Estimation irrigation water requirements with derived crop coefficients for upland and paddy crops in ChiaNan Irrigation Association,Taiwan

Field experiments were performed at the HsuehChia Experimental Station from 1993 to 2001 to calculate the reference and actual crop evapotranspiration, derived the crop coefficient, and collected requirements input data for the CROPWAT irrigation management model to estimate the irrigation water requirements of paddy and upland crops at the ChiaNan Irrigation Association, Taiwan. For corn, the estimated crop coefficients were 0.40, 0.78, 0.89 and 0.71 in the initial, crop development, mid-season and late-season stages, respectively. Meanwhile, the estimated crop coefficients for sorghum were 0.44, 0.71, 0.87 and 0.62 in the four stages, respectively. Finally, for soybean, the estimated crop coefficients were 0.45, 0.89, 0.92 and 0.58 in the four stages, respectively. With implementation of REF-ET model and FAO 56 Penman–Monteith method, the annual reference evapotranspiration was 1268 mm for ChiaNan Irrigation Association.In the paddy fields, the irrigation water requirements and deep percolation are 962 and 295 mm, respectively, for the first rice crop, and 1114 and 296 mm for the second rice crop. Regarding the upland crops, the irrigation water requirements for spring and autumn corn are 358 and 273 mm, respectively, compared to 332 and 366 mm for sorghum, and 350 and 264 mm for soybean. For the irrigated scheme with single and double rice cropping patterns in the ChiaNan Irrigation Association, the CROPWAT model simulated results indicate that the annual crop water demands are 507 and 1019 mm, respectively, and the monthly water requirements peaked in October at 126 mm and in January at 192 mm, respectively.     

Agricultural intensification in the Sahel – The ladder approach

Agricultural intensification in the Sahel can be described as climbing a ladder. The capital, labour, management and institutional requirements increase when farmers climb the ladder, but the potential gains are also higher. The first step on this ladder are agricultural practices without any financial outlay but with increasing labour demand, such as organic fertilizer use, seed priming, water harvesting and harvesting grains at physiological maturity to improve fodder quality. The next step on the ladder is the use of micro-fertilising, popularly known as microdose, at the rate of 0.3 g NPK fertilizer per pocket in sorghum and millet. The following step is the development of improved crop/livestock systems characterized by use of higher rates of mineral fertilisers and manure, increasing cowpea density and improved animal fattening. The last step presented on the ladder is the development of more commercially orientated agriculture characterized by development of cash crops, milk production and/or agroforestry systems. Evidences from the field support the observation that farmers intensify their production in a sequential manner similar to the way described in this paper. The technologies presented can facilitate agricultural intensification by reducing the risks and minimising the cost in agricultural production.     

Improving drought tolerance in rainfed lowland rice: An example from Thailand

A large portion of the world's poor farm in rainfed systems where the water supply is unpredictable and droughts are common. In Thailand there are approximately 6.2 million ha of rain fed lowland rice, which account for 67% of the country's total rice-growing area. This rice system is often characterised by too much and too little water in the same season. Farmers’ estimates of their annual losses to drought are as high as 45% in the upper parts of the toposequence. In contrast to irrigated rice systems, gains from crop improvement of rainfed rice have been modest, in part because there has been little effort to breed and select for drought tolerance for the target rainfed environments. The crop improvement strategy being used in Thailand considers three mechanisms that influence yield in the drought prone targets: yield potential as an important mechanism for mild drought (where yield loss is less than 50%), drought escape (appropriate phenology) and drought tolerance traits of leaf water potential, sterility, flower delay and drought response index for more severe drought conditions. Genotypes are exposed to managed drought environments for selection of drought tolerant genotypes. A marker assisted selection (MAS) scheme has been developed and applied for selection of progenies in the backcrossing program. The plant breeding program uses rapid generation advance techniques that enable early yield testing in the target population of environments (TPE) through inter-station (multi-location yield testing) and on-farm trials. A farmer participatory approach has been used to identify the TPE for the breeding program. Four terrace paddy levels have been identified, upper (drought), middle (drought prone to favorable) and lower (flooded). This paper reports the change in the breeding program for the drought prone rainfed lowland rice environments of North and Northeast Thailand by incorporating our knowledge on adaptation and on response of rice to drought.     

