ECONOMIC POLICIES FOR REGULATING AGRICULTURAL DRAINAGE WATER1

ABSTRACT: Agricultural drainage water is a major source of environmental pollution in many areas. This paper reviews the literature on the economics of nonpoint-source pollution and applies it to the regulation of agricultural drainage water. Four types of regulatory policies are considered. The empirical analysis is carried out for cotton production in the San Joaquin Valley of California. Variable inputs are the quantity of water applied and the type of irrigation system. All four policies can achieve economic efficiency under the conditions assumed here, but the policies differ in terms of the distributional impacts and administrative requirements.     

ALTERNATIVES TO THE USE OF AGRICULTURAL DRAINAGE WELLS1

ABSTRACT: A large number of agricultural drainage wells (ADWs) are located in north-central Iowa. These wells permit sediments, pesticides, nitrate, and bacteria in surface and subsurface drainage water to enter regional aquifers that are currently being used for drinking-water supplies, mostly by rural families and communities. This paper reports some possible alternatives to control the entry of surface and subsurface drainage waters into groundwater systems, and describes a methodology to make comprehensive economic feasibility studies of alternative drainage outlets. The estimated cost of providing main subsurface drains varied from $220 to $960 per hectare. If the use of ADWs was completely eliminated without providing alternative drainage, it is estimated that the average annual loss to the farmers of the area would be at least $270 per hectare in reduced crop yields. Of course, losses would be weather dependent and highly variable. Management practices to reduce the pollutant load in water draining to ADWs are also discussed.     

Biotechnology is not compatible with sustainable agriculture

Biotechnology increases commercialization of food production, which competes with food for home use. Most people in the world grow their own food, and are more secure without the mediation of the market. To the extent that biotechnology enhances market competitiveness, world food security will decrease. This instability will result in a greater gap between rich and poor, increasing poverty of women and children, less ability and incentive to protect the environment, and greater need for militarization to maintain order. Therefore, biotechnology should be discouraged. An active program to protect and strengthen local food production and to decrease reliance on industrial agriculture should be promoted.     

AN EVALUATION OF ALTERNATIVE POLICIES FOR CONTROLLING AGRICULTURAL NONPOINT SOURCE POLLUTION1

An economic analysis of nonpoint source pollution management was conducted for the Nansemond River and Chuckatuck Creek watersheds in Southeast Virginia. The potential effects of alternative public policies on farm income, land use, and pollution loadings were investigated. Regulatory programs could have quite different impacts depending on which pollutant is targeted. Cost-share rates greater than 50 percent would have little additional effect on pollution from crop enterprises, but would reduce pollution from livestock     

Biomethanation of plant materials and agricultural residues using dung samples as wild population of microbes and also with isolated methanogens

Recycling of plant materials and agricultural residues for biomethanation was attempted in vials. The methanogenic activities of certain sewage samples have also been tested. Both sterilized and non-sterilized biomasses were used. Biomethanation was carried out with dung samples (cow, goat, buffalo, piggery wastes and poultry wash) as wild populations of microbes and in combination with other microbial isolates (isolated in the laboratory).Biomethanation had been observed to be good in most cases and particularly with the sterilized biomass. Mixed inoculum (dung samples and poultry wash) was found to be best for biomethanation. Of the microbe isolates, isolates from buffalo, pig and paper mill wastes appear to be most effective. Pretreated sawdust and rice straw were found to be good subtrates for biomethanation. Of the different plant biomass used Spirogyra (algae), Ipomea and water hyacinth were most effective whereas Jatropa gossypifolia and Parthenium sp. were the least effective. Biomethanation of Spirogyra was carried out both in anoxic and oxic conditions. Though methane production decreased enormously under oxic conditions, definite methane production continued indicating that the biomethanation process is not exclusively anoxic. Similarly, biomethanation of sewage samples from different sewage treatment plants were carried out with and without isolated methanogens and methane production was found to be moderate.     

灾害对国民经济影响的定量分析模型及其应用

自然灾害对国民经济和人民生活能造成巨大的损失 ,因此 ,研究灾害对国民经济的影响具有重要的意义。灾害系统是一个十分复杂的系统 ,直接建立灾害对国民经济影响的定量分析模型比较困难。本文基于投入产出方法 ,讨论了直接和间接经济损失在投入 -产出表中的表达方式 ,建立了灾害损失评估的定量分析模型 ,并以农业为例 ,分析了自然灾害造成的农业总产值损失对整个经济系统的影响。     

WATER QUALITY MODELING OF ALTERNATIVE AGRICULTURAL SCENARIOS IN THE U.S. CORN BELT1

ABSTRACT: Simulated water quality resulting from three alternative future land‐use scenarios for two agricultural watersheds in central Iowa was compared to water quality under current and historic land use/land cover to explore both the potential water quality impact of perpetuating current trends and potential benefits of major changes in agricultural practices in the U.S. Corn Belt. The Soil Water Assessment Tool (SWAT) was applied to evaluate the effect of management practices on surface water discharge and annual loads of sediment and nitrate in these watersheds. The agricultural practices comprising Scenario 1, which assumes perpetuation of current trends (conversion to conservation tillage, increase in farm size and land in production, use of currently‐employed Best Management Practices (BMPs)) result in simulated increased export of nitrate and decreased export of sediment relative to the present. However, simulations indicate that the substantial changes in agricultural practices envisioned in Scenarios 2 and 3 (conversion to conservation tillage, strip intercropping, rotational grazing, conservation set‐asides and greatly extended use of best management practices (BMPs) such as riparian buffers, engineered wetlands, grassed waterways, filter strips and field borders) could potentially reduce current loadings of sediment by 37 to 67 percent and nutrients by 54 to 75 percent. Results from the study indicate that major improvements in water quality in these agricultural watersheds could be achieved if such environmentally‐targeted agricultural practices were employed. Traditional approaches to water quality improvement through application of traditional BMPs will result in little or no change in nutrient export and minor decreases in sediment export from Corn Belt watersheds.     

SHORT TERM BENTHIC COLONIZATION DYNAMICS IN AN AGRICULTURAL STREAM RECOVERING FROM SLAUGHTERHOUSE EFFLUENTS1

ABSTRACT: The purpose of this study was to assess short term, macroinvertebrate colonization dynamics and biofilm accumulation in two agricultural streams, one of which had been recently exposed to chronic, intermittent organic effluents from a slaughterhouse. During the winter and summer, macroinvertebrates and biofilm were collected from brick substrates from four or three sites in the streams on a geometric time schedule (1, 2, 4, 8, 16, and 32 days of exposure). Invertebrate total densities stabilized quickly, but the mass of biofilm increased throughout the study periods. Invertebrate community indices (diversity, evenness, dominance, richness) differed between the unaffected, “agricultural reference” sites and the affected sites, below the point source. All sites were dominated by Baetis bicaudatus (mayfly), Hydrobia sp. (gastropod), and Dugesia tigrina (Turbellaria). Response of these taxa differed between seasons and exposure to organic effluents. Stream invertebrate colonization processes showed evidence of the perturbation after the inflow of organic effluents had stopped from the slaughterhouse. Chronic organic enrichment reduced the species richness in the potential pool of colonists. Three months after the organic inputs had stopped, colonization timing and community structure was not yet at levels evident in reference and upstream sites.