Water Supply Patterns Research Articles

Root foraging and yield components underlying limited effects of Partial Root-zone Drying on oilseed rape, a crop with an indeterminate growth habit

We report on two experiments with oilseed rape (Brassica napus L.) to test if partial root-zone drying techniques improve yield in a crop in which vegetative and reproductive growth overlap (indeterminate growth habit), and to investigate what plant morphological responses contribute to the yield that is realized. Deficit irrigation resulted in smaller plants with smaller yields but larger seeds compared to treatments with shallow groundwater (first experiment) and with fully watered conditions (second experiment). Different partial root-zone drying treatments (water supply patterns) under deficit irrigation, however, had little effect on plant growth and yield components (number of branches, branch lengths, number of pods, etc.). Our results suggest that partial root-zone drying doesn’t work well with oilseed rape. Detailed measurements of soil water contents and root distribution indicate that roots were extremely plastic, effectively foraging for water, and these root responses may have overwhelmed physiological effects of partial root drying on the shoot. Furthermore, in crops with indeterminate growth with a short vegetative growth phase, partial root-zone drying may be ineffective in enhancing the major yield components. Further reasons for the lack of success are discussed.

Socio-environmental factors and ascariasis infection among school-aged children in Ilobu, Osun State, Nigeria

The risk factors predisposing children to ascariasis transmission in a rural community of Osun State, Nigeria were investigated from November 2005 to April 2006. Children below 16 years of age were examined at the household level after information on biodata, access to water supply and sanitation, socio-economic status of their parents and degree of cohabitation with their parents was collected using a questionnaire. Of 440 children examined, overall prevalence was 60% and median intensity was 1548 eggs per gram (epg) (min. 48 epg; max. 55464 epg). Infection patterns were gender comparable and age dependent, with peak prevalence (67.8%) occurring in children aged 5-9 years and peak median intensity (4368 epg) in children aged >or=15 years. Logistic regression analysis revealed that prevalence was influenced by patterns of water supply and sanitation, parents' educational background, number of biological parents living with a child and number of playmates a child has. These findings suggest that socio-environmental risk factors which play a role in disease transmission need to be taken into account when formulating sustainable control strategies for ascariasis and other intestinal parasites in Nigeria and elsewhere.

Climate variability and change in the drylands of Western North America

We argue that it is important to expand the consideration of climate in the context of provision of ecosystem services in drylands. In addition to climate change, it is necessary to include climate variability on timescales relevant to human and ecological considerations, namely interannual to decadal and multidecadal. The period of global instrumental record (about a century and a half long at the very most) is neither an adequate nor an unbiased sample of the range and character of natural climate variability that might be expected with the climate system configured as it is now. We base this on evidence from W. N. America, where there has recently been a major multi-year drought, of a scale and intensity that has occurred several times in the last 2000 years, and on attempts to provide explanations of these phenomena based on physical climatology. Ensembles of runs of forced climate system models suggest the next 50 years will bring much more extensive and intense drought in the continental interior of North America. The trajectory followed by the supply of ecosystem services will be contingent not only on the genotypes available and the antecedent soil, economic and social conditions but also on climate variability and change. The critical features of climate on which patterns of plant growth and water supply depend may vary sharply during and between human generations, resulting in very different experiences and hence, expectations.

Global warming threat on water resources and environment: a review

Global warming, greenhouse effect, and the climate change problems are long-term anthropogenic consequences that are expected to threaten water related demand and supply patterns in the near future. These problems may be identified linguistically on a logical basis to take the necessary precautions, and implement mitigation strategies after vulnerability possibilities are assessed using fuzzy logic. Climate change effects are the focus of many scientific, engineering, economic, social, cultural, and global nuisances, and these effects awaits cost-effective remedial solutions. Extreme events such as floods and droughts and modified groundwater recharge may be influenced by climate change.

Water Scarcity in Chennai: A Financial-Economic Appraisal of Rain Water Harvesting

The present day shortage of water, quite often termed, as water crisis is a human made disaster. Two major shifts in water management account for this disaster, the state emerging as the provider of water supply and the decline in the practice of technology of using rainwater. In a city like Chennai, in the present scenario, the most feasible and comprehensive solution to tackle the problem of water shortage is to adopt rainwater-harvesting techniques with their costs. Considering the acute problem of water scarcity that many are likely to face in the near future, it would seem prudent not to ignore the direct management of nature's simplest and most fundamental source of fresh water, rain. The paper mainly deals with the water demand and supply pattern of Chennai city and explains how implementing Rain Water Harvesting (RWH) can fill up the yawing gap between the demand and the supply pattern. The paper also examines the different types of RWH structures that can be adopted in residential apartments. The paper mainly discusses the economical parameters in the implementation of RWH as well as intervention of government in rainwater Harvesting (RWH). Finally the paper suggests measures to ease the water scarcity in Chennai. Using the cost-benefit analysis (net present value of benefit) incorporating risk and uncertainty, the study shows that the economically RWH System is viable and worthwhile, compare with financial analysis.