Alternative cropping strategies for assured and efficient crop production in upland rainfed rice areas of eastern India based on rainfall analysis

The productivity of rice in rainfed upland soils of eastern India is very low (<1 t/ha) and unstable because of erratic monsoon, moisture deficit during dry spells, light textured with less fertile soils and several biological constraints (weeds, pests and diseases). Keeping the urgent need of augmenting the productivity of vast rainfed upland rice ecosystem of eastern India (4.3 million ha), crop diversification technology was generated through on-farm research trials in representative upland rice soils of eastern India after analyzing agro-climatic (rainfall variability, probability and onset of effective monsoon) and edaphic (soil water retention properties) constraints and prospects. Based on rainfall analysis, direct seeded, low water requiring, rice substituted alternative upland crops namely maize, groundnut, pigeonpea, greengram and blackgram (sole or intercropping) was sown in light textured upland rice soils on 24th meteorological weeks (11–17 June) in 3 years 2000–2002 with two to three summer ploughings during pre-monsoon shower (May). Study revealed that in deficit rainfall years (2000 and 2002), when rice yield was affected adversely in light textured upland, higher rice equivalent yield and rain water use efficiency were obtained from groundnut+pigeonpea intercropping followed by sole groundnut and sole pigeonpea. Study also revealed that productivity of rice substituted crops in the same upland did not fluctuate much between rainfall excess (2001) and rainfall deficit years (2002 and 2000). Double cropping in rainfed upland rice soils was also explored through maize–horsegram/sesamum rotation with increased productivity and rainwater use efficiency. The crop diversification technology was found to be very effective for drought mitigation.     

乘坐式多功能农用车设计与试验

水稻是我国主要粮食作物,一年最多可以种3季,使用乘坐式高速插秧机种植水稻,其每年作业时间为60 d左右。为了增加高速插秧机利用率、降低农户生产成本,研发设计了乘坐式多功能农用车。该农用车以高速插秧机底盘为行走部件,设计两根动力输出轴,通过搭载耕、种、管、收等功能部件,实现了水稻生产全程机械化。该机具田间试验作业效果良好,推广应用前景广阔。      

Bioenergetic and energy constraints in increasing cereal productivity

The grain yield potential of cereal crops such as wheat, rice, barley, oats and sorghum has increased by genetic improvement in the harvest index (grain yield/biological yield). Such alterations in the harvest index were analysed from the point of view of intrinsic energy and nitrogen, phosphorus and potassium requirements. A higher harvest index, without any reduction in biological yield, increases the harvest of: (a) energy (MJ) in the above ground parts of the crop and (b) nitrogen and phosphorus in the grain. In addition, it enhances the fertiliser requirement of the crop. From bioenergetic considerations, higher grain yields, obtained by improving the harvest index, represent a path which demands least increments in photosynthate and nutrient inputs. The other alternatives available for increasing cereal productivity, once the upper limits of the harvest index are reached by breeding, have higher costs in terms of photosynthate and fertiliser requirements (energy inputs). There seems to be no other immediate plant breeding alternative to increase productivity without additional energy (fertiliser) inputs.     

A rule-based method for the development of crop management systems applied to grain sorghum in south-western France

A generic approach is proposed for the development and testing of crop management systems in contrasting situations of water availability. Ecophysiological knowledge, expertise, regional references and simulation models are combined to devise management strategies adapted to production targets and constraints. The next stage consists of converting these crop management strategies into logical and consistent sets of decision rules. Each rule describes the reasoning which is used to apply a technical decision by taking account of observed or simulated environmental conditions or predicted agronomic risks.

This approach was applied to design crop management systems for grain sorghum (Sorghum bicolor L. Moench.) in south-western France. For spring-sown crops, management (sowing date, plant density, varietal choice, N fertilizer rate and timing) was based on water availability, both for economic and environmental reasons. Specific sets of decision rules were written for irrigated and rainfed conditions. The establishment of rules was based on agronomic principles (e.g. for plant density) or on the application of a simulation model (e.g. for sowing date, variety). N fertilization and irrigation were applied using combined N and water dynamic models.

A novel methodology combining crop diagnosis, analytical trials and crop simulation was developed to evaluate the management systems. An irrigated and a rainfed rule-based management system were compared near Toulouse (S.W. France) from 1995 to 2002. The profitability of rainfed low-input management was confirmed for sorghum in spite of high yields under irrigation (up to 10 t ha⁻¹). The adaptation of sorghum management in rainfed conditions was mainly achieved through early maturing cultivars and by reducing N applications by 65%.     

