Irrigation Doses Research Articles

Improvement of Salt Leaching Efficiency and Water Content of Soil through Irrigation with Electro-Magnetized Saline Water

While the advantageous effects of using magnetic and electromagnetic treatment (ET) of brackish and saline waters on soil salinity reduction in the root zone were largely reported, more studies are needed to answer questions about the soil salt leaching efficiency and the effect of the duration of the exposure to ET. For this aim, pot experiments were conducted using an Aqua-4DR physical water treatment device. The first experiment included two trials. The first trial considered five concentrations: C0:1.0; C1:4.5; C2:9; C3:13.5; and C4:18 dS m−1. The results revealed that the volume and the salt concentrations of the drained waters were significantly higher under irrigation with ET saline waters than those provided by untreated waters. The drained fraction of water varied from 20 to 26% under irrigation with untreated water and increased from 33 to 56% under irrigation with electro-magnetized water, indicating an improvement in the salt leaching. The second trial was carried out with different irrigation doses. The results showed that the higher the dose, the more obvious and significant the ET effect. The different treatment durations of water exposure revealed that the volume and salinity of drained water significantly increase as the ET duration increases. An increase in the ET duration also induces an increase in the soil water content of around 2.5%. Based on the experimental findings, we may conclude that the ET of saline water can reduce the adverse effect of salinity on the top soil, but these leached salts are carried away in depth and there is no concentration limit of water to the effect of the ET.

The Origin and Type of Inoculum Determine the Effect of Arbuscular Mycorrhizal Fungi on Tomato under Different Irrigation Regimes

Arbuscular mycorrhizal fungi (AMF) play a crucial role in the resilience of plants subjected to water deficit. The objective of this study was to evaluate the impact of AMF from a semi-arid and humid ecosystem, applied as inocula (two monospecific and two consortia), and three irrigation doses (100%, 85%, and 70%) on tomato plant growth. A factorial experiment in a completely randomized design was used. Colonization with monospecific inocula (EH and ES) showed contrasting differences at 85% and 100% irrigation rates. With gradually increasing irrigation rates, colonization decreased with the CH consortium, while the CS consortium showed similar colonization levels at all three irrigation rates. AMF from humid environments (monospecific or in a consortium) did not affect equatorial diameter when the irrigation rate was reduced by 15%, while polar diameter was similar at all three irrigation rates. Inocula from the semi-arid ecosystem promoted the greatest equatorial and polar diameters at the 100% irrigation dose. The monospecific inoculum of C. etunicatum (ES) showed great potential to promote plant growth and development at the 100% irrigation dose and could be a biotechnological tool to improve tomato yield under conditions similar to those of this study.

Impact of different irrigation & trace metals treatments on onion (Allium cepa L.) plant growth cultivated in rural and urban soils

AbstractThe present research attempts to evaluate the response of Allium cepa L. to different irrigation treatments and to indicate the optimum scheme along with plant growth, throughout a pot experiment during Spring 2021. The experimental procedure consisted of two different soil types, three treatments of irrigation and two levels of Cu and Zn (low and high), in four replications each. Irrigation events started when the lower allowable limit (LAL) reached a defined percentage of filed capacity (FC): 40% FC, 60% FC, and 75% FC and an irrigation event occurred with irrigation doses (Dn) equal to 60% FC, 40% FC, and 25% FC, respectively, to reach the value of FC. According to the results, the minimum yield was achieved by both soil types when Cu and Zn solution concentration and water stress were at their highest levels, although light texture soil (loamy sand—LS) allowed for superior growth. The optimum scheme was: the lower concentration of Cu and Zn solution along with LAL equal to 60% FC at the loamy sand soil. The outcomes suggest that frequent short irrigation doses at light-texture soils can result in yield response indicators when planted in pots. Furthermore, the influence of Cu and Zn cations at low concentrations can be advantageous for onions because Cu cations provide protection against fungal diseases, while Zn cations serve as nutrient support reducing the risk of metals deficiency.

Low-cost small-scale irrigation for developing an agroforestry system in the semi-arid zone of Niger: case of the apple of the Sahel (Ziziphus mauritiana L.)

