Irrigation Water Use Research Articles

Spatiotemporal dynamics of irrigated cropland water use efficiency and driving factors in northwest China’s Hexi Corridor

BackgroundAgricultural irrigation is an important practice to safeguard crops against drought and enhance grain yield in arid regions. The Hexi Corridor, known as a classic arid region, faces significant pressure on agricultural production and food security due to the scarcity of water resources. There is an urgent need to investigate agricultural water use of the irrigated regions. Water use efficiency (WUE), defined as the ratio of gross primary productivity (GPP) to actual evapotranspiration (ET), serves as a valuable indicator linking carbon assimilation and water loss. It enables the quantification of areas where water can be utilized more effectively. However, the long-term spatiotemporal dynamics of WUE and driving mechanism in the irrigated areas of the Hexi Corridor remain unclear.ResultsThis study used GPP calculated by a light use efficiency model (EF-LUE), ET estimated by an ETMonitor model and irrigated cropland maps across China (IrriMap_CN) to examine the spatiotemporal dynamics of irrigated cropland WUE and its controlling factors in the Hexi Corridor from 2001 to 2018. The results are as following: (1) The average annual WUE was approximately 1.34 ± 0.38 g C kg−1 H2O yr−1, with an increasing trend of 0.012 g C kg−1 H2O yr−1, and faster growth observed during 2011–2018 compared to 2001–2010. (2) The contribution of GPP to WUE trends and WUE interannual variability (IAV) was greater than that of ET. (3) The dominant climatic factors of WUE IAV in the Hexi Corridor were SPEI, precipitation, and soil moisture. (4) The standardized Structural Equation Model (SEM), incorporating the relationship between WUE and factors such as water, energy, NDVI, and water-saving irrigation, explained 81% of the variation in irrigated cropland WUE. Here, biological factors (GPP and NDVI) were the primary factors influencing WUE variability, and water-saving irrigation had a stronger indirect effect than climate factors (water and energy) on variation in WUE.ConclusionsOur findings offer valuable theoretical insights into the mechanisms governing the interaction between the carbon and water of irrigated cropland, guiding the management of water resources and land in agricultural practices within the Hexi Corridor.

A Holistic Irrigation Advisory Policy Scheme by the Hellenic Agricultural Organization: An Example of a Successful Implementation in Crete, Greece

The aim of this communication article is to present a successful irrigation advisory scheme on the island of Crete (Greece) provided by the Hellenic Agricultural Organization (ELGO DIMITRA), which is well adapted to the different needs of farmers and water management agencies. The motivation to create this advisory scheme stems from the need to save water resources while ensuring optimal production in a region like Crete where droughts seem to occur more and more frequently in recent years. This scheme/approach has three different levels of implementation (components) depending on the spatial level and end-users’ needs. The first level concerns the weekly irrigation bulletins in the main agricultural areas of the island with the aim of informing farmers and local water managers about crop irrigation needs. The second level concerns an innovative digital web-based platform for the precise determination of the irrigation needs of Crete’s crops at a parcel level as well as optimal adaptation strategies in the context of climate change. In this platform, important features such as real-time meteorological information, spatial data on the cultivation type of parcels, validated algorithms for calculating crop irrigation needs, an accurate soil texture map derived from satellite images, and appropriate agronomic practices to conserve water based on cultivation and the geomorphology of a farm are considered. The third level of the proposed management approach includes an open-source Internet of Things (IoT) intelligent irrigation system for optimal individual parcel irrigation scheduling. This IoT system includes soil moisture and atmospheric sensors installed on the field, as well as the corresponding laboratory soil hydraulic characterization service. This third-level advisory approach provides farmers with specialized information on the automated irrigation system and optimization of irrigation water use. All the above irrigation advisory approaches have been implemented and evaluated by end-users with a very high degree of satisfaction in terms of effectiveness and usability.

