Smallholder farmers and forestry development: A study of rural land use in Bendel,Nigeria

The supply of forest products has lagged behind the demand in Bendel State, Nigeria. This derives from unplanned growth of wood-based industries and low capital input in afforestation programmes. Another reason has to do with the general misconception that the supply of timber to wood-based industries is solely a government venture. In the face of these problems, forest regeneration efforts within the reserves could not keep pace with the rate of timber exploitation. It is on the basis of the foregoing deficiencies of wood supply that the land outside reserve boundaries forms an alternative source of timber production.The study described in this paper explored ways of integrating tree planting into the traditional farming system. Data were collected through a questionnaire survey. A sampled population of 300 rural farmers was randomly selected from 32 settlements in Bendel State.Available data indicate high prospects for wood production by the smallholder farmers. This form of land use is favoured by the land tenure system, willingness of farmers to plant trees and the long fallow periods of between 6 and 12 years. However, successful adoption of tree planting relies heavily on cost-sharing devices between government and rural farmers, virile extension services and the possibility of free crops to generate cash flow.     

Water management and crop production for food security in China: A review

Food security is a high priority issue on the Chinese political agenda. China’s food security is challenged by several anthropogenic, sociopolitical and policy factors, including: population growth; urbanization and industrialization; land use changes and water scarcity; income growth and nutritional transition; and turbulence in global energy and food markets. Sustained growth in agricultural productivity and stable relations with global food suppliers are the twin anchors of food security. Shortfalls in domestic food production can take their toll on international food markets. Turbulence in global energy markets can affect food prices and supply costs, affecting food security and poverty. Policy safeguards are needed to shield food supply against such forces. China must make unremitting policy responses to address the loss of its fertile land for true progress towards the goal of national food security, by investing in infrastructure such as irrigation, drainage, storage, transport, and agricultural research and institutional reforms such as tenure security and land market liberalization. The links between water and other development-related sectors such as population, energy, food, and environment, and the interactions among them require reckoning, as they together will determine future food security and poverty reduction in China. Climate change is creating a new level of uncertainty in water governance, requiring accelerated research to avoid water-related stresses.     

Evaluation of crop yield models for cowpea in Nigeria

Three phasic models namely, Hanks (H-2), Stewart (S-2) and the Hall–Butcher (H–B), were evaluated on cowpea irrigated using a line source sprinkler system. Three sets of field data (1983, 1985, and 1986) were collected; the 1985 data were used for calibration while the 1983 and 1986 data were used for evaluation of the models. The model performance that most accurately matched the measured data was then used to simulate the most water-efficient irrigation schedule and deficit irrigation analysis for cowpea in Nigeria. Results showed that the models gave good estimates of cowpea grain yield with the H-2 model performing slightly better than the other two models. The weighted root mean square deviations were 0.043, 0.094, and 0.213 for the H-2, S-2 and the H–B model, respectively. Simulation studies with the H-2 model showed that irrigating at 40% moisture depletion is the most water-efficient schedule for cowpea and that greater yield from a given optimum seasonal water application for deficit irrigation can be achieved by splitting the seasonal deficit among the growth stages.     

中央财政支持粮食生产的成效、问题和建议

在中央财政的强力支持下,我国粮食生产取得了"十一连增",但仍然面临着许多问题,中央财政只有进一步健全粮食增产财政保障机制,在调动农民和地方政府积极性、完善粮食市场调控机制的同时,大力支持高标准农田建设和农业科技进步,促进农业和粮食生产方式的根本转变,才能推动粮食综合生产能力建设不断迈上新台阶。     

Evapotranspiration components and dual crop coefficients of coffee trees during crop production

