Canadian Western Hard Red Spring (CWRS) wheat is recognized as premium quality wheat, ideal for breadmaking due to its superior milling qualities, baking characteristics and protein content. Organic wheat production is becoming more prevalent in Canada, due to increasing consumer demand for organic wheat products. Differences may exist in the baking and milling quality of wheat grown under conventional and organic management, a result of the dissimilarity between organic and conventional soil and crop management practices. Five CWRS cultivars released from 1885 to 1997 were grown under conventional and organic management and were assessed for their breadmaking potential. Several traits were investigated, including test weight, protein content, flour yield, kernel hardness and several mixograph parameters. Test weight was higher under conventional management, while no differences in protein content were observed between organic and conventionally grown wheat. Higher sodium dodecyl sulfate sedimentation (SDSS) volume, a reflection of gluten strength, was observed under conventional management, while there was a trend towards higher dough strength under organic management. Cultivars differed in grain protein, flour yield, kernel hardness and mixograph parameters, with Park and McKenzie superior to the others, particularly Red Fife, a much older cultivar. Management×cultivar interaction effects suggest that cultivars exhibit somewhat different baking characteristics when grown in the two management systems. There was no evidence that older cultivars (developed prior to the widespread use of pesticides and fertilizers) are better suited, in terms of breadmaking quality, for organic production.

Natural resource conservation should be fundamental to organic agriculture, including the prevention of soil erosion. Soil erosion in the olive orchards of southern Spain is recognized as a serious problem causing environmental, economic and social repercussions, both on and off-site. This study describes the changes in soil management practices that accompanied a shift from conventional to organic olive farming and the corresponding effect of those management practices on erosion risk in the province of Córdoba, Andalusia. Interviews with 107 farmers were carried out in two different geographic areas to assess the socio-economic factors influencing farm management decision-making, and on-farm erosion risk evaluations and soil data (organic matter, aggregate stability, infiltration and vegetative ground cover) were taken on 25 farms to assess the effects of those decisions on soil erosion risk. Results from this study show that the shift to organic farming in olive orchards in the province of Córdoba has been accompanied by increased protection of the soil and lowered erosion risk. The most important changes in soil management practices associated with the transition from conventional to organic agriculture were the reduction in tillage and the increase in management systems that incorporate a vegetative cover controlled either by grazing livestock or mowing. However, the shift to organic farming has had more impact in the south of the province than in the north where farm management systems have historically led to less erosion.

A study was conducted on the Teaching and Research Farm of the Rivers State University of Science and Technology, Nigeria to evaluate the nutritional suitability of four treatments, namely a commercial type broiler diet as compared with the commercial diet supplemented with either fresh centrosema (Centrosema molle), pueraria (Pueraria phaseoloides), or waterleaf (Talinium triangulare) leaves. These diets were fed to 120 day-old chicks (Lohmann Brown) over a 62-day period with treatments arranged in a completely randomized design (CRD). Chemical composition of broiler basal diets differed significantly from the three green foliage supplements. Dry matter (DM) of leaf meals ranged from 97.8 to 227.0 g kg−1 which was significantly (P<0.05) lower than that of broiler basal diets which averaged 900 g kg−1. Crude protein (CP) of leaf meals, however, ranged from 182.0 to 244.0 g kg−1 which was generally higher than basal diets (130–153 g kg−1). Similarly, crude fiber (CF) was highest for centrosema and pueraria leaves (330–342 g kg−1) and lowest in basal diets (164–222 g kg−1). However, ether extract (EE) and nitrogen-free extract (NFE) were significantly higher in broiler basal diets. Broiler daily and total feed intake over 62 days were similar between treatments and the control, averaging 112 g d−1, while diets containing waterleaf were slightly (2.5%) lower. Total and daily bodyweight (BW) gains (2110 g and 34 g d−1) were also similar between treatments and the control, except that gains where the broiler diet was supplemented with centrosema foliage were 2.9% higher. A higher feed conversion ratio (FCR) and lower protein efficiency ratio (PER) for the diet supplemented with pueraria indicates a higher feed efficiency and better protein efficiency in the commercial control diet. Carcass characteristics with the commercial control diet included greater (P<0.05) intestinal length and gizzard and spleen weights than with green foliage supplements. However, broiler carcass weight was generally lowest (P<0.05) in the control group (64.3 g/100 g BW) and highest in the waterleaf group (71.3 g/100 g BW). Small differences in carcass weight among the treatments tested reduces the effectiveness of green feeds for practical and economic intensive broiler production. However, increased effectiveness of green feed supplementation for broiler production might likely be observed where broilers are managed on fenced rangelands planted to selected green feeds or in integrated systems where other livestock (rabbits, sheep, goats, etc.) are jointly reared. These results support the recommendation that leaf meals of green feeds should be incorporated into broiler diets in future studies.