How to get green with agricultural footprint: A global analysis of carbon emissions, environmental taxes, and agrochemical use

The agriculture sector, being highly vulnerable to climate change, plays a pivotal role in achieving green and sustainable economies. As the 2030 Agenda emphasizes the integrated development of environmental, social, and economic dimensions, it is crucial to understand how agricultural practices affect sustainability. This study investigates the environmental impact of the agricultural sector on the green economy by examining key environmental factors, such as agricultural energy emissions, environmental taxes, irrigated water use efficiency, fertilizer use, and pesticide application. The analysis is conducted using the Panel Quantile Autoregressive Distributed Lag (QARDL) model, with robustness checks performed through the comparison with the Panel ARDL model, using data from 2000 to 2020. To assess the green economy, an index is constructed based on 20 indicators related to environmental, social, and economic sustainability. The results show that agricultural energy emissions, despite their environmental cost, are positively associated with green economy development, highlighting the trade-off between high productivity and environmental degradation in a resource-efficient economy. Improved water use efficiency is found to enhance agricultural sustainability and production. Additionally, environmental taxes and regulations exert a significant positive effect on both environmental preservation and social welfare. Contrary to the belief that reducing agricultural production will lower carbon emissions, the study suggests that adopting environmentally friendly practices and imposing targeted taxes are more effective strategies. The findings also reveal a negative relationship between excessive fertilizer use and the green economy, indicating the need for minimal fertilizer application to promote sustainability. The study concludes with specific policy recommendations. Governments, particularly in countries that have not yet adopted sustainable agricultural practices, should implement environmental taxes and regulations to promote carbon neutrality and support the Sustainable Development Goals. These measures are essential to balancing economic growth, environmental sustainability, and social equity in the agricultural sector.

Are Water Use Efficiency and Effectiveness Relatively Lower in Arid Zones? Comparative Analyses of the Water Productivity of Typical Crops

Agriculture is the largest water user of all sectors. In arid regions in particular, achieving efficient water use in agriculture is an important way to solve water scarcity. However, the difference in water use efficiency between arid and humid regions has long been a focus of academic debate. Many studies consider water use efficiency to be higher in humid areas due to the abundance of water resources. This view is based on the fact that less irrigation in humid areas may lead to higher crop yields and better conditions for agricultural production; however, it ignores the efforts of researchers and agricultural workers in arid zones who have attempted to develop efficient water-saving technologies, as well as the effect of natural conditions on agricultural production. Correctly evaluating the efficiency of agricultural water use in arid zones is important for achieving efficient use of water resources, as well as for water management decisions. This study calculates the yield structure and water productivity of typical crops in both arid and humid regions in China based on the footprint theory and other methodologies. This approach allows for an accurate assessment of irrigation water benefits in various regions, providing a scientific basis for improving agricultural water use efficiency under different climatic conditions. The study results indicate that the average reliance on blue water for wheat and cotton gradually increases from 49.9% to 93.6% as regional aridity intensifies, ranging from the Central China Humid Region to the Northwest China Arid Region. Similarly, the average contribution of blue water to crop yield rises from 31.0% to 100%, while irrigation water productivity increases from 0.27 kg·m−3 to 0.53 kg·m−3. Finally, this study concludes that, in arid zones with lower precipitation and more hours of sunshine, a higher dependence on blue water for crop growth and development leads to a higher productivity of irrigation water. In addition, in arid zones, the focus should be on optimizing the use of irrigation water and improving irrigation technology and efficiency, while, in humid zones, there should be more use of natural precipitation to efficiently reduce dependence on irrigation water.

Earthworms Transport Agents of Micro-plastic in Soil

Earthworm activity results in vermicomposting rich in vitamins, growth hormones, proteases, amylases, lipases, cellulose, chitinase, and immobilized microflora and macro and micronutrients. After the enzymes are expelled from the worms, they still break down organic materials. The benefits of using vermicomposting in agricultural production include decreased water use for irrigation, reduced pest and termite attacks, decreased weed growth, faster seed germination and rapid seedling growth and development, more fruits per plant (in vegetable crops), and more seeds produced annually (in cereal crops). Without using agrochemicals, vermicomposting and earthworms can increase horticulture output. Vermicomposting has advantages, although its application is still relatively new. This review aims to raise awareness about this particular local soil amendment.

