Food and Agriculture Organization of the United Nations- FAO
Payments for Environmental Services (PES) from Agricultural Landscapes
In watershed protection services
Water quantity
Farmers can contribute to water quantity mainly by promoting a more efficient use of the water in agricultural production. Nevertheless, more research is needed on the exact relationships and time lags between the introduction of sustainable land management practices for water conservation and the measurable improvements in water quantity.
Farmers may adopt changes in agricultural practices – thus contributing to water quantity – by promoting the recharge of groundwater aquifers and a more efficient use of the water in agricultural production. There are several farm-level strategies that can increase water use efficiency(10), for example:
- reduction of soil evaporation by using conservation tillage practices and mulch;
- enhancing soil organic matter for better moisture storage
- planting more water-efficient crop varieties;
- enhancing soil fertility and mploying supplemental irrigation in rain-fed systems to increase productivity;
- decreasing water losses from inadequate irrigation techniques and infrastructure;
- reducing crop water requirements through inducing microclimatic changes, like wind barriers, shade cover or vegetative soil cover; and
- reusing wastewater for agricultural purposes.
Recent studies (12) report considerable improvements using a combination of these methods. In areas where integrated pest and nutrient management, conservation tillage and agroforestry practices have been introduced, improvements in water productivity have been achieved, especially in rainfed agricultural systems- see box 2.1.
Box 2.1 - Examples of water management methods and their results| A combination of resource-conserving management practices in rainfed agriculture including: (i) integrated pest and nutrient management, (ii) conservation tillage, (iii) and agroforestry, could yield average increases in water productivity ranged from: • 16 % for irrigated rice • 29 % for irrigated cotton • 70 % for rainfed cereals • 102 % for legumes • 108 % for roots and tubers(13) |
|
|
| Zero tillage, could result in 70-90% reduction in runoff, increase in water infiltration, reduction on soil erosion and consequent reduction in sediments and pollutants carried to water bodies, depending on soil type.(14) |
|
(10)Section based on Pretty, J.N., Noble, A.D., Bossio, D., Dixon, J., Hine, R.E., Penning de Vries, F.W.T. & Morison, J.I.L. 2006. Resource-conserving agriculture increases yields in developing countries. Environmental Science and Technology (Policy Analysis), 40(4): 1114-1119.
(11)adapted from PASOLAC. 1999. Guía técnica de conservación de suelos y agua Programa para la Agricultura Sostenible en Laderas de América Central- PASOLAC
(12) For an overview of methods see World Overview of Conservation Approaches and Technologies- WOCAT which provides tools that allow Soil and Water Conservation (SWC) specialists to share their knowledge and assist them in making decisions in the field and at the planning level.
(13) adapted from Pretty, J.N., Noble, A.D., Bossio, D., Dixon, J., Hine, R.E., Penning de Vries, F.W.T. & Morison, J.I.L. 2006. Resource-conserving agriculture increases yields in developing countries. Environmental Science and Technology (Policy Analysis), 40(4): 1114-1119.
(14) adapted from Hebblethwaite, J.F. 1993. Conservation tillage as a tool to conserve soil, moisture, energy, and equipment in large and small crop production systems. In J.P. Srivastava & H. Alderman, eds. Agriculture and environmental challenges: Proceedings for the 13th agricultural sector symposium. The World Bank, Washington, DC.
