Reduced Water Supply Research Articles

Cut-off irrigation as an effective tool to increase water-use efficiency, enhance productivity, quality and storability of some onion cultivars

Water management is becoming commonplace in discussions of high-yield farming and modern agricultural best practices. A field experiment undertaken in the Northern region of Egypt, Kafr El-Sheikh Governorate, with four cut-off furrow irrigation treatments (100%, full irrigation – considered as a control; 90%, 80% and 70% of strip length) was used to compare the effects of reduced water supply on onion (Allium cepa, L.) production via assessing three different cultivars (e.g., Giza red, Giza 20 and Behairy red). A strip-plot design with three replicates was employed in this regard during two successive seasons (2014–2015/2015–2016). Regardless of onion type, water supply at 80% level resulted in higher marketable and total bulb yield (t/ha) with improved quality traits and storability compared to other irrigation treatments. There have been few significant interspecies differences. The most notable significant differences were recorded in Giza red and Behairy red for all studied characteristics. The highest results were reached with Giza red under the use of 80% irrigation level. In addition to the excellence in improving the overall quality and harvestable yield, this treatment (80% watering) has produced relatively good results with respect to the consumptive water-use efficiency, water productivity and showed significant benefits in terms of saving irrigation water. Maximum water saving was obtained under the use of 70% irrigation treatment, but in the absence of a good and economically unacceptable yield. The traditional technique (100% water supply) consumed much water, surpassing the most effective treatment (80%) by 1195.77 cubic meter per hectare (i.e., 11.96 cm in depth/height). In conclusion, cut-off irrigation technique is considered an efficient and effective intervention approach for onion yield increases while maintaining post-harvesting quality and water savings. However, extending the study beyond onion is critical to increase the range of benefit with regard to other crops, as well for adequate management of water under deficit irrigation conditions.

Responses of native and invasive woody seedlings to combined competition and drought are species-specific.

Woody species invasions are a major threat to native communities with intensified consequences during increased periods of summer drought as predicted for the future. Competition for growth-limiting nitrogen (N) between native and invasive tree species might represent a key mechanism underlying the invasion process, because soil water availability and N acquisition of plants are closely linked. To study whether the traits of invasive species provide an advantage over natives in Central Europe in the competition for N under drought, we conducted a greenhouse experiment. We analyzed the responses of three native (i.e., Fagus sylvatica L., Quercus robur L. and Pinus sylvestris L.) and two invasive woody species (i.e., Prunus serotina Ehrh. and Robinia pseudoacacia L.) to competition in terms of their organic and inorganic N acquisition, as well as allocation of N to N pools in the leaves and fine roots. In our study, competition resulted in reduced growth and changes in internal N pools in both native and invasive species mediated by the physiological characteristics of the target species, the competitor, as well as soil water supply. Nitrogen acquisition, however, was not affected by competition indicating that changes in growth and N pools were rather linked to the remobilization of stored N. Drought led to reduced N acquisition, growth and total soluble protein-N levels, while total soluble amino acid-N levels increased, most likely as osmoprotectants as an adaptation to the reduced water supply. Generally, the consequences of drought were enhanced with competition across all species. Comparing the invasive competitors, P. serotina was a greater threat to the native species than R. pseudoacacia. Furthermore, deciduous and coniferous native species affected the invasives differently, with the species-specific responses being mediated by soil water supply.

Practical Implications of Different Phenotypic and Molecular Responses of Evergreen Conifer and Broadleaf Deciduous Forest Tree Species to Regulated Water Deficit in a Container Nursery

Recent climatic changes have resulted in an increased frequency and prolonged periods of drought and strained water resources affecting plant production. We explored the possibility of reducing irrigation in a container nursery and studied the growth responses of seedlings of four economically important forest trees: broadleaf deciduous angiosperms Fagus sylvatica L., Quercus petraea (Matt.) Liebl., and evergreen conifers Abies alba Mill. and Pinus sylvestris L. We also studied markers of water stress including modifications of biomass allocation, leaf anatomy, proline accumulation, and expression of selected genes. Growth of the broadleaved deciduous species was more sensitive to the reduced water supply than that of conifers. Remarkably, growth of the shade tolerant Abies was not affected. Adjustment of biomass allocations was strongest in P. sylvestris, with a remarkable increase in allocation to roots. In response to water deficit both deciduous species accumulated proline in leaves and produced leaves with shorter palisade cells, reduced vascular tissues, and smaller conduit diameters. These responses did not occur in conifers. Relative transcript abundance of a gene encoding the Zn-finger protein in Q. petraea and a gene encoding the pore calcium channel protein 1 in A. alba increased as water deficit increased. Our study shows major differences between functional groups in response to irrigation, with seedlings of evergreen conifers having higher tolerance than the deciduous species. This suggests that major water savings could be achieved by adjusting irrigation regime to functional group or species requirements.

