Supplemental Irrigation Water Research Articles

The Effect of Drainage and Subirrigation From a Small Drainage Water Recycling Reservoir on Corn and Soybean Yields in Eastern North Carolina

Highlights The Drainage Water Recycling (DWR) reservoir stored enough water to meet irrigation demand in three of four growing seasons. Subirrigation raised the groundwater table by an average of 15 cm. On average, DWR increased corn and soybean yields by 0.52 Mg ha-1 (8%) and 0.45 Mg ha-1 (17%), respectively. Subirrigation from the small size DWR reservoir did not protect corn from extended dry conditions during the growing season. Nutrients recycled back to the field via supplemental irrigation were not large enough to reduce fertilizer application rate. Abstract. Drainage water recycling (DWR) has been proposed as a source of supplemental irrigation to increase crop production resilience to extended and more frequent dry periods during the crop growing season; however, the system’s potential benefits have not been adequately quantified. The main objective of this study was to assess the performance of a DWR system for providing water for supplemental irrigation to corn and soybean at a research site in eastern North Carolina and quantify corn and soybean yield responses during 4 growing seasons (2018-2021) with varying weather conditions. Two treatments were implemented at the study site: DWR and the control (CT) treatment. The CT treatment was a 11.23 ha non-irrigated field that was primarily drained by a surface drainage system. The DWR treatment (11.48 ha) had a subsurface drainage system that provided drainage during the wet periods and subirrigation during the dry periods of the growing season. A small size reservoir (5,458 m3) was used to collect surface runoff and subsurface drainage and subirrigate the DWR treatment. Results showed that the DWR reservoir stored enough water to meet irrigation requirements in 3 of the four growing seasons and provided 5 to 73 mm of irrigation to the DWR treatment. Subirrigation raised the groundwater table by an average of 15 cm, which helped increase the upward movement of soil water to the root zone and meet crop evapotranspiration demand. DWR increased corn yields by 0.13 and 0.91 Mg ha-1 (1% and 79%) and soybean yields by 0.31 and 0.59 Mg ha-1 (9% and 30%). Subirrigation, which is generally less efficient than overhead irrigation methods, did not optimize the use of the limited water stored in the small reservoir and could not provide enough protection to corn against prolonged dry conditions in the 2019 growing season. The amount of nutrients recycled back to the field through subirrigation was not large enough to help reduce fertilizer application rate. Overall, the results demonstrated that DWR is a promising practice for increasing the resilience of crop production in the southeastern U.S. to the uncertainty in precipitation, which is expected to intensify by climate change. Monitoring the performance of DWR for longer periods with varying factors of weather, soil, and system design and management would help guide the design and management of the system to optimize the performance and minimize the implementation cost. Keywords: Drainage water management, Drainage water reuse, Irrigation reservoir, On-farm water storage, Subsurface drainage, Supplemental irrigation.

Breeding for salt tolerance in wheat: The contribution of carbon isotopic signatures

Use of low-quality water for supplemental irrigation is expected to become soon a common practice in the Mediterranean area, where durum wheat is the main cultivated cereal. Breeding for salt stress tolerance may contribute to the improvement of wheat resilience to irrigation with brackish water. Various traits can be considered as indicators of salt stress tolerance, which include agronomical and physiological criteria. However, the complexity of salinity tolerance mechanisms, the G × E interaction and the lack of correlation between controlled and open field conditions causes uncertainty in the selection process. The present review highlights the main advantages and limitations of different agronomical and physiological traits used in screening for salt stress tolerance in wheat. Special focus is given to carbon and nitrogen isotope discrimination, that remains a bottleneck in breeding for salt stress tolerance. The use of different statistical tools to analyse data related to salt stress tolerance is also discussed in this review.

