followed by the wild accession S. pennellii. On the other hand, the lowest intrinsic efficiency of wateruse was found in the UFU22/F 2 BC 1 #8 and UFU47/F 2 BC 1 #11genotypes. It was also found that the wild accession was 64% more efficient than the cv. Santa Clara. High photosynthetic rate associated with low stomatal conductance (Gs) are characteristics find in plants with tolerance to water stress, which also has a higher intrinsic efficiency of wateruse (Pazzagli et al., 2016). In environments with limited water resources, the positive magnitude of these parameters becomes essential for the adequate functioning of plants and also for demonstrating the physiological plasticity of the species to abiotic factors (Funk and Vitousek, 2007; Li et al., 2008; Silva et al., 2008).
With projected increased frequency of drought, and decreased availability or increased cost of water for agriculture, increasing the efficiency of wateruse in agriculture is an important goal . In addition to crop management strategies, inherent increases in crop wateruseefficiency (WUE) could be useful in reaching this goal. For a given leaf to air difference in water vapor pressure (VPD), the ratio of photosynthesis to transpiration, termed leaf wateruseefficiency, is inversely related to the ratio of substomatal CO 2 concentration to ambient CO 2 concentration (C i /C a ) . The realization
Primary and secondary data was collected for the study. Structured open ended and close ended questionnaires were used to collect primary data. The questionnaires were administered to the farmers by enumerators. Data that was collected included: irrigation technologies, gender issues, household size, farm size, age, literacy, farming experience, livestock ownership, extension, soil type, amount of water, residues, slope, distance from Homestead, labor, income levels and the off farm income. To determine the economic efficiency of wateruse in the small scale irrigation systems, the Data Envelopment Analysis (DEA) was used. The appropriate model showing the wateruseefficiency in production and profitability. DEA analysis does not only determine the efficiency rate of a system, but also recommends target values for inputs and outputs responsible for inefficiencies within a system. The original work by Charnes, Cooper and Rhodes (1978) is attributed to have coined the term Data Envelopment Analysis (DEA) and the development of the dual pair of linear programming method into the equivalent ratio form (popularly known as the CCR model). This development provided a basis for analysing efficiency (Cooper et al., 2011; Ding et al., 2015).
Abstract. Amid an increasing water scarcity in many parts of the world, virtual water trade as both a policy instrument and practical means to balance the local, national and global water budget has received much attention in recent years. Building upon the knowledge of virtual water accounting in the literature, this study assesses the efficiency of wateruse embodied in the international food trade from the perspec- tives of exporting and importing countries and at the global and country levels. The investigation reveals that the virtual water flows primarily from countries of high crop water pro- ductivity to countries of low crop water productivity, gener- ating a global saving in wateruse. Meanwhile, the total vir- tual water trade is dominated by green virtual water, which constitutes a low opportunity cost of wateruse as opposed to blue virtual water. A sensitivity analysis, however, suggests high uncertainties in the virtual water accounting and the es- timation of the scale of water saving. The study also raises awareness of the limited effect of water scarcity on the global virtual water trade and the negative implications of the global water saving for the wateruseefficiency and food security in importing countries and the environment in exporting coun- tries. The analysis shows the complexity in evaluating the efficiency gains in the international virtual water trade. The findings of the study, nevertheless, call for a greater empha- sis on rainfed agriculture to improve the global food security and environmental sustainability.
A b s t r a c t. Soil water storage and crop wateruseefficiency (WUE) were monitored in a randomised complete block design experiment set up on a 0.7 ha field plot with treatments that consisted of five fallow treatments, namely Guinea grass (Panicum maximum Jacq.PAF), Kaliko plant (Euphorbia heterophylla Linn. EUF), tropical kudzu (Pueraria phaseoloides(Roxb) Benth.(PUF), native fallow without fertilizer (NNF), and native fallow with fertilizer applied during subsequent cropping (NFF). The fallow crops were ploughed under and cultivated to maize (Zea mays) in the subsequent season and the water storage and crop wateruseefficiency were monitored. Fluctuations in soil water storage were found to be dependent on rainfall and soil profile characteristics. The amount of water stored in the soil was consistently the highest under NNF (25%) and the least under PUF (19%). Maize dry matter yield (0.46 - 3.38 t ha -1 ) and WUE (0.011 t ha -1 mm -1 - 0.030 t ha -1 mm -1 ) were the highest at 29 days after planting (29 DAP) and at 45 DAP under TPU. At 75 DAP dry matter yield for EUF improved (8.88 t ha -1 ), while NFF was the highest (10.12 t ha -1 ). Wateruseefficiency calculated in terms of grain yield (WUE-GY) having a value of 0.018 t ha -1 mm -1 was found to be the highest under NFF, followed by the results from EUF and PUF (0.015 t ha -1 mm -1 ), while NNF (0.011 t ha -1 mm -1 ) was significantly (p £ 0.05) the lowest. Short fallow with Pueraria phaseoloides, therefore, appeared to be an attractive alternative for sustaining the wateruseefficiency of continuously cropped farmlands.
