Total Water Use Research Articles

Water gain and water loss of some freshwater aquaculture ponds at Kausalyaganga, Orissa, India

Hydrological data were collected from the six ponds of 0.05 ha size in the farm of the Central Institute of Freshwater Aquaculture, Bhubaneswar, India. Data on rainfall, run-off, evaporation, and seepage were collected from these ponds for the years 2013 and 2014. The rainfall was 175 ± 3.0 and 202 ± 5.0 cm in 2013 and 2014, respectively. The run-off was 36 ± 1.2 and 29 ± 1.0 cm, in these ponds, in 2013 and 2014, respectively. Average evaporation was 0.30 cm/d in 2013 and 0.37 cm/d in 2014. The average seepage was 0.22 cm/d in both the years. The loss from the evaporation and seepage could be compensated through the regulated inflow of groundwater from wells/canals. The total amount of well/canal water in an average year to compensate the water loss through evaporation and seepage was calculated and for the 1.0 ha pond, 9800 ± 200 m3 of water in 2013 and 13,700 ± 300 m3 of water in 2014. Accordingly, the harvested water could be 12,000 ± 200 m3 in 2013 and 15,000 ± 300 m3 in 2014, respectively. The consumptive water use was 3.15 ± 0.3 m3/kg fish and 3.35 ± 0.2 m3/kg fish in 2013 and 2014, respectively. The total water use in these embankment ponds was 5.15 ± 0.5 m3/kg fish and 5.66 ± 0.6 m3/kg fish in 2013 and 2014, respectively.

EFFECT OF POULTRY MANURES AND WATER STRESS ON GROWTH AND YIELD OF POTATOES SOLANUM TUBEROSUM L. IN GYPSIFEROUS AND SANDY SOIL

A pot experiment was conducted in the fall season of 2017 in Falluja – Anbar Province to study the effect of poultry manure and water stress on growth and yield of potatoes in gypsiferous (Loam) and sandy soil (Loamy sand). Poultry manure was added to soils in two levels (0 and 2 %) , and irrigation was done after depletion of 40% and 60% of the available water. Traits like plant height, leaf area, root mass and total yield and water use efficiency was measured.Values of plant growth were superior for in gypsiferous soil compared to them in sandy soil where highest value of plant height reached 87 cm and leaf area reached value of 69 cm2 plant-1, while root mass value was superior for plants in sandy soil 13.2 gm plant-1 compared to gypsum soil 9.5 gm plant-1.Poultry manures caused a significant increase of growth traits of potato where plant height increased by 44.44 %, leaf area increased by 28.46% , while root mass decreased by 33% in gypsiferous soil .Growth traits values significantly reduced at irrigation at moisture depletion of 60% compared to the irrigation at 40% depletion . Total yield of potato was 34.010 ton ha-1 in sandy soil and 28.020 ton ha-1 in gypsiferous soil, application poultry manures increased total yield significantly as the increasing percentage reached 20.7% in sandy soil and 30.0% in gypsiferous soil. Total yield values decreased as moisture depletion increased from 40% to 60% with reduction percent of 28.8% in sandy soil and 25.7% in gypsiferous soil. Sandy soil had the best water use efficiency reached 21.950 kg m-3 compared to 21.273 kg m-3 in gypsiferous soil .

Influence of Wheat Establishment Techniques and Previous Kharif Season Crops on Productivity, Profitability, Water Use Efficiency, Energy Indices and Soil Properties in Central India

A three-year field study was conducted to explore the efficacy of wheat (Triticum aestivum) crop establishment techniques comprising conventional tillage (CT), minimum tillage (MT), zero tillage (ZT) and broad bed furrow (BBF) after harvest of kharif (rainy) season crops of paddy (Oryza sativa), pigeon pea (Cajanus cajan), pearl millet (Pennisetum glaucam) and cluster bean (Cyamopsis tetragonoloba). Pooled data showed that yield attributing characters and grain yield of wheat were significantly higher which was recorded under BBF followed by ZT, CT ≈ MT. Likewise significantly, higher grain yield was recorded after harvest of pigeon pea followed by pearl millet, paddy and cluster bean, respectively. Grain yield of wheat grown after previous kharif season crops was significantly higher under BBF after harvest of paddy, pigeon pea and pearl millet, whereas ZT proved to be better after harvest of cluster bean. The study revealed that BBF method saved maximum of US$ 101 ha−1 followed by ZT (US$ 76 ha−1) and MT (US$ 43 ha−1) as compared with total cost of production under CT (US$ 497 ha−1). Net return was higher by 199 US$ ha−1 with BBF and US$ 156 ha−1 with ZT compared with CT (US$ 844 ha−1). Total water use by wheat was higher after cluster bean (38.6 cm) and least after paddy (35.7 cm). Total water use by wheat establishment techniques was 10.6 cm and 2.7 cm higher under CT compared with BBF and ZT, respectively. The delayed establishment of wheat after CT required more energy, while timely sown crop needed less energy and produced more energy, use efficiency and productivity of energy. After harvest of third crop of wheat, physicochemical properties significantly improved sown after pigeon pea compared to other kharif season crops. The overall improvement of physicochemical properties under BBF followed by ZT compared with MT and CT.

