to be an underexploited crop in British agriculture. In this paper an attempt is made to assess the prospects for expansion of the area of lucerne in Britain from an economic viewpoint, concentrating on lucerne as a conservation crop. Under good management lucerne is shown to have lower production costs than grass and its inclusion in the diet of dairy cows, but not beef cattle, could significantly lower winter feed costs. However, under apparently similar growing conditions, lucerne yields on different farms vary significantly, ranging from 9 to 13 t dry matter ha⁻¹ a⁻¹. At the lower yields, the economic attraction of growing and feeding lucerne in place of grass is small. Moreover, since potential lucerne production is concentrated in the south and east of Britain, lucerne competes with other arable crops. For lucerne to offer a gross margin per unit area comparable with these, the price for conserved lucerne would have to be set at a level at which dairy farmers would derive little economic advantage from feeding it. Thus, although lucerne is a forage crop with some potential, at present it is likely to offer economic possibilities only where producers can combine high yields with on-farm utilization of the crop.     

Crop losses and the economic impact of insect pests on Brazilian agriculture

Among the various sectors of the Brazilian economy, agriculture plays a prominent role, generating jobs and income for the country. However, the agricultural sector faces systematic annual losses due to pests and diseases. The damage caused by insect pests is one of the primary factors leading to the reduced production of major crops. The study presented here estimates the production losses of major crops caused by insects and the economic impact related to the direct damage caused by insects, to the purchase of insecticides, and to medical treatment for humans poisoned by insecticides. The results indicate that insect pests cause an average annual loss of 7.7% in production in Brazil, which is a reduction of approximately 25 million tons of food, fiber, and biofuels. The total annual economic losses reach approximately US$ 17.7 billion. These results are important for government policies in the agricultural sector, as well as indicate the need for updated data regarding the losses caused by insects in Brazil and the need for systematic monitoring of these losses.     

Agricultural intensification and the loss of habitat,species and amenity in British grasslands: a review of historical change and assessment of future prospects†

Grassland in Britain is a plagioclimax vegetation type. All lies on land originally cleared from forest and, without some form of management, would revert to forest through a process of natural succession. Traditionally managed, unsown grasslands nonetheless resemble more natural grasslands in other parts of the world and contain a substantial proportion of our native flora and fauna. They are also often important for recreational activities. Agricultural intensification over a long period has led to a loss in their extent, species and amenity. Reconciling agricultural and environmental objectives in grassland management is very difficult because increased fertility and production invariably leads to species loss. Current overcapacity in the agricultural industry is leading to the switching of some agricultural support from food production to countryside management. As a result some arable and intensively managed grass is being managed more extensively. However future production technologies may be so efficient that very many fewer stock are required with the result that much marginal grassland may revert once again to forest.     

棉花新品种主要农艺及经济性状综合评价的研究

在不同生态点条件下，棉花主要农艺及经济性状之间有明显的差异。纤维品质中以麦克隆值的变异最大，产量性状中以单株成铃的变异最大。通过分析，在不同生态点下建立了纤维品质与籽棉产量的线性回归模型(Y=-2488．2380 36．4393X1 19.0355X2-6．9988X3-14．8041X4 0．1763X5)和产量性状构成因素与籽棉产量的线性回归模型(Y=-362．2510—1．7261X1 44．5081X2 22．5925X3-70．6397X4 18．7370X5)，以揭示主要农艺及经济性状之间的量化关系。     

Insect pests and associated root pathogens of sainfoin in western USA

Sainfoin, Onobrychis viciifolia, Scop., is a perennial forage legume that was introduced into North America as an alternative to alfalfa, Medicago sativa L. Sainfoin does not cause bloating in livestock, is comparatively drought-resistant, and is not attacked by several economically important alfalfa insect pests. Plant survival in long-term sainfoin fields is reduced by root pathogens that invade through scars caused by root-feeding insects. Sitona scissifrons Say (Coleoptera: Curculionidae) weevils feed in sainfoin foliage and their larvae attack roots. Weevil populations were suppressed by application of carbofuran for two years in a newly established field. During the third year, there were fewer feeding scars and a lower incidence of tap-root disease in treated plots, indicating larval activity was associated with incidence of disease. In a seven-year trial near Bozeman, MT, alfalfa weevils. Hypera postica (Gyllenhal) (Coleoptera: Curculionidae), and pea aphids, Acrythosiphon pisum (Harris) (Homoptera: Aphididae) attacked alfalfa but not sainfoin. Both crops were attacked by S. scissifrons, however, as well as by a complex group of plant bugs, including Lygus elisus VanDuzee, L. hesperus Knight, and Adelphocoris lineolatus (Geoze) (Hemiptera: Miridae). A seed-infesting insect, Bruchophagous spp. (Coleoptera: Curculionidae), was found in only sainfoin.     