Cultivation of the ‘Apple of the Sahel’ (also known as Indian Jujube) is central to the food security, nutrition, and income of rural communities in developing countries like Niger. However, rainfall variability significantly impacts the development of this plant. This study aims to determine the effects of seasonal water regimes on the growth and productivity of the Apple of the Sahel. The trials were conducted in 2020 and 2021 during the rainy and dry seasons at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) experimental site in Sadore, Niamey, Niger. The experiment was arranged in a factorial design with three irrigation doses (D) and three irrigation systems (G) as main and subplot factors, respectively. The sub-subplot factors were irrigation frequencies (F) and growth boosters (B), each with two levels. In the dry season, irrigation dose application significantly (p = 0.001) increased soil volumetric water content (vwc). A similar increase in soil vwc was achieved under small-scale drip irrigation with an application of the same dose of organic material (p = 0.001). The diameter of the Apple of the Sahel trees significantly increased (p = 0.03) under the small-scale drip irrigation systems with 6.72 mm recorded under the two-drip irrigation system (G2) as compared with the manual system (G0). In the dry season, the total fruit harvest of Apple of the Sahel recorded had increased (p = 0.04) under the irrigated system, varying from 112 to 246% depending on the number of drippers, and compared to the manual system. These results highlight that small-scale drip irrigation should be used in combination with appropriate water and fertilizer management to improve water availability and tree yield in agroforestry systems in arid regions such as Niger.

Optimizing irrigation schedules of greenhouse tomato based on a comprehensive evaluation model

In the context of climate change, water availability has emerged as a pressing concern in agriculture, indicating the urgency to enhance irrigation management. Nevertheless, accurately quantifying irrigation schedules in diverse climates and soil textures remains a complex challenge. Here, a three-year irrigation experiment (2020–2022) of greenhouse tomato was conducted at three typical locations (Yulin, Yangling and Hanzhong) in northwest China. The irrigation schedules were determined by the cumulative evaporation (CE) measured from a 20 cm pan. A total nine treatments were set by combining three irrigation frequencies (IF) with three single doses (ID). Twenty indices related to tomato growth, photosynthesis, yield and water use, fruit quality, and environmental benefit were evaluated comprehensively by using TOPSIS (technique for order preference by similarity to ideal solution) and GRA (grey relational analysis) methods of combining weights based on game theory. The results showed that the indicator with highest weight was yield, followed by crop water productivity and vitamin C. The optimal ranges of irrigation frequency (irrigation dose) were determined as follows: 10.00–11.08 mm (0.81–0.90 CE) in Yulin, 13.12–15.68 mm (0.77–0.89 CE) in Yangling, and 11.44–16.40 mm (0.67–0.77 CE) in Hanzhong, respectively. This study introduces a method applied to prioritize the key indicators for irrigation scheduling, providing a reference for optimizing irrigation practices in greenhouse tomato production and improving water management in agriculture.

Green Manuring and Irrigation Strategies Positively Influence the Soil Characteristics and Yield of Coriander (Coriandrum sativum L.) Crop under Salinity Stress

This study shows the influence of soil salinity and irrigation dose on biomass production and its impact on some edaphic indicators and functions. For this purpose, an experiment was carried out in two representative soils from Murcia (SE Spain), one slightly saline (LS) and the other saline (S), where an oat–vetch green manure was intercalated between a spinach cycle and a coriander cycle; the latter being subjected to three different irrigation doses (deficient, optimum and surplus). Rapid response indicators (ECext, cations and anions in the soil solution, etc.) were monitored, as well as the material balances, in particular C and salts. Green manure and crop residues increased soil OC by 12.5% and reduced Na+ and NO3− concentrations. Total biomass production was also affected by salinity, both in oat–vetch, 35.9 and 31. 9 tm ha−1 in LS and S, respectively, and in the coriander crop, where the irrigation dose was decisive, obtaining around 29 tm ha−1 with the optimum and surplus doses and significantly lower amounts with the deficit dose: 20.4 tm ha−1 in LSD and 14. 0 in SD. Therefore, it is necessary to adjust the irrigation doses, since deficit irrigation significantly reduces production and the surplus does not lead to an increase with respect to the optimum, while also causing ions to leach to depth horizons, as is the case for NO3−, Cl− and Na+, with the consequent risk of contaminating the water table.

