• Authors:
    • Abol-Maatey, S. M.
    • Medany, M. A.
    • Abou-Hadid, A. F.
  • Source: Acta Horticulturae
  • Volume: 659
  • Issue: 1
  • Year: 2004
  • Summary: Agricultural practices used to be implemented based on timely fixed operations. This included selection of crops, cultivars, sowing dates, field preparation, trees training and pruning, irrigation, fertilization, and pest and disease control. Although such fixed agenda was useful for centuries in Egypt as a traditional system, it doesn't consider variations such as in daily weather, new crops, new pests, and new irrigation and fertilization systems. Therfore, adaption of the current information technologies in the fields of automatic real-time weather stattions, computer facilities, internet availability, as well as the available wealth of information, was a logical avenue. This work aims at introducing the basic structure of the new agricultural agenda (AG_AGENDA®). It is a computer tool that embraces crop, cultivar, planting date, daily crop production operations from planting to harvesting including weed, pest and disease control, irrigation requirements, fertilizer requirement according to the source of fertilizer. In addition, it includes details for field preparation, videos for fruit trees pruning, pictures of most prevailing weeds and methods to control, crop characteristics and expected yield, recommendations for the suitability of cultivars to a given region, scientific and general information for many definitions as well as regular and detailed maintenance of irrigation system. Detailed description of the flow charts of the processes are included. A step-by-step print screens are presented from the start of input till the recommended operation of the day.
  • Authors:
    • Jones, P. G.
    • Atieno, F.
    • Kruska, R. L.
    • McCrabb, G.
    • Thornton, P. K.
    • Reid, R. S.
  • Source: Environment, Development and Sustainability
  • Volume: 6
  • Issue: 1-2
  • Year: 2004
  • Summary: Climate change science has been discussed and synthesized by the world's best minds at unprecedented scales. Now that the Kyoto Protocol may become a reality, it is time to be realistic about the likelihood of success of mitigation activities. Pastoral lands in the tropics hold tremendous sequestration potential but also strong challenges to potential mitigation efforts. Here we present new analyses of the global distribution of pastoral systems in the tropics and the changes they will likely undergo in the next 50 years. We then briefly summarize current mitigation options for these lands. We then conclude by attempting a pragmatic look at the realities of mitigation. Mitigation activities have the greatest chance of success if they build on traditional pastoral institutions and knowledge (excellent communication, strong understanding of ecosystem goods and services) and provide pastoral people with food security benefits at the same time.
  • Authors:
    • Vine, E.
  • Source: Mitigation and Adaptation Strategies for Global Change
  • Volume: 9
  • Issue: 1
  • Year: 2004
  • Summary: Carbon C sequestration in terrestrial ecosystems and geologic formations provides a significant opportunity for California to address global climate change. The physical size of its resources (e.g., forests, agriculture, soils, rangeland, and geologic formations) and the expertise in California provides a substantial foundation for developing C sequestration activities. Furthermore, the co-benefits c sequestration - such as improved soil and water quality, restoration of degraded ecosystems, increased plant and crop productivity, and enhanced oil recovery - are significant. In fact, C sequestration often represents a "no regrets" strategy - implementing C sequestration provides multiple benefits, even without the advent of global climate change. Nevertheless, researchers need to address several issues to determine more accurately the potential, benefits, and costs of sequestering C in California's terrestrial ecosystems and geologic formations, as well as to identify the most promising sequestration methods and their optimal implementation. One key issue is the type of regulatory constraints facing developers of C sequestration projects: what permits are needed for developing these projects? The permitting process may impede the penetration of sequestration technologies into the market if the costs (including transaction costs) of obtaining the permits are too burdensome and costly. For example, at least nine federal regulations and seven state regulations will potentially influence C sequestration projects in California. This paper also provides an example of the types of permits needed for developing a C sequestration project, using California as an example. It is possible that a C sequestration project may have to obtain a total of 15 permits (3 federal, 6 state, 6 local), before it even starts to operate. In the concluding section, we offer some suggested areas for research and activities for policy makers.
  • Authors:
    • Shi, Y.
    • Jjemba, P. K.
    • Song, Q.
    • Li, F.
