Synergistic development path of conventional and unconventional water in China: From the perspectives of output and substitution elasticities

An integrated adaptive allocation model for unified optimization of conventional and unconventional water resources based on fairness and efficiency

How to optimize the allocation of research resources? An empirical study based on output and substitution elasticities of universities in Chinese provincial level

Synergetic conservation of water and energy in China's industrial sector: From the perspectives of output and substitution elasticities

Papaya (Carica papaya L.) is essential for food security, providing economic benefits in tropical and subtropical regions. However, its high water requirements pose challenges, especially in water-scarce areas like Cape Verde. This study hypothesises that reclaimed water (RW) irrigation can promote papaya production and investigates how water can be managed to ensure sustainability and increase agricultural productivity. An experiment was conducted using Carica papaya L. var Solo-nº8, focusing on subsurface drip irrigation (SDI) with RW. Three irrigation treatments were compared, namely, T1: RW with SDI; T2: RW with drip irrigation (DI); and T3: conventional water (CW) with SDI. The study evaluated crop yields and water use efficiency (WUE) over 13 months, monitoring soil and water quality and papaya growth and yields. Despite quality concerns, RW maintained soil fertility and ensured sustainable reuse. Papaya demonstrated high adaptability and productivity under experimental conditions. T1 significantly increased the cumulative fruit yield (69 t/ha) compared to T2 (65 t/ha) and T3 (62.7 t/ha). T1 also had the highest WUE (5.97 kg/m3), demonstrating the effectiveness of RW and SDI in optimising water use. The results indicate that RW can be a viable alternative to conventional water sources, providing new insights into sustainable agricultural practices and improving food security in arid and semi-arid regions.

Cape Verde is a semiarid country where lack of rainfall exacerbates the scarce resources available for livestock which, therefore, make it very vulnerable to climate change. By providing reclaimed water (RW) for irrigation, it is possible to decrease forage importation. Subsurface drip irrigation (SDI) improves health security by preventing contact between water and harvested plants. Sorghum is a water-efficient crop that provides good nutritional value. The aim of this experiment was to study the nutrient and fiber contents of the Sorghum Payenne variety using subsurface (T1) and surface (T2) drip irrigation by RW vs. conventional water (T3) and plant maturity to assure the feasibility of water reuse to produce forage. Ntot–Ptot–Ca–Mg and Na were significantly higher in the RW plants than in the conventional water ones. Ntot–Ptot–K and Fe contents significantly lowered, while Ca–Na and Mn significantly rose as plant maturity increased. All the fiber values meet the Nos. 2 and 3 quality standards, and the Prime and No. 1 for NDF and ADF, respectively. The obtained good forage quality let to avoid the competence of conventional water and to reuse nutrients added by RW. If generalized, this solution would reduce forage importation by improving food sovereignty and farmers’ profitability, and would enhance resilience against climate change effects.

This chapter outlines the potential and role that underground low quality water and non conventional water (recycled grey water, desalinated and domestic effluent water), have and can play in the preparation of drought mitigation plans especially in relation to the satisfaction of the domestic water supply needs. Low quality underground water, if available in aquifers within the city or village perimeters, can replace 34–42% of the good quality total domestic supply, which can be used in toilet flushing and for the irrigation of gardens. Similarly grey water discharged within the domestic effluents, which may vary from 36–41% of the total supply of an average household, after collection within the household perimeter can be treated and recycled to the system thus saving a percentage equal to 36–41% of the total domestic water consumption. The low quality water abstracted from the aquifers and the grey water discharged with the household waste can be developed and made available for use within a very short time on an individual basis, the water can be used without serious problems, the capital costs involved are relatively small (can be subsidized by the government), and can be repaid within 3–4 years with the savings made from the savings of potable water. The recycled domestic effluents, whose quality is improved with tertiary treatment is suitable for the irrigation of almost all plants (Roumagnac 1995), is a very effective method of drought mitigation (Smith and Bernard, 1995) but this usually takes a long time to materialize, 5–10 years, but the farmers already using good quality natural water will rarely accept to use it, claiming its unsuitability for irrigation. Finally desalinated water from seawater or from brackish water increases the water availability, water quality is not a problem and it can be made available within very short time. The limitations/objections for using the desalinated water are emanating from its relatively higher marginal cost than the existing supplies and the alleged adverse environmental impacts.

A stochastic frontier approach (SFA) model of translog production function was constructed to analyze the growth effect of agricultural production factors on grain production in China. Under the condition of unchanged cultivated land, the agricultural labor, capital, and water were regarded as input elements of the agricultural production function. The maximum likelihood estimation (MLE) method was used to analyze the technical efficiency, output elasticity, substitution elasticity, and relative variability of grain production in China from 2004 to 2018. The results showed that: (1) For the technical efficiency and output elasticity of the input factors of grain production, there were significant differences in different provinces. For example, the water resource was insufficient in Beijing and Shanghai, but the output elasticity of water was high. Heilongjiang was rich in water and had high technical efficiency. For Xinjiang, water was sufficient, but its output elasticity was deficient and the technical efficiency didn’t increase. (2) The overall technical efficiency level was relatively low and was still declining year by year; the output elasticity of water was much greater than that of capital. There was still great potential for grain growth. (3) Optimizing resource allocation and controlling the appropriate ratio of input factors to develop grain production could achieve the maximum benefits. Finally, according to the empirical results, this paper put forward some practical policy suggestions for optimizing the allocation of input factors, especially water and capital, which can ultimately improve agricultural productivity by improving technical efficiency.