A Future for the Dead Sea Basin: Water Culture among Israelis, Palestinians and Jordanians

The Dead Sea basin plays a major role for regional economic development (industry, tourism and agriculture) in the Middle East. This potential is threatened by the steady disappearance of the Dead Sea. Since around 1930 the water level of the Dead Sea has fallen by about 25 m, about half of this alone in the last 20 years. The Dead Sea is a transboundary resource shared by Israel, the Palestinian Authority and Jordan. The Dead Sea is the terminal point of the Jordan River watershed and as such, it serves as a barometer for the health of the overall system. Its rapid decline reflects the present water management strategies of the riparian and upstream countries. This includes the different water cultures of the three countries. Throughout history, the Dead Sea basin has served as a source of refuge and inspiration for followers of Judaism, Christianity and Islam. Today, the religious significance of the Dead Sea is being overshadowed by its rapid disappearance. This may be explained in part by the water cultures of the three countries that influence water policy in the region. Ideology, together with culture and tradition, such as that of Zionism in Israel, has played a central role in water development in the region. In many cases, this has been at the expense of the environment. Elements pertaining to environmental security and water culture and tradition, whereby a sustainably managed environment provides for social, economic as well as environmental benefits are evident with regards the Dead Sea. The decline for example, undermines its potential as a tourist destination, despite the enormous investment in hotel and resort infrastructures in Israel and in Jordan. The decline also raises ethical issues about the exploitation of water resources by present generations at the expense of this natural heritage to future generations. This paper provides an analysis of a European Union funded project whose aims are to synthesize and assess existing physical and socio-economic data and to assess options for a better future for the Dead Sea. It will identify the patterns of water supply and use in the region, and the factors that control these patterns, including those of water culture. The underlying assumption is that solutions for a sustainable development than today’s scenario will not come from simply providing more water for development, but from a new land and water management system, indeed ethic, that is sensitive to social, cultural and ecological resources thereby providing security and stability across cultures, economic sectors and nations.

Increasing crop productivity when water is scarce—from breeding to field management

To increase crop yield per unit of scarce water requires both better cultivars and better agronomy. The challenge is to manage the crop or improve its genetic makeup to: capture more of the water supply for use in transpiration; exchange transpired water for CO 2 more effectively in producing biomass; and convert more of the biomass into grain or other harvestable product. In the field, the upper limit of water productivity of well-managed disease-free water-limited cereal crops is typically 20 kg ha −1 mm −1 (grain yield per water used). If the productivity is markedly less than this, it is likely that major stresses other than water are at work, such as weeds, diseases, poor nutrition, or inhospitable soil. If so, the greatest advances will come from dealing with these first. When water is the predominant limitation, there is scope for improving overall water productivity by better matching the development of the crop to the pattern of water supply, thereby reducing evaporative and other losses and fostering a good balance of water-use before and after flowering, which is needed to give a large harvest index. There is also scope for developing genotypes that are able to maintain adequate floret fertility despite any transient severe water deficits during floral development. Marker-assisted selection has helped in controlling some root diseases that limit water uptake, and in maintaining fertility in water-stressed maize. Apart from herbicide-resistance in crops, which helps reduce competition for water by weeds, there are no genetic transformations in the immediate offing that are likely to improve water productivity greatly.

Economic viability of photovoltaic water pumping systems

A comparison of the economic viability of photovoltaic and diesel water pumping systems is presented for system sizes in the range 2.8 kW p to 15 kW p. Actual performance data from installed systems are employed for the base case. Sensitivity analysis is carried out to generalize results for other locations and conditions. The effect of system oversizing due to mismatch of water supply and demand patterns on the economic viability of PV water pumping system is illustrated based on real data and three-year operational experience of eight installations. Investment prospects in PV water pumping applications for different selling price scenarios of water have been investigated.