  • Source: Soil Biology and Biochemistry
  • Volume: 36
  • Issue: 11
  • Year: 2004
  • Summary: Microbial biomass C (MBC) is one of the soil properties used as an indicator for the fertility status of a soil. A study was conducted on a semi-arid Loess Plateau in China. The field was planted with spring wheat and mulched with plastic film for various lengths of time. Our primary objectives were to (i) explore the influence of film mulching on soil MBC and soil fertility, and (ii) seek an effective approach of maintaining and improving sustainability of cropland mulched with plastic film in two growing seasons. Four treatments were tested, non-mulching (M0), mulching for 30 days after sowing (M30), mulching for 60 DAS (M60) and mulching for the whole growing period (Mw). An increasing air temperature with time within the growing season promoted soil MBC in the two growing seasons, but a severe drought led to a lower MBC in 2000 compared with the wet year of 1999. Film mulching promoted MBC significantly in the 2 years, but decreased soil organic carbon (SOC). SOC is very low in the experimental soil, accounting for the higher MBC/SOC ratio compared with ratios reported by others. The SOC is greatly reduced in the non-mulched and the Mw treatments compared to the M30 and M60 treatments. In conclusion, the benefits of film mulching in semi-arid agricultural systems are enormous but realizing their full potential depends on how long the mulching material is maintained during the growing season. In the system tested, it is desirable to mulch the plots for 30–60 DAS in order to enhance microbial biomass and cycling of nutrients and also to provide a more stable soil micro-environment that generates more residues in the rhizosphere.
  • Authors:
    • Pu, X. P.
    • Kang, M. Y.
    • Hu, Z. Z.
    • Long, R. J.
    • Dong, S. K.
  • Source: Grass and Forage Science
  • Volume: 58
  • Issue: 3
  • Year: 2003
  • Summary: Abstract The productivity and nutritive value of some cultivated perennial grasses, Bromus inermis (B), Elymus sibricus (S), E. nutans (N), Agropyron cristatum (A), Poa crymophila (P) and mixtures B + N, S + A, B + S + A, S + B + N, N + S + A, B + S + N + A, B + N + A + P, B + S +A + P and S + N + A + P, in the alpine region of the Tibetan Plateau were investigated. Elymus nutans and E. sibricus and the mixtures, B + S + N + A, B + S +A + P and S + N + A + P, were most productive with yields of dry matter (DM) of between 11 000 and 14 000 kg-1 of biomass annually in the second harvest year. Acid-detergent fibre (ADF) concentrations increased (P < 0·05), and crude protein (CP) concentrations and in sacco DM degradability values decreased (P < 0·05) with the maturity of the cultivated grasses. Swards, based on these species and mixtures, have the potential to be the main choices for cultivation in the Tibetan Plateau because they produce more nutrients than other grass species and mixtures. Late August (flowering stage of dominant grasses) is the optimum time for harvesting as the yield of rumen-degradable CP is highest that of DM relatively high and the DM degradability is satisfactory.
  • Authors:
    • Yang, H.
    • Walters, D. T.
    • Dobermann, A.
    • Cassman, K. G.
  • Source: Annual Review of Environment and Resources
  • Volume: 28
  • Issue: 1
  • Year: 2003
  • Summary: Agriculture is a resource-intensive enterprise. The manner in which food production systems utilize resources has a large influence on environmental quality. To evaluate prospects for conserving natural resources while meeting increased demand for cereals, we interpret recent trends and future trajectories in crop yields, land and nitrogen fertilizer use, carbon sequestration, and greenhouse gas emissions to identify key issues and challenges. Based on this assessment, we conclude that avoiding expansion of cultivation into natural ecosystems, increased nitrogen use efficiency, and improved soil quality are pivotal components of a sustainable agriculture that meets human needs and protects natural resources. To achieve this outcome will depend on raising the yield potential and closing existing yield gaps of the major cereal crops to avoid yield stagnation in some of the world's most productive systems. Recent trends suggest, however, that increasing crop yield potential is a formidable scientific challenge that has proven to be an elusive goal.
  • Authors:
    • Thornton, P. K.
    • Jones, P. G.
