Enhance Food Production Research Articles

How CYCLOPS keeps an eye on plant symbiosis

The availability of phosphorus and nitrogen are major limitations to plant growth, and as such our agricultural processes apply these nutrients at high concentrations to crop plants through fertilizer. Although fertilizer application has greatly enhanced food production it comes at a significant price: the chemical fixation of nitrogen depends on high levels of fossil fuels, making fertilizers a significant cost of food production and a major cause of greenhouse gas emissions from agriculture. A number of plants have entered beneficial interactions with microorganisms that facilitate the uptake of nitrogen and phosphorus from the soil. In this issue of PNAS Yano et al. (1) provide new insights into a novel genetic component in the plant that allows the establishment of these nutrient-capturing symbioses.

Soils and sustainable agriculture. A review

Enhancing food production and supporting civil/engineering structures have been the principal foci of soil science research during most of the 19th and the first seven or eight decades of the 20th century. Demands on soil resources during the 21st century and beyond include: (i) increasing agronomic production to meet the food needs of additional 3.5 billion people that will reside in developing countries along with likely shift in food habits from plant-based to animal-based diet, (ii) producing ligno-cellulosic biomass through establishment of energy plantations on agriculturally surplus/marginal soils or other specifically identified lands, (iii) converting degraded/desertified soils to restorative land use for enhancing biodiversity and improving the environment, (iv) sequestering carbon in terrestrial (soil and trees) and aquatic ecosystems to off-set industrial emissions and stabilize the atmospheric abundance of CO2 and other greenhouse gases, (v) developing farming/cropping systems which improve water use efficiency and minimize risks of water pollution, contamination and eutrophication, and (vi) creating reserves for species preservation, recreation and enhancing aesthetic value of soil resources. Realization of these multifarious soil functions necessitate establishment of inter-disciplinary approach with close linkages between soil scientists and chemists, physicists, geologists, hydrologists, climatologists, biologists, system engineers (nano technologists), computer scientists and information technologists, economists, social scientists and molecular geneticists dealing with human, animal and microbial processes. While advancing the study of basic principles and processes, soil scientists must also reach out to other disciplines to address the global issues of the 21st century and beyond.

SOIL CARBON SEQUESTRATION TO MITIGATE CLIMATE CHANGE AND ADVANCE FOOD SECURITY

World soils have been a source of atmospheric carbon dioxide since the dawn of settled agriculture, which began about 10 millennia ago. Most agricultural soils have lost 30% to 75% of their antecedent soil organic carbon (SOC) pool or 30 to 40 t C ha−1. The magnitude of loss is often more in soils prone to accelerated erosion and other degradative processes. On a global scale, CO2-C emissions since 1850 are estimated at 270 ± 30 giga ton (billion ton or Gt) from fossil fuel combustion compared with 78 ± 12 Gt from soils. Consequently, the SOC pool in agricultural soils is much lower than their potential capacity. Furthermore, depletion of the SOC pool also leads to degradation in soil quality and declining agronomic/biomass productivity. Therefore, conversion to restorative land uses (e.g., afforestation, improved pastures) and adoption of recommended management practices (RMP) can enhance SOC and improve soil quality. Important RMP for enhancing SOC include conservation tillage, mulch farming, cover crops, integrated nutrient management including use of manure and compost, and agroforestry. Restoration of degraded/desertified soils and ecosystems is an important strategy. The rate of SOC sequestration, ranging from 100 to 1000 kg ha−1 year−1, depends on climate, soil type, and site-specific management. Total potential of SOC sequestration in the United States of 144 to 432 Mt year−1 (288 Mt year−1) comprises 45 to 98 Mt in cropland, 13 to 70 Mt in grazing land, and 25 to 102 Mt in forestland. The global potential of SOC sequestration is estimated at 0.6 to 1.2 Gt C year−1, comprising 0.4 to 0.8 Gt C year−1 through adoption of RMP on cropland (1350 Mha), and 0.01 to 0.03 Gt C year−1 on irrigated soils (275 Mha), and 0.01 to 0.3 Gt C year−1 through improvements of rangelands and grasslands (3700 Mha). In addition, there is a large potential of C sequestration in biomass in forest plantations, short rotation woody perennials, and so on. The attendant improvement in soil quality with increase in SOC pool size has a strong positive impact on agronomic productivity and world food security. An increase in the SOC pool within the root zone by 1 t C ha−1 year−1 can enhance food production in developing countries by 30 to 50 Mt year−1 including 24 to 40 Mt year−1 of cereal and legumes, and 6 to 10 Mt year−1 of roots and tubers. Despite the enormous challenge of SOC sequestration, especially in regions of warm and arid climates and predominantly resource-poor farmers, it is a truly a win-win strategy. While improving ecosystem services and ensuring sustainable use of soil resources, SOC sequestration also mitigates global warming by offsetting fossil fuel emissions and improving water quality by reducing nonpoint source pollution.