Modelling the effects of irrigation reliability on pasture growth in a dairy system in Canterbury

The Canterbury Plains is an area of low rainfall, and large pasture growth responses to irrigation have been demonstrated. As the demand for irrigation water has increased, questions about water allocation impacts on dairy farm production and profit have arisen. This study used farm systems modelling to predict the impacts of water allocation on dairy farming. The model farm was based on a spray irrigated farm, fed from the Rangitata River. A multi-year approach with rainfall, temperature and water supply all affected by weather highlighted both average impacts and the variability in impacts between years. Shifting from dryland to irrigated increased yield and decreased annual variability. A 20% range in water allocated within the four irrigated scenarios gave a 7% range in pasture yield, but there were no differences in annual variability between scenarios in either water supplied or pasture yield. Analysis of simulation results indicated that clusters of poor years and the relationship between dryland and irrigated yields may be important sources of variability for dairy farmers to consider. Interactions between local climate, the seasonal water supply pattern from different irrigation schemes, soil type and irrigation hardware will influence the impacts of restricting water availability on individual farms. The results of this study emphasise the need to consider the role of water storage, climatic patterns, feed storage, use of run-off blocks and the regional balance of water demands as important factors in reducing production variability on-farm and in the region. Keywords: farm systems, pasture yield, Whole Farm Model, yield variability

Highlights of Drought Policy and Related Science in Australia and the U.S.A.

Patterns of water supply and use in Australia and the U.S.A. differ in many ways. This results in different perceptions concerning the nature of drought and policy approaches to its management. This paper discusses the differences and similarities and explores lessons that policy makers in both countries can learn from one another. A key difference between the two countries is that whereas drought is perceived in Australia essentially in terms of its impact on agriculture, in the U.S. both perceptions and policy are also heavily influenced by the impact of drought on urban communities. This has led to different policy emphases. In 1992 Australia established its National Drought Policy; the U.S. is presently considering the adoption of a national drought policy. These policies highlight drought being accepted as part of natural climate variability, rather than as a natural disaster. They also emphasize the protection of the natural resource base.

災害時無線ライフライン情報監視システムへのＧＩＳの応用

This paper describes a basic concept of a wireless lifeline data gathering project at TAO Hamamatsu Lifeline Research Center. The gathered information creates a GIS database. Using the database the system provides emergency control including active shutoff of lifelines. It also enables rescue personnel to make a restoration plan by predicting damaged portions of the lifelines. For the prediction the system reduces a network into a feasible size and derives a resistance value by linear approximation. Assuming several links damaged, it simulates water flow to make a number of water supply patterns in a prediction database. After a disaster the most fitted pattern is chosen. Implementation of the system reveals that the execution time is reduced by a factor of 80000 and that in 39 days the prediction database including 700 million patterns can be created.

The interaction between water and nitrogen translocation in a rhizomatous sedge (Carex flacca).

In order to examine whether the translocation of water and nitrogen in clonal plants is interdependent, interramet translocation of these two resources was investigated in the greenhouse. Two-ramet systems of Carex flacca were imposed to different spatial patterns of water and nitrogen supply. The experimental design allowed to examine the effects of water heterogeneity on nitrogen sharing, and, vice versa, the effects of nitrogen heterogeneity on water sharing. Interramet translocation of both water and nitrogen was quantified by stable isotope labelling. If one of the ramets was deprived of water, nitrogen or both resources (parallel resource heterogeneity), resource translocation towards this ramet was markedly enhanced compared to a control treatment in which both ramets received ample water and ample nitrogen. Under these conditions, the amount of water or nitrogen translocated was not significantly affected by the pattern of heterogeneity of the other resource imposed on the two-ramet system. If one of the interconnected ramets was rooted in dry but nitrogen-rich soil and the other ramet was placed in nitrogen-deficient but well-watered soil (reciprocal resource heterogeneity), a significant amount of water was translocated towards the ramet in dry soil, while the low-N ramet hardly received any nitrogen. These results show that little nitrogen is translocated between ramets in a direction opposite to the transpiration stream within the rhizome. However, nitrogen may be translocated independently from water if both are transported in a similar direction within the clonal system. The effects of translocation on ramet performance (in terms of transpiration, nitrogen accumulation, and biomass) were assessed by comparing interconnected ramets with isolated (severed) ramets that were treated identically. Integration enhanced the performance of ramets deficient of one or both of the resources. In case of water translocation, the transpiration and growth of the water exporting (donor) ramets was similar to the transpiration and growth of their isolated counterparts. When nitrogen was heterogeneously supplied, however, nitrogen accumulation and growth of the donor ramet was reduced to the same extent as the performance of the nitrogen-deficient ramet was increased. Water translocation thus enhanced the performance of the whole plant, while nitrogen only reduced the differences in ramet performance within the plant. In the case of the reciprocal heterogeneity treatment, the benefits of translocation were strongly unidirectional towards the ramet in dry soil. The data for this treatment suggested that total nitrogen accumulation was enhanced by the acquisition of nitrogen from the dry pot as a result of "hydraulic lift" and water exudation in the dry soil. We conclude that nitrogen translocation in clonal plants, and the associated benefits in terms of resource utilization and growth, may strongly depend on the pattern of interramet water transport. The implications are discussed for studies of physiological integration in clonal plants and the patterns of interramet resource sharing in the field.