Some of the dynamic aspects of wateruseefficiency are more difficult to predict. For example, soil-water is conventionally thought to be completely ‘unavailable’ until it reaches a state of gravitational equilibrium, called “field capacity” by agronomists (e.g. Gardner 1968) and the “drained upper limit” by horticulturalists (Harden 1988). This concept is completely arbitrary though, because plants under water stress do not wait to absorb water until the energy status of the irrigation water reaches ‘field capacity’ - they immediately start taking up water in response to the ambient vapour pressure deficit. Nevertheless, excessively large hydraulic conductivities do remove a considerable amount of water before plants can extract it. This explains the link between the availability of soil- water and an arbitrary matric head describing its energy status, even though this varies from 5 to 33 kPa depending on circumstance. Similarly, at the dry end, excessively low hydraulic conductivity limits the rate at which water can move toward plant roots. We know from experience (and limited experimental evidence – e.g. Gardner 1965) that unsaturated hydraulic conductivity declines precipitously with increasing matric head, and that this varies with soil type. We don’t, however, understand how to manage irrigation water efficiently to prevent leaching of nitrogen and other soluble compounds in horticultural operations, even using trickle- or drip-irrigation (Thorburn et al 2003; Mmolawa and Or 2000). Our understanding of the way in which hydraulic properties of Australian soils change as they drain and dry out is also limited (Cresswell & Paydar 1996). Research is therefore needed to link our understanding of how soil hydraulic properties change during drying with irrigation management so that we minimize leaching, even with drip-irrigation.
An experiment in large pots placed outside under natural conditions was conducted in Canberra (147°E, 35°S) between October 1989 and January 1990. The mean minimum and maximum temperatures for the duration of the experiment were 10.1 °C and 23.6 °C. The mean solar radiation and vapour pressure deficit were 26 MJ n r 2 d’1 and 1.6 kPa. There were three barleys (Galleon, O'Connor and Ulandra), three bread wheats (Kulin, Meteor and Rosella), two durum wheats (Altar 84 and Carcomun), two triticales (Dua and AT 30) and two oats (Echidna and Hakea). Seeds of the late flowering cultivars (Ulandra, Rosella, AT 30 and Hakea) were pregerminated at 2 °C. Three seeds of each genotype were sown 3 cm below the soil surface in large pots (1 m tall and 10.3 cm diameter) containing a fertile soil. These were later thinned to one healthy plant per pot when the first leaf had fully expanded. A 4 cm cover of perlite was placed over the soil surface to prevent evaporation from soil. There were two water treatments - a control that was maintained near field capacity, and a droughted treatment, in which no water was applied after the time of sowing. In the control treatment, the weight of water lost from each pot in the previous week was added in three instalments over the next seven days. There were four replicates of each cultivar in each treatment. Pots were protected from rainfall with a moveable cover. Wateruse (transpiration) was determined by weighing each pot at weekly intervals in both the control and drought treatments from sowing to maturity. The date of anthesis of the main stem of each plant was recorded. Plants were harvested in January when they reached physiological maturity. Heads were separated from stems and leaves and were weighed separately. Roots were not extracted but the crown below the soil surface was included in the harvest sample. Total dry weight (DW) was recorded after oven-drying the plant samples at 80 °C for 48 h and plant transpiration efficiency (TEDW) was calculated as the ratio of total DW (excluding roots) to total wateruse. In the drought treatment, seedlings of Ulandra barley were eliminated because of their poor growth
Beans (Phaseolus vulgaris, L.) are one of the most important leguminous crops in Egypt for local marketing and export. The cultivated area with snap beans in Egypt is about 59.3 thousand feddans (feddan = 0.42 hectare), produced about 249.4 thousand tons (Ministry of Agriculture and Land Reclamation, 2015).Green bean cultivation is expanded in the new reclaimed lands in Egypt, which is characterized as an arid land with limited sources of irrigation water. Therefore, growers have to adopt modern techniques of cultivation to improve wateruseefficiency. Water management is a critical factor of bean production (Abdel-Mawgoud, 2006). Plant growth stages are affected by moisture availability in soil during the growth cycle. Low irrigation level reduced vegetative growth of plant as shoot weight, leaf area and number of leaves (Mahmoud, 2000; El-Noemani et al., 2009 on peas and Abdel-Mawgoud, 2006; El-Shawadfy, 2008 on beans). Moreover, increasing irrigation level increased the yield and pod quality of beans (Amer et al., 2002; Metin et al., 2005, Abdel-Mawgoud, 2006;Onderet al., 2006;El-Shawadfy, 2008). El-Noemani et al.(2010)mentioned that increasing irrigation level up to 100% of Et 0 exhibited the highest vegetative growth of bean plants. Meanwhile, the highest yield was