Quantifying crop water consumption is essential for many applications in agriculture, such as crop zoning, yield forecast and irrigation management. The objective of this study was to determine evaporation (E), transpiration (T) and dual crop coefficients (Ke and Kcb) of coffee trees during crop production (3rd and 4th year of cultivation), conducted under sprinkler and drip irrigation and no irrigation, in Londrina, Paraná State, Brazil. Crop evapotranspiration (ET) was measured by weighing lysimeters cultivated with plants of cultivar IAPAR 59, E was measured by microlysimeters installed on the lysimeters and T was obtained by the difference between ET and E. The crop coefficient (Kc) was determined for the irrigated treatments as the ratio between ET and the reference evapotranspiration (ETo). Similarly, evaporation coefficient (Ke) and basal crop coefficient (Kcb) were determined as the ratio of E and T, respectively, to the value of ETo, which was estimated by the ASCE Penman-Monteith method on an hourly basis. The values of E and Ke varied due to atmospheric demand and water application method. Those factors, in addition to crop phenology and leaf area evolution, also influenced T and Kcb. Regardless irrigation treatment, the measured values of E represented 35% of ET, while T was 65% of ET. The recommended values of Ke were 0.46 and 0.26 for sprinkler and drip irrigation, respectively. The recommended values of Kcb were 0.52 and 0.82 for sprinkler-irrigated, and 0.5 and 0.65 for drip-irrigated treatments, varying as a function of daily ETo (ETo ≥ or <3 mm day⁻¹, respectively).     

The food marketing system: Implications of the green revolution programme in Nigeria

This paper focuses on the food marketing system in three selected markets in the Kwara State of Nigeria as it affects the new agricultural development programme known as the Green Revolution.Analysis shows that, on average, transportation costs alone make up 54·5% of the total marketing costs. Seasonality is a problem in the food marketing industry in the area of study and in Nigeria in general.Analysis also indicates that there is no formal system of providing information. Most information is transmitted by informal sources.The paper therefore suggests ways of reforming these services if Nigerians are to benefit from the success of the Green Revolution.     

Water use, crop coefficients, and irrigation management criteria for camelina production in arid regions

Camelina sativa (L.) Crantz is an oilseed crop touted as being suitable for production in the arid southwestern USA. However, because any significant development of the crop has been limited to cooler, rain-fed climate-areas, information and guidance for managing irrigated-camelina are lacking. This study measured the crop water use of a November-through-April camelina crop in Arizona using frequent measurements of soil water contents. The crop was grown under surface irrigation using five treatment levels of soil water depletion. The seed yields of treatments averaged 1,142 kg ha⁻¹ (8.0% seed moisture) and were generally comparable with camelina yields reported in other parts of the USA. Varying total irrigation water amounts to treatments (295–330 mm) did not significantly affect yield, whereas total crop evapotranspiration (ET_c) was increased for the most frequently irrigated treatment. However, total ET_c for the camelina treatments (332–371 mm) was markedly less than that typically needed by grain and vegetable crops (600–655 mm), which are commonly grown during the same timeframe in Arizona. The camelina water-use data were used to develop crop coefficients based on days past planting, growing degree days, and canopy spectral reflectance. The crop coefficient curves, along with information presented on camelina soil water depletion and root zone water extraction characteristics will provide camelina growers in arid regions with practical tools for managing irrigations.     

Modeling the role of irrigation in winter wheat yield,crop water productivity,and production in China

Irrigation plays an important role in increasing food production in China. The impact of irrigation on crop yield (Y), crop water productivity (CWP), and production has not been quantified systematically across regions covering the whole country. In this study, a GIS-based EPIC model (GEPIC) was applied to simulate Y and CWP for winter wheat (Triticum aestivum L.) in China at a grid resolution of 5 arc-minutes and to analyze the impacts of reducing irrigation water on wheat production. The findings show that irrigation is especially important in improving CWP of winter wheat in the North China Plain (NCP), the “bread basket” of China. On average, the provincial aggregate CWP was 56% higher under the irrigated than that under the rainfed conditions. The intensification of water stress and the associated increase in environmental problems in much of the NCP require critical thoughts about reducing water allocation for irrigated winter wheat. Two scenarios for irrigation reduction in the NCP provinces are presented: reducing irrigation depth (S1), and replacing irrigated winter wheat by rainfed winter wheat (S2). The simulation results show that S1 and S2 have similar effects on wheat production when the reduction in irrigation water supply is below 20% of the current level. Above this percentage, S2 appears to be a better scenario since it leads to less reduction in wheat production with the same amount of water saving.     