A Review on Monthly Water Balance Models for Water Resources Investigations

Research on the development and application of monthly water balance models has been carried out since the 1940s. A good body of experience has been gained for many models, and a review of these models is needed. Beginning with the development of monthly water balance models from the earliest times, this paper discusses the relevance of various aspects of the practical application of such models. Monthly water balance models were introduced originally to evaluate the importance of different hydrologic parameters under a variety of hydrologic conditions. Present applications of water balance models are directed along three main lines: reconstruction of the hydrology of catchments, assessment of climatic impact changes, and evaluation of the seasonal and geographical patterns of water supply and irrigation demand.

Satellite derived crop calendar for canal operation schedule in Bhadra project command area, India

Spatial information on crop calendars in the command areas of irrigation systems is useful to irrigation engineers in order to achieve chronological synchronization between water delivery pattern and crop life cycle. Such synchronization is vital for efficient use of water. The capability of satellite remote sensing technology to generate spatial crop calendar information in an irrigated command area and its usefulness in the evaluation of water delivery patterns are demonstrated in this paper. The study pertains to the major crop paddy during the rabi season (December to June) of 1992-93, in the Bhadra project command area of Karnataka state, India. Analyses of multidate Normalized Difference Vegetation Index (NDVI) profiles of paddy crop generated from Indian Remote Sensing (IRS) satellite data for each distributary command reveal three distinct growth patterns in the study area with each pattern characterized by a particular crop calendar. The spatial variability in crop calendar over the total command area has thus been derived. The ground truth data obtained in crop cutting experiments (CCEs) validate the satellite derived crop calendar. Distributary wise, water delivery data have been studied in conjunction with the satellite derived crop calendar to determine whether the existing pattern of water delivery covers the required length of crop life cycle in the command area. It was found that the water supply was stopped about 30 days before harvesting in some distributaries and in some about 20-30 days before harvesting. A list of distributaries with greater lags between cessation of water supply and crop harvest was provided to irrigation system engineers to aid their plans for providing a reliable and predictable irrigation service. This is possible either through reorganization of canal operation schedule or through educating farmers about the need for adjusting their agricultural activities to match water supply patterns.

Prediction of leaf area indices and yields of wheat

SUMMARYChanges in leaf area index (LAI) of wheat are predicted by using information on daily heat units, atmospheric evaporative demand, water supply and nitrogen. The results of experiments on two different soils at Punjab Agricultural University Farm, Ludhiana, India from 1987 to 1990 showed that the rate and extent of leaf area development and its decline were dependent on the amount and pattern of water supply. Maximum leaf area index (LAImax) during the three years was found to depend on a combined effect of NO3-N in the 180 cm soil profile at sowing plus fertilizer N added. A relative growth factor (RGF) to scale cumulative water supply commensurate with crop growth was computed, which takes into account the combined effect of crop demand and supply of water and nitrogen from the soil. For adequately irrigated wheat, leaf area senescence could be predicted from cumulative potential evapotranspiration (PET). However, under droughted conditions, water supply, along with PET, also affected leaf area senescence. The dependence of wheat grain yield on LAImaxin conjunction with water supply subsequent to attainment of LAImaxwas almost linear. It is concluded that, for adequately irrigated wheat, N availability at sowing and cumulative PET determines LAImaxand the pattern of leaf development. Wheat grain yield is determined by LAImaxand cumulative water supply from LAImax to maturity.

Effect of pattern of water supply on Vicia faba L. 4. Simulation studies on yield variability.

Effect of pattern of water supply on Vicia faba L. 4. Simulation studies on yield variability.