Water Use Dynamics in Double Cropping of Rainfed Upland Rice and Irrigated Melons Produced Under Drought‐Prone Tropical Conditions

AbstractAgricultural expansion and intensification is occurring in seasonally dry regions of Central America, while droughts are intensifying due to increasing water demand and climatic change. Empirical measurements of water consumption of major crops in this region are scarce but crucial to assess agricultural water use dynamics in the light of increasing regional water conflicts. We empirically quantify total crop water use (CWU) and water footprints (WFs) of rainfed upland rice (wet season) and groundwater‐irrigated melons (dry season) grown sequentially as a double cropping system, one of the major cropping systems in the seasonally dry province of Guanacaste in northwestern Costa Rica. Data for this study cover 2 years and were measured with a state‐of‐the‐art eddy covariance water and carbon flux station. Upland rice only consumed green water (CWUgreen = 383 L/m2), while melons only consumed blue water (CWUblue = 177 L/m2). Irrigation was found to be 1.5 times larger than the actual melon water consumption, with better irrigation efficiencies than reported for melon farms in Brazil but slightly inferior to farms in Spain. Melon WFblue was 79 m3/t, a much lower value than global and regional estimates reported but similar to values reported for melons produced in Brazil or Spain. Upland rice WFgreen (681 m3/t) was reported for the first time and was proven to be much lower than flood irrigated‐rice WFblue‐green. Our results demonstrated lower overall water demand for upland rice‐melon double crop compared to the two other major monocultures of the region (flood‐irrigated rice and irrigated sugar cane).

Decomposing the Driving Factors of Water Use in China

Based on the national input–output table, a comparable price non-competitive input–output table was compiled for 2002, 2007, and 2012. The influence factors of price and product imports were removed from the table. Furthermore, a water-use input–output table was constructed based on the links between the economic system and water resources management. With the multi-factor structural decomposition analysis (SDA) model developed in this paper, the driving forces of water use were decomposed into 18 factors, and quantitative effect results were obtained. Total water use in China increased by 3.9% from 2002 to 2007 and by 5.4% from 2007 to 2012 with the combined effects of multiple factors. For example, the increase in economic scale raised water use by 46.6% and 45.5%, respectively. Advancement in agricultural technology (production and water-saving technologies) reduced water use by 14.9% and 19.8%, respectively. Reducing the proportion of thermal/nuclear power and increasing the price of electricity have water use-reducing effects. Changes in the mode of development considerably reduced water use by 9.5% and 5.3%, respectively. Water-use management should focus on factors that have great influence on water use and show high water-use sensitivity.

Assessing Economic Changes Due to an Expanding Dairy Industry in the Texas High Plains

AbstractThe dairy industry in the Texas High Plains has experienced rapid expansion in the past two decades. This study assesses the impact of the increased presence of dairies on overall water use, crop composition, and the local economy. The increase in water use related to the dairy industry from 2000 to 2015 was primarily due to an increase in demand for drinking by the cows (direct water) as well as an increased demand for silage (indirect water). However, a comparative analysis (dairy presence vs. no dairy presence) from a single year indicates minimal impacts on total water use due to dairies. During the same time period, the number, size, and employment of related local business establishments have increased economic activity in rural areas. Editor's note: This paper is part of the featured series on Optimizing Ogallala Aquifer Water Use to Sustain Food Systems. See the February 2019 issue for the introduction and background to the series.