Land Reform for Peace? Rwanda's 2005 Land Law in Context

A decade ago, Rwanda embarked on a major land reform programme. The government envisaged a new land law, supported by a land policy, and claimed that the new tenure system would contribute to enhancing food production, social equity and the prevention of conflict. The Land Law was finally passed in the summer of 2005. The UK Department for International Development (DFID) has taken on significant responsibility for monitoring the reform programme. This article provides a contextualized reading of the new Law. It argues that its emphasis on the obligation to consolidate fragmented family plots and register them will exacerbate social tension, but that some of the potential for social strife may be reduced because the state will allow flexibility in how the Land Law is implemented.

Food Choice in an Interdisciplinary Context

AbstractReform of agricultural policies, notably the continuing elimination of production‐enhancing subsidies, makes it possible for policies to respond to social issues such as the rural environment and health in future. In this paper, we draw on a Rural Economy and Land Use (RELU) research project which is examining the potential for the development of healthy food chains and the implications for human health and the environment. One of the key issues to be addressed is consumers’ willingness to pay for the nutritionally enhanced food products from these new chains, but it is evident that only a partial understanding can be gained from a traditional economics approach. In the paper, we discuss how economists are beginning to incorporate views from other disciplines into their models of consumer choice.

The effect of crop density on yield components enhancing food production efficiency

The determination of optimal quantity of seeds is a highly important task, not only from agrotechnical, but also from economic point view, after all it basical determines he cost of growing. We have to take into consideration the habitat, the nutritive supply, the quality of seed-bed and seeds, the way and quality of sowing and the needs of breed for the determination of seed quantity. Regarding the work of Ragasits (1998), there is a relation between the density of plants, the formation of shoots and the development of spikes in the case of cereals. The competition between plants leads to self-regulation in dense sowing circumstances, which involves the reduction of side-shoots and the number of grain per spikes in the time of spike formation, and it finally leads to the reduction of crops, regarding to Ragasits (1998). By contrast, Pek&ry (1971) pointed out that the increase of seed quantity did not affect the crop size of wheat as a conclusion of the research, which was done with 3 breeds on two different habitats. Kuti at al. (1971) draw the conclusion from the examination of wheat breed called Bezosztaja 1, that crop yield was decreasing while the quantity of seeds was increasing in average sowing time. Despite this fact, they had different results when examining the effect of different seed quantities in the same sowing time: under the early sowing circumstances the big amount of seeds was disadvantageous, but in last sowing the disadvantage was not presented. Kuti at al. (1985) researches show that the examined winter wheat breeds gave different crop yield sowing different seed quantity, respectively, the crop yield was affected not only by the properties of breeds, but by the age-group and by sowing date as well. The authors could not find significant differences regarding the effect of the number of germs on the crop yield in the average of years, breeds and sowing dates. By contrast, a research of Szalai (1985) shows, that the number germs is an important crop-assign agro technical factor. The author revealed that less than 300 seeds m"2 cause important loss in the crop yield, up to 600 seeds m"2 the yield is increasing, but above 600 seeds m"2 the yield is not changing on its merits, although it shows a decreasing tendency. Examining the elements of crops he pointed out, that the number of hibernated plants and the number of mature spikes increased while the number of seeds increased, but the estimated crop-improving effect of the higher number of spikes was degraded by the less grain yield of spikes. Anderson at al. (1992) experienced in a three years research, that the number of spikes decreased by the increase of the density of sowing. Tdthnd (1999) examined the elements of the props, and showed that in the case of loose stand the number of grains per spikes was significantly increasing. Pan et al. (1994) examining the effects of the seed density and sowing time concluded, that the negative effects of delay sowing can be corrected by increasing the number of germs, respectively bigger seed density causes the number of plants and spikes per area unit.