The Conservation Agriculture Project (CAP) of the North Dakota Natural Resources Trust (Trust) has demonstrated a new concept for delivering conservation education that improves farm economics while enhancing environmental health, restoring landscape functions and providing societal benefits. The 5-year project, initiated by the Trust in 2000, incorporated Resource Analysis Teams to assist four farmers and farm families serving as a demonstration in developing and implementing holistic farm plans. Resource Analysis Team members were agricultural, environmental, conservation and economic professionals. Resource Analysis Teams met with each demonstration farm family twice each year in a non-threatening setting, usually around the family's kitchen table. The integration of diverse knowledge bases resulted in an educational roundtable with all participants being educators and students at the same time. As round-table participants became familiar with the intricacies of each particular farm and with each other, adversarial relationships dissolved and team members worked together to move the farms toward sustainability—economic, environmental and social. This approach differs from most federal conservation programs to date, which have approached on-farm conservation in a piecemeal manner, only protecting a parcel of land or a critical problem area. For those programs, responsibility for searching out and implementing conservation practices has fallen primarily on the farmer, who also has had to assume associated risks. The Conservation Agriculture Project has demonstrated that the Resource Analysis Team approach yields positive results for the environment, wildlife, farm families and society while enhancing information delivery and improving communication and acceptance among diverse groups with varying agendas. Most importantly, it has demonstrated the need and positive impacts of delivering conservation education directly to farmers and ranchers, who manage 43% of the land nationwide.

Renewable Agriculture and Food Systems is a multi-disciplinary journal which focuses on the science that underpins economically environmentally and socially sustainable approaches to agriculture and food production. The journal publishes original research and review articles on the economic, ecological and environmental impacts of agriculture; the effective use of renewable resources and biodiversity in agro-ecosystems; and the technological and sociological implications of sustainable food systems. It also contains an open discussion Forum, which presents lively discussions on new and provocative topics. However, the opinions of the Forum and responses are solely those of the authors and do not necessarily reflect the opinions of Renewable Agriculture and Food Systems or Cambridge University Press.

Weed management is often the most troublesome technical problem to be solved in organic farming, especially in poorly competitive crops like vegetables. A four-year (2000–2003) series of trials was established to assess the possibility of adopting an innovative non-chemical weed management system in organic carrot grown on the Fucino plateau, i.e., the most important carrot-growing area in Italy. The system utilized for physical weed control was based first on a false seedbed technique followed by pre-sowing weed removal, performed with a special 2 m wide 6-row spring-tine harrow. Prior to crop emergence, a pass with a flame weeder equipped with four 50 cm wide-open flame burners was also performed. Post-emergence weed control consisted of one or more hoeing passes with a purpose-designed 11-tine precision hoe equipped with spring implements (torsion weeders and vibrating tines), in addition to hand weeding. This innovative system was applied to a novel planting pattern (sowing in ten individual rows within 2 m wide beds) and compared to the standard management system of the area (sowing within 2 m wide beds but in five bands, use of spring-tine harrowing and flame weeding pre-emergence and of traditional hoeing post-emergence). The new system was tested in different commercial farms including both early and late-sown carrot. Assessments included machine operative characteristics, labor time, weed density and biomass, crop root yield and yield quality, and economic data (physical weed control costs and crop gross margin). Compared to the standard system, the innovative system usually resulted in reduced labor time (from 28 to 40%) and total costs for physical weed control (on average −416 € ha−1). Use of the precision hoe resulted in intra-row weed reduction ranging from 65 to 90%, which also led to a marked reduction in the labor required for hand weeding. In 2001 the two systems did not differ in terms of yield and yield quality, whereas in 2002 and 2003 the innovative system showed a higher mean density of carrot plants (from 28 to 55%), root yield (from 30 to 42%), and gross margin (from 40 to 100%). Carrot yield was higher in farms which adopted an early sowing whereas root commercial quality was somewhat variable between systems and years. In general, results obtained with the innovative management system look very promising.