Determining Consumptive Water Use for Corn Cultivation at High Altitudes: A Comparative Study of Three Methods

A desirable water supply in agriculture requires quantitative methods to determine crop requirements. De-termination of hydric request of maize Var INIAP 102 is promising, mainly at altitudes over 2000 meters above sea level. This study analyzed three methods (lysimeter, evaporimeter tank, and empiric formula FAO) to determine Chimborazo province's hydric requirements for Var INIAP 102. Vegetative and yield variables were recorded, and the effect of different water films on the vegetative growth of maize was de-termined. When water was more available in the soil, the vegetative growth, yield, and pod weight per plant of maize Var INIAP 102 were higher. This study is of great importance because determining the hydric requirement of maize Var INIAP 102 was done for the first time in Chimborazo province and will support farmers in better water use for irrigation. Keywords: irrigation sheet, lysimeter, sweet corn, water requirements, evaporation tank

Determining Consumptive Water Use for Corn Cultivation at High Altitudes: A Comparative Study of Three Methods.

A desirable water supply in agriculture requires quantitative methods to determine crop requirements. De-termination of hydric request of maize Var INIAP 102 is promising, mainly at altitudes over 2000 meters above sea level. This study analyzed three methods (lysimeter, evaporimeter tank, and empiric formula FAO) to determine Chimborazo province's hydric requirements for Var INIAP 102. Vegetative and yield variables were recorded, and the effect of different water films on the vegetative growth of maize was de-termined. When water was more available in the soil, the vegetative growth, yield, and pod weight per plant of maize Var INIAP 102 were higher. This study is of great importance because determining the hydric requirement of maize Var INIAP 102 was done for the first time in Chimborazo province and will support farmers in better water use for irrigation. Keywords: irrigation sheet, lysimeter, sweet corn, water requirements, evaporation tank

Soybean Yield Simulation and Sustainability Assessment Based on the DSSAT-CROPGRO-Soybean Model.

In order to ensure national grain and oil security, it is imperative to expand the soybean planting area in the Xinjiang region. However, the scarcity of water resources in southern Xinjiang, the relatively backward soybean planting technology, and the lack of a supporting irrigation system have negatively impacted soybean planting and yield. In 2022 and 2023, we conducted an experiment which included three irrigation amounts of 27 mm, 36 mm, and 45 mm and analyzed the changes in dry mass and yield. Additionally, we simulated the potential yield using the corrected DSSAT-CROPGRO-Soybean model and biomass based on the meteorological data from 1994 to 2023. The results demonstrated that the model was capable of accurately predicting soybean emergence (the relative root mean square error (nRMSE) = 0, the absolute relative error (ARE) = 0), flowering (nRMSE = 0, ARE = 2.78%), maturity (nRMSE = 0, ARE = 3.21%). The model demonstrated high levels of accuracy in predicting soybean biomass (R2 = 0.98, nRMSE = 20.50%, ARE = 20.63%), 0-80 cm soil water storage (R2 = 0.64, nRMSE = 7.78%, ARE = 3.24%), and yield (R2 = 0.81, nRMSE = 10.83%, ARE = 8.79%). The biomass of soybean plants increases with the increase in irrigation amount. The highest biomass of 63 mm is 9379.19 kg·hm-2. When the irrigation yield is 36-45 mm (p < 0.05), the maximum yield can reach 4984.73 kg·hm-2; the maximum efficiency of soybean irrigation water was 33-36 mm. In light of the impact of soybean yield and irrigation water use efficiency, the optimal irrigation amount for soybean cultivation in southern Xinjiang is estimated to be between 36 and 42 mm. The simulation results provide a theoretical foundation for soybean cultivation in southern Xinjiang.

