Home Step-by-step production Growth Water management. Print this page. Continuous flooding helps ensure sufficient water and control weeds. Lowland rice requires a lot of water. Construct field channels to control the flow of water to and from your field. Construct field channels to control the flow of water to and from your field The construction of separate channels to move water to and from each field greatly improves the control of water by individual farmers.
Prepare the land to minimize water loss and create a hard pan. Prepare the land to minimize water loss and create a hard pan Large amounts of water can be lost during land soaking prior to puddling when large and deep cracks are present due to drainage of water down the cracks, beyond the root zone. Till the soil to fill cracks Perform shallow tillage operations before land soaking. Puddle the field to reduce water loss For clayey soils that form cracks during the fallow period, puddling results in a good compacted hard pan For coarse sandy soils, puddling may not be effective For heavy clay soils, puddling may not be necessary to reduce water losses because of the low infiltration rate of such soils; however, puddling may still be necessary if the soil was cracked prior to primary tillage, if weeds are present prior to transplanting, or if the soil is too hard or cloddy for transplanting after soaking Despite reducing water loss, the action of puddling itself consumes water.
Level the field. Level the field A well-leveled field is crucial to good water management. Read: Leveling implements Laser leveling. Construct bunds and repair any cracks or holes. Construct bunds and repair any cracks or holes Good bunds are a prerequisite to limit water losses. Bunds should be high enough at least 20 cm to avoid overflowing during heavy rainfall. Read: How to construct bunds. For continuous flooding For safe Alternate Wetting and Drying For continuous flooding Continuous flooding of water generally provides the best growth environment for rice.
Policy brief: AWD reduces green house gas emissions and saves water Direct seeded rice Keep the soil moist but not saturated from sowing till emergence, to avoid seeds from rotting in the soil. Planting « Previous step. Water management.
Soil fertility Next step ». Login to your personal dashboard for more detailed statistics on your publications. Edited by Ralph Wurbs. Edited by Rolando Chamy. We are IntechOpen, the world's leading publisher of Open Access books.
Built by scientists, for scientists. Our readership spans scientists, professors, researchers, librarians, and students, as well as business professionals. Downloaded: Improving water productivity WP , a measure of performance generally defined as the physical quantity or economic value derived from the use of a given quantity of water Molden et al.
Increasing WP to obtain higher output or value for each drop of water used can play a key role in mitigating water scarcity Molden et al. Global projections show that increases in WP and expansion of irrigated areas are required to account for half of the long-term increase in global water requirements for a food supply that will ensure food security of the projected population Tropp et al. WP is currently considered a more appropriate indicator of water system performance than the most widely used efficiency indicators, both classical and neo-classical Seckler et al.
Under classical efficiency indicators, surface and groundwater drainage are counted as losses even when beneficially reused downstream, while neoclassical efficiency integrates water recycling into the concept of water-use efficiency Sekler et al. Unlike irrigation efficiency indicators, WP provides more information on the amount of output that can be produced with a given amount of water Guerra et al. Also, WP can capture differences in the value of water for alternative uses Wichelns, However, physical WP is not different from water-use efficiency WUE when expressed in terms of yield per unit amount of water consumed.
Location The research was conducted in Kapunga rice irrigation scheme in the Usangu plain. Climatic conditions The general climatic pattern of the study area is tropical wet-and-dry characterized by uni-modal type of rainfall, moderate to high temperature, low wind speeds, and high relative humidity. Topography and hydrology The Usangu plain is situated at meters above the sea level. Research process and methods 4.
Soil water balance analysis Before water balance analysis is carried out, the irrigation system was identified and defined to consist of Kapunga large rice farms, Kapunga small holder farms and associated irrigation and drainage canals surrounding the rice irrigation farms Figure 5. Physical water productivity determination Water balance components together with crop yield measurements were used to empirically determine crop water productivity as the ratio of crop yield kg to amount of water available and or depleted at field level Eqns.
Value of irrigation water for paddy The value of irrigation water economic productivity of water for paddy was estimated using a theoretical generalized profit model.