Effect of fertilization on water use and yield of hops in mature hop plantation

The effect of decreasing nutrient availability on the ecophysiology and production of hop cones was studied in a plantation of cultivar 'Premiant', in Žatec hop growing region, Czech Republic. The plantation used to be fertilized by 60 t of manure ha(-1) year(-1) until November 2011 when it was discontinued as a part of the measures towards organic farming. Measurements of total evapotranspiration from the plantation using the Bowen ratio energy balance method, transpiration of hop bines by the means of sap flow, soil water and nutrient availability were conducted from 2011 to 2014. The yield of hop cones and the content of alpha acids were monitored in this period too. The concentration of total soil nitrogen (N) dropped from 19.4 mg kg(-1) in March 2012 to 8.2 mg kg(-1) in November 2014. Similarly, the content of N in leaves declined from 4.1% of dry mass in 2012 to 2.5% in 2014. The ratio between total evapotranspiration from the plantation to the potential evapotranspiration (PET) was not affected by the soil nutrient availability and did not vary among the years of study, ranging between average to 91 and 96% of PET. In the contrast to total evapotranspiration and PET, the proportion of hop transpiration on the total evapotranspiration steadily declined from 74 to 46% in 2011 and 2014, respectively. Plant regulation of stomatal conductance changed, bringing along lower stomatal aperture, especially upon the conditions of low vapor pressure deficit. In line with decline in transpiration and stomatal conductance, yield of alpha-acids declined from 204 kg ha(-1) in 2011 to 97 kg ha(-1) in 2014. To sum up, after the stop in fertilizing, total water use of the plantation remained similar as before, but the transpiration and production of alpha acids ha(-1) significantly decreased.

Increased Production of Mustard (Brassica juncea L.) with Application Capillary-Irrigation System

Increased Production of Mustard (Brassica juncea L.) with Application Capillary-Irrigation System. Application of capillary irrigation system on mustard is expected to increase the crop productivity. The aims of this study was to calculate the use of water of mustard with application capillary irrigation using wick and flanneland to determine the best combination of irrigation capillary tools of capillarity system. The design of this study used two factors and three replications. The first factor was wick materials (S), consistings two level: the flannel wick (S1), and stove wick (S2). The second factor was the dosage sawdust (M), consists two level: 0 % of sawdust (M1), and 50 % of sawdust (M2).The research results showed that total water use of M1S1 is 169.7 ml and M1S2 is 107,91 ml, M2S1 is 198.4 ml, and M2S2 is 151.76 ml. The best combination of this research obtain on M2S1, the second cultivating media, the soil by using soil with silty clay loamtexture which mixed50 % of sawdust and the wick of flannel.

Adaptive management of water resources based on an advanced entropy method to quantify agent information

Abstract Adaptive management is currently an important method to optimize the management of complex water resources systems. Regional water resources adaptive management was conducted based on the advanced theory of a complex system multi-agent model; the state of an agent was tracked and modified by information entropy theory, which was improved by using individual standard deviations. With the goal of optimizing the adaptation of each agent of the region, water resources in the major grain production area of China were managed under the constraints of the total annual available water resources and water use efficiency requirements for 2015 and 2030. By introducing the adaptive water resources management in 2015, the domestic benefits and economic benefits increased by 2.90% and 14.81%, respectively, with respect to observed values. The ecological benefits declined by 3.63%, but ecological water demand was fully satisfied, and the ecological water environment was improved. Given the water use efficiency targets in 2030, applying adaptive management resulted in an increase of domestic, economic, and ecological benefits of 34.29%, 21.14%, and 1.78%, respectively. The results show that the adaptive management method presented can help managers to balance the benefits of various agents to determine the direction of water resources management decisions.

Water use of Al Samr (Acacia tortilis) forests irrigated with saline groundwater and treated sewage effluent in the hyper-arid deserts of Abu Dhabi

The arid forests planted in Abu Dhabi provide a variety of valuable ecosystem services. The forests need to be irrigated, and currently groundwater (GW) provides the bulk of this water. However GW recharge is very low, and reserves are rapidly dwindling and becoming more saline. In 2016, Law 5 was passed in Abu Dhabi with the objective to set GW extraction limits and define irrigation-usage allowances. Here we sought to define the usage allowance for Al Samr trees, and this work complements our previous research on Al Ghaf and Al Sidr forests. We have measured tree water-use, ETc, using sapflow monitoring of GW-irrigated trees, and trees irrigated with treated sewage effluent (TSE). Maximum rates of tree water-use, ETc, were found to around 10 L d−1, and there are two distinct deciduous periods where ETc briefly dropped below 2 L d−1. The total annual water use of the TSE-irrigated trees was 2.2 kL y−1, which is about 25% higher than the 1.8 kL y−1 for the GW-irrigated trees.For Law 5, we recommend that the irrigation allocation for Al Samr trees be simply based on a constant ETc of 10 L d−1. So for GW irrigation, allowing for a 25% factor-of-safety, and a 25% salt-leaching fraction, the recommended allocation would be 15 L d−1. This represents a saving of 75% from the current practice of irrigation 60 L d−1. For TSE, without the need for salt leaching, the irrigation allocation would only need to be 12.5 L d−1.