Development and application of DRAINMOD model for simulating crop yield and water conservation benefits of drainage water recycling

Drainage water recycling (DWR) is an emerging practice that has the potential to increase crop yield and improve water quality. DWR involves capturing and storing subsurface drainage water and surface runoff in ponds or reservoirs, and using this water for supplemental irrigation during dry periods of the growing season. The main objective of this study was to enhance DRAINMOD model to simulate the hydrology and crop yield of DWR systems. The expanded model; named DRAINMOD-DWR, has a new module that conducts a water balance of the storage reservoir and simulates the interaction between the reservoir and the field, irrigated from and/or draining into the reservoir. The model predicts the long-term performance of DWR as affected by weather conditions, soil type, crop rotation, reservoir size, and irrigation and drainage management. Three performance metrics were defined based on model predictions to quantify irrigation, crop yield, and water capture benefits of DWR. To demonstrate the new features of the model, uncalibrated DRAINMOD-DWR was applied to a hypothetical DWR system with continuous corn using a 50-yr (1970–2019) weather record in Eastern North Carolina, U.S. Different reservoir sizes were simulated to demonstrate how the model can predict the effect of storage capacity on the system’s performance. The model predicted that a 3.0-m deep reservoir with a surface area of 4% of the field area would optimize corn yield for the simulated conditions. The model application clearly demonstrated the DRAINMOD-DWR model’s capability of optimizing the DWR system design to avoid under-sizing or over-sizing the storage reservoir, which reduces system’s performance and increases implementation cost. Research is needed to test DRAINMOD-DWR using field measured data, and to develop routines for simulating the fate and transport of nutrients and sediment in the storage reservoir, which would enable the model to predict the water quality benefits of DWR.

Reducing greenhouse gas emissions and increasing yield through manure substitution and supplemental irrigation in dryland of northwest China

Achieving carbon neutrality is a global goal, and increasing crop yield while reducing agriculture-related greenhouse gas (GHG, including CO2, CH4, and N2O) emissions is an urgent challenge. In the dryland of northwest China, the high input of nitrogen (N) fertilizer drives high GHG emissions. Replacement of part of the N fertilizer with manure (NM) and adding supplemental irrigation water (NMW) to NM can significantly increase crop yields. However, it is still unknown whether the increased yield would induce more GHG emissions. In this study, the change in GHG emissions were investigated under conventional farmer N application (FN), NM and NMW in winter wheat cropping systems. The two-year study showed that the global warming potential, greenhouse gas intensity and carbon footprint of NM and NMW were 3–25%, 21–42% and 9–18% lower, respectively, than those of FN, owing to the lower N fertilizer and the associated N2O emissions under NM and NMW. In addition, compared with FN, CO2 emissions during the growing season were higher under NM and NMW; however, due to the 23–40% higher biomass productivity, NM and NMW neutralized and fixed more CO2 (21–39% higher net ecosystem productivity) than FN. Therefore, NM and NMW could be favorable agronomic practices in the Loess Plateau when considering the dual goal of maintaining acceptable yields while reducing GHG emissions.

MORE CROP PER DROP: THE MAGIC OF SWEET POTATO (Ipomoea batatas L.)

<p><strong>Background:</strong> Water is the most valuable resource in agriculture. Agricultural development in semi-arid eastern Kenya is essentially dependent on intermittent rainfall. An accurate estimate of sweet potato water usage and productivity is considered a significant feature of conservation agriculture under such climatic conditions. <strong>Methodology:</strong> The research was conducted for two seasons, from December 2018 to April 2019 and October 2019 to March 2020, with the aim of quantifying the water use efficiencies of two sweet potato varieties, Kabode and Bungoma. Assuming that there were no variations in water-use efficiency between the two varieties. The experiment was established as RCBD for the two seasons. Treatments comprised of sole sweet potato varieties of Kabode and Bungoma, together with their intercrops with common beans. <strong>Results:</strong> Seasonal effective rainfall values were 302 and 639.2 mm, whereas the mean saturation pressure deficit recorded was 2.5 and 2.4 Kpa for S (I) and S (II), respectively. This presented S(I) with 815.1 mm ET<sub>crop</sub> demanding 622.1 mm irrigation water, whereas S(II) envisaged a 3.3% decrease in ET<sub>crop</sub> values; 788 mm and requiring 427.6 mm of supplemental irrigation water to attain optimal sweet potato yields. Similarly, the test crops paraded WUE values of 39.8 and 30.0 kg ha<sup>-1 </sup>mm<sup>-1 </sup>and water productivity indices based on rain water were 1.11 and 0.95 kg m<sup>−3</sup> for Kabode and Bungoma varieties, respectively. HI for S (I) were 40.8 and 35.4% whilst 54.2 and 46.8 % for Kabode and Bungoma varieties, respectively. <strong>Implications:</strong> WUE values of the sweet potato crop increased from warm-dry season S (I) to the warm-wet season S (II), as Kabode portrayed a higher adaptability. These results provide an acumen for decision making in the setting of climate change.<strong> Conclusions:</strong> Kabode variety differed significantly with Bungoma variety in their abilities to efficiently use water, thus portraying its adaptability in such a peculiar environment. The climatic environment: dew point temperatures and saturation pressure deficit had no significant impact on sweet potato water use efficiency.</p>