Strategic mechanisms are developed by plants to adapt to adverse environmental conditions (Trewavas, 2005), be it water-useefficiency or drought tolerance. From a physiological point of view, it is expected that for the most efficient genotypes, agronomical wateruseefficiency will not be the most tolerant to lack of the resource. Under adverse conditions, functional and structural traits of plant tissues, e.g., leaves and roots, are altered, which interferes with the maintenance of the plant, affecting yields (Sultan, 1995). However, the amount of metabolic resources available to stressed plants is limited (Zandalinas et al., 2018; Trewavas, 2005). Due to the reduced metabolic resources in stressed plants, the allocation and distribution of these compounds among the different plant structures is affected, with implications for each of the strategies adopted by the plant (Trewavas, 2005). In this way, according to Maia et al. (2011), with the increasing demand for resources to develop strategic mechanisms, plants can become inefficient in the use of resources in response to environmental challenges.
application of 3, 5 and 7 days of disappearance of standing water respectively. Continuous standing water (5cm) was maintained in all plots up to 28 days after transplantation (DAT) to avoid pre-apprehended weed infestation that could be awesome during crop establishment stage. A bowl of 1.5 liters was used to irrigate the plots from the buffer zones by throwing water in. The seedlings were transplanted maintaining hill to hill distance of 15cm and row to row distance of 25cm. The first and the last hills were kept at 7.5cm away from their nearest levees resulting in 25 hills along the length and 10 hills along the width. Since the grains of BRRI hybrid 2 got ripened earlier than the BRRIdhan 28, the former was harvested (23 April 2011) two weeks earlier than the harvesting date (May 12, 2011) of the latter. Matured plants inside 1m square of land were harvested for subsequent analysis. Moisture content of the grains, however, was adjusted to 14% equivalent moisture content after measuring through digital grain moisture meter for subsequent analysis. Quantitative information related to yield and all the yield contributing characters viz. plant height, effective tillers, length of the panicle, no. of spikelets per panicle, no. of filled and unfilled grains per panicle, 1000 grain weight, grain yield, straw yield, harvest index and wateruseefficiency of the two varieties (BRRIdhan 28 and BRRI hybrid2) were analyzed to obtain the effect for AWDI on rice production.
The main concern in cultivating crops has always been water availability. To increase food pro- duction, water plays a major role after securing a large portion of land area. Knowledge of the fac- tors influencing crop wateruseefficiency and hope to increase the efficiency has continued to be an objective in many modern studies. The gap between irrigation supply and demand is increasing from year to year as a result of an increase in population growing rate and people moving from place to place. Searching for new water may be a too difficult and very expensive process, so the shortest and easiest way is to maximize the wateruseefficiency throughout optimizing wateruseefficiency and the first step on that is determination of the actual crop water requirements.
Finally, fresh water resources are becoming ever scarcer in the world. As population growth and climate change takes its toll on available supplies, the world must look on to ways of effectively curbing these effects and securing their water resources. This is particularly the case with the Middle East, where the scarcity of the resource poses a problem and where the forecasts seem grim. To avoid any rising conflicts, regional cooperation must lead to the development of all available water resources and ensure that they are not wasted. The mismanagement of the resource by the government caused by a lack of financial and technical means is leading to an extremely valuable waste in water that could be easily transported and utilized elsewhere. Ultimately, water must be viewed for its worth, as a resource that creates and sustains life and as such must be managed properly to ensure that every bit of it is nourishing and sustaining life in the region, and more extensively on planet earth.