Effect of different tillage and residue management practices on crop and water productivity and economics in maize (Zea mays) based rotations

In recent years, increasing water and labor scarcity & production cost, decreasing farm profitability and climatechange- induced variability are major challenges faced by the farmers of Indo-Gangetic Plains (IGP) in South Asia. Conservation agriculture (CA) based best-bet crop management practices may increase crop productivity, profitability and conserve the natural resources. In a 2-year (2012-2014) study, we assessed the effects of six combinations of tillage and crop establishment (TCE) and residue management options on crop & water productivity, profitability and soil thermal and moisture regimes in maize (Zea mays)-wheat (Triticum aestivum L.) (MW) and maize-chickpea (Cicer arietinum L.) (MC) rotations in Western IGP of India. The treatments consisted of both crops sown on permanent raised beds with residue (PB+R) and without residue (PB-R); zero tilled flat with residue (ZT+R) and without residue (ZT-R) and conventional tilled flat with residue (CT+R) and without residue (CT-R). Overall, 2-year mean maize, wheat and chickpea grain/seed yield was found to be 17.0-23.2, 20.8-24.8 and 22-31.7% higher under CA-based PB+R/ZT+R than CT-R, but it was 5.3-10.9, 4.9-8.4 and 13.8-22.8% higher than CT+R, respectively. The yield of maize, wheat and chickpea was significantly (P<0.05) higher in CA-based PB+R and ZT+R systems compared to CT-R right from first year onwards. The MW and MC, 2-year mean system productivity (based on maize equivalent yield- MEY) was higher by 21.1-21.9 and 18.7-27.5% in CA-based systems (PB+R & ZT+R) than in the CT-R, respectively. CA-based PB+R and ZT+R practices reduced the total system water use in MW and MC rotations by 75-112 mm and 55-90 mm and resulted enhanced system water productivity (WP) compared to CT-R system. Irrespective of crop rotations and TCE practices residue management treatments enhances the soil moisture (in the range of 14.5 to 30.4% during winter and monsoon seasons) and also moderates the soil temperatures. Economic profit for MW and MC rotations was always significantly (P<0.05) higher (168-445 and 215-619 US$/ha/year) in CA-based systems than in CT-R. Findings of our study shows that MW and MC rotations under CA-based system is one of the way for improving crop productivity, WP and farm income with less risk of extreme temperature and moisture stress while sustaining the natural resources in Western IGP of India and other similar agro-ecologies of South Asia.

Regulated deficit irrigation strategies for different potato cultivars under continental Mediterranean-Atlantic conditions

This paper presents the calibration and validation processes of the MOPECO model for the simulation of 4 commercial potato cultivars (Zorba, Mirari, Monalisa and Leire), using the data from a three-year field experiment (years 2010, 2011 and 2012; two per cultivar) under deficit irrigation conditions in the Basque Country region of Spain. The optimized regulated deficit irrigation (ORDI) strategy was used in combination with the typical meteorological year (TMY) methodology to determine irrigation strategies aimed at increasing the irrigation water productivity of potato crop under real farming conditions and limited volumes of irrigation water. The growing degree-days for the whole growth cycle were 1958 °Cd, while the calibrated crop yield response (Ky) values for the growth stages proposed by FAO-56 were 0.45 (vegetative period), 0.70 to 0.90 (yield formation), and 0.25 to 0.40 (ripening) depending on the considered cultivar. The validation results showed that MOPECO is suitable for simulating the yield versus total water (gross irrigation + effective rainfall) use under the climatic and soil conditions in this study (normalized root mean square error from 7.2 to 8.5% between observed and simulated levels). ORDI maximized the yield of the crop for different volumes of available irrigation water. The irrigation water productivity differed according to the cultivar, increasing for lower volumes of irrigation water (from 23.0 kg m−3 to 58.1 kg m−3 for Monalisa and Mirari cultivars, irrigated with 100% and 40% of the requirements, respectively).