Calibration and validation of solar radiation-based equations to estimate crop evapotranspiration in a semi-arid climate

The Abtew and Jensen-Haise solar radiation-based equations were used to estimate evapotranspiration, considering the limited climatic data in many locations. Both equations were proven to successfully predict the potential evapotranspiration (ETO) compared with the standard Penman–Monteith (PM) method in two Mediterranean countries. Calibration of the constant coefficient k of the Abtew equation showed substantial differences compared to recommended values (1.22 vs. 0.53), with the highest values observed during September (1.46). Validation of ETO measurements using calibrated Abtew equation against the PM method indicated a high correlation coefficient (r2 = 0.97, RMSE = 0.61). Further, evapotranspiration requirements, using the calibrated empirical equation, were calculated for olives (449 mm) and citrus (807 mm) showing a good agreement with recommended values for dry climate regions. Therefore, the tested equations could be safely used to predict frequencies and doses of irrigation in semi-arid climates, considering limited climatic data availability.

Promotion of Improved Onion (Nafis Variety) Production Technology under Irrigated Conditions in Nyangatom District, Low Land Area of South Omo Zone

Onion is an important cash crop that could enhance the income of agro-pastoralists in Nyangatom woreda as the area has huge potential for water availability from the Omo River and fertile land. However, access to improved onion variety is limited in the area. Thus, this study aimed to demonstrate the improved onion variety with its agronomic management in the production season. Onion growers were purposely selected and have taken training on onion production by using recommended doses of fertilizers, pesticides, irrigation, and suitable agronomic practices. Each agro-pastoralist covered 0.064 hectares of land by improved onion. The recorded data from the field experiment and agro-pastoral perceptions were analyzed through simple descriptive and preference ranking tools. From the result of the demonstration trial, the mean bulb yield of the improved onion (Nafis variety) was 125 qt/ha. The average return obtained from the sale of onion bulbs per hectare was 334,925 Ethiopian birr. Moreover, the benefit-to-cost ratio of improved onion production was 8.34:1, which indicates the benefits outweigh the costs, suggesting a positive return on improved onion production in the area. The agro-pastoralist’s preference further showed that the Nafis variety was the best one or superior to the local variety in terms of its high-yielding ability, dark green leaf color, medium bulb size, and market preference. Therefore, the authors suggest the respective government and non-government bodies to further promote improved onion in the area.

Effect of Water Regime and Soil Maintenance Mode on Vegetative Growth and Peach Tree Production

The peach tree is a very water-demanding species that is affected by water stress, which is worsening due to global warming. The soil environment is also influenced by tillage and cropping methods, which affect the water content, temperature, aeration, and organic matter of the soil. Weed control is one of the most crucial cultural practices in arboriculture since weeds can compete with fruit trees for resources. This paper aims to measure the impact of water stress combined with different soil maintenance methods on vegetative growth and peach tree production. Different evapotranspiration conditions (ETc) were used. Two irrigation doses R1 (80% of ETc) and R2 (100% of ETc) were combined with three soil maintenance modes T1 (Sapping), T2 (Sickle tillage), and T3 (Chemical maintenance). The findings highlighted water stress reduces the growth and development of the peach tree but did not have a significant impact on yield when the irrigation dose was reduced by 20%. The sapping and sickle maintenance modes recorded the best results for most of the parameters, while the chemical maintenance mode had a positive effect on the total number of fruits and yield under the 100% of ETc water regime.

Utilization of Vermicompost Sludge Instead of Peat in Olive Tree Nurseries in the Frame of Circular Economy and Sustainable Development

The survival of newly planted seedlings and their successful development after transplantation, including faster plant growth, improved plant quality, larger production, and the absence of dependence on arable land, is one of the primary goals of horticultural nurseries. Although peat is the most frequently used amendment in commercial potting substrates, exploiting it degrades essential ecosystems like peatlands and uses slowly renewable resources. This study evaluated the growth and nutrition of olive-rooted cuttings when peat was partially or completely replaced with vermicompost, searching for more sustainable methods and recovering urban wastewater treatment sludge sequentially. The progress of the plants’ growth was compared to that of corresponding plants in which commercial peat had been used as substrate. Leachates from every procedure were also examined, and the results revealed that trace element and heavy metal contents were much lower than those deemed hazardous for aquifers and soil. The outcomes indicated that peat might be effectively replaced with vermicompost sludge, promoting plant growth without further fertilizer. Comparatively to olive cuttings grown in peat-based substrates, those grown in compost-based substrates experienced improved nutrition and development. Further, it was found that irrigation doses were significantly reduced in treatments with a significant amount of vermicompost as the water drained more slowly. A technical-economic analysis was being conducted in the meantime, illustrating the financial benefits for a nursery when peat is replaced with vermicomposted sludge.