The wintergreen couch trial was located in Bay 6 of Section 5 of the property. This trial was initiated on the 19 th January 2007 and was harvested on the 1 st May 2007. During this time frame the turf was irrigated on Mondays, Wednesdays and Fridays, except if there was a rainfall event. The irrigation quantities were calculated using ETo figures from the on farm weather station. In the event of a rainfall event that quantity of rain (in mm) was taken off the ETo figures and the turf was not watered until the ETo was again positive. During this period three enviroscan soil moisture meters were placed on site. The first was placed in bare soil, the second in medium coverage and the third in fully established turf. The purpose of this placement was to see the difference in crop wateruse at different stages of crop cover and growth. They were also used to tell if the soil profile was being over irrigated. During this trial the sprinkler system was evaluated for distribution uniformity and it was decided that the sprinkler heads and nozzles be changed to try to improve uniformity results. Urea was added to the trial site at thirty day intervals to boost crop growth rate, increase colour and to lower turf water
Growth of cultural and economic level of societies has caused conversion of villages to cities and establishment of wastewater treatment plant in cities. Wastewater treat- ment plants discharge significant amounts of wastewater into natural waterways and their output at the most critical time (the hottest day that crop water need reaches to maximum due to physiological conditions) reaches to the highest amount. Hence, with regard to permanent and accessible wastewater and study on performance and production of forage per water or wastewater consumption unit, the research project was performed in form of statistical plan of totally random blocks with four treat- ments in three replications during three years. The results indicate that function of forage at the third year of project implementation has increased than the first and second years. Treatments 2 and 4 (the treatments to use wastewater) had greater function than treatments 1 and 3 (treatments that have irrigated with well water), found with significant difference. In average, function of forage (dry and wet) in treatments irrigated with wastewater than the treatments irrigated with well water has been greater to 37 and 32 percent regardless of consumption amount. Water con- sumption efficiency in the treatments to use wells water and wastewater equals to 0.867 and 1.09 kg production of dry hay per cubic meter of water or wastewater.
concentration (Ci) and rate of transpiration (E). The clones were also assessed for photosynthetic ratios such as intrinsic WUE, instantaneous WUE, intrinsic carboxylation efficiency and mesophyll efficiency in order to identify elite clones of Eucalyptus tereticornis for clonal forestry programmes and also for planting drier areas so as to reclaim the waste lands. The results showed a significant variability for the physiological parameters such as Pn, gs, E and Ci and the derived ratios such as intrinsic WUE, instantaneous WUE, intrinsic carboxylation efficiency and intrinsic mesophyll efficiency in the clones of Eucalytus tereticornis. Clones were categorized based on their photosynthetic efficiency and some clones such as Et 130, Et 242, Et 008 and Et 027 were identified as superior clones as they had efficient stomatal regulatory capacity combined with better carboxylation efficiency and are ideal planting stock especially for drier areas. The superior clones which are identified based on photosynthetic efficiency could be considered as choice materials for further tree breeding programmes.
This study showed higher reduction in grain yield than shoot dry matter as affected by root pruning. Fang et al. (2010) found that root pruning of winter wheat in winter resulted in less wateruse before the stem elongation stage, but root pruning in spring saved more water at the vegetative stage. As a result, root pruning may have exposed the plants to lower water stress during grain filling and improved post-heading accumulation of dry matter. The reason for greater accumulation of dry matter could be due to decrease of carbon consumption by the root system which improves yields if the carbon is re-allocated to grains (Fang et al., 2010). Plants root-pruned at anthesis had a higher rate of leaf photosynthesis and lower rate of root respiration, which resulted in a significantly higher grain yield at maturity when compared with controls (Ma et al., 2010).
related mechanisms of plant and soils including (1) plant ecophysiological strategy on stomata opening and clos- ing, (2) photosynthetic compensation of plant commu- nity, and (3) partitioning of ET into transpiration and evaporation (Hu et al. 2008; Sun et al. 2015). For ex- ample, in hyper-arid deserts, vegetation is sparse, drought-tolerant plants such as C4 herbs or shrubs be- come abundant, and water is lost to atmosphere primar- ily through evaporation from bare soils rather than plant transpiration, causing higher sensitivity of evaporation to dryness than GPP and transpiration, which could pro- duce a negative correlation of WUEet to drought but null correlations in WUEt and IWUEt, respectively. Hence, analyzing each component flux of ecosystem WUE to climate changes and comparing the different re- sponse of WUE parameters at leaf and ecosystem level may provide more useful insights to understand the coupled carbon – water flux process in dryland ecosys- tems than different WUE parameters applied separately.
Distance from the source of irrigated water to farm (m) Negative Ownership of irrigation system Positive Education level (dummy variable) Positive Farmer’s irrigation experience (years) Positive Extension contact (dummy variable) Positive Access to credit (dummy variable) Positive