Modeling Container-grown Euphorbia pulcherrima Production System Components: Impacts on Carbon Footprint and Variable Costs Using a Life Cycle Assessment

A model production system for a 15.2-cm poinsettia (Euphorbia pulcherrima) in the north Atlantic region of the United States was developed through grower interviews and best management practices and analyzed using a life cycle assessment (LCA). The model system involved direct sticking of unrooted cuttings. The propagation phase was 4 weeks, followed by 9 weeks of irrigation using a boom system and 4 weeks of flood-floor irrigation. The carbon footprint, or global warming potential (GWP), for the plant was calculated as 0.474 kg carbon dioxide equivalent (kg CO2e), with a variable cost of $1.030. Major contributors to the GWP were the substrate and filling pots, fertilization, the container, irrigation, and overhead electricity. The major contributors to variable costs were the unrooted cuttings and labor to prepare and stick ($0.471). Furthermore, the substrate and filling containers and irrigation were notable contributors. Material inputs accounted for 0.304 kg CO2e, whereas equipment use was estimated to be 0.163 kg CO2e, which comprised 64.2% and 35.8% of total GWP, respectively. Material inputs accounted for $0.665 (64.6%) of variable costs, whereas labor accounted for 19.6% of variable costs for this model. Water use per plant was 77.2 L with boom irrigation for the 9 weeks during production spacing (32.8 plant/m2) and represented 64% of the total water use. LCA was an effective tool for analyzing the components of a model system of greenhouse-grown, flowering, potted plants. Information gained from this study can be used by growers considering system alterations to improve efficiency.

An academic analysis with recommendations for water management and planning at the basin scale: A review of water planning in the Segura River Basin

Water resources management is particularly challenging in water-scarce basins, where low water availability is combined with a potential water demand exceeding the supply capacity of the natural system. This is the case of the Segura River Basin in south-eastern Spain. This paper aims at analysing the usefulness of incorporating new hydrological data and perspectives to improve the understanding of water availability and management and help promote more integrated water planning in the Segura Basin. In this basin, agriculture amounts to approximately 1366 hm3/year and accounts for 80% of the total blue water use. The forest and agriculture use of soil water amounts to 3065 and 1962 hm3/year, respectively. The unaccounted virtual water trade is also relevant and helps in mitigating water scarcity in the basin. The basin is a net virtual water-exporting region, with an average export of 1598 hm3/year, mainly in the form of fruits and vegetables, and imports approximately 1253 hm3/year, mainly related to feed for pig farms. Virtual water imports are four times larger than the disputed water transfer rate to the Segura Basin from other river basins. Water productivity analyses by sub-sectors are useful in understanding the economic rationale of the basin activities. Two types of agriculture coexist in the basin, namely, intensive industrial agriculture and occupational farming, which maintain the territory and landscape. From a Mediterranean country perspective, the analysis recommends considering climate fluctuations and temporal variability and trends of water availability and use, moving beyond the average values considered in river basin management plans. Groundwater reserve depletion continues to occur at a rate of 231 hm3/year, as water from wells is currently cheaper than using desalinated water in farms, and it does not cause boron-related water quality problems for irrigation. If socially costly administrative measures are not taken, groundwater reserve depletion will continue.

General Equilibrium Analysis of the Cobenefits and Trade-Offs of Carbon Mitigation on Local Industrial Water Use and Pollutants Discharge in China.

Carbon mitigation strategies have been developed without sufficient consideration of their impacts on the water system. Here, our study evaluates whether carbon mitigation strategies would decrease or increase local industrial water use and water-related pollutants discharge by using a computable general equilibrium (CGE) model coupled with a water withdrawals and pollutants discharge module in Shenzhen, the fourth largest city in China. To fulfill China's Nationally Determined Contributions (NDC) targets, Shenzhen's GDP and welfare losses are projected to be 1.6% and 5.6% in 2030, respectively. The carbon abatement cost will increase from 56 USD/t CO2 in 2020 to 274 USD/t CO2 in 2030. The results reveal that carbon mitigation accelerates local industrial structure upgrading by restricting carbon-, energy-, and water-intensive industries, e.g., natural gas mining, nonmetal, agriculture, food production, and textile sectors. Accordingly, carbon mitigation improves energy use efficiency and decreases 55% of primary energy use in 2030. Meanwhile, it reduces 4% of total industrial water use and 2.2-2.4% of two major pollutants discharge, i.e., CODCr and NH3-N. Carbon mitigation can also decrease petroleum (2.2%) and V-ArOH (0.8%) discharge but has negative impacts on most heavy metal(loid)s pollutants discharge (increased by -0.01% to 4.6%). These negative impacts are evaluated to be negligible on the environment. This study highlights the importance of considering the energy-water nexus for better-coordinated energy and water resources management at local and national levels.