Preliminary investigation of catchment hydrology in response to agricultural water use innovations: A case study of the Potshini catchment – South Africa

Water use system innovations encompass various techniques for storing and conserving water resources in different mediums for domestic and livestock use including agricultural production. Although, several authors have indicated that rainwater harvesting techniques, especially for upgrading smallholder farming systems, are not new but have been practiced since ancient civilizations, the impacts of such water use innovations on eco-hydrological systems are rarely assessed, especially from a cascading spatial and temporal perspective. The need to quantify the supposedly potential and related hydrological impacts of water use innovations on a catchment and river basin at large, led to the on-going research study aimed at investigating the biophysical consequences at different spatial and temporal scales in the Thukela river basin, of increased productivity in smallholder rainfed agriculture enabled through adoption at larger spatial scale of integrated land use management and water use system innovations. In this paper we discuss and outline the approach used in setting up the research study in one of the catchments in the Thukela river basin, the Potshini catchment, in the KwaZulu-Natal Province of South Africa in an effort to seek answers to the question: “What is the impact of adapting water use innovations in a predominantly agricultural area on catchment ecology and hydrology?” The approach incorporates a catchment monitoring network, hydrological modelling and application of a remote sensing technique, the Surface Energy Balance Algorithm for Land (SEBAL), for spatially estimating the total evaporation in the region covering the Potshini catchment and beyond. Preliminary results indicate that water use innovations in the Potshini catchment have influenced the partitioning of rainfall, by significantly reducing surface runoff over agricultural lands under conservation tillage practices, with a reduction of above 100%, while encouraging infiltration and deeper percolation into the soil. It is envisaged that, on accomplishment, the study will contribute to formulation of sustainable adaptation of water use innovations and up-scaling strategies to enhance food production and hydro-ecological balance in semi-arid savannahs of Africa, at which stage hydrological modelling will form an important part of the study.

Advances in elucidating biogeochemical processes in soils: It is about scale and interfaces

Contributions in biogeochemical research have immensely benefited humankind, including enhanced food production and the quality of our environment. This overview paper focuses on recent breakthroughs in elucidating biogeochemical processes in soils and other natural materials and delineates frontiers for the present decade and beyond. Frontiers will undoubtedly involve multiple spatial and temporal scale investigations, elucidation of reactions at biological, chemical, and physical interfaces, and the use of advanced in situ technologies in combination with interdisciplinary research.

Fisheries and water productivity in tropical river basins: Enhancing food security and livelihoods by managing water for fish

Faced with growing pressure upon freshwater resources, increased water productivity in agriculture is essential. Efforts to do so however need to consider the wider role of water in sustaining food production. This paper considers the importance of water management in sustaining fish production in tropical river basins, and the potential for enhancing food production and income to farmers by integrating fish production into some farming systems. Specific examples from selected river systems and irrigated farming systems in Africa and Asia are provided. These highlight the benefits of integrating the water requirements for fish into water allocation decisions. In some cases, these benefits can be realised without any reduction in the water available for other purposes, while in others, a trade-off needs to be considered. The nature of these trade-offs needs to be better understood for better decision making in water management.