Returns from small ruminant production in South West Nigeria

Dwarf goats and sheep are ubiquitous in the humid zone of West Africa, although only as a supplement to cash and food crop production. This paper presents estimates of the returns obtained from these small ruminants under traditional production systems. Returns are, on average, high, but variable, especially in view of disease risks. Apart from disease control measures to reduce mortality, improved nutrition is needed for intensifying production. At current levels of management neither pasture production nor housing and hand-feeding are likely to yield increased returns. Alley farming, a system of intercropping with shrub species and the feeding of shrub trimmings to small ruminants, seems a promising alternative.     

Simulation model for dryland crop production in the canadian prairies

Modern commercial agriculture is characterised by rapid technological change. These new technologies complicate decision-making for farm managers. Effective decision-making in this environment requires a systematic means of evaluation—one that attempts to evaluate the consequences of various management and production choices before resources are committed. The systems model described in this paper is considered to be an important step in this direction. The model provides a means for testing new production alternatives for cereal and oilseed crops in western Canada without actual farm application and thus of eliminating some of the trial and error associated with conventional decision-making methods. It does not replace the farm manager as the decision maker but it does provide information to facilitate his management function.     

Optimal spacing and cultivation intensity for an industrialized crop production system

The overall design of an industrial crop production system should optimize the system's global parameters, such as total area required, intensity of cultivation and general production schedule. The key element is the optimal intensity of cultivation for the prevailing climatic and economic environments. A single-state-variable vegetative crop model (e.g. lettuce) was used to optimize a crop production system for two economic environments: quota- and area-limited production. A strictly uniform weather (every hour of the season) was assumed initially. Continuous spacing was a central control element. The main conclusions of the analysis with our model are: (1) plants of all ages can grow together in a single climatic compartment; (2) spacing should be scheduled to maintain a constant canopy density; (3) optimal canopy density is an increasing function of available light and a decreasing function of temperature; (4) where produce-price is high relative to the prices of rent and energy, the optimal cultivation intensity for an area-limited operation is higher than for a quota-limited operation; the opposite is true where rent is expensive; and (5) the marginal price to be paid for supplementary light is smaller where available natural light is more plentiful.     

Increasing profits and reducing risks in crop production using participatory systems simulation approaches

The development of cropping systems simulation capabilities world-wide combined with easy access to powerful computing has resulted in a plethora of agricultural models and consequently, model applications. Nonetheless, the scientific credibility of such applications and their relevance to farming practice is still being questioned. Our objective in this paper is to highlight some of the model applications from which benefits for farmers were or could be obtained via changed agricultural practice or policy. Changed on-farm practice due to the direct contribution of modelling, while keenly sought after, may in some cases be less achievable than a contribution via agricultural policies. This paper is intended to give some guidance for future model applications. It is not a comprehensive review of model applications, nor is it intended to discuss modelling in the context of social science or extension policy. Rather, we take snapshots around the globe to ‘take stock’ and to demonstrate that well-defined financial and environmental benefits can be obtained on-farm from the use of models. We highlight the importance of ‘relevance’ and hence the importance of true partnerships between all stakeholders (farmer, scientists, advisers) for the successful development and adoption of simulation approaches. Specifically, we address some key points that are essential for successful model applications such as: (1) issues to be addressed must be neither trivial nor obvious; (2) a modelling approach must reduce complexity rather than proliferate choices in order to aid the decision-making process; (3) the cropping systems must be sufficiently flexible to allow management interventions based on insights gained from models. The pro and cons of normative approaches (e.g. decision support software that can reach a wide audience quickly but are often poorly contextualized for any individual client) versus model applications within the context of an individual client's situation will also be discussed. We suggest that a tandem approach is necessary whereby the latter is used in the early stages of model application for confidence building amongst client groups. This paper focuses on five specific regions that differ fundamentally in terms of environment and socio-economic structure and hence in their requirements for successful model applications. Specifically, we will give examples from Australia and South America (high climatic variability, large areas, low input, technologically advanced); Africa (high climatic variability, small areas, low input, subsistence agriculture); India (high climatic variability, small areas, medium level inputs, technologically progressing; and Europe (relatively low climatic variability, small areas, high input, technologically advanced). The contrast between Australia and Europe will further demonstrate how successful model applications are strongly influenced by the policy framework within which producers operate. We suggest that this might eventually lead to better adoption of fully integrated systems approaches and result in the development of resilient farming systems that are in tune with current climatic conditions and are adaptable to biophysical and socio-economic variability and change.     