Integration of crops and livestock has the potential to provide a multitude of benefits to soil and water conservation and nutrient cycling efficiency, while reducing economic risk and increasing profitability. We conducted a field study from May 2002 to October 2005 to determine crop and cattle responses to three management factors on a Typic Kanhapludult in Georgia, USA. Summer grain/winter cover [sorghum (Sorghum bicolor L. Moench) or corn (Zea mays L.)/rye (Secale cereale L.)] and winter grain/summer cover [wheat (Triticum aestivum L.)/pearl millet (Pennisetum glaucum L. R. Br.)] were managed with either conventional tillage (CT) or no tillage (NT) and with or without cattle grazing of cover crops. All crops were successfully established, irrespective of tillage and cover crop management. Although pearl millet was often lower in the plant stand with NT than with CT, plants compensated with greater biomass on an area basis. Across years, grain yield of sorghum (1.9 Mg ha−1 during three seasons) and corn (7.3 Mg ha−1 in one season) was 25% greater under NT than under CT when the cover crop was not grazed. Wheat grain yield (2.7 Mg ha−1 during three seasons) was unaffected by tillage and cover crop management. Unharvested stover production of summer grain crops was greater with NT than with CT (6.5 versus 4.1 Mg ha−1; P<0.001). Grazing rye rather than allowing it to accumulate as surface residue reduced summer grain yield 23% and reduced standing grain-crop dry matter 26% under NT, but had no effect under CT. In contrast, grazing pearl millet rather than allowing it to accumulate as surface residue increased wheat standing dry matter yield by 25±14% (mean±standard deviation among 3 years and two tillage systems). Ungrazed cover crop production was greater under NT than under CT for rye (7.0 versus 6.0 Mg ha−1; P=0.03) and pearl millet (10.2 versus 7.6 Mg ha−1; P=0.01). Calf daily gain was either greater or tended to be greater under NT than under CT on rye (2.27 versus 2.09 kg head−1 d−1; P=0.15) and pearl millet (2.05 versus 1.81 kg head−1 d−1; P=0.05). Total cattle gain per grazing season was either greater or tended to be greater with NT than with CT on rye (350 versus 204 kg ha−1; P=0.01) and pearl millet (324 versus 277 kg ha−1; P=0.15). Net return over variable costs was greater with grazing than without grazing of cover crops (US$302 versus −US$63 ha−1; P<0.001). Livestock grazing of cover crops had variable effects on subsequent crop production, but increased economic return and diversity overall. Therefore, an integrated crop–livestock production system with conservation tillage is recommended as a viable option for producers to diversify farming operations to avoid risk, improve ecological production of crops, and potentially avoid environmental damage from soil erosion and nutrient loss.

In the winter of 2004–2005, over 300 of West Virginia's farmers' market vendors were surveyed with regard to sales levels, promotional techniques and operational characteristics such as hours worked, types of products produced and length of season. Vendors were categorized based on part-time, full-time or retired status, and full-time farmers, both with and without off-farm jobs, were found to be distinct from part-time and retired vendors with respect to 2004 total farmers' market sales and the percentage of household income from farmers' markets. Econometric analysis [ordinary least squares (OLS)] was performed to identify the impact of explanatory variables on total farmers' market sales, percentage of household income from farmers' market sales and amount of household income from farmers' market sales. Independent variables such as bargaining, cost-plus pricing, selling at markets outside West Virginia and providing print materials were found to have a positive impact on annual sales. The number of products produced, distance traveled to market and number of weeks at market were also positively related to the percentage of income obtained from farmers' market sales. Both part-time and retired producers received a lower percentage of household income from farmers' markets relative to full-time producers. Retired and part-time, along with limited-resource vendors (with annual household income less than $20,000) were also found to have lower total sales in the 2004 season. Identifying the characteristics associated with greater farmers' market sales and a higher reliance on such sales for household income will help in the sustained success of markets as engines of economic development and small farm viability.