A multiregional input–output optimization model to assess impacts of water supply disruptions under climate change on the Great Lakes economy

This paper presents a water-restricted multi-regional input–output model to evaluate the economic impacts of water supply reductions in the Canadian Great Lakes Basin (GLB), one of the largest freshwater reservoirs in the world. The proposed model, first of its kind applied to the GLB, aims to minimize the impact of water supply disruptions on the GLB-economy, measured by the loss of GDP. A new flexible economic optimization procedure is introduced, capable of imposing resource constraints and ensuring minimal supply levels for intermediate and final consumption at the same time. The model accounts for inter-regional trade between different lake regions. The impacts of two climate change scenarios on water security and the economy are investigated, with and without additional food and energy security restrictions. The proposed economic optimization model holds promise as a new tool for resource-restricted Input–Output analyses.

Effects of Moderately-Reduced Water Supply and Picking Time on the Chemical Composition of Pickling Cucumber (Cucumis sativus L.) in Open Field Cultivation

As climate change evokes changing precipitation patterns, the cultivation of vegetable crops in open fields might become more difficult in the future. Nowadays, many vegetable growers are already facing relatively long unprecedented precipitation-free periods. In many growing regions, irrigation is only available to a limited extent or not at all, and the cultivated plants will suffer from moderate water stress more often. Therefore, we examined the effects of moderately-reduced water supply on the chemical composition of pickling cucumber, cultivated in an open field and in a separate greenhouse trial. In the field trial, the reduced water supply treatment (RWS) provided 85–90% of the total water amount of the well-watered control treatment (CTR), applying a randomized block design with six replications comprising two consecutive weekly harvest periods. In fruits obtained by cultivation with reduced irrigation, levels of malic acid, calcium, and magnesium significantly increased, while those of phosphate, phosphorous, nitrogen, and iron decreased based on dry matter. Fresh matter-related results additionally revealed a decrease of myo-inositol and zinc, while sugars and total phenols remained unchanged. In the greenhouse experiment, the RWS obtained 60% of the irrigation amount of the CTR. Here, single cucumber compartments (exocarp, mesocarp, and endocarp) were examined. Chemical compositions changed in a similar, but more pronounced, manner as compared to the open field trial. The levels of individual, nutritionally relevant carotenoids in the peel of pickling cucumber, like lutein and β-carotene, were affected by RWS. Regarding the nutritional quality of fresh marketable cucumber fruits, malic acid, certain minerals and trace elements, as well as the carotenoids were shown to be sensitive to moderate water reduction.

Assignment of Irrigation Norms for Available Water Reserves Taking Into Account Soil Heterogeneity as a Water Saving Approach to Crop Irrigation

Water-saving irrigation regimes for crops include reducing irrigation costs by reducing water supply. However, it also affects obtaining maximum crop yields, and increasing the fertility of the land, and avoiding negative environmental consequences. Creating the optimal, most favorable, comfortable level of soil moisture is a difficult task, which is influenced by many factors. One of the approaches to the appointment of irrigation norms is to take into account the heterogeneity of the soil profile and available moisture reserves. Formulas for calculating irrigation rates for available moisture reserves allow rational use of irrigation water, minimizing losses. The calculation was carried out according to two formulas - according to A.N. Kostyakova both for available moisture reserves for the 0-60 cm layer as a whole and layers every 10 cm. The choice of the estimated year was based on the availability of a water balance deficit, defined as the difference between the water consumption E and precipitation Pe for the calculation period. As a result of calculations, the following results were obtained: taking into account the heterogeneity of the soil profile, it is possible to save from 100 to 400 m3 / ha during the growing season without loss of crop yield.

Water crisis - beyond the destruction

A major issue related to the environment, is namely the lack of water and in general the reduction of clean water supplies over time, mostly in our days due to climate change. Through the projection of scientific data, we want to raise the issue and above all to make people feel the importance of the situation. Then, under the context of awareness raising, we present suggested solutions that we have found to solve this serious problem. We also need to add our own solution for an economical method of water desalination and purification. This will reduce the feeling of water scarcity without however being a definitive solution.