Estimating irrigation water use from remotely sensed evapotranspiration data: Accuracy and uncertainties at field, water right, and regional scales

Irrigated agriculture is the dominant user of water globally, but most water withdrawals are not monitored or reported. As a result, it is largely unknown when, where, and how much water is used for irrigation. Here, we evaluated the ability of remotely sensed evapotranspiration (ET) data, integrated with other datasets, to calculate irrigation water withdrawals and applications in an intensively irrigated portion of the United States. We compared irrigation calculations based on an ensemble of satellite-driven ET models from OpenET with reported groundwater withdrawals from hundreds of farmer irrigation application records and a statewide flowmeter database at three spatial scales (field, water right group, and management area). At the field scale, we found that ET-based calculations of irrigation agreed best with reported irrigation when the OpenET ensemble mean was aggregated to the growing season timescale (bias = 1.6–4.9 %, R2 = 0.53–0.74), and agreement between calculated and reported irrigation was better for multi-year averages than for individual years. At the water right group scale, linking pumping wells to specific irrigated fields was the primary source of uncertainty. At the management area scale, calculated irrigation exhibited similar temporal patterns as flowmeter data but tended to be positively biased with more interannual variability. Disagreement between calculated and reported irrigation was strongly correlated with annual precipitation, and calculated and reported irrigation agreed more closely after statistically adjusting for annual precipitation. The selection of an ET model was also an important consideration, as variability across ET models was larger than the potential impacts of conservation measures employed in the region. From these results, we suggest key practices for working with ET-based irrigation data that include accurately accounting for changes in soil moisture, deep percolation, and runoff; careful verification of irrigated area and well-field linkages; and conducting application-specific evaluations of uncertainty.

Development of growth-stage specific crop coefficient for drip irrigated wheat crop grown in climatic conditions of Jalandhar, Punjab

The crop coefficient (Kc) values given in FAO-56 report need to corrected for local conditions due to differences in climate, soil types, and water management practices. Therefore, present study was undertaken to develop growth-stage-specific Kc values of wheat grown under drip irrigated conditions for two years (2022-23 and 2023-24) at Jalandhar, Punjab. The developed Kc values are 0.36, 0.77, 1.05, 0.69, and 0.25 during initial, development, mid, late, and end growth stages, respectively. These average Kc values can be effectively utilized to schedule irrigation for drip-irrigated wheat crops in the Jalandhar region of Punjab. Irrigating wheat crop under drip irrigation with developed Kc values not only enhances grain yield by 36% but also improves IWUE by three times and saves 61% use of irrigation water as compared to conventional irrigation practices (flood irrigation).

Efficiency of Irrigation Water Use in Egyptian Agricultural Production

Efficiency of Irrigation Water Use in Egyptian Agricultural Production

Plant stress index (PSI) based irrigation scheduling of wheat in Punjab, India

A field experiment was caried out over a period of two years (2022-23 and 2023-24) at Lovely Professional University, Phagwara, Punjab with eight irrigation treatments (based on PSI, soil moisture depletion &amp; critical growth stages) and four replications in RBD Design. The different irrigation levels had an impact on plant growth, parameters contributing to yield, grain and straw production, as well as irrigation water use efficiency (IWUE). Among all the PSI based irrigation treatments, schedule irrigation at 0.50 PSI was found the best irrigation level for growing wheat with significant grain yield (5.67 t ha-1), IWUE (0.092 t ha-1 cm) and gave 11.16% water saving over I50% FC (irrigation as per farmer practices). To schedule irrigation as per the soil moisture depletion approach, irrigation levels I50% FC and I75% FC result in maximum grain yield over PSI &amp; critical growth stage-based irrigation treatments, but this practice does not support sustainable wheat production in water-scarce regions. Therefore, irrigation can be tailored for wheat crops based on 0.5 PSI in water-scarce and water-abundant regions of Punjab.

