Improving water resources management using different irrigation strategies and water qualities: Field and modelling study

The aim of this study was to investigate the effects of two different irrigation strategies, regulated deficit irrigation, RDI and partial root drying, PRD using surface freshwater (SW) and brackish treated wastewater (TWW) for maize and potato crops. The SALTMED model has been applied using the field measurements of two cropping seasons 2013 and 2014 at the Canale Emiliano Romagnolo, CER’s experimental farm located in Mezzolara di Budrio (Bologna, Italy). In 2013, PRD irrigated potato received 17% less irrigation water than RDI but produced nearly the same yield as under RDI. The water productivity, o naverage, was 11% higher for PRD compared with RDI. For maize 2014 season, the PRD strategy received almost 15% less irrigation water, but produced a yield only 6% lower than that of RDI and gave equal water productivity to RDI. Given that the two strategies received the same amount of rainfall the results favour the PRD over RDI. Had the site not received above average rainfall (258 mm in 2013 and 259 mm during the 2014 growing seasons), PRD might have produced higher yield and water productivity than RDI. In terms of model simulations, overall, the model showed a strong relationship between the observed and the simulated soil moisture and salinity profiles, total dry mater and final yields. This illustrates SALTMED model’s ability to simulate the dry matter and yield of C3 and C4 crops as well as to simulated different water qualities and different water application strategies. Therefore, the model can run with “what if” scenarios depicting several water qualities, crops and irrigation systems and strategies without the need to try them all in the field. This will reduce costs of labour and investment

Is the partial root drying irrigation method suitable for sandy soils? Field experiment and modelling using the Saltmed model

This study investigated the impact of regulated deficit irrigation (RDI) and partial root drying (PRD) on soil moisture, dry matter, and yield and water productivity of maize grown in sandy soil in Egypt. The experiment was conducted in 2013 and included eight treatments of RDI and PRD. Four RDI treatments [100% full irrigation requirement, FI (control), 80% FI, 60% FI and 40% FI] and four PRD treatments [100% PRD, 80% PRD, 60% PRD and 40% PRD] were conducted. The experimental and simulated results using the SALTMED model showed that maize yields obtained under RDI were higher than those obtained under PRD; this may be due to the fact that the soil is sandy and the PRD treatment received relatively less irrigation water. The latter perhaps have led to a smaller and narrower wetted soil volume within the root zone, and possibly some of the water was partly lost below the root zone due to the high infiltration rate commonly associated with sandy soils. The correlation between the observed and simulated grain yield showed that the SALTMED model was able to simulate grain yield and water productivity for all treatments with high accuracy, producing an average R2 of 0.98 and 0.95, respectively

Applying partial root drying drip irrigation in the presence of organic mulching. Is that the best irrigation practice for arid regions? Field and modelling study using the saltmed model

This research aimed at investigating the impact of irrigation systems, a deficit irrigation strategy and organic mulching using rice straw on maize water productivity in Egypt's arid conditions. The field experiment included 16 treatments over 2 seasons, 2015 and 2016. Irrigation systems were a drip irrigation system (DIS) and a furrow irrigation system (FIS), while the irrigation strategies were 100% full irrigation (FI), 75% FI, 50% FI and partial root drying (PRD). Organic mulching using rice straw (OMRS) was also investigated. The experimental results indicated that there was a positive impact of applying a PRD strategy by drip irrigation in the presence of organic mulching on the yield (12.6 t ha‐1 for 2015 and 12 t ha‐1 for 2016) and on the water productivity of maize (4.81 kg m‐3 for 2015 and 4.58 kg m‐3 for 2016), but under the control treatment (FIS with 100% full irrigation and without organic mulching) yield was 7.22 t ha‐1 for 2015 and 7.34 t ha‐1 for 2016 and water productivity of maize was 0.64 kg m‐3 for 2015 and 0.62 kg m‐3 for 2016. The SALTMED model simulated reasonably well the soil moisture and salinity distribution as well as maize dry matter, yield and water productivity for all treatments, with R2 of 0.998, 0.997 and 0.996, respectively. The results support the use of a PRD strategy by a drip irrigation system accompanied by an organic mulch of rice straw instead of the commonly used furrow irrigation. The PRD would save more fresh water, achieve higher yields and water productivity. In addition, mulching would reduce evaporation losses, retain soil moisture and increase organic matter content