Distinct evolution history of magmatic oxygen fugacity and its control on associated porphyry Cu deposits under subduction and collisional settings

Porphyry deposits occur not only in subduction zones, but also in collisional belts worldwide. The magmatic oxygen fugacity (ƒo2) is an important element for the formation of porphyry, and influences the processes in source, migration, and precipitation of Cu and other chalcophile elements. Magmatic sulphur exists mainly as sulphate () at higher oxygen fugacity, which combines with chalcophile elements (e.g., Cu, Au) as ion complexes then formed the ore‐bearing magma. In contrast, magmatic sulphur exists mainly as sulphide (S2−), sulphide will precipitate easily. A magmatic event usually involves multiple intrusive activities. These porphyries have various ƒo2 evolutions, implying that they are formed in different formation environments or dynamic mechanisms. In a subduction setting, plates begin to dehydrate and then partial melting occurs in the early stage of subduction. Following the extensive dehydration, partial melting occurs as the plate diving deeper. As a result, the later magma is more oxidative than the earlier one. While under the collisional setting, porphyritic magma is likely related to the previous arc magmatism of subduction or juvenile mantle components in the thickened lower crust. The hydrous and metalliferous fertile magma formed. Then, reduction of water supply is the possible factor that leads to the gradually decrease of ƒo2. As a result of this study, metallogenic elements are usually developed in later porphyritic magma at a subduction environment, but in the early porphyritic magma at a collisional environment. This can provide guidance for prospecting of porphyry deposits in multi‐phases of porphyritic magma districts.

A tiered stochastic framework for assessing crop yield loss risks due to water scarcity under different uncertainty levels

Agricultural production in arid and semi-arid regions is threatened by increased droughts (climate change) and groundwater depletion. Farmers increasingly must weigh the short-term economic gains from irrigation against the long-term aquifer longevity needs. Risk-based deficit irrigation is proposed to tackle this trade-off. A tiered risk assessment approach is developed to evaluate crop yield loss risks as a function of crop water supply (CWS) from irrigation and precipitation. Risk is defined as the probability of obtaining a crop yield below a pre-specified threshold. Logistic regression is used to quantify risks as a function of CWS, if the producer can specify a fixed minimum yield threshold. Distribution regression is used to develop the cumulative distribution function of the crop yield assuming heterogeneous model parameter and is useful when the producer can estimate CWS but cannot specify a minimum yield threshold. Finally, the CWS is also modeled as a stochastic variable and the crop yield risk conditioned on CWS risk is computed using the Kolmogorov axiom. The methodology is illustrated using a cotton production case-study in the Southern High Plains of Texas. Logistic regression indicated that crop yield risk was a nonlinear function of CWS. CWS corresponding to ∼80 % of the total crop water demand was enough to reach negligible crop yield risks. Heterogeneous cotton yield distribution was modeled using Box-Cox-Cole-Green function with location and scale parameters being nonlinear and linear functions of CWS respectively and a stationary shape parameter. Irrigation at lower CWS reduced the risks substantially but the risk reductions were marginal at higher CWS. The conditional distribution of crop yield risk indicated that CWS corresponding to ∼80 %–85 % of crop water demand was enough to bring down risks. The tiered risk assessment provides a rational risk-based approach to evaluate the impacts of crop water supply reductions and promote deficit irrigation practices.

Synthesizing existing frameworks to identify the potential for Managed Aquifer Recharge in a karstic and semi-arid region using GIS Multi Criteria Decision Analysis

Imbalance between water supply and demand is increasing in many parts of the world. Lack of water security is attributed to climate change, population growth and unsustainable abstraction of groundwater. Managed Aquifer Recharge (MAR) can increase groundwater recharge, facilitate higher water availability and accessibility, and hence reduce water supply deficit. This paper investigates the potential of MAR in a karstic and semi-arid region with the use of GIS Multi Criteria Decision Analysis (GIS-MCDA). While previous studies have focused on MAR techniques and MAR suitably mapping separately, this paper combines technique selection and suitability mapping to emphasize the importance of considering both. The methodology was applied for a karstic and semi-arid region, using the Ramotswa Transboundary Aquifer Area (RTAA) as case study. MAR suitability mapping of the selected MAR technique was carried out with six thematic layers using Weighted Linear Combination (WLC) decision rule. The objective was to identify suitable areas for implementation of spreading methods and generate MAR suitability maps to guide decision-making in such implementation. The suitable areas were identified at the border between Botswana and South-Africa. The study develops a methodology for GIS-MCDA considering spreading method for a karstic aquifer, but more research is needed to assess the methodological transferability to other karstic and semi-arid regions.