Conservation agriculture and smallholder farming in Africa: The heretics’ view

Conservation agriculture is claimed to be a panacea for the problems of poor agricultural productivity and soil degradation in sub-Saharan Africa (SSA). It is actively promoted by international research and development organisations, with such strong advocacy that critical debate is stifled. Claims for the potential of CA in Africa are based on widespread adoption in the Americas, where the effects of tillage were replaced by heavy dependence on herbicides and fertilizers. CA is said to increase yields, to reduce labour requirements, improve soil fertility and reduce erosion. Yet empirical evidence is not clear and consistent on many of these points nor is it always clear which of the principles of CA contribute to the desired effects. Although cases can be found where such claims are supported there are equally convincing scientific reports that contradict these claims. Concerns include decreased yields often observed with CA, increased labour requirements when herbicides are not used, an important gender shift of the labour burden to women and a lack of mulch due to poor productivity and due to the priority given to feeding of livestock with crop residues. Despite the publicity claiming widespread adoption of CA, the available evidence suggests virtually no uptake of CA in most SSA countries, with only small groups of adopters in South Africa, Ghana and Zambia. We conclude that there is an urgent need for critical assessment under which ecological and socio-economic conditions CA is best suited for smallholder farming in SSA. Critical constraints to adoption appear to be competing uses for crop residues, increased labour demand for weeding, and lack of access to, and use of external inputs.     

Multifunctional benefits of sainfoin mixtures: Effects of partner species,sowing density and cutting regime

Grass–legume mixtures have proven successful at improving the sustainability of grasslands. Their ability to suppress unsown species is particularly important for sainfoin (Onobrychis viciifolia), a forage crop with valuable bioactive compounds, yet low competitiveness. In this 3‐year study, the suitability of six partner species cultivated in mixtures with sainfoin at different annual numbers of cuts and partner sowing densities were evaluated. Mixture yields outperformed average monoculture yields by 31%, reduced the ratio of unsown species by 65% and increased the symbiotic N₂ fixation up to 158 kg ha^?1. A key finding of the study was the highly differential patterns of development of the partner grass species over the 3 years. These patterns of development had a large effect on the persistency of the proportion of sainfoin in the mixtures, which varied in the third year between 17% (when grown with Dactylis glomerata) and 38% (with Lolium perenne). These findings contribute to the further development of sustainable grass–legume systems, as evidence for the successful cultivation of sainfoin as an alternative legume species can help diversification, and knowledge of mixture development supports more persistent legume proportions.     

Establishment and production of common sainfoin (Onobrychis viciifolia Scop.) in the UK. 2. Effects of direct sowing and undersowing in spring barley on sainfoin and sainfoin-grass mixtures

The dry matter (DM) yield and herbage quality of swards of sainfoin ( Onobrychis viciifolia ), meadow fescue ( Festuca pratensis ,) and tetraploid perennial ryegrass ( Lolium perenne ) grown in monocultures and in four sainfoin:grass mixtures (0·33 sainfoin:0·66 meadow fescue, 0·66 sainfoin:0·33 meadow fescue, 0·33 sainfoin:0·66 perennial ryegrass and 0·66 sainfoin:0·33 perennial ryegrass), established by direct sowing or undersowing in spring barley, were investigated over 3 years in a field experiment in the UK. Direct sowing produced a mean yield across all species and mixtures of 1·8 t DM ha⁻¹ in the establishment year, whereas undersowing produced no measurable yield except for that of the spring barley. Undersowing reduced the yields of sainfoin and sainfoin-grass mixtures in the first full-harvest year but not in the second. The annual yield of a monoculture of sainfoin was 7·53 t DM ha⁻¹ and that of sainfoin-grass mixtures was 8·33 t DM ha⁻¹ averaged over 3 years. Both sainfoin and the sainfoin-grass mixtures had higher annual DM yields than the grass monocultures. The mixture of 0·66 sainfoin:0·33 meadow fescue gave the highest mean annual yield (9·07 t DM ha⁻¹) over the 3 years. There was a higher proportion of sainfoin maintained in mixtures with perennial ryegrass than with meadow fescue. The proportion of sainfoin in sainfoin–meadow fescue mixtures declined from 0·62 in the first year to 0·32 in the third year, whereas the proportion in sainfoin–perennial ryegrass increased from 0·48 in the first year to 0·67 in the second year and remained stable in the third year.     