Evapotranspiration and crop coefficients of irrigated biomass sorghum for energy production

New cultivars of sorghum for biomass energy production are currently available. This crop has a positive energy balance being irrigation water the largest energy consumer during the growing cycle. Thence, it is important to know the biomass sorghum water requirements, in order to minimize irrigation losses, thus saving water and energy. The objective of this study was to quantify the water use and crop coefficients of irrigated biomass sorghum without soil water limitations during two growing seasons. A weighing lysimeter located in Albacete (Central Spain) was used to measure the daily biomass sorghum evapotranspiration (ET_c) throughout the growing season under sprinkler irrigation. Seasonal lysimeter ET_c was 721 mm in 2007 and 691 mm in 2010. The 4 % higher ET_c value in 2007 was due to an 8 % higher evaporative demand in that year. Maximum average K _c values of 1.17 in 2007 and 1.21 in 2010 were reached during the mid-season stage. The average K _c values for the 2 years of study were K _c-ini: 0.64 and K _c-mid: 1.19. The seasonal evaporation component was estimated to be about 18 % of ET_c. The average basal K _c (K _cb) values for the two study years were K _cb-ini: 0.11 and K _cb-mid: 1.17. The good linear relationship found between K _cb values and the fraction of ground cover (f _c) and the excellent agreement found between Normalized Difference Vegetation Index and different biophysical parameters, such as K _cb and f _c, will allow monitoring and estimating the spatially distributed water requirements of biomass sorghum at field and regional scales.     

Irrigation management for optimizing crop production and nitrate leaching on grassland

Six supplementary irrigation management options for grazed grassland were defined and their effects on both agricultural production and nitrate leaching to the groundwater were studied. Data were available from the De Marke experimental farm for sustainable dairy farming. The calibrated and validated simulation models SWACROP and ANIMO were used to calculate the effects of the different irrigation management options on crop transpiration, and on water fluxes and nitrate concentrations for three fields of the farm. Comparisons with the common practice at the farm were made. A change in application volume from 25 to 15 mm per irrigation resulted in higher irrigation efficiencies and lower annual water use for supplementary irrigation with only small changes in the ratio of actual and potential transpiration (T_a/T_p). The advisory system ‘irrigation planner’ generally also resulted in high irrigation efficiencies combined with a reduction of water use and a small effect on the transpiration ratio. The different irrigation strategies had no significant effect on nitrate concentrations in the leachate from two dry fields studied. For the relatively wet field in this study an increase of irrigation water use would improve agricultural production conditions and reduce nitrate concentrations at 1 m depth. For the evaluation of environmental effects of irrigation management options it is advised to assess the actual nitrate concentrations and not only the water fluxes, which potentially cause solute leaching.     

Plantable stem supply system for IITA cassava varieties in Oyo State of Nigeria

The overall system for supplying plantable stems of improved cassava varieties from the International Institute of Tropical Agriculture (IITA) was surveyed for Oyo State where IITA is situated. This study examined the relation of spread of adoption of these varieties during the period of 1976 through 1985 to the supply of planting materials. Based on completed questionnaires, reconnaisance visits to 21 of the 24 local government areas of Oyo State, coupled with official documents and personal communications, the team found that: (i) effective distribution of plantable stems to the majority of cassava farmers did not begin until the second half of the 1976–1985 decade, (ii) the required capacity for, and rate of multiplication of IITA cassava varieties was grossly inadequate, (iii) the varieties are yet to be introduced to some localities due to a poor stem supply system for these cassava varieties and (iv) a large potential exists for further adoption of IITA varieties if farmers can obtain more plantable stems. This study identified the short supply of plantable stems to farmers as the chief obstacle to a wider spread, adoption, and use of IITA improved cassava for meeting the food needs of cassava-dependent rural farm families in Oyo State. A greater catalytic role is recommended for IITA to ameliorate the stem supply situation.     