The influence of different Acacia senegal agroforestry systems on soil water and crop yields in clay soils of the Blue Nile region,Sudan

The purpose of this study was to test the hypotheses that (1) the tree Acacia senegal competes for water with associated agricultural crops, and the soil water content would vary spatially with tree density and type of management; (2) the microclimate created by trees would favourably affect the soil water content and improve the growth of associated agricultural crops. Trees were grown at 5 m × 5 m or 10 m × 10 m spacing alone or in mixture with sorghum or sesame. Soil water content was measured using a neutron probe at three depths, 0–25, 25–50 and 50–75 cm; and at different stages of crop development (early, mid, and late). Crop growth and yield and the overall system performance were investigated over a 4-year period (1999–2002). Results showed no significant variation in the soil water content under different agroforestry systems. Intercropping also resulted in a higher land equivalent ratio. No significant variation was found between yields of sorghum and sesame when these crops were grown with or without trees. The averages crop yields were1.54 and 1.54 t ha⁻¹ for sorghum; and 0.36 and 0.42 t ha⁻¹for sesame in intercropping and pure cultivation, respectively. This suggests that at an early stage of agroforestry system management, A. senegal has no detrimental effect on agricultural crop yield. However, the pattern of resource capture by trees and crops can change as the system matures. There was little competition between trees and crops for water suggesting that in A. senegal agroforestry systems with 4-year-old trees the clay soil has enough water to support the crop growth over a whole growing season up to maturation and harvest.     

Economics of rainwater harvesting for crop enterprises in semi-arid areas of East Africa

This paper presents an analysis of economics of rainwater harvesting by poor farmers in Tanzania. A questionnaire was used to survey 120 households to obtain information on the performance of their enterprises over 6 years (1998–2003). The information was mainly based on recollection as few farmers kept detailed records. Actual monitoring and measurements of yield and inputs was done in the farmers’ enterprises over 2 years during 2002/2003 and 2003/2004 production seasons. The analysis was done for four categories of rainwater harvesting systems differentiated by the size of catchments from which water is collected and the intensity of concentration and/or storage of the collected rainwater. These categories are: micro-catchments, macro-catchments, macro-catchments linked to road drainage and micro or macro-catchments with a storage pond. Results show that rainwater harvesting for production of paddy rice paid most with returns to labor of more than 12 US$ per person-day invested. These benefits are very high due to the fact that without rainwater harvesting it is not possible to produce paddy in the study area and rainfed sorghum crop realizes a return to labor of only US$ 3.7 per person-day during above-average seasons. For the rainwater harvesting systems, those designed to collect water from macro-catchments linked to road drainage, performed best during both categories of seasons. The results also show that contrary to expectations, improving rainwater harvesting systems by adding a storage pond may not lead to increased productivity. Another finding that goes against the widely held belief is that rainwater harvesting results in more benefits during the above-average seasons compared to below-average seasons. It is therefore, concluded that there is a potential for combining rainwater harvesting with improved drainage of roads. The construction of rural roads in semi-arid areas can beneficially be integrated with efforts to increase water availability for agricultural needs.     

Use of saline–sodic waters through phytoremediation of calcareous saline–sodic soils

Use of poor-quality groundwater has become inevitable for irrigation to compensate rapidly increasing water demands in many arid and semiarid regions. Salinity and sodicity are the principal soil and water quality concerns in such areas. Many saline–sodic and sodic soils have saline or saline–sodic subsurface drainage waters. Amelioration of these soils needs a source of calcium (Ca²⁺) that can replace the excess exchangeable sodium (Na⁺). Most of these soils, however, contain calcite (CaCO₃) of extremely low solubility. The native calcite does not supply adequate levels of Ca²⁺ for soil amelioration as do other chemical amendments. Phytoremediation may help ameliorate such soils through cultivation of certain crops tolerant to ambient soil salinity and sodicity. This amelioration strategy works through plant root action to help dissolve CaCO₃ to supply adequate Ca²⁺ without the application of an amendment. During a 3-year field experiment conducted under irrigated conditions, we evaluated phytoremediation against soil application of gypsum and farm manure, and water treatment with sulphuric acid on a calcareous saline–sodic soil (pH_s=8.0–8.4, EC_e=24–32 dS m⁻¹, SAR=57–78, CaCO₃=45–50 g kg⁻¹ for the top 0.15 m depth; Calcic Haplosalids). A saline–sodic water (EC=2.9–3.4 dS m⁻¹, SAR=12.0–19.4, RSC=4.6–10.0 mmol_c l⁻¹, SAR_adj=15.6–18.4) was used to irrigate the rice (Oryza sativa L.) and wheat (Triticum aestivum L.) crops grown in rotation. Active desalinisation and desodication processes were observed in all the treatments. After the final wheat crop, the 1.2 m soil profile EC_e was 7±0.5 dS m⁻¹ and SAR was 15±2 with non-significant treatment differences, indicating comparable soil amelioration effect of phytoremediation with other treatments. Better crop yields were obtained from the manure-treated plots, owing to its annual addition to the soil that possibly improved soil fertility. Phytoremediation needed minimum capital input because no initial investment was made to purchase the amendments.     