The Effect of Increasing Irrigation Rates on the Carbon Isotope Discrimination of Apple Leaves

13C discrimination (Δ13C) has been used in research as an indicator of water availability in crops; however, few data are available concerning fruit trees. The aim of this study was to examine the effect of irrigation on the Δ13C values of apple leaves. We assumed that Δ13C would increase with irrigation intensity. The Δ13C of apple trees (Malus domestica) cv. ‘Red Jonaprince’ was determined in the years 2019–2022. Leaf samples were collected in spring, in June, at the beginning of the irrigation campaign, and in autumn, in September, following the harvest. The irrigation doses were applied to replenish the water consumption, 0% (ET0), 50% (ET50), 75% (ET75), and 100% (ET100), of the calculated evapotranspiration (ET) levels. In November, the leaves collected from different positions on the shoots were sampled, assuming the Δ13C signature would reflect the changes occurring in the water supply during their growth. The irrigation rates had a significant effect on the Δ13C of the leaves when the data for the spring and summer months were pooled. On average, Δ13C increased from 20.77‰ and 20.73‰ for ET0 and ET50, respectively, to 20.80‰ and 20.95‰ for ET75 and ET100, respectively. When the data obtained for the spring and summer months were analysed separately, the effect of irrigation was weak (p < 0.043). The Δ13C value was always higher for treatment ET100 than treatment ET0, for individual experimental years and terms; however, the differences were minor and mostly insignificant. The leaf position had a strong significant effect on Δ13C; the values gradually decreased from the leaves growing from two-years-old branches (22.50‰) to the youngest leaves growing at the top of the current year’s shoots (21.07‰). This order was similar for all the experimental years. The results of the experiment suggest that 13C discrimination in apples is affected not only by water availability during growth, but also by the use of C absorbed in previous years.

NIR spectroscopy: a tool for determination of maturity stage of sweet cherries and their quality after different irrigation doses

NIR spectroscopy: a tool for determination of maturity stage of sweet cherries and their quality after different irrigation doses

Effect of different soil amendments on irrigation and crop yields in the oases of southern Tunisia

In the oasis agro-system, salinization and hydromorphy are the principal degradation factors that negatively affect the soils. These two processes are the result of the rise of the water table caused by the overdose of irrigations. To counteract soil degradation and restore field productivity, the oasis farmers turn to use sandy and manure amendments. Therefore, three treatments (Control (C), sandy amendment (T1) and combined amendments composed by sand and manure (T2)) has been applied in Nefzaoua oasis to evaluate the effect of different amendments on oasis soil fertility, irrigation parameters, and barley yield. Results showed that T2 enhanced yield parameter (3,07 t/ha) compared to control treatment (1.85 t / ha) thanks to the improvement in the total nitrogen concentration (1.38 g kg -1), soil organic carbon (28.74 g kg- 1) and therefore C / N ratio (20.78) for T2 treatment at the level of the 0-20 cm layer. The results revealed that sand + manure combination (T2) enhanced the irrigation dose that can be effectively applied for the barley plants (19.61 mm) compared to the control treatment (15.49 mm) and T1 treatment (12.26 mm). In addition, the combined treatment T2 declined significantly the oasis soil bulk density leading to rise the porosity of the top layers (0-20 cm). Our results obtained confirmed the effectiveness of the combined amendment composed of sand and manure in improving the fertility and productivity of the amended oasis soil. Keywords: Soil amendments, irrigation, agro-system, soil degradation

Effect of removing the spring flush and irrigation on the reflowering and late ripening of cactus pear Opuntia ficus-indica (L.) Mill.

The effect of removing the spring flush and three irrigation doses on cactus pear’s reflowering and late ripening were studied. Removing the spring flush (scozzolatura practice) and irrigation have a significant effect (p ≤ 0,05) on the reflowering and late ripening of cactus pear. In not irrigated and not scozzolaturated plants (NINSP), the flowering extended from March 10 to May 25, 2017, and the ripening extended from May 20 to August 15, 2017. Whereas, in irrigated and scozzolaturated plants (ISP) the reflowering extended from June 15 to August 24, 2017, and the ripening extended from July 21 to November 20, 2017. The number of growths was higher in ISP (92-103 per plant) than in NINSP (81 per plant). Fruit yield was higher in NINSP (56.2 t ha-1) than in ISP (26.2-36.5 t ha-1), but fruit mass (123-131 g) and fruit length (7.83-7.92 cm) were higher in ISP than in NINSP (fruit mass: 103 g and fruit length: 7.72 cm). The rate of juice in fruits was also higher in ISP (49-55 %) than in NINSP (43 %), and the content of sugars was higher in NINSP (15.20 °Brix) than in ISP (13.83-14.56 °Brix).