Opportunities and challenges for implementing managed aquifer recharge models in drought-prone Barind tract, Bangladesh

This study focuses on the Barind tract, a drought prone area situated in the north-west region of Bangladesh where inadequate rainfall and limited surface water have created high dependence on groundwater for irrigation and other purposes, leading to significant declines in groundwater level. Managed aquifer recharge (MAR) offers a potential solution to restore groundwater levels. This study sets out to identify the opportunities and challenges for implementing MAR in the Barind tract. To accomplish this aim, different data sets including bore log lithology, rainfall, groundwater levels, information about re-excavated ponds, dighis, kharies, beels, check dams, rubber dams, dug wells and other necessary information were collected from the Barind Multipurpose Development Authority (BMDA) and other sources and analyzed. Major opportunities for MAR are identified for about 2000 km of re-excavated kharies (canals) containing about 750 check dams, more than 3000 re-excavated ponds, a number of beels (comparatively large marshes) and other water bodies which are used to conserve runoff storm water for supplementary irrigation. The conserved water can be used for groundwater recharge and subsequently abstracted for irrigation. Furthermore, roof-top rain water from buildings can also be used for groundwater recharge purposes. In contrast, the major challenges include the high turbidity of storm water runoff leading to clogging of MAR structures, inadequacy of conventional direct surface methods of recharge due to the presence of a 15 m or more thick upper clay layer with limited percolation capacity, and lack of practical knowledge on MAR. Therefore, overcoming the challenges for MAR application is a prerequisite to maximize the opportunities from MAR that can support the sustainable use of groundwater resources.

Actual condition of groundwater use as supplementary irrigation water resource in a paddy-dominated alluvial fan

Actual condition of groundwater use as supplementary irrigation water resource in a paddy-dominated alluvial fan

Multiobjective land–water allocation model for sustainable agriculture with predictive stochastic yield response

AbstractConsider an agricultural land–water resource allocation problem in which yields are spatial dependent and stochastically correlated. To achieve sustainability, we formulate a multiobjective (MO) optimization problem, in which the decision maker determines the cultivation areas and the supplemental irrigation water levels at different locations, with social, economic, and environmental goals in mind. For the social goal, we minimize the root mean squared difference of incomes among locations. For the economic goal, we minimize the production risk. We show that minimizing production risk is equivalent to maximizing the service level, when demand is normally distributed. For the environmental goal, we minimize the resource utilization. Assume that the yield vector at different locations follows a multivariate normal distribution. We formulate the MO optimization problem using a weight global criterion method, and we provide a sufficient condition for convex quadratic programming. We demonstrate the applicability of our proposed framework in the case study of sugarcane production in Thailand. To capture yield response to water, we propose several models including linear and nonlinear regressions, and we obtain the closed‐form expression for the linear and probit yield response models. The numerical experiment reveals that our solution significantly improves the social and economic goals, compared to the current policy. Finally, we illustrate how to apply our model to quantify the monetary value from reducing yield variability, which could be resulted from smart irrigation or precision agriculture.

Manurial amendments and source of water for supplemental irrigation of sawah-rice system influenced soil quality and rice yield