Water Resources of the Middle East

ABSTRACT This article presents an overview of the water resources available in the Middle East region (Israel, Jordan, Lebanon, Syria, Iraq and Turkey.) The countries of the Arabian peninsula as well as those of Northern Africa are not considered here. Water balances are presented for the countries studied and the water supply and consumption patterns in the main river basins of the area (Euphrates/Tigris, Jordan, Litani and Orontes) are described. The point is made that the combination of rapid population growth, together with limited water resources is creating a potentially very dangerous situation. Possible solutions include conservation measures, more efficient use of the limited water resources and future interbasin transfer schemes within the region.

Effect of pattern of water supply on Vicia faba L. 3. Plant water relations, expansive growth and stomatal reactions.

Faba beans cv. Minica, Wierboon, Kristall, Felix, Optica and Alfred grown in the field in the Netherlands were irrigated to near field capacity, or water stressed, between the onset of flowering and the end of the growing season. Leaf water potential ( psi ), osmotic potential ( pi ) and turgor (P) were linearly related to leaf relative water content (RWC) with no significant differences between cultivars. At full turgor, pi hardly differed between water supply treatments, and the slopes of pi vs. RWC were not significantly different between treatments, indicating the absence of osmotic adjustment. Water supply did not affect the slope of P vs. RWC, and it was concluded that the faba bean cultivars lacked mechanisms to keep P high during water stress. Internode growth during flowering was 2-3 times greater in the well watered than in the stressed treatment. In greenhouse studies with cv. Minica, vegetative growth decreased linearly with decreasing P. Maximum stomatal conductance in the field decreased with psi from an estimated maximum level of 1.0 s/cm (at full turgidity and light intensity >800 micro E/msuperscript 2 per s), following a negative exponential curve. It was concluded that vegetative (expansive) growth decreases faster with decreasing P or psi than the stomatal conductance (and most probably faster than the rate of photosynthesis). It is suggested that this result may help to explain the positive effect of mild water stress on reproductive growth in faba beans. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Effect of pattern of water supply on Vicia faba L. 2. Pod retention and filling, and dry matter partitioning, production and water use.

Pod retention and pod filling of V. faba was studied under different patterns of water supply. Mild water shortage during flowering, followed by plenty of water after flowering (d-i), resulted in high seed yields at lower stem nodes (defined as the first podding node to node number 11) in cv. Alfred. The inverse treatment (i-d: plenty of water during flowering, followed by increasing water shortage after flowering), but also i-i (plenty of water during and after flowering), showed 20-60% lower seed yields at those nodes. This effect was mainly due to a lower number of pods per node. In i-i, but not in i-d, the low pod retention at lower nodes was compensated for at higher nodes (defined as from node 12 to the last podding node). These results helped to explain the mechanism of the interaction between water supply pattern and the development of reproductive sinks. The quantitative consequences of these effects on the relation between total water use and seed yield are discussed. Without taking into account different water supply patterns, a linear relation between total water use (represented by total DM production) and seed yield already explained 75-85% of the variation in seed yield. If different water supply patterns were included in the regression analysis, >90% of the variation in seed yield could be explained. The i-i patterns, compared with d-i, resulted in suboptimum DM partitioning to reproductive organs, but showed a smaller seed yield variability. This indicated that defining and maintaining the optimum level of (mild) water shortage under varying climatological conditions needed further attention. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Effect of pattern of water supply on Vicia faba L. 1. Dry matter partitioning and yield variability.

V. faba cultivars including cv. Minica, Kristall, Alfred and Optica were grown with (a) full irrigation, or restricted irrigation (b) after the start of flowering, (c) after the end of flowering, (d) before flowering or (e) during flowering. Irrigation from the start of flowering stimulated vegetative growth but reduced initial reproductive growth and final seed yield compared with restricted water during flowering only. In 1982-84 using cv. Minica, treatment (e) gave high av. seed yields (7 t/ha), optimum harvest index (0.61 g/g) and a relatively small range of seed yields (2.2 t/ha), while (d) gave 7.1 t/ha, lower harvest index (0.57) and a small range of seed yields (1.4 t/ha). The other treatments and no irrigation gave much lower seed yields and a larger range of seed yields. Treatment (c) gave the lowest harvest index. Similar results were obtained with cv. Alfred. It was concluded that the amount and distribution of rainfall was a major reason for variability in seed yield of this crop. (Abstract retrieved from CAB Abstracts by CABI’s permission)