Results and discussions 4. Soil water balance at scheme level For the water balance analysis, conservation of mass requires that, for the domain over the time period of interest, inflows are equal to outflows plus any change of storage within the domain. Soil water balance at plot level At field level, total inflows to the rice plot is partitioned into the amount of water used for rice nursery seedbed mm , rotavation or paddling mm , transplanting mm and effective rainfall- P eff mm.
Table 1. Soil water balance components at field plot level. Table 2. Estimates of ET c for rice under different climatic conditions. Physical water productivity Productivity of water for rice in Kapunga irrigation scheme varies between 0.
Table 3. Water productivity of rice. Table 4. Farming input in rice production Apart from irrigation water, farmers need capital, non water inputs and labour to facilitate field operation during the crop season.
Table 5. Non water farm inputs per hectare for paddy rice in Kapunga large irrigation scheme. Labour input per hectare A number of labour dependent activities are normally conducted during the rice crop season 6.
Table 6. Labour use in field operation on paddy rice farm in Kapunga large irrigation scheme. Cost of farming operation, labour and farming inputs The cost of rice farming can be divided into three main categories 7. Table 7. Cost of farming operation, labour and farming inputs. Crop yield, input contribution and economic return to water Rice crop yield varies between kg and kg with average yield of kg.
Variable Minimum Maximum Mean Yield kg Total revenue Tsh , 3,, 2,, Capital Tsh , , , Labour Tsh , , , Non water inputs Tsh , , , Return to water Tsh 3, 1,, , Table 8.
Crop yield, total revenue and per hectare share of production inputs. Estimated value of water for rice production The value of water for rice in the study area is estimated using the three water balance indicators established at plot level, i.
Table 9. More Print chapter. How to cite and reference Link to this chapter Copy to clipboard. Available from:. Over 21, IntechOpen readers like this topic Help us write another book on this subject and reach those readers Suggest a book topic Books open for submissions. More statistics for editors and authors Login to your personal dashboard for more detailed statistics on your publications.
Access personal reporting. More About Us. Water Balance Components. Nursery watering. Crop growth up to harvesting. Rainfall P. Moisture change. Losses percolation, evaporation. ET c [mm]. Lage et al. Mohan et al.
Sub-humid south India. Jehangir et al. Sub-tropical semi arid rice-wheat zone, Pakistan. Ahmad et al. Semi-arid climate Pakistan and India. Water use components. Irrigation I. Crop evapotranspiration ET c. WP ETc. Tuong and Bouman Literature under Asian field conditions. Zwart and Bastiaanssen Review of 82 publications of the last 25 years. Cai and Rosegrant Global averages based on production scenarios. Farm input. Amount of fertilizer application. Rice seedlings kg. First application after transplanting kg.
Second application after transplanting kg. Herbicide litres. Insecticide litres. Sacks bagging for harvested rice. Farm operations. Farm clearing. Preparation of rice nurseries. First weeding. Second weeding. Fertilizer application. Herbicide application.
Insecticide application. Bunds clearing. Bird scaring. Canal cleaning. Winnowing, stitching bags and drying. Farming operation and labour. Cost of farm input. Field activity. Farm Input. Unit cost Tsh. Renting of the farm. Plowing the farm.
Nursery seedbed preparation. Herbicides D. Weeding First and Second. Labour for fertilizer application. Cost of insecticide application. Cost of herbicide application. The result of fine-tuned drip irrigation is that less than half of the water is needed than the quantity used in a traditional flooded paddy. During a pilot project Netafim, the company which once pioneered drip irrigation in arid landscapes around Israel, set up rice fields at various locations in Europe all the way to South Asia.
At a farm in northeast Italy, high-quality rice is grown side-by-side in paddies employing both the traditional method and the new drip-irrigation technique. Reportedly the new drip-irrigation technique has yielded rice equal in quality to crops cultivated in the flooded paddies at a much reduced environmental cost. Not only is plenty of freshwater saved in the process but methane emission also goes down to zero as growing switches from anaerobic to aerobic, according to the company, which took a decade to hone its new drip-irrigation method, including the best way to plant, water and fertilize rice.
On the downside, an initial investment of pipes, pumps and filters can be pricey for farmers, but over the long term the shift away from flooding can yield great benefits for them, especially in arid regions like parts of India and Pakistan where freshwater is a prized commodity already in short supply.
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