This paper reports on the initial findings of an ongoing research project to capture differences in pest management strategies and decision-making among growers using the California Pesticide Use Reports (PUR) database. Analysis was performed for prunes in Sutter and Yuba counties to identify on-farm innovation by analyzing the PUR for best management practices to reduce pesticide use. Results showed that large variations in pesticide use were present in 2000, with a range of less than 5 kg to more than 41 kg of pesticide applied per hectare (ha) crop planted in Sutter County and a range of less than 2 kg to close to 30 kg per ha crop planted in Yuba County. Among the 42 growers selected cultivating more than 80 ha, five growers in Sutter County and three growers in Yuba County in 2000 were identified as low pesticide use growers. The results indicated a surprising number of low to no fungicide users and an even higher number of growers using no herbicides in both counties. Twenty-nine viable low pesticide use growers were identified overall among the total 294 growers in the Sutter and Yuba counties. However, there were no spatial patterns of where these low pesticide use growers' fields were located. The transition from higher-risk active ingredients (AIs) to reduced-risk AIs used by many of the low pesticide users suggests intentional substitution. Initial yield data indicate that quantity and quality were not adversely affected by low use growers employing reduced-risk pesticides, fewer (AIs) per field, and lower rates per chemical than their moderate to high use counterparts. Diverse collaborators consisting of university researchers, environmental and community organizations, state government scientists, and growers worked together throughout the entire project, beginning with defining the research parameters, then interpreting the results, and finally suggesting practical applications for the outcomes. The paper also highlights the effectiveness of using such collaborative research relationships to explore low pesticide use alternatives, to directly exchange research findings with growers, and to encourage a farmer-to-farmer extension model.

Management of Oriental fruit moth, Grapholitha molesta (Busck), in apple using an ‘Enhanced Integrated Pest Management (IPM)’ program comprised of a hedgerow barrier, pheromone-based mating disruption and reduced-risk [non-organophosphorous (OP) or carbamate] insecticides was investigated over a 5-year period. The barrier was comprised of a planting of three rows of hybrid poplar, Populus deltoides Bartr.×Populus nigra L., one row of Italian alder, Alnus cordata L. (nectar reward), and one row of white pine, Pinus strobus L. The hedgerow completely surrounded the perimeter of the apple orchard and was treated with garlic and a low rate of pyrethroid insecticide in 4 of the 5 years. The Enhanced IPM program significantly reduced G. molesta populations as measured by moth captures in pheromone traps. Captures of G. molesta were significantly higher in apple orchards treated with OP and carbamate insecticides, ‘Conventional IPM’, and either not surrounded by the hedgerow or with the barrier present but not treated with the repellent compounds. To explain these differences in G. molesta control, and the potential non-lethal effect of hedgerow barriers on G. molesta orchard colonization, we studied the adult vertical movement in a traditional unsprayed standard apple orchard at three different heights: 0.95, 1.95 and 3.20 m, respectively. In the overwintering generation at a height of 0.95 and 1.95 m, the mean number of moths captured per sampling period was 14.64 and 14.84, respectively, and only 2.95 at 3.20 m. However, the number of individuals captured in the second and third generations was not significantly different at the three different heights. Fruit damage evaluated before ‘June drop’ closely corresponded to the distribution of moths captured during the overwintering generation. Fruit damage at a height of 1.95 and 3.20 m was 5.8 and 3.5%, respectively. These results indicated that G. molesta is a weak flyer and that hedgerow barriers exerted some influence in the colonization of the orchard by limiting the free movement of adults from the overwintering generation. Thus, hedgerow barriers seem to limit early migration and establishment of G. molesta in the orchard. This in turn may reduce the size of the following generations and makes subsequent control easier under the Enhanced IPM program.