Contribution Of Indigenous Knowledge (IK) To Conservation And Utilization Of Biodiversity And Enhancment Of Livelihood In South- East Nigeria

This paper specifically outlines the contribution of indigenous knowledge (IK) to the conservation and utilization of biodiversity and enhancement of livelihood in South East Nigeria. It enumerates the importance, usefulness and typical examples of indigenous knowledge in use in South East Nigeria. It also looks at the problems of indigenous knowledge and suggests likely solutions to make indigenous knowledge sustainable by combining it with modern technology. It is clear that with proper knowledge of indigenous technology, biodiversity would contribute to enhance food production thus completing the requirement for reversing poverty. Biodiversity is the major part of natural capital and both its protection and conservation can yield benefit to improve the livelihoods of the poor. Both rural and urban dwellers especially the urban poor depend on biodiversity in the form of non-timber forest products, foods, medicines and domestic energy supplies. Global Approaches to Extension Practice Vol.1(1) 2005: 64-73

Biophysical potential for soil carbon sequestration in agricultural systems of the Old Peanut Basin of Senegal

Carbon sequestration in soil organic matter is increasingly advocated as a possible win–win strategy in the rehabilitation of degrading dryland agro-ecosystems because it simultaneously contributes to the reduction of global atmospheric greenhouse gas concentrations while enhancing local land productivity. A study was conducted in Senegal's Old Peanut Basin to assess current carbon stocks and to examine management options for their increase. Average soil and woody biomass carbon contents were 11.3 and 6.3 t carbon (C) ha −1, respectively. CENTURY, a biogeochemical model, was used to simulate soil and biomass carbon over a period of 25 and 50 years under a series of land use and management options. These simulated practices resulted in C dynamics ranging from −0.13 t C ha −1 yr −1 from a worst-case millet–sorghum rotation to +0.43 t C ha −1 yr −1 on intensively managed agricultural fields. Agroforestry simulations involving Faidherbia albida (Del.) Chev. and Leucaena leucocephala (Lam.) deWit. also resulted in promising carbon gain (+0.22 and +0.12 t C ha −1 yr −1, respectively), suggesting that improving agricultural practices is key to enhancing food production and mitigating climate change. Results from a sensitivity analysis suggest that woody biomass carbon is more sensitive to long-term changes in precipitation and temperature than soil carbon. Other management strategies likely to result in lower rates of soil carbon sequestration, including short-term improved fallows, should also be considered viable opportunities because promoting too narrow a set of ‘best management practices’ risks weakening local adaptability and opportunistic management regimes, both of which are crucial elements in small-scale farming systems in drylands.

Rainwater harvesting - an alternative for securing food production under climate variability

Food insecurity is still a challenge in some remote and mountainous areas in China. When studying the impact of climate variability on food production, we should pay even more attention to the rainfed area. This is because the larger part of agriculture is the rainfed one and climate variability has more negative impacts on the rainfed agriculture than on the irrigated one. The traditional dry farming practices based on the principle of storing as much rain in the soil as possible and making best use of soil water could not bridge the gap between the time that the corp needs water and the time that rain occurs, so its effects on enhancing food production under climate variability is limited. Combining artificial water supply from rainwater harvesting systems with the traditional dry farming practices is an innovation in water management in rainfed agriculture. Experiences in the recent two decades indicate that rainwater harvesting irrigation can well mitigate the drought caused by the climate variability and bring the rainfed agriculture to a new level.

A perspective from the food industry.

Biotechnology has the potential to meet the ever-increasing demand for enhanced food production. However, several factors besides scientific and agricultural advances can disrupt the progress of this field. This article reviews the interactions between political, regulatory, international, activist, consumer, and scientific entities. A discussion of the precautionary principle is included.