Determining superior cropping patterns for small farms in a dryland rice environment: Test of a methodology

A methodology for cropping systems research was proposed in 1975. It involved the farmer as an active participant in the research, with test patterns grown on his land under joint farmer-research management. Experience with the use of this methodology in developing a dryland rice-based cropping systems test site in the Philippines is discussed.The potential for increased crop productivity in the major dryland rice-producing region of eastern Batangas province, where the predominant cropping pattern involves dryland rice followed by field corn, was studied by testing the impact of these cropping pattern alternatives: following rice with field crops other than the local Orange flint corn, an intercrop pattern, and a three-crop-per-year pattern. Cooperating farmers applied the alternative patterns on 1000 m² plots adjacent to their rice-corn plots. Some patterns showed yield instability and poor pest resistance. None had any adverse effect on the yield of the next rice crop when compared with the traditional pattern.The research opened several directions in which dryland rice-based patterns may be improved. A shift to an improved corn variety showed promise as an effective means of increasing pattern productivity. Soybeans and sorghum were the outstanding alternative crops to follow rice. Intercrops with corn were productive, but may fit only if labour requirements are not excessive and labour productivity is fairly high.     

Spatial and temporal trends of water productivity in the lower Mekong River Basin

We estimate the physical and economic water productivities of rice and upland crops grown in the Lower Mekong River Basin and we examine their spatial and temporal trends. We discuss the constraints to low productivity, suggest measures for improvement and show the future productivity requirements for food security for increased population. Both the physical and economic water productivities of rice are higher in Vietnam, moderate in Laos, and lower in Thailand and Cambodia. In contrast, the physical water productivities of upland crops such as sugarcane and maize are highest in Thailand. The economic water productivity of upland crops is higher in Laos followed by Vietnam, Cambodia and Thailand, and is much higher than that of rice. However, the economic productivity of all crops is dominated by the productivity of rice, particularly lowland rainfed rice, which is the dominant crop in the Lower Basin. The intra-regional variation (among the provinces within a country) of productivity is not substantial. There is an increasing trend of both physical and economic water productivity in all four riparian countries; however, the increase is more prominent in Laos and Vietnam. The economic productivity of upland crops is much higher than that of rice and therefore cultivation of more upland crops can significantly increase farm-level incomes, with positive impacts on reducing poverty. Increasing upland crops areas is unlikely to have any impact on the food security of the basin. The current rate of increase of both production and productivity of rice is considerably greater than the rate required to feed the expected extra population by 2050, suggesting that food security is not threatened by the population increase. There appears to be considerable scope to increase productivity and maintain the export potential of the basin.     

Modelling the competition for light and nitrogen between rice and Echinochloa crus-galli

The competition for light and nitrogen between rice (Oryza sativa L.) and barnyardgrass (BYG; Echinochloa crus-galli (L.) Beauv. ssp. hispidula) in an irrigated paddy is described by means of simulation.

(1) Growth and development of both rice and BYG are simulated with the same plants model which accounts for tiller production and for mass growth of leaf, culm, root, and grain on each tiller. (2) Competition for light depends on the plant height and the vertical leaf area distribution, and is expressed as the share of incident light absorbed by rice and BYG, respectively. (3) Competition for nitrogen is based on the proportion of root space explored by rice and BYG and is estimated from the respective root mass. (4) The model, originally developed for rice, is validated here for BYG planted in monoculture at different densities. (5) The model predictions on biomass growth of competing rice and BYG are compared to field data collected in a replacement experiment. (6) The effect of BYG competition on rice yield is demonstrated for various rice and BYG planting densities.     