Index-Based Alteration of Long-Term River Flow Regimes Influenced by Land Use Change and Dam Regulation

The growing population and expansion of rural activities, along with changing climatic patterns and the need for water during drought periods, have led to a rise in the water demand worldwide. As a result, the construction of water storage structures such as dams has increased in recent years to meet the water needs. However, dam construction can bring significant alterations to the natural flow regime of rivers, and it is therefore essential to understand the potential effects of human structures on the hydrological regime of rivers to reduce their destructive impacts. This study analyzes the hydrological changes in the Shahrchai River in response to the Shahrchai Dam construction in Urmia, Iran. The study period was from 1950 to 2017 at the Urmia Band station. The Indicators of Hydrological Alteration (IHA) were used to analyze the hydrological changes before and after regulating, accounting for land use changes and climatic factors. The results revealed the adverse effects of the Shahrchai Dam on the hydrological indices. The analysis showed an increase in the average flow rate during the summer season and a decrease in other seasons. However, the combined effects of water transferring for drinking purposes, a decrease in permanent snow cover upstream of the dam, and an increase in water use for irrigation and agricultural purposes resulted in a decrease in the released river flow. Furthermore, the minimum and maximum daily flow rates decreased by approximately 85% and 65%, respectively, after the construction of the Shahrchai Dam. Additionally, the number of days with maximum flow rates increased from 117 days in the pre-dam period to 181 days in the post-dam period. As a concluding remark, the construction of the Shahrchai Dam, land use/cover changes, and a decrease in permanent snow cover had unfavorable effects on the hydrological regime of the river. Therefore, the hydrological indicators should be adjusted to an acceptable level compared to the natural state to preserve the river ecosystem. The findings of this study are expected to guide water resource managers in regulating the sustainable flow regime of permanent rivers.

Impact of Irrigation Management Decisions on the Water Footprint of Processing Tomatoes in Southern Spain

The water footprint is an increasingly demanded environmental sustainability indicator for certifications and labels in agricultural production. Processing tomatoes are highly water-intensive, and existing studies on water footprint have uncertainties and do not consider the impact of different irrigation configurations (e.g., surface drip irrigation (SDI) and subsurface drip irrigation (SSDI)) and irrigation strategies. This study presents a two-year experimental investigation to determine the water footprint of processing tomatoes grown in southern Spain (Andalusia) and the impact of SSDI and deficit irrigation. Five irrigation treatments were established: SDI1 (surface drip irrigation without water limitation), SDI2 (surface drip irrigation without water limitation adjusted by soil moisture readings), SSDI1 (subsurface drip irrigation without water limitation and a dripline depth of 15 cm), SSDI2 (similar to SSDI1 but with mild/moderate water deficit during the fruit ripening stage), and SSDI3 (subsurface drip irrigation without water limitation and a dripline depth of 35 cm (first year) and 25 cm (second year)). Measurements included crop vegetative growth, leaf water potential, leaf gas exchange, nitrate concentration in soil solution, and crop yield and quality. The soil water balance components (actual evaporation, actual transpiration, deep drainage), necessary for determining the total crop water footprint, were simulated on a daily scale using Hydrus 2D software. Results indicated that SSDI makes more efficient use of irrigation water than SDI. The water footprint of SSDI1 was 20–35% lower than that of SDI1. SSDI2 showed similar water footprint values to SDI1 under highly demanding environmental conditions and significantly lower values (≈40%) in a year with lower evaporative demand. The dripline depth in SSDI was critical to the water footprint. With a 35 cm installation depth, SSDI3 had a significantly higher water footprint than the other treatments, while the values were similar to SSDI1 when the depth was reduced to 25 cm.

Optimal use of irrigation water and fertilizer for strawberry based on weighing production benefits and soil environment

Optimal use of irrigation water and fertilizer for strawberry based on weighing production benefits and soil environment

Modeling climatic, terrain and soil factors using AHP in GIS for grapevines suitability assessment

