For the removal of nutrients from eutrophic stream water polluted by non-point sources, an artificial aquatic food web (AAFW) system comprising processes of phytoplankton growth and Daphnia magna grazing was developed. The AAFW system was a continuous-flow system constructed with one storage basin of 3 m³ capacity, one phytoplankton tank of 3 m³ capacity, and one zooplankton growth chamber of 1.5 m³ capacity. The system was optimized by setting hydraulic retention time of phytoplankton tank as 3 days and D. magna density as 740-1000 individual l⁻¹. When the system was operated on eutrophic stream water that was delivering 471 g of total nitrogen (TN) and 29 g of total phosphorus (TP) loadings for 45 days, 250 g (53%) of TN and 16 g (54%) of TP were removed from the water during its passage through the phytoplankton tank. In addition, 64 g (14%) of TN and 4 g (13%) of TP were removed from the water by harvesting zooplankton biomass in the zooplankton growth chamber, resulting in significant overall removal rates of TN (69%), nitrate (78%), TP (73%), and dissolved inorganic phosphorus (94%). While the removal efficiency of the AAFW system is comparable to those of other ecotechnologies such as constructed wetlands, its operation is less limited by the availability of space or seasonal shift of temperature. Therefore, it was concluded that AAFW system is a highly efficient, flexible system for reducing nutrient levels in tributary streams and hence nutrient loading to large aquatic systems receiving the stream water.

The scarcity of grazing and water for an animal has a negative effect on household welfare and food security either by affecting livestock production directly, affecting crop or off-farm income due to labor reallocation or through its direct impact on time leisure consumption.The economic impacts of resource (grazing and water) scarcity on welfare are undermined. Thus, a better understanding that is derived from the factual evidence is required. The first objective of this paper is to explore the link between natural resource scarcity and per capita food consumption expenditure (PCFE) as proxy for welfare and food security followed by the second objective of analyzing whether this effect is uniform across all quantile groups and there is gender differential effect using distance and shadow price as resource scarcity indicators. The paper used a relatively unique data set from a randomly drawn 518 sample farmers in Northern Ethiopia. To address our first objective, we employ the IV two-stage least square estimation for welfare and probit model for food security drawing on non-separable farm household model.Our estimates show that about 48% of the households were food secure while 52% were food insecure. Our results confirmed the theoretical prediction that resource scarcity affects household PCFE and food security adversely as predicted by the downward spiral hypothesis. The results indicate that animal feed and water scarcity have an important impact on welfare and food security. As expected, in aggregate, reducing time spent searching for water per day leads to an increase in PCFE and food security. Similarly, a decrease in time wastage for searching grazing increase PCFE and food security respectively, and an increment of PCFE and food security is achieved by a reduction in crop residue transporting time per day.The gender differential analysis signals that increasing resource scarcity results in low PCFE and food security, with the male are considerably likely to have less food consumption expenditure and being food insecure more as compared to female households. The total impact of time spent searching for water, grazing, and transporting straw on per PCFE is − 0.142%, − 0.102%, and − 0.092%, respectively, and decreasing reaching time to a water, grazing, and straw source by 0.6 min will increase PCFE by 354 ETB, 254 ETB, and 229 ETB for the median household. Depending on results from the quantile regression, the effect of water and feed scarcity is not uniform across the food consumption distribution.

Grazing potential (GP, in % day&minus;1) was estimated for the plankton communities of 13 Greek lakes covering the trophic spectrum, in order to examine its sensitiveness in discriminating different classes of ecological water quality. Lakes with high GP values exhibited high zooplankton biomass dominated by large cladocerans or/and calanoids while lakes with low GP values had increased phytoplankton biomass and/or domination of small-bodied zooplankton indicating intensive fish predation. GP successfully distinguished among ecological water quality classes (estimated using the phytoplankton water quality index PhyCoI) indicating its potential use as a metric for ecological water quality assessment. As a next step, PhyCoI index was modified to include GP as a metric in order to enhance the phytoplankton-based ecological status classification of lakes incorporating zooplankton as a supporting factor. The PhyCoI<inf>GP</inf> successfully assessed the ecological water quality in accordance with PhyCoI classification whereas it was significantly correlated with the eutrophication proxy TSI<inf>SD</inf> based on Secchi Depth. Thus, we propose to use the modified phytoplankton index PhyCoI<inf>GP</inf> for monitoring the ecological water quality of lakes.

This study aims at analyzing the impact of water and soil conservation strategies on households? food security in the North-western part of Benin. It was conducted in the municipalities of Boukombé and Ouaké. Three villages were studied. From random way, 180 producers were investigated. The causes of soil degradation, water and soil conservation strategies, available food supply and food consumption frequency were collected. Degradation factors were analyzed using discourse analysis and prioritized using the Friedman test. Food supply and frequency of consumption were compared between beneficiaries and non-beneficiaries of the projects using the Student t test. Land degradation is caused by socio-cultural factors (overexploitation of lands, trees? cutting, late bush fires, grazing, agroforestry and monoculture) and natural factors (heavy rains and steep gradient of the soils). The first three factors are respectively the exploitation of land, trees? cutting and late bush fires practice in both towns. Food reserves before the new crops were not affected by exogenous strategies released by the erosion control projects. But the frequency of food consumption is improved statistically among project beneficiaries than non-beneficiaries. This confirms the theory of Boserup | E Janvier et al., 'Impacts of water and soil conservation strategies on households? food security in North West of Benin', International Journal of Agricultural Science Research, vol. 3(10), pp.196-202, Academe Research Journals, 2014