Soil and water management research on adapting the promising sawah ecotechnology for lowland rice farming in West Africa has largely focused on the abundant inland valleys; floodplains which too represent a huge agricultural resource in the region have not been so involved. Sawah refers to a bunded, puddled and leveled basin for rice, with water inlets and outlets for irrigation and drainage, respectively. In conventional sawah, soil fertility is augmented using mineral fertilizers, with an option to harness lowland water resources for use in small-scale irrigation to create the so-called sawah typologies. In this study, we evaluated the effects of three manurial amendments (rice husk, rice-husk ash and poultry droppings, each at 10 t ha–1) and NPK 20:10:10 at 400 kg ha–1 interacting with source of water (spring or pond) used for supplemental irrigation of three sawah typologies in a floodplain in southeastern Nigeria. Plots amended with poultry droppings and supplemented with spring water recorded the overall best performance of the sawah-rice system; the control being the unamended non-supplemented (solely rainfed) plots recorded the worst. Rice-husk ash and rice husk enhanced soil pH and soil organic carbon, respectively. The three sawah typologies showed a consistent trend thus spring-supplemented ≥ pond-supplemented ≥ non-supplemented sawah. Rice grain yield was influenced by soil total nitrogen and the sum of the three plant-nutrient basic cations (K+ , Ca2+ and Mg2+), with the influence of K+ alone being the greatest. To enhance rice performance including grain yields in floodplain sawah, farmers should utilise poultry droppings as soil manure and spring water for supplemental irrigation.

Scheduling Supplementary Irrigation for Maize Production: Analysis of the Requirements for Climate Smart Farming for Rural Development

The erratic rainfall pattern in sub Saharan Africa is a major threat to rainfed agriculture by consistently reducing yield due to water deficit and threatening food security. In order to address this problem, supplementary irrigation during the raining season is increasingly being encouraged to reduce water deficits during dry spells. The aim of this study is to design a supplementary irrigation for maize cropping during the raining season by using climatic data and water from surface runoff from a nearby catchment area. Climatic data for the study area was used to analyse the water requirement of maize during the rainy season and to propose an irrigation schedule. The results indicated that, out of 620.00 mm (3100 m3) water requirement for the entire growing cycle of maize on a 0.5 ha field, the supplementary irrigation water requirement represents more than a third of the water need of maize during periods of dry spell in the maize crop cycle. With a reservoir volume of 600.00 m3 and a net irrigation application of 60 mm (300 m3), about 5 irrigation applications (with a flow rate of 25.00 m3/hr for 6 hours a day) is required to supplement the irrigation water requirement of maize that can help alleviate soil moisture stress and increase crop yield during critical growth stages.

Climatic Variability and Estimation of Supplementary Irrigation Water Needs of Selected Food Crops in the Sokoto-Rima River Basin, Nigeria

The study investigated the effects of rainfall and temperature variability on crop water requirements of selected food crops in the Sokoto-Rima River Basin, Northwest of Nigeria. Rainfall and temperature datasets were obtained from the Climatic Research Unit (CRU) TS 3.21 of the University of East Anglia, Norwich, for a period of 70 years (1943-2012). The suitability of CRU datasets were verified by correlating the datasets with measured rainfall data of Yelwa synoptic station, from the Nigerian Meteorological Agency. Selected food crops were used for estimating supplementary irrigation water needs in the River basin. Results of Mann-Kendal, Spearman’s Rho and linear regression tests showed strong evidence of increasing annual temperature and potential evapotranspiration with corresponding decrease in rainfall amounts, especially in the northern parts of the basin which houses big irrigation projects and dams such as the Goronyo Irrigation and the Bakolori Dam and Bakolori Irrigation Project. This will impact on the water availability within the basin, through reduction in surface and ground water supply for ongoing irrigation and other water resources projects. Water requirements for selected crops were modeled to ascertain crop sensitivity to climatic variability which will aid in the design of supplementary irrigation water needs models. Results showed that even in the rainfall months, supplementary irrigation of varying quantity is required to complement rainfall, most especially, in the northeast of the basin. Surprisingly, the month of May which marks commencement of rainfall, recorded the highest water need and this has implication for agriculture yields in the region.

Providing irrigation water as a public utility to enhance agricultural productivity in Uganda

Vagaries of weather remain a significant challenge to enhancing agricultural productivity, farmers' incomes, and economic growth for most developing countries. In Uganda, strategies for intervention are hindered by lack of countries with similar socio-economic, environmental, and economic characteristics from which to draw experience. This paper proposes the provision of supplemental irrigation water as a public utility to enhance agricultural productivity among smallholder farmers in Uganda. It uses nationwide surveys, administrative data, and expert consultation to explore the rationale for irrigation, the potential of supplemental irrigation, and the commercial and operational basis for adopting the proposed system.