Offshore entrainment of anchovy larvae and its implication for their survival in a frontal region of the Kuroshio

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 248:237-244 (2003) - doi:10.3354/meps248237 Offshore entrainment of anchovy larvae and its implication for their survival in a frontal region of the Kuroshio Yuji Okazaki1,*, Hideaki Nakata1, Shingo Kimura2, Akihide Kasai3 1Faculty of Fisheries, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan 2Ocean Research Institute, University of Tokyo, 1-15-1 Minamidai, Nakano, Tokyo 164-8639, Japan 3Graduate School of Agriculture, University of Kyoto, Kyoto 606-8502, Japan *Email: f1333@cc.nagasaki-u.ac.jp ABSTRACT: Focusing on an incidence of coastal water entrainment into the Kuroshio frontal region, we looked at the fate of anchovy larvae Engraulis japonicus originating from coastal spawning grounds and entrained into the frontal region with the coastal low salinity water. Drifters were released in the low salinity water of the Kuroshio frontal region, and observation and sampling were conducted during drifter tracking from 18 to 21 May 1997. Naupliar copepod abundance and copepod production were high in the low salinity water at an early phase of the tracking, but decreased with elapsed days. Anchovy larvae were most abundant on the coastal side of the Kuroshio, especially in the low salinity water. Their ages estimated from otoliths were consistent with those inferred from the advective transport speed from the coastal spawning ground. The estimated biological mortality rate of first-feeding larvae (less than 7 d old) in the low salinity water was 0.71 d-1, which was high compared to rates previously reported for Engraulis spp. This high mortality could have been caused by poor nutritional conditions due to decreasing copepod production and abundance, suggesting that the offshore entrainment of fish larvae originating from coastal water could be unfavorable for their survival. The encounter with a frontal eddy would enhance food production and the subsequent survival of anchovy larvae in the frontal region; otherwise, they may perish due to low food availability. KEY WORDS: Anchovy larvae · Offshore entrainment · Kuroshio front · Larval survival Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 248. Online publication date: February 20, 2003 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2003 Inter-Research.

What is the limit of up-scaling rainwater harvesting in a river basin?

The semi-arid savannah environment (SASE) of sub-Saharan Africa are characterized by low erratic rainfall which result to high risk of droughts, intra-seasonal dry spells and frequent food insecurity. The main occupation is subsistence small-scale rainfed agriculture and livestock production, which normally compete for the limited water resources. The main challenges to improving the livelihoods of the small-scale farmers are how to upgrade rainfed agriculture to improve rural livelihoods and conserve nature, and upgrade upstream landuse in balance with water needs for human and ecosystems downstream. There is an increased interest in opportunities of improving rainfed agriculture through adoption of rainwater harvesting (RWH) technologies. However, there is inadequate knowledge on hydrological impacts and limits of up-scaling rainwater harvesting at a river basin scale. Rainwater harvesting has a potential of addressing spatial and temporal water scarcity for domestic, crop production, livestock development, environmental management and overall water resources management is SASE. However, this potential has not been exploited despite the occurrence of persistent low agricultural production and food shortage in sub-Saharan Africa. The need to quantify this perceived potential and related hydrological impacts on a river basin led to the on-going research project titled “hydrological impacts of up-scaling RWH on upper Ewaso Ng’iro river basin water resources management”. It is envisaged that the study will contribute to formulation of sustainable RWH up-scaling strategies to enhance food production and hydro-ecological balance in semi-arid savannahs of Africa. This paper presents the preliminary findings of the study mainly focusing on assessment of the potential of RWH technologies for improving food and water availability especially in semi-arid regions of eastern Africa. This was achieved by evaluating six RWH case studies selected from four countries (Ethiopia, Kenya, Tanzania and Uganda). Despite the success of a number of RWH systems, the rate of adoption is still low, hence making their impacts marginal. Nevertheless, there is a knowledge gap on the limits of up-scaling RWH in a river basin, which the other components of the study will address. The assessment of the hydrological impact of up-scaling RWH technologies is expected to provide answers to the question, what is the limit of up-scaling rainwater harvesting in a river basin?