Systems approaches for the design of sustainable agro-ecosystems

The complexity of agricultural systems and the need to fulfil multiple objectives in sustainable agro-ecosystems call for interdisciplinary analyzes and input from a wide variety of disciplines in order to better understand the complete agronomic production system. Systems approaches have been developed to support these interdisciplinary studies; their development and use have increased strongly in the past decades. Agronomic systems have pronounced spatial and temporal dimensions. Spatial aspects can be distinguished at crop, field, farm, regional and higher levels while processes at each spatial level have characteristic temporal components. Systems analysis in agronomic systems implies the use of various types of knowledge, such as expert knowledge including stakeholder expertise and knowledge derived from scientific measurements and model-simulations. The latter two can be derived from different types of studies: simple, rapid and cheap procedures, which are often relatively unreliable, at one end of the scale and complex, cumbersome and expensive data-intensive procedures at the other end. Selection of proper procedures for specific issues, both in terms of measurements and in applying simulation models, needs attention. Each problem requires its own research approach. Based on the output requirements and data availability, the proper systems approach has to be selected. Examples of these different procedures are given in this paper. Considering the type of problems to be studied in agronomic systems, different procedures can be followed to address the issues raised at a specific scale. These procedures start with a proper analysis of the system followed by studies that are projectory, exploratory, predictive, or are focused on decision support. Examples will be provided. Increasingly, systems approaches include stakeholders to fine-tune problem definition, the research itself, and the implementation of results. Stakeholders are farmers and citizens on farm and community levels and policy makers and planners at higher levels of aggregation. A comprehensive interdisciplinary analysis of agricultural production systems is seen as a necessary condition for the development of innovative, sustainable systems for the future. Systems for improving crop production systems are presented in this paper as well as applications of systems approaches at the farm and regional levels with emphasis on selecting the right approach.     

Relationships between available soil water and indicators of plant water status of sweet sorghum to be applied in irrigation scheduling

Optimal crop production depends greatly on available soil water, and it is therefore important to know when and how much to irrigate in order to attain agronomic potential. In this work, plant indicators are used to assess water stress. These are compared with available soil water to find the critical point for irrigation scheduling of sweet sorghum. The experimental trial was carried out in Bečej, in the Vojvodina region, on a sweet sorghum crop, grown in moderate climatic conditions on a well-drained, deep chernozemolic meadow soil. Plant indicators tested were predawn and midday leaf water potential and crop and air temperature difference. All the methods were sensitive to water deficit in plants, but not all can be used for irrigation scheduling. The predawn leaf water potential was the most reliable parameter among those tested due to its relative independence from weather conditions and a valid indicator of plant water status. This was not the case with canopy-air temperature difference. The predawn leaf water potential corelation with available soil water indicates that the threshold value for irrigation scheduling of sweet sorghum is when the former has decreased to –0.45 MPa. This corresponds to a soil water depletion to about 10% of available water in the active root zone. The canopy-air temperature difference was sufficiently sensitive to indicate the onset of mild plant water stress, although it showed a certain threshold value when water shortage appeared, which occurred when the air and canopy temperature were the same. Received: 9 April 1996     

Technology adoption by resource-poor farmers: considering the implications of peak-season labor costs

Seasonally-specific cultivation patterns of farm crop enterprises often create periodic labor shortages. New technologies that require labor inputs during such labor-scarce seasons are less likely to be adopted. Financial ex ante assessments of technology alternatives, however, neglect the implications of seasonal labor shortages. Standard returns to labor estimates assume that the value of labor to farmers is constant despite temporary increases in demand. This paper develops an alternative measure, returns to opportunity-costed labor (RTOCL), which discerns the seasonally-changing costs of labor. RTOCL more accurately reflects farmer decision criteria and serves as a useful measure in ex ante analysis of technology interventions. A case study of a bush fallow agricultural system in the Peruvian Amazon illustrates how seasonal labor shortages lead to farm management tradeoffs that affect the prospects of technology adoption. Two improvements of a new upland rice variety are contrasted: higher yield versus early maturity. Empirical results of an agro-economic mathematical model reveal that the early maturity characteristic enables rice to become more complementary to peak-season labor demands of the agricultural system. This early maturity characteristic permits farmers to cultivate larger areas and reap greater financial benefits than a variety with a high yield characteristic. Model results support the need to address heterogeneous seasonal labor demands when developing and disseminating agricultural technologies intended to benefit resource-poor farmers.     