Supplemental irrigation water rights and climate change adaptation

Adaptation to water scarcity induced by future climate change will be crucial for the viability of agricultural economies in many areas of the world. In this paper, we study the acquisition of supplemental irrigation water rights as an adaptation strategy undertaken by irrigation-dependent farmers in response to historical climate change. By exploiting the panel structure of a unique dataset of farm-level supplemental right adoption decisions in the state of Oregon, we establish a relationship between climate conditions, competition for local water resources, and the acquisition of supplemental rights. Our results indicate that a warmer, drier climate increases the likelihood that irrigated farms acquire supplemental rights, suggesting that farmers in Oregon have used supplemental rights to adapt to historical climate change. We also find evidence of heterogeneous effects suggesting that junior irrigators, groundwater-dependent irrigators, and farmers with access to a relatively lower volume of water have been most affected by historical climate change with respect to their supplemental water right acquisition decisions.

Offsetting land degradation through nitrogen and water management during maize cultivation under arid conditions

AbstractThe best management of soil, irrigation, and crop nutrients is among major components of sustainable agriculture that reduces groundwater contamination, prevents soil degradation, and guarantees the best resource use efficiency. Trials were conducted to optimize maize (Zea mays L.) yield by experimenting various irrigation water regimes, nitrogen (N) application rates, and methods in 96 pots under arid environmental conditions during autumn 2012. Crop hydrological and agronomic characteristics were assessed under a completely randomized design with factorial arrangements. Water and N stress to the plants under observation significantly reduced the water potential, osmotic potential, and turgor pressure of the leaves. Crop growth rate and total dry matter production were significantly improved by an increase in N fertilizer application up to 300 kg ha−1 (equivalent to 4.8 g N pot−1) for all water regimes. Grain per cob, 1,000‐grain weight, and final grain yield were higher at 100% field capacity with the application of 300 kg N ha−1 under the soil N application method than those under foliar N application treatments. The best N rate for optimum grain production was attained by 300 kg ha−1 with 575‐mm supplemental irrigation water ha−1. The quadratic equation fitting revealed that the effect of N on crop growth parameters was higher than that of the supplemental irrigation; therefore, a water deficit may partly be managed by adding N to the soil. These water and N managements may be used in formulating agricultural practices to avoid degradation of lands for soil and environmental conditions similar to those of the current study warranting a field research.

Linacre Derived Potential Evapotranspiration Method and Effect on Supplementary Irrigation Water Needs of Tomato/Cabbage/Carrot

The study examined the dynamic nature of water balance parameters over Kano town, a semi-arid environment and impact of Linacre derived potential evapotranspiration method on the supplementary irrigation water needs of selected crops. Monthly Rainfall and Temperature data were collected from the Nigerian Meteorological Agency, Lagos for the period 1953-2012. The study observed that there is a steady decline in annual precipitation over Kano from the first decade (1953-1962) to the fifth decade (1993-2002), after which there was a sign of weak recovery in the last decade (2003-2012). For water loss through potential evapotranspiration, there was a steady rise from the first decade (1953-1962) to the fifth decade (1993-2002), and then followed by a sudden decline in the last decade (2003-2012). The total average of water storage on the other hand, first experienced a rise between the first two decades (1953-1962) and (1963-1972), followed by a steady decline, up until the fifth decade (1993-2002) and finally a rise in the last decade (20032012). The total average of soil water deficit experienced a steady rise between the first and the fifth decades (1953-1962) to (1993-2002), this was followed by a decline in the last decade (20032012). Finally, the total average of water surplus experienced a steady decline between the first and the fifth decades. The observed decline in precipitation, storage, and water surplus, and the rise in water loss from potential evapotranspiration and soil water deficit, suggests that there have been changes in the climatic pattern over Kano and this could be seen in the supplementary irrigation water needs of Tomato/Cabbage/Carrot.

Improvement of Supplementary Irrigation Water Quality for Rain-Fed Agriculture in the Semi-Arid Region Using Magnetization Techniques

Rain-fed agriculture depends on the groundwater as a supplementary source of irrigation. The poor quality of water from the hard rock area is applied to the crops to save the crop. Continuous irrigation leads to degradation of soil, drip irrigation system as well plants. This study assessed the damages on the drip irrigation system and soil, inflicted by the use of low-quality irrigation water. The quality of water was improved with reference to raw water in terms of pH (1.57% - 5.88%), EC (3.08% - 10.08%), ions (0.96% - 46%) by using magnetization method, without disrupting the existing irrigation system in the basaltic aquifer in semi-arid to the arid condition. This was demonstrated before the farmers in central India.