  • Source: Conservation Ecology
  • Volume: 5
  • Issue: 2
  • Year: 2003
  • Summary: Making decisions in natural resource management involves an understanding of the risk and uncertainty of the outcomes, such as crop failure or cattle starvation, and of the normal spread of the expected production. Hedging against poor outcomes often means lack of investment and slow adoption of new methods. At the household level, production instability can have serious effects on income and food security. At the national level, it can have social and economic impacts that may affect all sectors of society. Crop models such as CERES-Maize are excellent tools for assessing weather-related production variability. WATBAL is a water balance model that can provide robust estimates of the potential growing days for a pasture. These models require large quantities of daily weather data that are rarely available. MarkSim is an application for generating synthetic daily weather files by estimating the third-order Markov model parameters from interpolated climate surfaces. The models can then be run for each distinct point on the map. This paper examines the growth of maize and pasture in dryland agriculture in southern Africa (includes the southern part of Tanzania, Malawi, much of Mozambique, and all of Zimbabwe, and extends west from the Indian Ocean to include Zambia, the southeastern part of the Democratic Republic of Congo and small portions of Angola). Weather simulators produce independent estimates for each point on the map; however, we know that a spatial coherence of weather exists. We investigated a method of incorporating spatial coherence into MarkSim and show that it increases the variance of production. This means that all of the farmers in a coherent area share poor yields, with important consequences for food security, markets, transport, and shared grazing lands. The long-term aspects of risk are associated with global climate change. We used the results of a global circulation model to extrapolate to the year 2055. We found that low maize yields would become more likely in the marginal areas, whereas they may actually increase in some areas. The same trend was found with pasture growth. We outline areas where further work is required before these tools and methods can address natural resource management problems in a comprehensive manner at local community and policy levels.
  • Authors:
    • Rozelle, S.
    • Hu, R.
    • Huang, J.
    • Pray, C. E.
  • Source: The Plant Journal
  • Volume: 31
  • Issue: 4
  • Year: 2002
  • Summary: Bt cotton is spreading very rapidly in China, in response to demand from farmers for technology that will reduce both the cost of pesticide applications and exposure to pesticides, and will free up time for other tasks. Based on surveys of hundreds of farmers in the Yellow River cotton-growing region in northern China in 1999, 2000 and 2001, over 4 million smallholders have been able to increase yield per hectare, and reduce pesticide costs, time spent spraying dangerous pesticides, and illnesses due to pesticide poisoning. The expansion of this cost-saving technology is increasing the supply of cotton and pushing down the price, but prices are still sufficiently high for adopters of Bt cotton to make substantial gains in net income.
  • Authors:
    • Wall, D. H.
    • Pockman, W. T.
    • Jobbagy, E. G.
    • Banner, J. L.
    • Jackson, R. B.
  • Source: Nature
  • Volume: 418
  • Issue: 6898
  • Year: 2002
  • Authors:
    • Li, X. Y.
    • Zhao, H. L.
    • Gao, C. Y.
    • Li, F. R.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 91
  • Issue: 1-3
  • Year: 2002
  • Summary: Winter wheat (Triticum aestivum L.) monoculture is common in wheat-growing areas of the Loess Plateau of northwest China. This system is characterized by nearly 3-month summer fallow from wheat harvest at the end of June or early July to sowing in late September. It not only lowers the overall precipitation-use efficiency because of the large amount of evaporation from the bare soil surface during the fallow period but also entails high risk of erosion by summer rainstorms. There is a need to develop more effective cropping systems to replace the current production system. Seven alternative rotations, mainly using wheat, rapeseed, corn, potato, pearl millet, linseed, alfalfa and sweetclover, were established and their use of environmental resources, production performance, energy efficiency, soil fertility sustainability, and soil conservation effectiveness were compared with continuous wheat cropping. The rotations had greater potential use of environmental resources. Despite showing no clear advantage in grain yields, all rotations were significantly higher in total above-ground biomass production and more efficient in energy transformation compared with continuous wheat cropping. After a 3-year cycle, the rotations did not adversely affect soil bulk density but some rotations significantly increased soil water-stable aggregates compared with the initial measurement. For the rotations based on the inclusion of legumes, the availability of N was apparently improved but the total P was substantially reduced compared with the initial measurement and continuous wheat cropping. An assessment of soil conservation effectiveness with a weighted soil conservation effectiveness index (WSCEI) indicated that the rotations performed much better than continuous wheat cropping in conserving soil and water resources. This study also strongly recommend that it is feasible to cultivate winter wheat followed by a 3-month legume fallow crop in year I and then a summer crop cultivation in the next. This system provides a soil cover during both erosion-prone rainy periods while leaving the soil bare for about 7 months (October-April) every 2 years. Another alternative is to cultivate winter wheat followed by a 15-month legume crop cultivation in years I and 2 and then a summer crop in year 3. This system allows the soil to be covered during three rainy periods while leaving the soil bare for about 7 months every 3 years. As most of this 7-month period is winter with low rainfall (snow) and temperatures below 0degreesC, not only is soil evaporation very low but the risk of erosion is also low. (C) 2002 Elsevier Science B.V. All rights reserved.