The effect of saline irrigation water on the yield of pepper: experimental and modelling study

The present study investigates the impact of using saline water on pepper crop yield and the application of a numerical model in predicting soil moisture and relative yield under saline irrigation conditions. In the greenhouse experimental study conducted in Antalya, Turkey, the effects of different irrigation regimes with salinity treatments using a drip irrigation system were investigated for two pepper varieties. The irrigation regimes consisted of four irrigation treatments with four salinity levels in two cropping seasons—spring 2011 and autumn 2011. The numerical model SALTMED was used and calibrated using measured soil moisture of a control experiment run during spring 2011. After the calibration, the model was validated using other experimental treatments during spring 2011 and all the experimental treatments in autumn 2011, with appropriate salinity stress parameter π50 values which are calibrated versus the highest salinity treatments in the spring 2011 and autumn 2011 experiments. The predicted results show the ability of the model to reproduce the measured soil moisture at three soil layers 0–20, 20–40 and 40–60 cm. The predicted relative yield results are in good agreement with measured data. Although the numerical model SALTMED has been used in several studies in the past, this is the first study that illustrates the potential capacity of the model for use in managing greenhouse production

Yield, Quality and Water Consumption of Stevia rebaudiana Bertoni Grown under Different Irrigation Regimes in Southern Italy

Stevia rebaudiana Bertoni is a herbaceous perennial plant originating in the north-east of Paraguay. Its leaves contain low-calorie sweetening agents that can be used as a natural alternative to artificial sweeteners. The leaves are consumed in special human diets and for the treatment of various diseases. The aim of the present work is to study water consumption, yield potential and quality characteristics of this species under different irrigation levels in southern Italy. The field work was carried out in 2006-2007. Irrigation treatments consisted of a control (T100), irrigated with 100% restitution of water consumption and two treatments that received a water depth of 33% (T33) and 66% (T66) of treatment T100. Watering volume was estimated to replenish the soil profile to field capacity for a depth of 0.40 m. The crop was harvested twice a year, and agronomic performance as well as the major cation and glycoside contents (stevioside and rebaudioside A) were evaluated. Overall, the crop coefficients were similar between the two years, although in each year the second growing period showed higher values due to the higher evaporative demand of this period. Interactions of years with irrigation treatments and harvest time were not significant either for yield or yield components. In both cuts the T100 treatments achieved 40% higher leaf dry yield than T33, while T66 showed intermediate values. The harvest index and water use efficiency showed no differences between the two cuts for the same treatments, while the values of both indices decreased with the increase in irrigation regime. Stevioside, rebaudioside A and cation content in the leaves were unaffected by irrigation regime. In order to develop the field cultivation of this species, field experiments are required to prepare a cultivation protocol as well as a genetic improvement program to develop varieties that better respond to the local environment

SALTMED model as an integrated management tool for water, crop, soil and N-fertilizer water management strategies and productivity: field and simulation study

This paper is a follow-up from a paper which described the SALTMED model. In this paper the focus is on the model application,using data of tomato and potato from field experiments in Italy, Greece (Crete) and Serbia. Drip full irrigation, drip deficit irrigation, drip as partial root drying (PRD), sprinkler and furrow irrigation were used in the 3-yr experiment between 2006 and 2008. In drip-irrigated experiments, the drip line was 10–12 cm below the surface. Dry matter, final yield, soil moisture and soil nitrogen were successfully simulated. The study showed that there is a great potential for saving water when using subsurface drip, PRD or drip deficit irrigation compared with sprinkler and furrow irrigation. Depending on the crop and irrigation system, the amount of fresh water that can be saved could vary between 14 and 44%. PRD and deficit drip irrigation have proved to be the most efficient water application strategies with the highest water productivity