Multiple Cropping after the Rice Harvest in Rainfed Rice Cropping Systems in Khon Kaen Province, Northeast Thailand

(ProQuest: ... denotes non-US-ASCII text omitted.)IntroductionIn rainfed rice fields in Northeast Thailand, only a single crop of rice is commonly planted in the rainy season. Moreover, the yield of rice is generally low, averaging 1.7 t/ha. The low productivity coupled with low and fluctuating prices and high input costs severely limits the profitability of rice production and keeps many farmers trapped in poverty. Cropping intensification through multiple cropping could be a way to increase productivity and boost rural incomes.In the past, multiple cropping was rarely practiced in Northeast Thailand due to the limited biophysical resources (e.g., low and erratic rainfall, infertile sandy soils, limited availability of surface water supplies, serious problem of insect pests, long duration of the rice crop) (Terd et al. 1976a; 1976b; 1978a; 1978b; Aran et al. 1977a; 1977b; 1977c; KKU-Ford Cropping System Project 1982; Rambo 1991; Viriya 2001). Even when experimental multiple cropping systems were agronomically successful, farmers did not adopt them (Vichain and Aran 1990), mostly due to social and economic constraints, including limited markets for crops, labor competition, and lack of capital and knowledge (Rigg 1985; Vichain and Aran 1990). Although the factors limiting the adoption of multiple cropping were well understood in the context of rainfed agriculture in the 1980s, the situation in the Northeast has undergone rapid change since then. The context for multiple cropping is now quite different from what it was in the past. Key changes include the widespread adoption of the drought-tolerant RD6 glutinous rice variety and use of diesel pumps to provide supplementary irrigation water from newly dug farm ponds, which have helped to stabilize rice yields in years of low rainfall. The resulting higher and more stable yields of glutinous rice have allowed farmers to plant a larger share of their land with non-glutinous KDML105, which is raised as a cash crop, providing rural households with a new source of income. Agricultural intensification is occurring to an extent unimaginable just a few years ago. Relying on remittances sent back to their families by migrant workers, as well as cash earned by engaging in off-farm employment in new factories and service jobs in local urban centers, Isan farmers have been rapidly adopting modern agricultural technology, including increased use of chemical fertilizers, pesticides, and farm machinery (Grandstaff et al. 2008). Multiple cropping and cultivation of high-value crops to supply growing urban markets are also more commonly practiced (Rambo 2012).In Khon Kaen Province, farmers now employ a variety of locally developed double cropping systems to grow cash crops after the rice harvest and thus raise farm incomes. Some farmers grow high-value vegetable crops after the rice harvest, such as Chinese radish (Patcharaporn and Orawan 2011), tomato for seed production (Prapatsorn and Wareerat 2010), glutinous corn (Uraiwan et al. 2010), and various green vegetables, which provided a net income of USD7,727-12,733 per hectare per season. Even though some examples of multiple cropping after rice have been reported, there have been no detailed studies on the localities, planted areas, types of crops, and number of households adopting these systems; nor has there been any detailed analysis of the factors associated with the occurrence of each system of multiple cropping. This research, therefore, was undertaken in order to identify localities, planted areas, types of crops, and number of households growing crops after the harvest of rainfed rice in Khon Kaen Province and to identify physical, social, and economic factors associated with the occurrence of these cropping systems.MethodologyStudy AreaThe study area was the whole of Khon Kaen Province, Northeast Thailand. It is located between latitude 15°40' to 17°5'N and longitude 101°45' to 103°45'E. …

Managing the trade-offs among yield increase, water resources inputs and greenhouse gas emissions in irrigated wheat production systems