Putting an economic value on increases in grass production

An attempt was made to determine monetary values for grass which might be used by researchers to assess the likely economic implications of their findings. It is shown that the value of extra grass production will vary considerably depending on the use made of it. At 1982 price levels, estimated values for grass in the field ranged from 1–4 to 10–6 pence kg⁻¹ DM, with a modal value around 3–5 pence kg⁻¹ DM. At the same time, the seasonal distribution of the extra grass production is important since the value of extra grass at different points in the growing season may vary markedly. The way in which these values for grass may be used is illustrated, using as an example weed control during sward establishment. Finally, the sensitivity of investment returns to changes in the value placed on grass is discussed. Extreme caution is necessary in drawing general conclusions about benefits and costs from an evaluation based on a specific value for grass.     

Leaf protein production and use on the farm: an economic study

A linear programming model to provide information on the economic feasibility of on-farm production and use of leaf protein from grass is described. The unwilted grass is mechanically separated into a protein-rich ctird, which is fed to pigs or other non-ruminants, and a high-dry matter, fibrous residue which is ensiled and fed to ruminants. In the model, the gross margin from a livestock farm which uses a conventional silage system for a dairy herd is compared with that from the same farm using forage fractionation. The difference in gross margins is available to pay for the additional cost of the fractionation equipment and to provide additional profit. The model considers the machinery performance, costs and labour constraints within which the new system would have to operate if it were to be economic. Results indicate that under a wide range of farm sizes and situations, forage fractionation shows an economic advantage over present forage conservation methods if machinery of the required throughput and cost were to be developed for on-farm use.     

Movento, an innovative ambimobile insecticide for sucking insect pest control in agriculture: Biological profile and field performance

The tetramic acid derivative spirotetramat (brand name Movento^®), has shown an outstanding performance against sucking insect pests in laboratory and greenhouse assays as well as in semi-field and field trials. The product acts as an inhibitor of lipid biosynthesis and affects juvenile stages with additional effects on adult fecundity. There is no cross-resistance to any other insecticide. After foliar application spirotetramat penetrates through the leaf cuticle and is translocated as spirotetramat-enol via xylem and phloem, up to growing shoots and down to roots. This full ambimobility or two-way systemicity (phloem and xylem transport) ensures the control of hidden and soil living sucking pests after foliar application and protects new shoots. The worldwide field development of spirotetramat in Bayer CropScience AG resulted in numerous uses against many species of whiteflies, aphids, scales (soft and armoured scales), mealy bugs, psyllids and selected thrips species in vegetables, cotton, soybean, pome and stone fruit, grapes, hop, citrus, nut trees and banana. The new mode of action renders spirotetramat as an excellent rotation partner with existing products for the management of aphid, whitefly and psyllid populations, which are frequently resistant to conventional insecticides. Moreover, only low adverse effects have been found on beneficial arthropods, which make the product suitable for modern integrated pest management (IPM) systems. These unique properties contribute to safeguarding the crop yield potential both in quality and quantity. In this paper, the new chemistry is presented, compared with standard insecticides and novel applications in IPM systems are discussed.     

The role of synthetic pesticides in the intensification of highland agriculture in Thailand

The objective of this study is to quantify the relationship between synthetic pesticide use and agricultural intensification in the northern highlands of Thailand. We surveyed the crop management decisions of 295 farmers across 12 villages, and assessed the level of pesticide use in terms of monetary value, the active ingredients used, and using the Environmental Impact Quotient method. The results show that 77% of the farmers relied solely on synthetic pesticides for their pest management activities. The average farmer used 13.3 kg of active ingredients per hectare of agricultural land, but the variation was large. The highest levels of pesticide use were observed with the cultivation of cut flowers and greenhouse vegetables, while greater land use intensity was associated with increased usage of synthetic pesticides and a greater potential environmental impact. We found that those farmers following public certification of Good Agricultural Practices (Q-GAP), were neither able to reduce pesticide use nor its environmental impact. The findings suggest that to limit the environmental impact caused by the use of synthetic pesticides, greater priority must be given to developing and promoting non-synthetic methods of pest control together with gradually restricting the supply of highly hazardous pesticides.     

