Journal of Agriculture and Rural Development in the Tropics and Subtropics (JARTS)
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Quo vadis Süßwasser? Anmerkungen zum "Internationalen Jahr des Süßwassers 2003"
Full text linkThe United Nations General Assembly proclaimed in a resolution in 2002 the “Internnational Year of Freshwater 2003”. The aim of the year is to raise awareness of the importance of protecting and managing freshwater resources in a sustainable way. On occasion of the International Year of Freshwater the author highlights the competing demands and gives a short description of three scenarios of freshwater use. From these scenarios it can be concluded that only the establishment of a sustainable, integrated water management will avoid a water crisis and maintain food security
Use of Combined Economic Threshold Level to Control Insect Pests
Full text linkThe economic threshold level (ETL) is a key factor to be studied for insect pests control. It is difficult to monitor cotton insect pests separately, and it is not reasonable to base decision-making for spraying on an ETL of individual insects and ignore sub-levels of other cotton insect pests. So, we want to use a combined ETL in a way of insect units, to put all major insect pests to consideration as an insect pests‘ complex. This means delaying the first spray to give a chance for natural enemies to develop and then lower the number of sprays and consequently reduce the cost of production
Challenges to Organic Farming and Sustainable Land Use in the Tropics and Subtropics
Full text linkThe central aim of Organic Farming is to maintain and improve soil fertility as a means of supporting animal health by species-adapted animal keeping and feeding. These two aims have developed from the basic desire of many human beings to live in harmony with nature, ultimately emanating from a wish to sustain their own health.In industrialised countries of temperate humid climate, diseases of modern civilisation have been developing at an alarming rate. One of the main reasons is excessive and incorrect nutrition, resulting from alienation in preparing and making our own foodstuffs. In this respect, food procurement today looks at qualitative aspects, i.e. at changes in nutritional habits, especially at a reduction of excessive meat consumption, but also at taking precautionary action to ensure that foodstuffs are free of pathogenic agents and harmful substances. In many tropical and subtropical regions, man is not supplied with sufficient amounts of food. In this context food procurement means protection against hunger and help in the daily fight for survival. This means that the main focus is on quantitative aspects of food production. However, the risks of intensive farming also have a completely different magnitude in tropical and subtropical regions due to themuch more frequent occurrence of acute poisoning after the improper use of pesticides (Castillo, X., 2000).Organic Farming tries to meet the demands of man in temperate humid as well as in tropical and subtropical regions and to provide something of a unifying element. The tension between these different demands and the resulting exciting discussion is a specific feature of our faculty ”Ecological Agricultural Sciences” in Witzenhausen, with its strong roots in both Sustainable Tropical and Subtropical Agriculture and in Organic Farming.In the view of a soil biologist, who tends to consider the aspects of soil fertility, the basic principles of Organic Farming mainly rely on the efficient and careful use of natural resources in all climatic regions (Paoletti, M.C. et al., 1993; Lavelle, P. et al.,1999). Under temperate humid climatic conditions, Organic Farming is especially devoted to protection against environmental pollution. Under tropical and subtropicalclimates, the possibilities of human intervention are enormously restricted due to the environmental conditions, e.g. nutrient deficiency of many soils or the drought of the climate, even if sufficient mineral fertilizers were available (Prasad, R. and Power, J.F., 1997). A characteristic feature of Organic Farming is the attempt to integrate problems into a systematic approach, to resist the temptation of simple solutions in mono-causal reason-effect-relationships, e.g. in finding a soil biological reference number that gives a fertilizer recommendation with a constant value. The euphoria in the use of molecular biological methods in the area of gene technology generates the suspicion that scientists search with complex methods for apparently simple solutions. This leads to the expectation that crop yields can be miraculously increased, for example, by introducing and switching on a gene. Problems are dealt with by taking immediate action, leading to fast and furious campaigns. Tackling problems in a systematic way, often called a holistic approach, entails the inherent risk that a specific topic will be dealt with very superficially.It is a major problem that the transfer of knowledge from temperate humid to tropical/ subtropical regions is impossible or seriously restricted. The use of easily-soluble mineral P-fertilizers is n ot really useful in P-fixing soils regularly occurring in