CNAS

Australia

Peter Hayman, SARDI

"The challenge of less and more variable water supply for irrigated agriculture, trends to date, future adaptation opportunities and challenges"

Historically, irrigation in Australia was seen as a means of drought proofing and making the dessert bloom. There was abundant land, seemingly appropriate soils, solar radiation and temperature were not limiting; a case of simply add water. In the latter part of the 20th Century emphasis shifted from a pioneering view to an emphasis on productivity as measured by the amount of yield and returns per ML of water. Efficiencies were sought in the application of irrigation (eg drip irrigation and land levelling) and the timing of irrigation (irrigation scheduling). The vulnerability of irrigation in the Murray Darling Basin to the recent drought and emerging problems of rootzone salinity has highlighted what ecologists have long known about the tradeoffs between efficiency of a system and its resilience. This chapter will focus at the field and farm level and review the confused history of thinking about drought in a climate that is both arid and variabile before addressing the emerging challenge of climate change. The chapter will summarise opportunities and limits to adaptation options including further gains in efficiency, closer monitoring of water requirements, greater flexibility and the use of weather and climate forecasts.

California

Robert B. Hutmacher, University of California-Davis Plant Sciences Dept. and West Side Research and Extension Center

"Crop choices with limited water supplies: Sensitive growth stages, physiology of responses, and genetics impacting crop suitability"

Crop choices in water-limited areas shift not just with profit potential and management improvements, but can be impacted strongly by relative crop sensitivity at different growth stages to water deficits as aquifers or other water supplies are depleted, and availability and price of irrigation water become limiting. Understanding the physiological basis for and genetics available to impact crop responses to: (1) timing, duration, severity of water and heat stress; and (2) soil and water salinity and trace elements will become increasingly important for at least some crops grown in each farm or region in order to stretch limited water supplies and allow flexibility to shift limited water supplies or waters of different qualities to crops best suited to those supplies.

Mexico

Luis Rendón Pimentel, ICID Mexican Committee President and Irrigation Districts Manager, National Water Commission

"Drought plans in irrigation districts"

México’s 83 irrigation districts span over nearly 3 million hectares, and in 2007-8 used nearly 31 billion cubic meters of irrigation water that is provided from groundwater and surface water sources. Droughts are frequent phenomena in Mexico affecting water availability to irrigation districts. Drought plans are a policy tool that has been utilized to reduce impact on drought when it hits. The goal of the drought plan is to diminish the demand; to stabilize the water supply; to balance the watershed and aquifer, increasing  productivity of land and water, regional employment, and irrigation water users income; and to look for a balance between consumer and hydroelectricity generation. This chapter will review the effectiveness of some of the actions followed by the irrigation districts during drought time, including: modernization of the irrigation networks; real time irrigation scheduling; on-farm irrigation technology management; adoption of efficient irrigation technologies; promotion of low water demand crops required by market; rainfall harvesting; sustainable ground water management; recovery of runoff; reuse of treated waste water; and water importation from other watersheds. All of the above is made in concert with hydroelectric generation.

South Africa

W. Durand, ARC-Grain Crops Institute

"Drought adaptation measures and risk tolerance of commercial and subsistence maize farmers in the western Free State and Northwest Provinces"

South Africa has long been recognized as a country subjected to recurring droughts of varying spatial and temporal dimensions. White maize is the staple food of most of the South African population, particularly the poor. Sixty nine percent of the total South African white maize production is produced in the western Free State and Northwest provinces mainly under dry-land cultivation. The variability of the South African climate, especially drought periods, impacts on the country’s ability to produce maize in sufficient amounts to ensure food security. The study aims to explore the differences between commercial and subsistence farmers’ adaptation measures regarding their cultivation practices to avert the risk usually associated with the expected onset of the season and the intensity of the mid-summer drought. The financial risk tolerance of both sectors will be evaluated, as the costs of various agricultural inputs have an impact on a farmer’s ability to cope with drought. In the case of small scale and subsistence farmers, production capital is lost during a drought as it is used to buy food. The benefits of the shift from an impact-and relief-approach to a risk-reduction approach in the government drought management plan will be examined with the objective of improving food security.

Spain

Marta García-Mollá, Llorenç Avellà, and Carles Sanchis, Centro Valenciano de Estudios Sobre el Riego, Universidad Politécnica de Valencia

"Adaptive strategies on drought and water shortages by farmers in Mediterranean semiarid regions"

Agriculture in Southeastern Spain is conditioned by two overlapping facts: droughts (climatic events) and water shortages (events related to unbalanced supply and demand). In order to settle these recurrent episodes, public administrations have taken different measures which are well known and described in the literature. However, the strategies adopted by farmers are not so well known. The purpose of this study is to describe and analyze these measures implemented by farmers to deal with both droughts and scarcity: crop mix combinations (arable crops vs. fruits and vegetables), water recirculation, and technological change among others.