Alterations in the Chemical Composition of Spinach (Spinacia oleracea L.) as Provoked by Season and Moderately Limited Water Supply in Open Field Cultivation

The current use and distribution of agricultural water resources is highly prone to effects of global climate change due to shifting precipitation patterns. The production of vegetable crops in open field cultivation often requires demanding water applications, being impaired in regions where climate change will increasingly evoke water scarcity. To date, increasingly occurring precipitation-free periods are already leading to moderate water deficits during plant growth, e.g., in southern Europe. Among all vegetable crops, leafy vegetables such as spinach (Spinacia oleracea L.) are particularly vulnerable to limited water supply, because leaf expansion is highly dependent on water availability. Besides biomass production, water limitation might also affect the valuable nutritional composition of the produce. Therefore, we investigated the impact of moderately reduced water supply on the chemical composition of spinach, cultivated in the open field in three consecutive years. Two different water supply treatments, full and reduced irrigation, were used in a randomized block design consisting of three sets of six plots each. In the reduced water supply treatment, the total amount of supplied water, including both irrigation and natural precipitation, amounted to 90%, 94% and 96% in 2015, 2016 and 2017, respectively, of the full, optimal water supply treatment. Spinach grown under limited water supply showed significantly higher fresh biomass-based contents of polyols (e.g., inositol, glycerol), ascorbic acid, potassium, nitrogen, phosphorous, zinc and manganese, as well as total flavonoids and carotenoids. Increased dry biomass-based levels were found for total inositol, zinc and manganese, as well as decreased levels for malic acid, fumaric acid, phosphate and chloride. Furthermore, we report a high seasonal variation of several minor phytochemicals, such as single flavonoids. Spinacetin derivatives, spinatoside-glucoside as well as a rather unusual hexuronylated methylenedioxy flavonoid showed highest amounts when grown under relatively low irradiation in autumn. Levels of patuletin derivatives tended to increase under high irradiation conditions during spring. In summary, the chemical composition of spinach was shown to be highly sensitive to moderately reduced water supply and seasonal variation, but the overall nutritional quality of fresh marketable spinach was only marginally affected when considering health-related constituents such as minerals, trace elements, flavonoids and carotenoids.

Economics of irrigation water conservation: Dynamic optimization for consumption and investment

Measures to protect irrigation water supplies for food security continue to receive international attention to address growing water scarcity when faced by increased food demands combined with reduced water supply reliability. Yet, a common problem where water is delivered with earthen canals is delivery inefficiency combined with low economic values per unit of water. In many of the world's arid regions, climate stressed water shortages have raised the importance of discovering measures to improve irrigation delivery efficiency. However, little research grade work to date has presented an integrated analysis of the economic performance of irrigation delivery improvements faced by drought and climate stressed regions. This paper's unique contribution is to investigate the economic performance of water conservation infrastructure combined with dynamically optimized use of saved water. We develop a state-of-the arts empirical dynamic optimization model to discover land and water use patterns that optimize sustained farm income. Results from the upper watershed irrigation region of the Canadian Basin in the southwestern US show that canal and delivery system lining can raise the sustained economic value of water for crop irrigation. The saved water can see immediate use in dry years. It can also be stored in wet years to mitigate the most adverse impacts of future climate water stress. This double dividend is especially important in rain-fed watersheds for which surface water supplies for irrigation are difficult to forecast accurately. Findings light a path for water managers and other stakeholders who bear responsibility of finding economically responsible measures to improve irrigation water productivity in the world's dry regions.