The principal objections to the proposition that organic agriculture can contribute significantly to the global food supply are low yields and insufficient quantities of organically acceptable fertilizers. We evaluated the universality of both claims. For the first claim, we compared yields of organic versus conventional or low-intensive food production for a global dataset of 293 examples and estimated the average yield ratio (organic:non-organic) of different food categories for the developed and the developing world. For most food categories, the average yield ratio was slightly <1.0 for studies in the developed world and >1.0 for studies in the developing world. With the average yield ratios, we modeled the global food supply that could be grown organically on the current agricultural land base. Model estimates indicate that organic methods could produce enough food on a global per capita basis to sustain the current human population, and potentially an even larger population, without increasing the agricultural land base. We also evaluated the amount of nitrogen potentially available from fixation by leguminous cover crops used as fertilizer. Data from temperate and tropical agroecosystems suggest that leguminous cover crops could fix enough nitrogen to replace the amount of synthetic fertilizer currently in use. These results indicate that organic agriculture has the potential to contribute quite substantially to the global food supply, while reducing the detrimental environmental impacts of conventional agriculture. Evaluation and review of this paper have raised important issues about crop rotations under organic versus conventional agriculture and the reliability of grey-literature sources. An ongoing dialogue on these subjects can be found in the Forum editorial of this issue.

A critical step in the quantification of soil quality (SQ) is the selection of SQ benchmarks. The benchmarks used in this study were SQ ratings made by 32 farmer collaborators representing a range of farming systems, scales of operation and geographic locations in the Mid-Atlantic region of USA. Soils from 45 pairs of sites identified by their farmers as having good and poor SQ were sampled over three seasons and analyzed for 19 soil parameters. Farmer judgments of SQ were based on many factors, most commonly soil organic matter, crop performance, soil water availability and erosion history. Selected individual soil parameters were normalized and integrated into an additive SQ index (SQI). Three additional indices were developed using discriminant analysis. The level of agreement between individual parameters, SQIs and farmer SQ ratings was evaluated using paired t-tests and mean percent difference values. The additive SQI was found to have the highest level of agreement with farmer SQ ratings (P<0.0001), demonstrating that a linear combination of soil parameters can be assembled that is more in agreement with holistic SQ criteria, such as farmer SQ ratings, than individual soil parameters. Extractable C from microwave (MW) sterilized soil (a measure of microbial biomass) was the individual parameter that best agreed with farmer SQ ratings (P<0.0001). Five additional soil C parameters, as well as aggregate stability, also agreed well with farmer SQ ratings (all P values <0.0005). The three parameters with the highest ratio of mean percent difference to coefficient of variation (an indication of parameter reliability) were extractable C from MW sterilized soil, anthrone reactive C and macroaggregate stability (14.2, 7.7 and 3.7, respectively). Mineral fertility parameters (pH, Ca, Ca:Mg ratio, P and K) were not significantly related to farmer SQ ratings (P values >0.05). The strong relationships observed between soil C parameters, soil structural parameters and farmer SQ ratings suggest that efforts to improve SQ in the study region should focus on monitoring and enhancement of soil C and soil structure.