J Egah, 'Impacts of water and soil conservation strategies on households' food security in North West of Benin', International Journal of Agricultural Science Research, pp.196-202, 2014 | Th is study aims at analyzing the impact of water and soil conservatio n strategies on householdsâ?? food security in the North - western part of Benin. It was conducted in the municipalities of Boukombé and Ouaké. Three villages were studied. From random way, 180 producers were investigated. The causes of soil degradation, water and soil conservation strategies, available food supply and food consumption frequency were collected. Degradation factors were analyzed using discourse analysis and prioritized using the Friedman test. Food supply and frequency of consumption were compar ed between beneficiaries and non - beneficiaries of the projects using the Student t test. Land degradation is caused by socio - cultural factors (overexploitation of land s , trees â?? cutting , late bush fires, grazing, agroforestry and monoculture) and natural fa ctors (heavy rain s and steep gradient of the soils ). The first three factors are respectively the exploitation of land, trees â?? cutting and late bush fires practice in both towns. Food reserves before the new crops were not affected by exogenous strategies released by the erosion control projects. But the frequency of food consumption is improved statistically among project beneficiaries than non - beneficiaries. This confirms the theory of Boserup

Human activities use more than half of accessible freshwater, above all for agriculture. Most approaches for reconciling water conservation with feeding a growing population focus on the cropping sector. However, livestock production is pivotal to agricultural resource use, due to its low resource-use efficiency upstream in the food supply chain. Using a global modelling approach, we quantify the current and future contribution of livestock production, under different demand- and supply-side scenarios, to the consumption of “green” precipitation water infiltrated into the soil and “blue” freshwater withdrawn from rivers, lakes and reservoirs. Currently, cropland feed production accounts for 38% of crop water consumption and grazing involves 29% of total agricultural water consumption (9990km³yr⁻¹). Our analysis shows that changes in diets and livestock productivity have substantial implications for future consumption of agricultural blue water (19–36% increase compared to current levels) and green water (26–69% increase), but they can, at best, slow down trends of rising water requirements for decades to come. However, moderate productivity reductions in highly intensive livestock systems are possible without aggravating water scarcity. Productivity gains in developing regions decrease total agricultural water consumption, but lead to expansion of irrigated agriculture, due to the shift from grassland/green water to cropland/blue water resources. While the magnitude of the livestock water footprint gives cause for concern, neither dietary choices nor changes in livestock productivity will solve the water challenge of future food supply, unless accompanied by dedicated water protection policies.

This study sets out to measure CWU (litre/kg ECM, energy-corrected milk) of typical milk production systems in 60 dairy regions from 49 countries representing 85% of the world׳s milk production. The extended version of TIPI-CAL 5.2 including water model was used for data analysis.The results have shown the CWU/kg ECM ranged between 739L on the Danish farm to 5622 l on the Ugandan farm with a global average of 1833L. When looking at averages per region, the CWU was lowest in Europe (913L) and highest in Africa (3384L) with large intra- and inter-regional differences. Compared with grazing and intensive production system, low yielding cows on small-scale farms have the highest CWU/kg ECM. The key driver for variation in CWU/kg ECM is feed, accounting for 94–99% of the total CWU. Increasing milk productivity might be one of the promising ways to reduce CWU/kg ECM. However, this might also lead to the negative impact into water supply systems if this increase is dependent on land irrigation in water scarce areas. The findings of this study showed the need to address the location of the farm, the feed quality, feeding system and milk production intensity simultaneously when aiming at efficient water resource management which would help to contribute food production and livelihood security of dairy farmers worldwide.

Only a combination of nutrient load abatement and food-web management proved efficient for the management of water quality in the deep stratifying Wupper Reservoir. Reduction of nutrient loading, was completed in winter 1992/1993, but resulted only in reduced winter/spring mixing of phosphorus concentrations. Since the capacity of the diatom spring bloom to remove nutrients from the trophogenic layer of this slightly eutrophic water-body was never exhausted, the surplus of total phosphorus available to support summer algal growth remained unchanged. Thus, nutrient reduction alone did not improve the water quality, as expected. Subsequent replacement of the smaller Daphnia cucullata by the larger Daphnia galeata-hyalina complex that was attributable to successful food-web management did, however, result in a shift from a turbid to a clear water regime in 1999. Clearly, the zooplankton community, and therefore food-web structure, played an integral role in nutrient recycling and in the repartitioning of the phosphorus pool. As diatom settling and grazing became much more tightly linked with the appearance of the larger-bodied Daphnia galeata-hyalina complex, which exploits lower-level food resources as early as May, daphnids increasingly acted as a sink for phosphorus. This increased export fluxes out of the pelagic zone and leaves a smaller surplus of total phosphorus to support the accumulation of summer algae. Consequently, water transparency and total chlorophyll concentrations in summer improved with food-web restructuring, indicating real oligotrophication of Wupper Reservoir driven by internal feedbacks.