Beltéri saláta termesztés lehetőségének vizsgálata természetes erdőtalajon limitált öntözéssel

Indoor farming in the global vertical farming market has been growing by more than 8% annually since 2010 and 31.6% growth is expected by 2025. It promises to be a possible future form of agricultural practices producing local, fresh, high quality, lower-carbon food year-round. Indoor farming experiment was designed to using LED and neon lights and water source of a dehumidifier. Lettuce (Lactuca sativa L. var. capitata) was grown for 12 weeks in a naturally available forest surface soil, including its native biodiversity and biological activity. Two different levels of water supply were used, full- at 66%- and half- at 33% of the total water-holding capacity (WHC100%) of soil. Some of the physical-chemical, and soil-biological parameters, such as dehydrogenase- (DHA) and fluorescein diacetate (FDA) enzyme activities and the most probable number (MPN) of fungi and bacteria were assessed prior to and after lettuce cultivation. Although the abundance of countable microorganisms decreased appreciably by the end of the lettuce experiment, the growth of plants could result in an enhanced soil-biological enzyme activity of the used natural soil. DHA increased 4.2-fold at drought condition, and 2-fold at the optimal water supply. One can conclude that used natural forest soil with great fertility and biodiversity potential can provide a good facility for the indoor lettuce cultivation. Reduction of water supply can be further optimized with the required biomass-production of lettuce.

模拟喀斯特不同土壤生境下黑麦草对水分胁迫的生长和光合生理响应

PDF HTML阅读 XML下载 导出引用 引用提醒 模拟喀斯特不同土壤生境下黑麦草对水分胁迫的生长和光合生理响应 DOI: 10.5846/stxb201812052660 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31500399） Growth and photosynthetic physiological responses of Lolium perenne L. to water stress in the simulated karst soil habitats Author: Affiliation: Fund Project: China Postdoctoral Science Foundation 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以多年生草本黑麦草为对象，模拟喀斯特生境土壤特征设置浅而宽（Shallow and wide，SW：30×30×5 cm3）和深而窄（Deep and narrow，DN：10×10×45 cm3）两种土壤容器，以正常降水量为对照供水（W100%），设减水50%（W50%）和减水70%（W30%）共3种水分处理进行盆栽实验，探究了两种不同土壤生境中土壤水分变化对黑麦草生长及光合生理的影响，以进一步理解喀斯特地区植物的适应对策。结果显示：（1） SW生境对水分变化敏感，随供水减少土壤含水量显著下降。轻度减水下植物叶面积增大，光合速率提高，地上部分生长得到促进，但水分严重减少对其生长和光合生理有抑制作用，但地上质量分数和水分利用效率却显著升高；（2） DN生境保水能力较好，随供水减少土壤水分含量下降较为平缓。叶片相对含水量、气孔导度和比叶面积在各水分处理之间差异不显著，但严重减水条件下总生物量、地上质量分数和水分利用效率均有回升。研究表明：浅而宽生境中植物倾向于通过提高地上部分的生长，保持较高的光合速率，并向地上部分分配较多生物量来应对水分胁迫；而深而窄生境中植物会充分利用土壤空间条件，促进根系的生长来提高对水分的吸收，从而维持植物的生长。 Abstract:In karst area, the soil thickness is uneven and the soil habitats are highly heterogeneous. Shallow soil habitats with shallow wide soil are formed on hilly slopes and deep soil habitats with deep narrow soil are formed in the rock trenches. Availabilities of underground space and soil moisture are different in different habitats. The previous studies have focused on the ecological effects of soil thickness changes. However, the underground space is also very important for plant growth, even exceeding soil resources. Therefore, studying the effects of soil thickness on plants must consider the important roles of soil moisture and soil space. In this experiment, we used the perennial grass Lolium perenne L. as plant material. Simulating the soil characteristics in karst habitats, we set two kinds of soil containers including shallow and wide (SW:30×30×5 cm3) and deep and narrow (DN:10×10×45 cm3). Taking average daily precipitation in Chongqing for the past 30 years as the control water, three water treatments were control group (normal water conditions, W100%), mild water reduction (50% reduction, W50%), and heavy water reduction (70% reduction, W30%), respectively. The effects of soil moisture changes on the aboveground growth and photosynthetic physiology of L. perenne in two different soil habitats were explored to further understand the adaptation strategies of plants in karst area. The main results were as follows:(1) The SW habitats were sensitive to soil water changes, and soil water content in which decreased significantly with decreasing water application. Under mild water reduction, the growth of aboveground parts was promoted, mainly in the increase of leaf area and photosynthetic rate. However, the growth and photosynthetic physiology were inhibited under heavy water reduction, while the aboveground mass fraction and water use efficiency increased significantly. (2) The DN habitats had better water retention capacity, in which the soil water content decreased slowly with the water supply reduction. The relative leaf water content, stomatal conductance, and specific leaf area were not significantly different among three water treatments. However, the total biomass, the aboveground mass fraction, and plant water use efficiency all rebounded under heavy water reduction. Overall, the results suggested that plants in shallow and wide habitats tended to maintain higher photosynthetic rate by increasing the growth of aboveground parts, and distributing more biomass in the aboveground parts to cope with water stress; while plants in deep and narrow habitats sufficiently used soil space to promote root growth to increase water uptake for maintaining plants growth. 参考文献 相似文献 引证文献

