Gerir a escassez de água na agricultura de sequeiro exige uma abordagem integrada 21 can be used for livestock or as supplemental irrigation at critical periods and stages of plant life, particularly in the early stages of perennials when the root system is not yet able to retrieve water from profound soil. In Jordan, a country highly susceptible to climate change where 75 percent of cultivated land is rainfed, FAO is working with the government on the “Building resilience to cope with climate change in Jordan through improving water use efficiency in the agriculture sector “ project which provides rural communities the means to harvest rooftop rainwater for households and agriculture. In Yemen FAO supports Water Users Associations harvest water and recharge groundwater with small-scale structures to capture rainwater runoff in the wadis. And in Gadaref State, Sudan, FAO helped small-scale rain-fed farmers by integrating soil and water conservation and improving cropping patterns. By using innovative watershed management technologies, farmers reduced water runoff, boosted crop production with sorghum yields increased fourfold and groundnut yields sevenfold. Large-scale restoration for small-scale farming: In the Sahel, through its Action Against Desertification Programme in support of Africa’s Great Green Wall, FAO has been scaling-up mechanized water harvesting (see box 1), combined with the use of multiple local and adapted biodiversity (trees, shrubs and grasses) for food, feed and non-wood forest products, to restore hundreds of thousands of hectares of agrosilvopastoral systems including in Burkina Faso, Niger, Nigeria and Senegal. Delfino plough for mechanized land preparation in large-scale restoration In areas with 200- 600 mm annual precipitation, mechanized deep ploughing can be used for large land preparation (e.g. 50-200 hectares) using specialized Delfino ploughs that mimic the traditional half-moon of the Sahel farmers. The plough digs deeper (50-80 cm), breaking the soil’s hard crust and exposing the soil in a way that creates micro-dams/micro-catchments for better permeability and moisture retention. It can be used on slopes with up to a 10 per cent inclination, digging the half moons perpendicular to the slope. A tractor with a Delfino plough can work up to 15-20 hectares a day, creating about 500700 micro-catchments per hectare, comparatively, 100 workers/farmers (often women) would dig 1 hectare with about 300 micro-catchments a day. The Delfino group has set up a specialized maintenance garage (after-sales service) as well as a training school in West Africa for mechanics and tractor drivers using this equipment. The role of forests and trees: Forests and trees play a significant role in the water cycle from field to local and regional scales, facilitating infiltration, generating cooling and rainfall. Trees can often be seen as water users instead of water recyclers because they consume more water than shorter vegetation types such as grasses. The relationships between forests and water are however more complex. For instance, a study in the agroforestry parklands of Saponé in Burkina Faso found that, in this case, the optimum groundwater recharge happened at densities of 5-10 trees per hectare. Forests can have a key role in rain generation. Along Mediterranean hilly coastlines, especially in summer afternoons when marine advection is dominant, vegetation and trees create the additional atmospheric moisture that makes the water content in the air pass the tipping point to cloud formation and precipitation. The forests of the Amazon basin are particularly important for rainfed agriculture in the region by cycling immense volumes of water and moisture, regulating rainfall not only within the basin but also outside in the La Plata River basin, the Pantanal and west-central Brazil. This movement of moisture is done through moisture corridors or “flying rivers”. The Amazon basin can release approximately 20 billion tons of water into the atmosphere per day contributing approximately 70 percent of the annual mean water vapor input to the La Plata basin. Reduction of Amazon forests would have direct major impacts on agricultural production in the region. Modeling crop water needs in agriculture: Modeling crop water needs in agriculture is essential for understanding the specific water requirements of different species and varieties and support farmers choices. FAO is developing an innovative application to quantitatively evaluate drought risks and impacts on crop and water productivity and on water requirements. The Drought Impact Assessment Platform, D-IAP, builds on the FAO-developed AquaCrop growth model, to estimate crop production when drought occurs and carry out assessments under present climatic conditions and future climate change scenarios, considering rainfed and irrigated agricultural systems. Examples of changing cropping practices include the types of crops planted by farmers and also changing planting dates to ensure perfect timing for temperature and water requirements. Biodiversity and research for resilient rainfed agriculture: Drought-resistant species and varieties can withstand prolonged dry spells and erratic rainfall, contributing to the resilience of rainfed agriculture and food security. Many breeding efforts, in particular at lower latitudes, target tolerance of drought, heat, salinity and flooding. Drought-tolerant hybrid maize varieties developed by the International Maize and Wheat Improvement Center were found to have higher yields than non-tolerant varieties in on-farm trials in Southern Africa, especially under conservation agriculture. An FAO Project in Mozambique used demonstration plots
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