Pecologix Political Ecology Blotter » irrigation

Biomass Production by Desert Halophytes: Alleviating the Pressure on the Scarce Resources of Arable Soil and Fresh Water

A. Cherson — Fri, 11 Nov 2011 19:38:00 +0000

The utilization of plants for mitigating carbon dioxide accumulation in the atmosphere in Clean Development Mechanism (CDM) projects and biofuel production causes a severe burden on the limited sources of arable land and fresh water. This research is aimed at finding alternative plant types for biomass and biofuel production among desert halophytes. Such plants have the advantages of being naturally adapted to grow under the harsh desert conditions, on non-arable soils irrigated with reclaimed sewage or other types of brackish water. Exceptionally fast growing salt-resistant genotypes were identified among native populations of Tamarix of Israel. These may serve for future CDM projects and short-rotation forestry for biomass production. Another plant that originated from East Africa, Euphorbia tirucalli was also shown to be able to grow under desert conditions and saline water irrigation. This plant has been named in the literature as a potential source of biofuel.

The European Journal of Plant Science and Biotechnology 5 (Special Issue 2)

World has ‘enough water’ for future food needs

A. Cherson — Mon, 03 Oct 2011 23:38:22 +0000

They found that, in many areas, water production can be substantially increased without harming the environment. In Africa, for example, most cropland is rain-fed and only four per cent of available water is captured for crops and livestock.”Somehow, we have to get more food without taking more water — and the most promising way is through improving rain-fed agriculture,” said Cook.

http://www.tandfonline.com/toc/rwin20/36/1

Pitcher plant inspires ultimate non-stick surface

A. Cherson — Sat, 24 Sep 2011 15:02:06 +0000

By mimicking the leaves of a carnivorous tropical plant, US scientists have developed a surface so slippery that everything slides off: water, oil, blood, ice, jam and even ants. This kind of ‘omniphobic’ surface could be used to produce graffiti-repelling walls, self-cleaning windows and pipes that transport fluids easily and quickly.

DOI: http://dx.doi.org/10.1038/nature10447

Ed. Note: This could be very interesting as a coating for water and gas tubing.

Implications for the hydrologic cycle under climate change due to the expansion of bioenergy crops in the Midwestern United States

A. Cherson — Thu, 15 Sep 2011 00:04:45 +0000

Under present weather conditions, miscanthus and switchgrass utilized more water than maize for total seasonal evapotranspiration by approximately 58% and 36%, respectively. Projected higher concentrations of atmospheric CO2 (550 ppm) is likely to decrease water used for evapotranspiration of miscanthus, switchgrass, and maize by 12%, 10%, and 11%, respectively. However, when climate change with projected increases in air temperature and reduced summer rainfall are also considered, there is a net increase in evapotranspiration for all crops, leading to significant reduction in soil-moisture storage and specific surface runoff. These results highlight the critical role of the warming climate in potentially altering the water cycle in the region under extensive conversion of existing maize cropping to support bioenergy demand.

doi: http://dx.doi.org/10.1073/pnas.1107177108

Is Treated Wastewater Fresh Enough for the Farm?

A. Cherson — Sun, 04 Sep 2011 16:11:25 +0000

As freshwater resources dwindle, purified wastewater is increasingly discussed as a supplement for such high-volume uses as crop irrigation. In a 15-year field-scale test of this prospect, Assouline and Narkis studied the soil properties of an irrigated avocado farm in Israel; one side of the farm received natural fresh water, while the other received treated domestic wastewater that by most accounts was quite similar to the natural source but had increased dissolved organic matter, salinity, and suspended solids. Over the study period, several hydraulic properties of the clay-rich soil degraded in the plots that received treated wastewater, to the point that irrigation events created a smaller but more saturated volume of wetted soil. These conditions may have contributed to smaller root zones that ultimately led to lower crop yields. Because some soil horizons responded differently to the treated wastewater, it is not yet clear if treated wastewater will have this effect on other soil types or if precipitation patterns across different regions buffer against soil degradation.

DOI: http://dx.doi.org/10.1029/2011WR010498

Projected water consumption in future global agriculture: Scenarios and related impacts

A. Cherson — Sun, 28 Aug 2011 21:06:47 +0000

Global stress on water and land resources is increasing as a consequence of population growth and higher caloric food demand. Many terrestrial ecosystems have already massively been degraded for providing agricultural land, and water scarcity related to irrigation has damaged water dependent ecosystems. Coping with the food and biomass demand of an increased population, while minimizing the impacts of crop production, is therefore a massive upcoming challenge. In this context, we developed four strategies to deliver the biotic output for feeding mankind in 2050. Expansion on suitable and intensification of existing areas are compared to assess associated environmental impacts, including irrigation demand, water stress under climate change, and the productivity of the occupied land. Based on the agricultural production pattern and impacts of the strategies we identified the trade-offs between land and water use. Intensification in regions currently under deficit irrigation can increase agricultural output by up to 30%. However, intensified crop production causes enormous water stress in many locations and might not be a viable solution. Furthermore, intensification alone will not be able to meet future food demand: additionally, a reduction of waste by 50% along the food supply chain or expansion of agricultural land is required for satisfying current per-capita meat and bioenergy consumption. Suitable areas for such expansion are mainly located in Africa, followed by South America. The increased land stress is of smaller concern than the water stress modeled for the intensification case. Therefore, a combination of waste reduction with expansion on suitable pastures generally results as the best option, along with some intensification on selected areas. Our results suggested that minimizing environmental impacts requires fundamental changes in agricultural systems and international cooperation, by producing crops where it is most environmentally efficient and not where it is closest to demand or cheapest.

doi:10.1016/j.scitotenv.2011.07.019