Factors affecting on the adoption of recommended agriculture practices in drought affected farmers in Raichur District of Karnataka

Among the effects of climate change, drought is a higher risk dominant impinging factor of crop production. As the outcome of the effect reduced cropping area, reduced rice production, reduced water supply for agricultural activities were witnessed in the district. To mitigate the effect of drought on farming various technology practices were recommended to farmers to adopt. Technology practices as a whole level of adoption was moderate to high only in medium-to-large farm holders of both the groups of respondents. However the level of adoption found same between the respondents who have participated in the extension activities against who haven't participated in the same. It was observed that the regression coefficient of education (B=.020**) participation in extension activities (B=.077*) found significant in irrigated respondents. Whereas cultivable farm holding (B =.047***) membership in the social organisation (B=.103**), participation in extension activities (B =.171**) average gross annual family income of the respondents was found to be significant (B= -1.379E-006*) in rainfed respondents group. There is an urgency to analyse the efficiency of information dissemination system Based on the results programmes have to be formulated. The effectiveness of agricultural training should be evaluated and it should be taken up by the external agencies for the effective implementation of the technologies.

Risk Perceptions and Adaptation to Climate Change and Sea-Level Rise: Insights from General Public Opinion Survey in Florida

The Everglades is a unique ecosystem in Florida that offers a variety of ecosystem services (ES), including water supply and flood risk reduction, water purification, habitats for several endemic species, and recreational opportunities. Therefore, the ramifications of climate change, an imminent threat to the Everglades ecosystem, are going to affect these ecosystem services drastically. The climate-induced changes to the ecosystem services are going to affect people’s lives and livelihoods in the region. Thus, understanding public perception and preferences is an important step in addressing the impending risk. In this study, we used an online survey to assess residents’ perceptions about the risk of climate change and their views on mitigating potential consequences. We find that people’s perceptions and preferences are shaped by their level of education, age, participation in outdoor recreational activities, and elevation and distance from the shoreline of their residential location from the mean sea-level. In general, people who are concerned about the flooding risk and people who tend to prioritize environmental conservation are more likely to agree with the potential impacts of climate change and sea-level rise and more likely to support proposed measures for adaptation. We discuss the policy implications for developing socially acceptable plans based on the findings regarding people’s perception and preferences for adaptation in this region.

An analysis of unmet water demand under climate change scenarios in the Gualí River Basin, Colombia, through the implementation of Hydro-BID and WEAP hydrological modeling tools

Abstract Climate change can affect hydrological services in Andean basins, so a possible reduction in water supply can lead to not meeting the needs of different users, which has become a real challenge for decision-makers with regards to water management. This paper presents the results obtained from hydrological modeling exercises in the Gualí River Basin (Colombia) by combining the Hydro-BID modeling tool, which consists of an analytical hydrology database for Latin America and the Caribbean that provides a great advantage for countries with limited information and the Water Evaluation and Planning System (WEAP) modeling tool, in order to determine the potential impacts of climate change on unsatisfied demand for water in the basin. The results show a possible decrease in flow compared to current conditions; between 5.8% and 9.56% for CPR 2.6, and between 2.18% and 6.86% for CPR 8.5. The approach presented is useful to ensure that timely decisions are made to meet the demands of users under the conditions of climate change.

The effect of biochar amendment on the growth, morphology and physiology of Quercus castaneifolia seedlings under water-deficit stress