AbstractThe study carried out in Matera, Italy, used multi‐criteria decision‐making techniques and geographic information systems to identify optimal area management for sustainable grape production. Terrain parameters such as temperature, pH, humidity, soil texture, slope, altitude, nutrients and precipitation were considered. ArcGIS maps were created, and the northwest part of the field was identified as a favorable area. Fuzzy maps were generated, and measurements were taken in each area to determine optimal land management. The results revealed that 51% of the area was very highly suitable for agricultural activities, and 49% was considered high suitable. Receiver operating characteristic (ROC) analysis of the AHP results demonstrated a high level of accuracy, as indicated by the area under the curve (AUC). The produced maps indicated a similar trend of increasing zone management priorities for physico‐chemicals as depth fluctuate. Additionally, results showed that remote sensing indices were the most important variables to predict physico‐chemicals zone management. The study also highlighted that the majority of the area supported plant growth due to favorable temperature and humidity conditions, with only a small portion in the northwest showing less favorable results. By identifying management zones, the study aimed to protect crops, better use of irrigation water and improve yields. This study highlights the potential of integrating satellite remote sensing, GIS technology and AHP as a valuable tool for agricultural land use planners and policy makers in identifying optimal locations for managing grape production.

Precise partial root-zone irrigation technique and potassium-zinc fertigation management improve maize physio-biochemical responses, yield, and water use in arid climate

BackgroundTo optimize irrigation water use and productivity, understanding the interactions between plants, irrigation techniques, and fertilization practices is crucial. Therefore, the experiment aims to assess the effectiveness of two application methods of potassium humate combined with chelated zinc under partial root-zone drip irrigation techniques on maize nutrient uptake, yield, and irrigation water use efficiency across two irrigation levels.MethodsOpen-field experiments were carried out in two summer seasons of 2021 and 2022 under alternate and fixed partial root-zone drip irrigation techniques to investigate their impacts at two irrigation levels and applied foliar and soil applications of potassium humate or chelated zinc in a sole and combinations on maize.ResultsDeficit irrigation significantly increased hydrogen peroxide levels and decreased proline, antioxidant enzymes, carbohydrate, chlorophyll (a + b), and nutrient uptake in both partial root-zone techniques. The implementation of combined soil application of potassium humate and chelated zinc under drought conditions on maize led to varying impacts on antioxidant enzymes and nutritional status, depending on the type of partial root-zone technique. Meanwhile, the results showed that fixed partial root-zone irrigation diminished the negative effects of drought stress by enhancing phosphorus uptake (53.8%), potassium uptake (59.2%), proline (74.4%) and catalase (75%); compared to the control. These enhancements may contribute to improving the defense system of maize plants in such conditions. On the other hand, the same previous treatments under alternate partial root zone modified the defense mechanism of plants and improved the contents of peroxidase, superoxide dismutase, and the uptake of magnesium, zinc, and iron by 81.3%, 82.3%, 85.1%, 56.9%, and 80.2%, respectively.ConclusionsAdopting 75% of the irrigation requirements and treating maize plants with the soil application of 3 g l−1 potassium humate combined with 1.25 kg ha−1 chelated zinc under alternate partial root-zone technique, resulted in the maximum root length, leaf water content, chlorophyll content, yield, and irrigation water use efficiency.

Smallholder farmers’ willingness to pay for improved irrigation water use: the case of Menz Mama Midir Woreda in North Shewa Zone of Amhara National Regional State, Ethiopia

ABSTRACT The water use practices in Menz Mama Midir woreda are very traditional and inefficient. To lessen this problem, water pricing (valuation) has been considered to be a promising tool. This study, therefore, examined smallholder farmers' willingness to pay and determinants affecting their decisions to pay for improved irrigation water use in Menz Mama woreda, North Shewa zone, Amhara national regional state of Ethiopia. Cross-sectional data collected from 215 randomly sampled irrigation beneficiaries were used for analysis. The mean WTP from double bounded dichotomous elicitation method ranges from 164.027 Birr (4.17 USD) to 221.059 Birr (5.62 USD) per year per hectare of irrigable land. The result from the seemingly unrelated bivariate probit model estimation revealed that the sex of the household head, total annual farm income, size of irrigable landholdings of the household, frequency of extension contacts, amount of credit, and dissatisfaction with the existing irrigation service positively and significantly influenced farmers' WTP decisions. In contrast, off-farm income and bid values were negatively related to WTP decisions. Therefore, the aforementioned factors affecting farmers' decisions to pay should be taken into consideration when constructing irrigation schemes in the study area and areas with similar economic and socio-cultural settings.