Overview of African water resources contamination by contaminants of emerging concern

The water sustainability of the Segura River Basin (SRB), located in southeastern Spain, is being challenged as conventional available water sources fall short of meeting the authorised demands of the basin. In recent years, non-conventional water (NCW), such as desalinated and reclaimed water, has become part of the resource pool. However, it has not yet become crucial for irrigation water supply due to its relatively high cost and lower quality compared to conventional water. The new political framework in Spain, developed in the context of ecological transition, marks a notable shift for non-conventional water as a strategic resource for agriculture. This study examines the drivers and barriers influencing its acceptance through an analysis of farmers’ perceptions, conducted through interviews with twelve irrigation communities’ (ICs) representatives of the basin. Discriminant analyses of the data show that the farmers’ experience, along with factors pertaining to production, storage, and transportation costs, determines the acceptance and use of NCW.

Coordinated allocation of conventional and unconventional water resources considering uncertainty and different stakeholders

Under thhe drought conditions that have occurred in Bulgaria during the last decade, agricultural use of non-conventional water may be an important resource. This is a specific case of simultaneous purification and utilisation by soil ecological systems. However, using non-conventional quality water presents a number of ecological and health risks and poses problems connected with soil and surface and ground water contaminated and with producing crops of acceptable quality. Bulgaria's municipal, industrial, and rural wastewater reclamation and reuse, in addition to other non conventional water resources as sea water, drainage water and mineralised groundwater, may be a reliable source even in drought years and thus is capable of replacing potable used in agriculture. This paper reviews the work of the authors and their colleagues in assessing the irrigation potentials of waste water in Bulgaria.

On Nigeria's renewable energy program: Examining the effectiveness, substitution potential, and the impact on national output

Pakistan’s economy is mainly dependent on textile industry. Textile manufacturers and policy makers are giving priority to improve production efficiency in the textile industry. To compete with rival firms, production efficiency appeared more important than before. This study has analysed the production efficiency of textile manufacturing and exporting firms in Pakistan. The data from annual reports of limited companies registered on the stock exchanges of Pakistan has been used. Cobb-Douglas (half - normal) Stochastic Frontier output model and MLE technique have been applied. Empirical results demonstrate that on average, during the 2016-17, the variable “Cost of material” has the highest elasticity of output (0.719) while the variable “Salaries and wages” has the second larger elasticity of output (0.154). The third input (Energy charges) has elasticity of output 0.096, and the fourth input (Value of operating fixed asset) has the lowest elasticity of output (0.039). The level of production efficiency of the firms in Pakistan ranged from 66.5 percent to 96.73 percent with a mean 89.55 percent during the year. The average estimated value of “” indicated that majority (approximately 71.95%) of the variations in the firms’ output were due to difference in technical inefficiency (ui) and small (28.05 %) variations were due to random error (vi). Keywords: Textile Manufacturing and Exporting Firms, Technical Efficiency, Stochastic Frontier Output, MLE Technique, Cobb-Douglas Production Function.

Halophytes are capable of coping with excessive NaCl in their tissues, although some species may differ in their degree of salt tolerance. In addition, it is not clear whether they can tolerate other confounding factors and impurities associated with non-conventional waters. The experiment was performed in a greenhouse with Crithmum maritimum and Atriplex halimus plants, growing on soil and irrigated with two different water types: reclaimed wastewater (RWW) (EC: 0.8–1.2 dS m−1) and reverse osmosis brine (ROB) (EC: 4.7–7.9 dS m−1). Both species showed different physiological and nutritional responses, when they were irrigated with ROB. Atriplex plants reduced leaf water potential and maintained leaf turgor as consequence of an osmotic adjustment process. Atriplex showed higher intrinsic water use efficiency than Crithmum, regardless of the type of water used. In Crithmum, the water status and photosynthetic efficiency were similar in both treatments. Crithmum presented a higher leaf accumulation of B and Ca ions, while Atriplex a higher amount of K, Mg, Na and Zn. Crithmum plants irrigated with ROB presented higher concentrations of 1-aminocyclopropane-1-carboxylic acid and trans-zeatin-glucoside, whereas abscisic acid concentration was lower. Atriplex showed a lower concentration of trans-zeatin-riboside and scopoletin. The characteristics associated to water irrigation did not influence negatively the development of any of these species, which confirms the use of brine as an alternative to irrigate them with conventional waters.

Middle Eastern countries (ME) are expected to face severe water shortages in the near future. As most conventional water resources are already developed or over exploited, there is a need to develop non-conventional options to bridge water shortages. These options include brackish and sea-water desalination and fresh water imports from outside the region either by sea or land. Technically, non-conventional options are possible and feasible, however, depending on many factors, these options are available at a high capital investment with different costs and are associated with some environmental and ecological impacts and political considerations. Water and other conflicts in the region along with funding problems are the main obstacles to the implementation of such options in the ME. Integrating conventional and non-conventional water development options are found to be a more viable combination on the long term. Cooperation between ME countries is found to be a key factor to overcoming water shortage using non-conventional options. Therefore, it is concluded that non-conventional water options should be encouraged in the region and should be utilized to overcome not only water shortages but also to resolve conflicts and restore economic growth, peace, and stability among regional parties and people.