Integrated freshwater aquaculture,crop and livestock production in the Mekong delta,Vietnam: Determinants and the role of the pond

Promotion of integrated aquaculture with agriculture, including crops and livestock (IAA-farming), requires consideration of both bio-physical and socio-economic contexts. The major factors influencing the adoption of IAA-farming by households at three sites in the Mekong delta were identified. Special attention was given to the multiple roles ponds play in IAA-farming systems. Information was collected through semi-structured interviews and discussions with focus groups and key individuals. Data were analyzed using multivariate factor analysis, analysis of variance or participatory ranking methods. Three major IAA-systems were identified: (1) low-input fish farming integrated with intensive fruit production (system 1), (2) medium-input fish farming integrated with less intensive fruit production (system 2), and (3) high-input fish farming integrated with less intensive fruit production (system 3). System 1 was commonly practised in a rural fruit-dominated area with fertile soils, while systems 2 and 3 were more evident in peri-urban rice-dominated areas with less fertile soils. In the study area, only 6% of poor farmers adopted IAA-farming, while this was 42% for intermediate and 60% for rich households. Richer farmers tended to intensify fish farming and seek a more commercial orientation. The major factors why farmers did not start aquaculture were the inappropriateness of technology, insufficient land holding or poor access to extension services, limited farm management, and through a fear of conflicts associated with pesticide use on crops. The main motivations for practising IAA-farming included increased income and food for home consumption from the available farm resources while reducing environmental impacts. Further improvements to IAA-systems can be realized by strengthening nutrient recycling between different IAA-system components while enhancing farming output and safeguarding the environment.     

Adaptive optimization of crop production and nitrogen leaching abatement under yield uncertainty

The study develops a bio-economic crop management model that internalizes the environmental cost of nitrate pollution, accounts for stochastic weather, and includes an option for split fertilization. The integrated model is designed to indicate whether a producer can benefit from applying fertilizer several times during the growing season, in response to crop needs, rather than a single time, at sowing. The model is parameterized for the cultivation of spring malting barley (Hordeum vulgare L.) in Southern Finland. The costs of negative externalities from nitrogen leaching are internalized in the landowner’s decision problem through a pollution tax. The results indicate that without a pollution tax a single application of fertilizer gauged to meet the needs of the entire season is optimal. With a tax, the benefits of split application - applying varying amounts of fertilizer at selected stages of the growing season - increase significantly. In comparison to a single application of fertilizer at sowing, split fertilization improves yields, increases the total amount of fertilizer used, and reduces nitrogen leaching.     

Impacts of population growth, economic development, and technical change on global food production and consumption

Over the next decades mankind will demand more food from fewer land and water resources. This study quantifies the food production impacts of four alternative development scenarios from the Millennium Ecosystem Assessment and the Special Report on Emission Scenarios. Partially and jointly considered are land and water supply impacts from population growth, and technical change, as well as forest and agricultural commodity demand shifts from population growth and economic development. The income impacts on food demand are computed with dynamic elasticities. Simulations with a global, partial equilibrium model of the agricultural and forest sectors show that per capita food levels increase in all examined development scenarios with minor impacts on food prices. Global agricultural land increases by up to 14% between 2010 and 2030. Deforestation restrictions strongly impact the price of land and water resources but have little consequences for the global level of food production and food prices. While projected income changes have the highest partial impact on per capita food consumption levels, population growth leads to the highest increase in total food production. The impact of technical change is amplified or mitigated by adaptations of land management intensities.     

Managing water in agriculture for food production and other ecosystem services

Agricultural systems as well as other ecosystems generate ecosystem services, i.e., societal benefits from ecological processes. These services include, for example, nutrient reduction that leads to water quality improvements in some wetlands and climatic regulation through recycling of precipitation in rain forests. While agriculture has increased ‘provisioning’ ecosystem services, such as food, fiber and timber production, it has, through time, substantially impacted other ecosystem services. Here we review the trade-offs among ecosystem services that have been generated by agriculture-induced changes to water quality and quantity in downstream aquatic systems, wetlands and terrestrial systems. We highlight emerging issues that need urgent attention in research and policy making. We identify three main strategies by which agricultural water management can deal with these large trade-offs: (a) improving water management practices on agricultural lands, (b) better linkage with management of downstream aquatic ecosystems, and (c) paying more attention to how water can be managed to create multifunctional agro-ecosystems. This can only be done if ecological landscape processes are better understood, and the values of ecosystem services other than food production are also recognized.