Diversity of condensed tannin structures affects rumen in vitro methane production in sainfoin (Onobrychis viciifolia) accessions

Sainfoin is a non‐bloating temperate forage legume with a moderate‐to‐high condensed tannin (CT) content. This study investigated whether the diversity of sainfoin accessions in terms of CT structures and contents could be related to rumen in vitro gas and methane (CH₄) production and fermentation characteristics. The aim was to identify promising accessions for future investigations. Accessions differed (P < 0·0001) in terms of total gas and CH₄ productions. Fermentation kinetics (i.e. parameters describing the shape of the gas production curve and half‐time gas production) for CH₄ production were influenced by accession (P ≤ 0·038), but not by PEG. Accession, PEG and time affected (P < 0·001) CH₄ production, but accession and PEG interaction showed only a tendency (P = 0·08). Increase in CH₄ due to PEG addition was not related to CT content. Further analysis of the relationships among multiple traits (nutritional composition, CT structure and CH₄ production) using principal component analysis (PCA) based on optimally weighted variables revealed differences among accessions. The first two principal component axes, PC1 (57·6%) and PC2 (18·4%), explained 76·0% of the total variation among accessions. Loading of biplots derived from both PCAs made it possible to establish a relationship between the ratio of prodelphinidin:procyanidin (PD:PC) tannins and CH₄ production in some accessions. The PD:PC ratio seems to be an important source of variation that is negatively related to CH₄ production. These results suggested that sainfoin accessions collected from across the world exhibited substantial variation in terms of their effects on rumen in vitro CH₄ production, revealing some promising accessions for future investigations.     

Survival of plants of common sainfoin (Onobrychis viciifolia Scop.) in competition with two companion grass species

A 2-year experiment on competition between sainfoin ( Onobrychis viciifolia Scop.), meadow fescue ( Festuca pratensis ) and tetraploid perennial ryegrass ( Lolium perenne ) was conducted using plants grown in plastic containers outdoors. Root and shoot systems of sainfoin and the grasses were separated in order to investigate full and no competition of root and shoots, at two planting ratios (0·33 grass:0·66 sainfoin and 0·66 grass:0·33 sainfoin). Survival of sainfoin plants was lower at the higher grass:sainfoin ratio. More sainfoin plants died in the winter than during the growing season. Root competition had no effect on survival of sainfoin plants, but shoot competition reduced survival of sainfoin plants during one growing season. Companion grass species had no effect on survival of sainfoin plants, except in the first winter, when fewer sainfoin plants survived when grown with meadow fescue than perennial ryegrass.     

中国大米国际贸易的未来之路

介绍了中国大米贸易的现状及目前所面临的挑战与机遇。提出未来大米贸易的发展应立足国内,发展水稻生产,并积极参与国际市场分工;以市场为导向,从客户需求出发提供产品;发展产业化经营等措施。     

Remote sensing and GIS application for assessment of land suitability potential for agriculture in the IBB governorate, the Republic of Yemen

In the present study, an assessment of land suitability potential for agriculture in the study area of IBB governorate, Republic of Yemen has been conducted through close examination of the indicators of land characteristics and qualities. The objective of this study is to evaluate the available land resource and produce the potential map of the study area. Remote sensing data help in mapping land resources, especially in mountainous areas where accessibility is limited. Satellite imagery data used for this study includes data from multi-temporal Landsat TM which dated June 2001. The parameters taken into consideration were 16 thematic maps i.e., slope, DEM, rainfall, soil, land use, land degradation as well as land characteristics maps. Satellite image of the study area has been classified for land use, land degradation and soil maps preparation, while topo sheet and ancillary data have been used for slope and DEM maps and soil properties determination. The land potential of the study area was categorized as very high, high, moderate, low and very low by adopting the logical criteria. These categories were arrived at by integrating the various layers with corresponding weights in a Geographical Information System (GIS). The study demonstrates that the study area can be categorized into spatially distributed agriculture potential zones based on the soil properties, terrain characteristics and analyzing present land use. This approach has the potential as a useful tool for guiding policy decision on sustainable land resource management.     

The biotype concept and its application to insect pests of agriculture

The use of the term biotype of insect pests of agriculture is discussed in the broad context of species, populations and individuals. There have generally been two quite distinct usages and thus two different concepts. The first is a general concept which applies, confusingly, both to individuals and to populations of a species which share certain biological characteristics, usually concerning virulence on different host varieties, with little or no knowledge of their genetic bases. This is generally synonymous with the term host race, used by many authors. The second is a very specific concept in which a particular gene or genotype for virulence in a pest is known to correspond with a particular gene for resistance in a host plant—the gene-for-gene relationship. We argue that the first concept is so general as to be of little value, and in some examples, such as the brown planthopper of rice, is potentially misleading. The specific concept depends on detailed genetic analyses which are available for very few examples and is thus of limited applicability. We conclude that the confusion of the two distinct concepts is dangerous. It is not possible to argue from the general to the specific. The term biotype has often been used to cover our ignorance of the detail of any particular insect/plant interaction.