Worldwide evaluations of quinoa: preliminary results from post International Year of Quinoa FAO projects in nine countries

Chenopodium quinoa Willd, a high quality grain crop, is resistant to abiotic stresses (drought, cold, and salt) and offers an optimal source of protein. Quinoa represents a symbol of crop genetic diversity across the Andean region. In recent years, this crop has undergone a major expansion outside its countries of origin. The activities carried out within the framework of the International Year of Quinoa provided a great contribution to raise awareness on the multiple benefits of quinoa as well as to its wider cultivation at the global level. FAO is actively involved in promoting and evaluating the cultivation of quinoa in 26 countries outside the Andean region with the aim to strengthen food and nutrition security. The main goal of this research is to evaluate the adaptability of selected quinoa genotypes under different environments outside the Andean region. This paper presents the preliminary results from nine countries. Field evaluations were conducted during 2013/2014 and 2014/2015 in Asia (Kyrgyzstan and Tajikistan), and the Near East and North African countries (Algeria, Egypt, Iraq, Iran, Lebanon, Mauritania, and Yemen). In each country, the trials were carried out in different locations that globally represent the diversity of 19 agrarian systems under different agro-ecological conditions. Twenty-one genotypes of quinoa were tested using the same experimental protocol in all locations consisting in a randomized complete block design (RCBD) with three replicates. Some genotypes showed higher yields and the Q18 and Q12 landraces displayed greater adaptation than others to new environmental conditions. The Q21 and Q26 landraces were evaluated with stable and satisfactory levels of yield (>1 t.ha−1) in each of the different trial sites. This production stability is of considerable importance especially under climate change uncertainty. While these results suggest that this Andean crop is able to grow in many different environments, social, and cultural considerations remain crucial regarding its possible introduction as a staple food in new cropping systems around the world

Integrated management tool for water, crop, soil and N-fertilizers: the Saltmed model

Good management will be required to double food production by 2050. Testing management strategies is commonly carried out in the field. Such trials are costly and require quite a long time to produce consistent and reliable results. An alternative option to field trials would be the use of tested models. Models can run with ‘what-if’ scenarios depicting different types of field management. They are a less costly and faster alternative to field trials. In contrast to some existing models, the SALTMED 2013 model is designed for general applications that include various irrigation systems and water application strategies, water of different qualities, variety of crops and trees, different nitrogen based fertilizers and different soil types. The model can simulate up to 20 fields with different treatments, different crops, different irrigation systems and management as well as different N-fertilizer applications. The SALTMED model has been tested using field experiment data from Portugal, Italy, Denmark, Morocco, Egypt, Syria, Brazil and Iran. It successfully simulated soil moisture, salinity, nitrogen content, grain yield and total dry matter. The model provides academics, professionals and extension services with a management tool for crops, soil, water and nitrogen fertilizers. This paper describes the processes, the equations of the model and summarizes the different applications and results obtained

Quinoa Phenotyping Methodologies: An International Consensus

Quinoa is a crop originating in the Andes but grown more widely and with the genetic potential for significant further expansion. Due to the phenotypic plasticity of quinoa, varieties need to be assessed across years and multiple locations. To improve comparability among field trials across the globe and to facilitate collaborations, components of the trials need to be kept consistent, including the type and methods of data collected. Here, an internationally open-access framework for phenotyping a wide range of quinoa features is proposed to facilitate the systematic agronomic, physiological and genetic characterization of quinoa for crop adaptation and improvement. Mature plant phenotyping is a central aspect of this paper, including detailed descriptions and the provision of phenotyping cards to facilitate consistency in data collection. High-throughput methods for multi-temporal phenotyping based on remote sensing technologies are described. Tools for higher throughput post-harvest phenotyping of seeds are presented. A guideline for approaching quinoa field trials including the collection of environmental data and designing layouts with statistical robustness is suggested. To move towards developing resources for quinoa in line with major cereal crops, a database was created. The Quinoa Germinate Platform will serve as a central repository of data for quinoa researchers globally