Irrigation management techniques with anaerobic baffled reactor effluent: effect on rice growth, yield and water productivity

Abstract The study evaluated the effect of irrigation management techniques using anaerobic baffled reactor (ABR) effluent on the growth and yield of rice. It was hypothesized that irrigation techniques with ABR effluent have a significant effect on the growth, yield of rice, water productivity (WP) and water balance (WB). The experimental setup was a randomized complete block design for 2017 and 2018 cropping seasons, three treatments each with three replications. The treatments were alternating wetting and drying (AWD), continuous flooding irrigation (CFI) and wetting without flooding (WWF). The effect of irrigation management techniques was significant (P < 0.05) for the 2017 season but insignificant (P > 0.05) in 2018 on the yield. The effect of irrigation treatments on WP was significant (P < 0.05). The effects were not significant (P > 0.05) on the plant height, leave area index (LAI) and number of tillers per plant. However, the effect was significant (P < 0.05) on the number of panicles per plant. The effects of irrigation treatments were significant (P < 0.05) on number of irrigation, amount of irrigation, total water use and daily field WB. In conclusion, the result proved the acceptability of the hypothesis. AWD irrigation with ABR effluent should be encouraged among rice farmers.

Drainage and sewage system performance – Consequences of reductions in toilet flush volume

This study aims to evaluate impacts of reducing toilet flush volume from 6.8 to 4.8 Lpf with laboratory and field studies. In laboratory, 260 tests were performed including water consumption, waste removal and solid transport tests, in 20 different toilets produced by national and international manufacturers. These tests demonstrated that a simple reduction in flush tank water level was not a viable solution for reducing flush volume, due to flush energy loss. Toilets are designed to work with certain water volume, and reducing this volume without studying the consequences that this could cause, can make with the toilet fail. Toilets approved according the standards ABNT NBR15097, ABNT NBR15491 and ASMEA112.19.2 were installed in 10 houses. The monitoring of water consumption and sewage system videos were conducted during eight months. When 6.8-Lpf toilets were installed, the average toilet water consumption was 16.6L/inhabitant/day. For 4.8-Lpf toilets, this value increased to 17.6. The number of flushes/person/day increased after toilets replacement, indicating that users applied successive flushes. Videos showed blockages in sewage system horizontal pipes. Findings from this study suggest that low-flush toilets do not decrease total water use, and may result in increased water use. In addition, they can cause clogging and solid deposit on sewage system. Practical application: Many management failures have affected the world water availability. Water demand has increased with population growth, and unless the equilibrium between water demand and supply is restored, the world will face increasing water shortage. However, it is essential to study the way of reducing water consumption. Without an effective analysis, instead of bringing benefits to population, water consumption reduction can lead to clogging and negative consequences on sewage system performance, causing disorder to them. It is recommended that manufacturers did not reduce the toilet water consumption without a study on the impact caused on the sewage systems, as well as designers should be careful when specifying sanitary appliances.

Vermicompost and Manure Compost Reduce Water-Deficit Stress in Pot Marigold (Calendula officinalis L. cv. Candyman Orange)

This study was carried out to evaluate the impact of irrigation regime and potting media on morpho-physiological and biochemical characteristics of pot marigold. The experiment was arranged factorially based on a completely randomized design. The first factor was irrigation regime in three levels of 80, 60 and 40% available water content and the second factor was potting media in five levels of 20% vermicompost, 30% vermicompost, 20% manure compost, 30% manure compost and control (sand and soil in equal proportions). Morpho-physiological traits (plant height, stem diameter, number of flowering stem, root diameter, root length, root dry weight, aerial dry weight, total dry weight, relative water content, ionic stability and water use efficiency) and biochemical traits (malondialdehyde content, catalase and peroxidase activity, chlorophyll and carotenoid contents) were measured. Morpho-physiological parameters, chlorophyll and carotenoid decreased under water deficit, while increased with application of vermicompost and manure compost. Also, lipid peroxidation, catalase and peroxidase activity enhanced under water deficit, while decreased with application of vermicompost and manure compost. In other words, the application of vermicompost and manure compost in potting media reduced the harmful effects of water deficit. Total dry mass and water use efficiency were about 3-fold higher in plants grown in 30% vermicompost or 30% manure compost substrate compared to those in control plants. The results suggest that the application of 30% manure compost could be recommended as suitable potting media due to reducing the negative effects of water shortages, helping to nourish the plant, cheapness and accessibility compared with 30% vermicompost.