Three different cotton production strategies [certified organic, conventionally grown, and reduced insecticide input/integrated pest management (IPM)] were compared in field-sized replicates in the Northern San Joaquin Valley (NSJV), California, from 1996 to 2001. We measured arthropod abundance, plant development, plant density, pesticide use, cost of production, lint quality and yields in the three treatments. Overall pest abundance was low, and a key cotton fruit pest, Lygus hesperus Knight, known as the western tarnished plant bug (WTPB), did not exceed action thresholds in any treatment. Organic fields had significantly more generalist insect predators than conventional fields during at least one seasonal interval in all but one year. While there were no significant differences in plant development, plant densities at harvest were lower in organic than conventional and IPM fields. Some measures of lint quality (color grade and bale leaf rating) were also lower in the organic treatment than in either the IPM or the conventional treatments. Synthetic insecticides, not allowed for use in organic production, were also used in significantly lower quantities in the IPM fields than in the conventional fields. Over the 6-year period of the study, IPM fields averaged 0.63 kg of active ingredient (AI) insecticide per hectare, as opposed to 1.02 kg AI ha−1 for conventional fields, a reduction of 38%. Costs of production per bale were on average 37% higher for organic than for conventional cotton. This cost differential was primarily due to greater hand-weeding costs and significantly lower yields in organic cotton, compared with either IPM or conventional cotton. Average 6-year yields were 4.4, 5.4 and 6.7 bales ha−1 for organic, IPM and conventional treatments, respectively. Low world cotton prices and the lack of premium prices for organic cotton are the primary obstacles for continued production in the NSJV.

The medium to long-term environmental performances of organic, integrated and conventional olive-growing systems in the average conditions of the south of Spain are evaluated and compared with respect to soil erosion, soil fertility, rational use of irrigation water, water contamination, atmospheric pollution and biodiversity, based on experts’ knowledge. The aim of the research was to test the common implicit assumption of environmental superiority of the two alternative farming systems over the conventional system. For this purpose, the Analytic Hierarchy Process (AHP), a widely used multi-criteria decision-making tool, has been implemented. AHP enables us to deal with complex decision-making problems with multiple criteria, stakeholders and decision-makers, high uncertainty and risk, such as in the case of multi-criteria environmental comparison of alternative farming systems. Twenty experts in olive production, clustered into three groups according to their professional field of interest, were involved in the analysis. The utilization of experts' knowledge is justified when information relevant for urgent decision-making is not available, is partial or is time and resource demanding, and a holistic perspective is required. Indexes and procedures are proposed for group decision-making, to detect variation in expert opinions and differences between alternative systems' performances. Despite bias in the judgments of the groups of experts in some topics, results confirm the holistic environmental superiority of organic and integrated alternatives over the conventional olive system in Andalusia in the medium to long-term. The results represent a scientific base to justify and endorse institutional support regarding the promotion and implementation of organic and integrated olive-growing systems in the region, which are likely to result in greater social welfare.

Brassicaceae seed meals produced through the oil extraction process release biologically active glucosinolate secondary products and may be useful as a part of biological weed control systems. Before meal can be used most efficiently, recommendations for suitable planting dates that maximize weed control but reduce crop injury must be determined. Our objectives were to determine the impact of 1 and 3% (w/w) meal applications of Brassica napus L. (canola), Brassica juncea L. (oriental mustard) and Sinapis alba L. (yellow mustard) on crop emergence and weed biomass in a growth chamber and field study. Results from the growth chamber experiment indicated that lettuce emergence was reduced by at least 75% when planted into 3% S. alba-amended soil earlier than 5 weeks after meal application. After 5 weeks, emergence was not different among treatments. Crop emergence was not reduced by any meal treatment as compared to the no-meal treatment in year 1 of the field study. In year 2, crop emergence in each 1.2-m row was inhibited by all meal treatments and ranged from 16 plants in the 3% B. juncea treatment to 81 plants in the no-meal treatment. The difference between emergence results in year 1 and year 2 is likely due to differing climatic conditions early in the season prior to irrigation, and the method of irrigation used. Redroot pigweed (Amaranthus retroflexus L.) biomass was 72–93% lower in 1% B. juncea and 3% treatments relative to the no-meal control in the first weed harvest of year 1. These same treatments had 87–99% less common lambsquarters (Chenopodium album L.) biomass. By the second weed harvest, redroot pigweed biomass in meal treatments (0.02–1.6 g m−2) was not different from that in the no-meal treatment (0.97 g m−2). Redroot pigweed biomass in 3% B. juncea plots was reduced by 74% relative to the no-meal treatment in the first harvest of year 2. This treatment also reduced common chickweed [Stellaria media (L.) Vill.] biomass by 99% relative to the 1% meal treatments. While pigweed biomass was reduced by 3% B. juncea in the early part of the season, by the second harvest this same treatment had the greatest pigweed biomass. Despite significant variability between years, 3% B. juncea did provide early season weed control in both years. Repeated meal applications, however, may be necessary to control late season weeds. Inhibition of crop emergence appears to be highly dependent on the amount and distribution of water and needs to be further studied in field settings.