Integrated agricultural research and crop breeding: Allelopathic weed control in cereals and long-term productivity in perennial biomass crops

Future agricultural research will need to increasingly integrate ecological, physiological and molecular methods, in order to understand agricultural crops in situ and their interaction with the environment as well as organisms impacting on their long-term health and productivity (‘agricultural eco-genomics’). The need for integration will increasingly implicate on crop breeding strategies for most agricultural systems. In this paper, implications are highlighted for two contrasting areas of agricultural research related to sustainable crop production: first, the possibilities to utilize crop allelopathic activity to suppress weeds as an alternative to chemical weed control; and second the increasing interest to environmentally friendly and sustainable produce perennial energy crops on agricultural land. ‘Sustainability’ in agriculture is difficult to define unequivocally, but frequently implies the increased utilization of ecological processes. Breeding strategies towards increased utilization of allelopathic crops require initially the integration and verification of allelopathic processes in various agricultural contexts, because there is currently great uncertainty about the predictable operation of allelopathic activity in different ecological contexts. Breeding programs for future biomass crops, most promising are perennials such as Salix, would greatly benefit from the integration of ecological information affecting long-term productivity, e.g., eco-physiological growth determinants at stand level and the biological control of pests. Agricultural eco-genomics could facilitate a compromise between intensive agriculture and the frequently expressed demand for greater sustainability in agriculture.     

Yield and seasonal water productivity of sunflower as affected by tillage and cropping systems under dryland conditions in the Limpopo Province of South Africa

Sustainable food production in semi-arid tropical countries can be achieved through efficient utilization of rainwater. A field experiment to assess the grain yield, seasonal water use (WU), water use efficiency (WUE) and precipitation use efficiency (PUE) of sunflower (Helianthus annuus L.) intercropped with cowpea (Vigna unguiculata L.) on two tillage systems was conducted during the 2007/2008 and 2008/2009 cropping seasons at the University of Venda (22°58′ S, 30°26′ E at 596 m above sea level). The experiment was configured as a 2 × 2 × 2 factorial design with three replications. The tillage treatments were conventional tillage (CT) (control) and in-field rainwater harvesting (IRWH) system. The IRWH is a special crop production technique that promotes runoff on 2.0-m wide no-till strip between crop rows and collects the runoff water in basins where it infiltrates into the soil profile. The treatments in the cropping system (CS) consisted of a sole crop (sunflower or cowpea) and an intercrop (sunflower × cowpea). Results of the experiment revealed that IRWH led to a significant (P < 0.05) increase in sunflower grain yield in the second season but cowpea grain yield was not influenced by tillage systems. IRWH resulted in significantly higher WU, WUE and PUE of both crops compared to CT system in the second season. The CS had significant effects on sunflower grain yield in both seasons but none on the cowpea grain yield. WU was significantly higher in intercrops than in sole cowpea and sole sunflower in the first and second season, respectively. WUE and PUE were significantly greater in sole sunflower than in the intercrops but less in the sole cowpea than in the intercrops.     

Management of runoff stored in small tanks for transplanted rice production in the mid-hills of Northwest Himalaya

Scarcity of water in upland areas limits the growing of transplanted rice and the yield of rice grown under rainfed conditions is very low. As the first priority for the use of runoff recycling based water resources is in the dry season followed by the monsoon season, a strategy has been developed to use the surplus water (occurring during the early monsoon season) to grow transplanted rice without compromising the dry season irrigation. Field experiments revealed that under the mid-hill conditions, transplanted rice can be grown as transplanted in 5 cm standing water and thereafter tainted, requiring only 3.0–3.5 cm of water with a yield reduction of about 25% as compared to generally recommended intermittent submergence (2 days after the disappearance of water) requiring 100–130 cm of water. However, the reduction in yield was not significant if 1 week of initial ponding just after transplanting was created. Based on rainfall-runoff analysis, graphs were developed for runoff and volume of water available in water tanks in different durations of early monsoon periods, command-catchment area ratio and the volume of water available after irrigation which is to be used in dry season, as a function of runoff curve numbers. These graphs can be consulted directly to plan irrigation systems for transplanted rice in upland areas.