Water stress is one of the most important environmental stresses which can adversely affect soil fertility and plant growth in arid and semiarid regions. In this study, biochar was used as a type of soil amendment to improve the physiology of Chestnut-leaved oak (Quercus castaneifolia C.A.M.) seedlings and soil quality in water-deficit conditions. A randomized complete block design was conducted using three water regime treatments [100, 70 and 40% field capacity (FC)] and four application rates of produced biochar from hornbeam wood chips (control without biochar, B1, B2 and B3 with 10, 20 and 30 g kg−1 soil, respectively) in potted seedlings. The soil water-holding capacity in the 30 g kg−1 biochar was found to be higher than that in the non-biochar treatment under 100 and 40% FC. Water supply reduction to 40% FC decreased the soil total N, the available P and K, CEC, SOC and microbial respiration, as compared to the non-biochar soil used as the control; however, an increase in the B3 treatment was detected in the soil P and K at 100% FC. Severe water deficit (40% FC) induced a significant decrease in photosynthesis, transpiration, stomatal conductance and xylem water potential seedlings; even, in this case, the addition of the highest dose of biochar under the lowest water supply increased photosynthesis and stomatal conductance by 38% and 39%, respectively. Leaf nutrient concentration was also influenced by the treatment. The highest diameter and height growth and dry weight of the seedlings were observed in 100 and 40% FC under the B3 treatment. Plant biomass of the seedlings treated by B3 was increased by 55, 70 and 73%, in comparison with those attained by the control under 100, 70 and 40% FC irrigation, respectively. Generally, the use of the 30 g kg−1 biochar in the soil could alleviate the negative effects of water deficit and improve the growth of Q. castaneifolia seedling and soil quality with increasing the soil water-holding capacity, organic carbon and nutrient.

Long-term impact of deficit irrigation on the physiology and growth of grapevine cv. ‘Prima’ grafted on various rootstocks

Testing the globally popular grapevine rootstocks for affinity with new grape cultivars or tolerance potential to stress factors like drought is essential for districts where supplemental irrigation is more frequently needed due to the pressures of a global climate change. In this study, a seasonal evaluation of leaf gas exchange, leaf temperature, leaf greenness (chlorophyll content prediction) and vegetative development of Vitis vinifera L. cv. ‘Prima’ grafted to different rootstock genotypes having great variability in drought tolerance, were investigated. The experiment was conducted in a controlled experimental glasshouse on two-year-old soilless grown ‘Prima’ vines grafted on nine rootstocks [44-53 M, 5 BB, 140 Ru, Ramsey (Syn. Salt Creek), 99 R, Saint George (Syn. Rupestris du Lot), 41 B, 1613 C and 420 A]. A long-term deficit irrigation (DI) was imposed before bud break by reducing water supply to 40% of field capacity derived from concurrent measurements of water content of growth medium and maintained until the end of vegetation period. The rootstocks significantly modulated the physiology and vegetative growth of the scion cultivar in varying degrees according to their genetic features. Among them, 140 Ru rootstock found to be more prominent in terms of mitigating the adverse effect of water deficit on physiology and growth of the scion genotype ‘Prima’ as there were no significant difference between deficit and full irrigation treatments for most of parameters investigated. In general, the ‘Prima’ scion performed better when the rootstocks coming from V. berlandieri × V. rupestris pedigree rather than the others including V. berlendieri × V. riparia.

Long-term water-sediment multi-objectives regulation of cascade reservoirs: A case study in the Upper Yellow River, China

Water-sediment regulation (WSR) is an effective non-engineering measure to alleviate the problem of suspended river and bring benefit to flood control security in sediment-laden river. However, WSR may decrease the socio-economic benefit of reservoirs, for example, reduction of hydropower production and water supply. In order to satisfy the practical requirement of WSR and other utilization objectives, this paper presents a multi-objective operation model for a cascade reservoirs simultaneously considering the maximization water volume for WSR and power generation and water supply, as well as various complex constraints. Then, the Non-dominated Sorting Genetic Algorithm (NSGA-II) is improved to solve the aforementioned model and key control indicators of WSR are analyzed. Meanwhile, a sediment transport model has been introduced to quantify the effect of WSR. The models are applied to the cascade reservoirs in the Upper Yellow River. The following conclusion can be drawn from results (1) Pareto fronts of the model solution demonstrate a strong competition between WSR and water supply, water supply and power generation, a low sensitivity between WSR and power generation; (2) the ability of WSR in Upper Yellow River is 6 times in 24 years, which means the frequency of WSR is four years averagely; (3) 233.77 million tons of sediments are transported by long-term WSR in the Ningxia-Inner Mongolia reaches, account for 19.10% of sediment deposition; (4) the risk-free conditions of LYX and LJX reservoirs’ water volume for WSR are 137.42 × 108 m3 and 41.08 × 108 m3, respectively, which could be used as a reference in actual operation. The research results have an important practical significance and application for sediment control and governance of suspended river, and the multi-objective operation model of WSR proposed in this study can be effectively and suitably used in sediment regulation with similar conditions.