Fabrication of detonation nanodiamond@sodium alginate hydrogel beads and their performance in sunlight-triggered water release.

Agricultural water use accounts for around 70% of total water use in the world. Enhancing agricultural water use efficiency is a key way to cope with water shortage. Here, sunlight-responsive hydrogel beads consisting of sodium alginate (SA) matrix and detonation nanodiamond (DND) were fabricated by an ion gelation technique, which has potential applications in controlled water release. The interaction between the DND and SA matrix was investigated by Fourier transform infrared (FTIR) spectra and X-ray diffraction (XRD). UV-vis diffuse reflectance spectra verified DND can absorb solar energy in the UV, visible and even near-infrared regions. DND dispersed in the hydrogel matrix can absorb sunlight and generate heat, increasing the temperature of the matrix and resulting in slow release of water from the elastic beads. In addition, the effects of DND content and pH were systematically studied to evaluate their water adsorption properties. The swelling kinetics of DND@SA hydrogel beads in distilled water could be fitted well with a pseudo-second-order kinetic model. Six consecutive cycles of water release–reswelling indicated that their easy regeneration and reusability. The novel and eco-friendly hydrogel beads should be applicable to on-demand, sequential, and long-term release of water via light exposure.

Ten years of conservation agriculture in a rice–maize rotation of Eastern Gangetic Plains of India: Yield trends, water productivity and economic profitability

In recent years, scarcity of water, energy and labour, increasing production cost, decreasing farm profitability and climate-change-induced variability are major challenges faced by the farmers in the Indo-Gangetic Plains (IGP) of South Asia. Conservation agriculture (CA) based best-bet crop management practices may increase crop productivity and profitability, while conserving natural resources. In a 10-year (2007–2017) field study, we assessed the effects of four combinations of tillage and, crop establishment (TCE), and residue (R) management options for the crop and water productivity and profitability of rice-maize (RM) system in Eastern IGP of India. The treatments consisted of zero-till direct seeded rice followed by zero tilled maize (ZTDSR/ZTM); ZTDSR followed by maize both on permanent raised beds with residue (PBDSR/PBM (+R)); PBDSR followed by PBM without residue (PBDSR/PBM (-R)) and conventional till puddled transplanted rice followed by conventional till maize (PTR/CTM). Overall, mean rice grain yield was similar under ZTDSR/ZTM, PBDSR/PBM (+R) and PTR/CTM, but 5.0–7.9% higher than PBDSR/PBM (-R). However, the maize yield was significantly (P < 0.05) higher by 6–82% in CA-based PBDSR/PBM (+R) RM system compared to PTR/CTM and PBDSR/PBM (-R) right from first year onwards. The RM system productivity (rice equivalent yield, REY) was higher by 1.5–38% in CA-based systems [ZTDSR/ZTM; PBDSR/PBM (+R)] than in the PTR/CTM and PBDSR/PBM (-R) systems. APSIM model predicted yield of rice and maize under different TCE and residue management practices with cumulative probability distribution plots was higher and consistent in PBDSR/PBM (+R) and ZTDSR/ZTM compared to PBDSR/PBM (-R) and PTR/CTM, suggesting that CA plots has lower probability of low yield than CT. CA-based ZTDSR/ZTM and PBDSR/PBM (+R) practices reduced the total system water use by 151–341 mm and 212–423 mm, and resulted enhanced system water productivity (WP) by 27–57% and 39–68%, respectively compared to CT (PTR/CTM) system. Economic profit for RM system was always significantly (P < 0.05) higher (225–1028 US$/ha/year) in CA-based systems than in CT system. Our study shows that CA-based system under RM rotation is one of the ways for improving crop and water productivity and farm income, as well as sustaining the natural resources in smallholder production systems of Eastern IGP in India and other similar agro-ecologies of South Asia.