A pot experiment to determine the effects of summer cover crops and soil amendments on okra yields and population densities of various soil nematode taxa was conducted in two consecutive growing seasons in a subtropical region. Two cover crops, sunn hemp (Crotalaria juncea) and sorghum sudangrass (Sorghum bicolor×S. bicolor var. sudanense), were grown and returned to the soil with fallow as a control. As soon as these cover crops were harvested, they were soil-incorporated together with one of several organic amendments. These organic amendments were biosolids, N-Viro soil (a 1:1 mixture of coal ash and biosolids), coal ash, co-compost (a 3:7 mixture of biosolids and yard wastes), and yard waste compost compared with a control (no additional amendment). Other treatments were fumigation with MC-33 (a mixture of 33% of methyl bromide and 67% of chloropicrin) and cover crop removal (harvested and removed cover crops and their residues from the soil). A nematode-susceptible vegetable crop, okra (Abelmoschus esculentus L.), was grown under these treatments. Among organic amendments, the application of biosolids produced the highest okra yield and biomass, and greatly suppressed root-knot nematodes, Meloidogyne incognita, in the soil. Between these two cover crops, sunn hemp was superior to sorghum sudangrass in improving okra production and in suppressing root-knot nematodes. The result indicates that growing sunn hemp as a cover crop and applying certain organic amendments can improve okra production and suppress root-knot nematodes, which are very damaging to okra plants. Such combined practices show a significant potential for application in organic farming and sustainable agriculture systems in a tropical or subtropical region.

Systems advocating alternative agriculture would appear to be handicapped by the amount and the minutiae of human labor required. Is this really a threat to the continuity of farms associated with these systems? We do not believe that this directly hampers the survival of a farm. We advance the theory that continuity is not just down to chance; the farmer at the time chooses to prolong the life of the farm and more especially to look for a successor. We have shown through a study conducted in central France (Auvergne) that the main guarantee of organizational sustainability, that which sustains the business as a viable entity when another person takes over, is when a farmer thinks of his farm as an entity-cum-project supporting a meaningful life plan. A farmer might also see his farm solely as capital or as heritage, but neither of these last two attitudes is sufficient for him to ensure the spirit of his enterprise is passed on. There is a particularly large number of farmers in the first category (entity-cum-project) who adopt alternative farming practices, which are meaningful. It also seems to be the case that the manner of working is closely linked to the moral principles of farmers who use alternative systems. Moreover, the same objective amount of work that might be thought excessive in a system that puts strong emphasis on high productivity, is regarded as normal in an alternative system. Farmers often approach extension advisors to help reorganize their working conditions. We maintain that alternative systems have peculiarities with regard to work that make this type of advice difficult. Our aim is to help advisors clearly construct the input they give to the various types of farmers. We put forward a typology of possible practices as regards advice on work, according to assessments farmers have made about the amount of work they do and their way of working. The large number of hours devoted to an alternative farming activity and the nature of that activity, whether demanding or linked to practices thought archaic, are not always a handicap to the continuity of an alternative system. On the contrary, these features can be its hallmark.

The practice of ecological agriculture involves building the strengths of natural ecosystems into agroecosystems, purposely disturbed to produce food and fiber. The overall strategies include using practices that (a) grow healthy plants with good defense capabilities, (b) stressing pests, and (c) enhancing populations of beneficial organisms. These are accomplished by enhanced habitat management both above ground and in the soil. Many of the practices that contribute to the overall strategies are well known—such as intensive use of cover crops or reduced tillage. Reasons for why they have not been more widely used are discussed. The special challenges facing ecological agriculture in the poor countries of the Third World are also discussed. Re-engaging national governments in the active support of their agriculture and addressing the structural inequalities (including access to land) are essential to overcome the many problems facing farmers in the poor countries.