Assessing the Fates of Water and Nitrogen on an Open-Field Intensive Vegetable System under an Expert-N System with EU-Rotate_N Model in North China Plain.

Nitrate leaching, greenhouse gas emissions, and water loss are caused by conventional water and fertilizer management in vegetable fields. The Expert-N system is a useful tool for recommending the optimal nitrogen (N) fertilizer for vegetable cultivation. To clarify the fates of water and N in vegetable fields, an open-field vegetable cultivation experiment was conducted in Dongbeiwang, Beijing. This experiment tested two irrigation treatments (W1: conventional and W2: optimal) and three fertilizer treatments (N1: conventional, N2: optimal N rate by Expert-N system, and N3: 80% optimal N rate) on cauliflower (Brassica oleracea L.), amaranth (Amaranthus tricolor L.), and spinach (Spinacia oleracea L.). The EU-Rotate_N model was used to simulate the fates of water and N in the soil. The results indicated that the yields of amaranth and spinach showed no significant differences among all the treatments in 2000 and 2001. However, cauliflower yield under the W1N2 and W1N3 treatments obviously reduced in 2001. Compared with the W1 treatment, W2 reduced irrigation amount by 27.9-29.8%, water drainage by over 76%, increased water use efficiency by 5-17%, and irrigation water use efficiency by 29-45%. Nitrate leaching was one of the main pathways in this study, accounting for 8.4% of the total N input; compared to N1, the input of fertilizer N under the N2 and N3 treatments decreased by over 66.5%, consequently reducing gaseous N by 48-72% and increasing nitrogen use efficiency (NUE) by 17-37%. Additionally, compared with the W1 treatments, gaseous N loss under the W2 treatments was reduced by 18-26% and annual average NUEs increased by 22-29%. The highest annual average NUEs were under W2N3 (169.6 kg kg-1) in 2000 and W2N2 (188.0 kg kg-1) in 2001, respectively. We found that optimizing fertilizer management allowed subsequent crops to utilize residual N in the soil. Therefore, we suggest that the W2N3 management should be recommended to farmers to reduce water and N loss in vegetable production systems.

Assessment of climate change impact and resource-use efficiency of lettuce production in vertical farming and greenhouse production in Finland: a case study

PurposeOur aim in this study was to examine lettuce production in vertical farming or in conventional greenhouse production in Northern European conditions from the perspective of climate change impact and environmental sustainability. Further, the goal was to identify practices and choices that could mitigate adverse effects and increase resource-use efficiency, allowing the development of more sustainable production systems.MethodsThis article provides new information of the environmental impacts of lettuce production in greenhouses and vertical farming in Finland, compared using the life cycle assessment (LCA) methodology. The impact categories used were climate change impact, cumulative energy demand, resource use of fossil energy sources, resource use of minerals and metals, land use, and water scarcity. The system boundaries covered the production chains from cradle to farmgate, including inputs in production, as well as direct emissions caused by fertiliser use and the onsite composting of organic waste. The environmental impacts of the two production systems with different energy scenarios were assessed: (1) a greenhouse either with average or renewable energy; and (2) vertical farming either with average or renewable energy and with or without waste heat recovery. The data for vertical farming were based on one Finnish production site and supplementary data for the construction materials. The greenhouse data were based on a previous LCA investigation of average Finnish lettuce production.ResultsThe climate change and all other impact categories were lowest for lettuce produced in vertical farming with renewable energy and waste heat recovery. The climate change impact was largest for lettuce produced in greenhouse with average energy use. For energy use and energy resource use, the impacts of vertical farming were lower than greenhouse production, but for mineral and metal use and water scarcity, the impact of vertical farming was higher for average energy use without heat recovery. Direct land and irrigation water use on the production sites in Finnish circumstances represented only a small share of total land-use and water-use impacts on both production methods.ConclusionPaying attention to the energy source and heat recovery, the environmental sustainability can be advanced in both vertical and greenhouse production systems.