NITROGEN FERTILIZER RESPONSE AND USE EFFICIENCY FOR THREE CEREAL CROPS IN NIGER

Nitrogen (N) is one of the most limiting nutrients for cereal production in many areas of west Africa such as Niger. One of the strategies to improve yields is to choose crops with high N use efficiency (NUE) that can produce economic yield under limited water supply. Little information is available on comparative performance of pearl millet [Pennisetum glaucun (L.) R. Br.], sorghum [Sorghum bicolor (L.) Moench], and maize (Zea mays L.) for their NUE. A field experiment was conducted to evaluate several components of NUE for the three crop species on a Psammentic Paleustalf sand at two locations in 1997 and three locations in the 1998 rainy seasons in Niger. Nitrogen use efficiency components were calculated as incremental increases in yield per applied N or per plant N. Leaf area index and leaf chlorophyll were determined as concomitant data. Among the three cereals, sorghum and millet had greater responses to N (kg grain kg−1 N) than maize. Nitrogen use efficiency differed widely among species. Partial factor productivity (kg grain kg−1 N applied) was higher in sorghum and pearl millet than maize over three sites in two years and declined with increasing N levels. Agronomic NUE (Δ grain weight kg−1 N applied) was also higher in sorghum compared to pearl millet and maize over all N rates. Nitrogen recovery efficiency (Δ grain weight kg−1 N applied) was higher in sorghum followed by millet and lowest in maize. Marginally lower NUE for biomass production in pearl millet was associated with higher biomass yield in non-fertilized treatments. The ability of pearl millet to extract N from nutrient degraded sandy soils and its better drought tolerance is the primary reason for its adaptation to the Sahel where it produces a moderate although reliable grain yield. Although pearl millet tended to have better performance where frequent drought was prevalent, sorghum had higher yields than pearl millet under improved N management and thus can significantly contribute to enhancing food production in areas where good management is practiced. This study also indicated that N deficiency could be detected using a SPAD chlorophyll meter early enough to apply additional N for achieving target yield levels.

Impact of agroforestry intervention on soil fertility and farm income under the subsistence farming system of the middle hills, Nepal

Practices that minimize the rate of soil degradation, improve soil fertility, increase crop yields and raise farm income are key to sustaining agricultural productivity in the hills of Nepal. Against this background, this study examined the impact of an agroforestry intervention project on soil fertility and farm income based on a sample of subsistence farm households in Dhading district. The project was implemented in 1993/1994 to increase fodder production through the promotion of agroforestry. A total of 223 households (82 project and 141 non-project) were interviewed during May 1998–October 1998 to collect information on production and farmer’s perception toward agroforesty’s impact on soil fertility. Soil samples taken from both project and non-project areas were also analyzed to examine agroforestry’s impact on various soil nutrients. The soil analysis revealed that differences in amount of organic matter, nitrogen, phosphorus and potassium observed between the soils under agroforestry system and the conventional system were not significant at the 0.05 level. The benefit–cost analysis showed that the agricultural system with agroforestry was more profitable than the conventional system. The results also showed that the introduction of multipurpose trees, such as mulberry ( Morus alba) for sericulture could further enhance the profitability of agroforestry-based system. Thus, in the hills, agroforestry has potential for enhancing food production and farmers’ economic conditions in a sustainable manner through its positive contributions to soil fertility and household income.