large areas of tropical and subtropical regions (Castillo, X., 2000). Through promotion of soil microorganisms, e.g. by suitable soil organic matter management, P is much better held in biological cycles. However, knowledge about the control mechanisms of biological processes in tropical and subtropical soil is very sparse, especially considering the observation that the composition of the microbial decomposer community differs enormously in tropical and subtropical soils from those in humid temperate regions (Rees, R.M. et al., 1999).Not only is available knowledge regarding the large diversity of the tropical and subtropical regions restricted, but the realization of the farmers themselves is also hampered by quite different problems to those experienced in industrialised temperate humid regions.The cultural and political conditions, for instance with regard to property rights and the level of education, mean that the transfer of scientific knowledge can often only take place within very close limits (Bolanos, M.F., 2000). While the profession of a farmer requires an academic education in some countries of the European Union, land-using persons in tropical and subtropical regions are often very poorly educated, often lacking the most basic reading and writing skills. This problem is becoming increasingly serious with the increasing disappearance of rural traditions.A special advantage of Organic Farming is the fact that it always takes the social and political environment of human beings into consideration and not only the production of foodstuffs. Even more important for the development of sustainable agriculture in the tropics and the subtropics is the future oriented character of Organic Farming. In setting itself current limits in the means of production, its outlook into the future is unlimited
Counter Urbanization and Agricultural Input Productivity in Imo State of Nigeria
Full text linkThis study analyzed the productivity of agricultural inputs in the context of counterurbanization, a consequence of Nigeria’s fiscal policy reform, in Okigwe Local Government Area (L.G.A) of Imo State, Nigeria. Sixty counter-urbanities who settled for farming were randomly selected from four autonomous communities in the L. G. A for the study. Sources of primary data were structured questionnaires, market survey, interviewsand observation of farm activities Descriptive statistics, multiple regression and gross margin analyses were tools employed in data analysis.Results show that counter-urbanization has accelerated agricultural intensification and cultivation of marginal lands. Population density is significant and inversely related to output, while farm size, fertilizer application and fallow length were directly related to output. Labour and cropping density have not significantly affected output. Themarginal values of the variable inputs were measures of their efficiency usage. The average farm size, and output per hectare are less than those of non-migrants recordedsix years ago. Major sources of farmland were leasing and borrowing as opposed to inheritance. The study recommended among others provision of credit facilities for nonfarmsectors to reduce the number of return migrants engaged in farming
Phosphorus Availability Studies on Ten Ethiopian Vertisols
Full text linkThree chemical extraction methods (Olsen, Truog, and Warren and Cooke) were earlier recommended for soil available P determination on Ethiopian soils. In the present study, the applicability of these methods and two others ( Bray II and CAL methods) on ten Ethiopian Vertisols was tested using durum wheat and chickpea, which are traditional Vertisol crops in Africa. Results showed that the magnitude of soil available P extraction was in the order Truog CAL Olsen Bray II Warren and Cooke. The four methods excluding the CAL were highly significantly (P0.001) correlated with each other and also with crop P uptake. The CAL method was also correlated with most of the parameters, but the significance was not as high as that with the other extraction methods. The highest correlation was also obtained between wheat P uptake and the four extraction methods. None of the correlations involving dry matter yield were significant. Based on the results it can be generalized that wheat is a better indicator for P availability than chickpea. The results also show that the earlier recommended three methods are applicable to Vertisols and each method may be used in substitution of the other (with the exception of the Warren and Cooke method , the applicability of which on high pH soils may be limited) in case of need. Due to the shortage of chemicals often encountered in soil laboratories in Ethiopia, the need for testing multi-element extraction methods is recommended
Effect of Cover Crops, Lime and Rock Phosphate on Maize (Zea mays L.) in an Acidic Soil of Northern Guinea Savanna of Nigeria