Irrigation is a crucial measure for ensuring food security; however, the complex linkages among yield increases, water productivity, and greenhouse gas (GHG) emissions are unclear for irrigated wheat production in China. Here a meta-analysis was conducted to determine the trade-offs among yield increase, water productivity, and GHG emissions in irrigated Chinese wheat production systems. Grain yield in wheat irrigation systems with 172 mm of supplemental irrigation water increased by 23% owing to the increase in aboveground biomass, spike number, and grain number, whereas water productivity in irrigated wheat decreased by 6% compared to non-irrigated systems. Water productivity increased from 15.7 to 16.5 kg ha−1 mm−1 with conventional irrigation systems to 17.5 kg ha−1 mm−1 with optimized irrigation systems, similar to increases found in non-irrigated systems (17.8–18.0 kg ha−1 mm−1). Compared with non-irrigated systems, yield-scaled GHG emissions in irrigated systems decreased by 2–8% using surface water, and increased by 15–68% using groundwater. Yield-scaled GHG emissions in optimized irrigation systems decreased by 3–19% compared to conventional irrigation systems. In conclusion, irrigation was a crucial practice for ensuring food security, but water productivity and yield-scaled GHG emissions should be carefully considered when making design decisions. In the future, adoption of integrated irrigation management systems was crucial to achieve collective improvements in yield, water productivity, and environmental benefits.

Dry spell length analysis for crop production using Markov-Chain model in Eastern Hararghe, Ethiopia

The information on the length of dry spells could be used for deciding a particular crop or variety, supplementary irrigation water demand and for others agricultural activities. The study was conducted in three districts: Babile, Haramaya and Kersa, eastern Hararghe, Ethiopia. The aim of the study was to analyze dry spell lengths and its implications on crop production in eastern Hararghe, so as to minimize unexpected damage due to long dry spells and to have effective and efficient planning for farming communities. Thirty years of rainfall data for each district were collected form National Meteorological Agency of Ethiopia. Data quality control has been done prior to analysis. Markov-Chain model were employed to analyze the collected data. The result of the study revealed that dry spells were highly hitting Babile district comparing to the other two districts. The probability of dry spell lengths of 5 and 7 days in Babile district was found to be about 99 and 80%, respectively. Whereas, in Haramaya district, the probability of dry spell length of 5 days was found to be 80% during 181(Days of the Year) DOY, then it falls to below 50 % by 221DOY. Moreover, the probability of the occurrences of dry spells of 10, 15, and 20 days were below 5% in Haramaya district during the main rainy season. The study also investigated that in Kersa district, the probability of occurrences of the dry spell lengths of 5, 7, 10, 15, and 20 days were estimated to fall below 30%, showing that the area was better in crop production as compared to the rest districts. The annual rainfalls in all the districts were decreasing as per the trend line and variable in all the districts: Babile, Haramaya and Kersa districts, having the CV values of, 41, 34 and 31%, respectively. Information regarding dry spell length analysis has to be well understood at grass root levels to ensure food security via lifesaving irrigation schemes or any other options.

Restoring Soil and Water Resources and Mitigating Climate Change in India by Judicious Management of Agricultural and Urban Wastes

India's present population of 1.34 billion is increasing at the rate of 1.18% yr−1. India's food grain production of 273.4 million tonnes (Mt) in 2017 has to be increased from lesser arable land area, lower fertilizer use and reduced consumption of water for supplementary irrigation. Furthermore, degraded soils, affecting land area of 114.2 million hectare (Mha), must be restored and risks of any new soil degradation minimized. In this context, the importance of recycling bio-wastes (e.g., agricultural, municipal and industrial) to restore soil organic carbon (SOC) concentration and stock and improve soil health cannot be over-emphasized. Crop residues, 510–836 Tg yr−1. are a major source of C, plant nutrients, biofuels and industrial raw materials. Rather than in-field burning and used as traditional fuel, composting and using as mulch can reduce risks of erosion and improve soil health. Similarly, dung production in India, also a rich source of C and nutrients, must be recycled as manure and used in bioreactors to produce methane. Wasted grains, fruits and vegetables must also be composted and used as a soil amendments. Judicious use of bio-wastes can re-carbonize the biosphere, restore degraded soils and improve soil health, produce biofuels and other value addition industrial byproducts, and improve the environment. Conservative estimates of additional soil C sequestration by judicious management of crop residues and animal dung are 24 Tg C yr−1 worth US $3.0 billion of revenue for farmers and land managers from payments for ecosystem services. There is a strong need of enhancing the awareness about proper disposal and use of bio-wastes through environmental education in primary and secondary schools, and communication by IT services. Recycling of bio-wastes is also critical to advancing the Sustainable Development Goals of the U.N. (Agenda 2030), promoting “4 per Thousand” program of COP21, and upholding the “Swatchh Bharat” ideals. It is a win-win-win option.