PHYSICAL MANAGEMENT OF SOILS OF THE TROPICS: PRIORITIES FOR THE 21ST CENTURY

Increasing agronomic productivity and improving the quality of the environment are among the important goals of soil physical management in the tropics. Several perceptions, created by insufficient scientific data and misunderstanding of the basic processes, are being resolved by an improved data base and better understanding of the dynamics of soil physical properties and processes. Principal issues in the tropics for the 21st century include: (i) achieving food security; (ii) curtailing soil degradation and restoring degraded soils; and (iii) improving environment quality. These issues can be addressed by identifying and prioritizing research needs in soil physical management. Important among these are: (i) assessing soil physical constraints at farm scale; (ii) managing soil structure and tilth to minimize the risks of crusting, compaction, and hard-setting; (iii) quantifying and controlling soil erosion by water and wind, developing a cause-effect relationship between soil and climate factors, and evaluating the effects on productivity; (iv) managing soil-water, controlling soil salinity in irrigated agriculture, and developing water harvesting techniques in rain-fed agricultural systems; (v) studying the dynamics of soil physical properties in puddled soils of rice-based cropping systems; (vi) developing conservation tillage and residue management methods to improve soil tilth; (vii) understanding soil moisture retention characteristics in relation to plant available water capacity; and (viii) developing indicators of soil physical quality. Important environmental issues relevant to soil physical management are transport of agricultural chemicals into surface and ground waters, emission of greenhouse gases from soils to the atmosphere, and disposal of urban and industrial wastes. Soil physical management in the tropics must be based on a holistic approach to solve practical problems. It is also important to make the public aware of the contributions of soil science to society's well-being. In addition to enhancing food production, soil physical management needs to address environmental, engineering, social, legal, and archeological issues. Achieving these goals necessitates soil scientists working in close collaboration with engineers, climatologists, geologists, biologists, and specialists in GIS and geostatistics.

Recent Evidence on Farm Size and Land Productivity: Implications for Public Policy

Agricultural productivity is low in most of the developing countries including Pakistan. Moreover, slow and meandering agricultural growth is unable to keep pace with the fast and persistently growing population pressure in these countries. That in turn, has, continued to result in malnutrition and recurrent famines [Cornia (1985)]. Worse than this are the results of an ILO (1977) study, which has shown that food consumption inequalities have actually increased overtime not only in the food deficit countries but also in countries experiencing rapid agricultural growth. This points to the ever-hanging shadows of food deficiency and resulting malnutrition over the countries characterised by slow or negative growth in per capita food production and perverted income distribution [Cornia (1985)]. The only choice with these countries is to enhance food production and provide better access to food consumption for the poor masses.

Signaling by glutamate dehydrogenase in response to pesticide treatment and nitrogen fertilization of peanut (Arachis hypogaea L.).

The responses of glutamate dehydrogenase (GDH) to NH(4)(+) and herbicides offer a new approach for probing the effects of NH(4)(+)-pesticide interactions at the whole-plant level. Although pesticides and fertilizers have greatly enhanced food production, their combined biochemical effects are not known in detail. Peanut plants were treated with different rates of Basagran (3-(1-methylethyl)-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide), Bravo 720 (tetrachloroiso-phthalonitrile), and Sevin XLR Plus (1-naphthyl N-methylcarbamate), with and without 25 mM NH(4)Cl fertilization. Isoelectric focusing, followed by native 7.5% polyacrylamide gel electrophoresis (PAGE) fractionated the peanut seed GDH fully to its isoenzyme population patterns. The pesticide treatments induced positive skewing of the GDH isoenzymes, but NH(4)Cl-pesticide cotreatments induced a negatively skewed distribution. Basagran, Sevin, and Bravo increased the amination activities of GDH from 30.0 +/- 2.8 units in the control assay to 479.0 +/- 20.7, 63.0 +/- 5.8, and 35.2 +/- 2.2 units, respectively, therefore indicating a direct GDH-pesticide interaction. Neither the NH(4)(+) nor the pesticides increased the peanut seed protein yields above the threshold of 3.8 +/- 0.7 g per pot. But in the GDH combination of the signals from a pesticide and NH(4)(+), at least 70% of the pesticide signal was overridden by NH(4)(+) with concomitant increases in peanut seed protein yields to 7.0 +/- 1.8 g per pot. Basagran, Sevin, and Bravo possess different pesticidal properties, but their effects on GDH activity were related in the decreasing order of their nucleophilicity, viz. Basagran > Sevin > Bravo.