Full text linkPhosphorus deficiency is the major constraint to maize production in acidic soil of Heipang (9°38’, 8°53’) in Northern Guinea Savanna of Nigeria. The soil is high in sesquioxides and soluble aluminum and has high phosphate sorption capacity. To address this problem, a field trial was conducted between 1996-1997 to assess the responses of six tropical cover crops and maize to lime and applied rock phosphate and to evaluate the effect of these treatments on the performance and P nutrition of succeeding maize. Results of the trial showed that planting Chamaecrista rotundifolia, Lablab purpureus, Mucuna pruriens, and maize-Chamaecrista rotundifolia intercrop reduced the leaf Al concentration of succeeding maize by more than 38%. Although none of the six cover crops significantly increased grain yields of succeeding maize, C. rotundifolia was the most consistent in improving maize performance while Glycine max produced the least performance. Concentration of Mn in the index leaves of maize was significantly higher on plots where G. max preceded maize, thus accounting for the poor performance of maize on these plots. Application of Sokoto Phosphate Rock at 30 kg ha^(-1) to cover crops produced very significant improvement in the yields of succeeding maize. While liming with 1.35 t CaO ha^(-1) in 1997 raised the soil pH value by 0.2 and significantly improved total P uptake by maize
Perspectivas del Sector Cooperativo de Frutas y Hortalizas de la Unión Europea en el Contexto del Nuevo Modelo Europeo de Agricultura
Full text linkIn recent years, the fulfillment of trade agreements, such as The Uruguay Round, and the acceptance of competitiveness and multifunctionality in basic issues of agricultural development as a supplier of other kind of goods related with the environment, both have implied the dismantling of agricultural protection systems that altered free competitiveness in international markets.Also, European people are becoming more aware of organic products and “Integrated Production Systems” ensuring agricultural practices which are more respectful with the environment. The accomplishment and guarantee of such a group of agricultural practices might underlie protection mechanisms that use food safety and environmental respect as an excuse to keep competitors away of the European Market.In this sense, the agrarian associationism is without any doubt a necessary process to be able to respond to these new challenges making viable an agriculture model based on the Family Farms and as the European example shows, where the agrarian cooperatives have been the basic instrument for the development of the most efficient agricultures. At the same time, they present a clear syntony with the Common Agricultural Policy, before the new model of multifunctional agriculture, not only committed with taking place better, with quality and alimentary security, with the environment, with the territory, and with the rural development
Adoptability of New Technology in the Small-Holdings Tea Sector
Full text linkThe degree of adoption of recommended technology is a crucial factor in the tea smallholdings sector of the low country Sri Lanka as far as the yield is concerned. An empirical study was carried out to ascertain the present situation. Almost all the recommendations were grouped into 11 packages (selection of clones, fertilizer application, soil and moisture conservation, field establishment, training, infilling, weed control, pruning, shading, pest and disease control and plucking). A package consisted of sub indicators to reveal farmers’ adoption level. High, middle, low and non-adopters were given justified scores (according to their importance to the yield). The total of marks given to sub indicators was the adoption index of farmers. Though the mean adoption level was 71%, some packages such as pest and disease control, and weed control were marginally adopted. Highest adopted packages included plucking, clone selection, field establishment, and fertilizer application (above 75% level). Adoption level was positively correlated to education, number of dependents, labour use pattern, and subsidies and further, it was negatively correlated to land extent
Time-Course Changes in High Temperature Stress and Water Deficit During the First Three Days After Sowing in Hydro-Primed Seed: Germinative Behaviour in Sorghum
Full text linkBoth drought and heat stresses substantially influence the germination pattern and subsequent establishment rates of sorghum. The timing of high temperature occuarrance, along with water deficit after seed sowing is investigated and methods for its alleviateion are evaluated. Two experiments were conducted on CSV 15 sorghum seeds after soaking treatments in 2, 4 or 6g NaCl l−1 solutions. Several high temperature stress scenarios of 45◦C were administered at various times during the second day after sowing, or at a fixed time during the first, second or third days after sowing. Results revealed that the 18th hour of the second day after sowing is more sensitive, in terms of the final germination percentage and germination index attained, than the 6th, 12th or 24th hour. Seed treatment with 2g NaCl l−1 was superior to untreated seeds in its response to high temperature stress, attaning more positive germinative characteristics. Heat shock on the first day after sowing had more negative impacts on germination than on the second or third days. It also caused an increase in radicle growth at the expense of plumule growth, thus decreasing the plumule:radicle ratio