Estimation of corn coefficients with vegetation indices using multispectral camera and drone

Optimum irrigation scheduling and new technologies are the key to the successful practice of modern agriculture and natural resources, such as water management. Α three-year research project was conducted at Velestino, Magnesia, Greece. The aim was to study whether vegetation indices can be used to estimate the crop coefficients of corn in order to apply an intelligent method of irrigation using drones in the future. The normalised difference vegetation index (NDVI), the soil-adjusted vegetation index (SAVI), the renormalised difference vegetation index (RDVI) and a new index [difference infrared – green vegetation index (DIGVI)] were calculated using multispectral photos from a camera adapted to a drone. Three different methods were applied to calculate the crop coefficients: (i) the water balance and the FAO Penman-Monteith reference evapotranspiration, (ii) the climatic data, (iii) the vegetation indices. The irrigation dose covered 100% of the crop water needs according to the soil moisture measurements and the single crop coefficient values. The statistical analysis and the simple linear regression method showed that the corn crop coefficients can be estimated when these indices are used as independent variables.

Agro-Ecological Impact of Irrigation and Nutrient Management on Spinach (Spinacia oleracea L.) Grown in Semi-Arid Conditions

The environment is affected by most anthropogenic activities; among them, agriculture is one activity with more negative effects, especially when management is inadequate, causing soil degradation or contamination. This paper presents the results of an agronomic field trial on a spinach (Spinacia oleracea L.) crop. The objective of which was to monitor soil and crop properties under two doses of irrigation and organic fertilization. The results showed that the use of excessive doses of irrigation and fertilization increased the electrical conductivity (ECext) from 5.5 to 8.5 dS m−1 and the concentration of ions in the soil solution which, for the most soluble ions (NO3−, Cl−, Na+), leached towards the deep horizons, reaching 2194.8 mg L−1 in the case of NO3−. However, their use did not increase spinach production and is thus a waste of resources that increases the risk of soil salinization. Nutrient inputs to the soil were much higher than extractions (between 12% for N and 99% for Fe), partly because of agronomic management and especially because of the return of crop residues, which increased the organic carbon stock by about 2500 kg ha−1 (4–6%), enhancing its function as a CO2 sink. These surpluses form part of complex organic structures or are immobilized as carbonates or alkaline phosphates. Preservation of the agrosystem studied requires limiting the use of low-quality irrigation water and adjusting fertilization.

Irrigation of protected pepper crops according to growth stage using dynamic evapotranspiration estimates increases the water use efficiency

Current knowledge on crop irrigation in greenhouses is limited, and most irrigation measures are based on evapotranspiration (ET) estimated using external climatic conditions. Moreover, crop water requirement estimation by the Penman-Monteith (PM) model assumes complete coverage of the soil by the plants and usually does not account for partial cover, which changes during the growth of annual crops. The main goals of the present research were: (i) to develop and apply irrigation demand estimates for greenhouse pepper crops during their growth, based on internal meteorological conditions and real-time plant characteristics; and (ii) to examine the effect of that irrigation on yield. Experiments were conducted during two consecutive seasons in greenhouse pepper crops in the Jordan Valley region of eastern Israel. Four irrigation treatments were applied based on four different ET models: (i) PM model for outside reference evapotranspiration based on the FAO56 methodology, also denoted as the commercial treatment; (ii) PMrb model for pepper plants, which is a standard PM model in which a boundary layer resistance replaces the aerodynamic resistance; (iii) Shuttleworth-Wallace Layer (SWL) model which considers the soil and plants as separate interactive layers; (iv) Shuttleworth-Wallace Patch (SWP) model which considers the soil and plants as independent patches. The commercial treatment used external climatic conditions from a nearby meteorological station, whereas the other three treatments used internal meteorological conditions measured inside the greenhouse. Results showed a high correlation (R2 > 0.88) between leaf area index, vegetation cover fraction, and plant height during plant growth. Using the same meteorological conditions inside the greenhouse, the seasonal ET estimated by the PMrb model, which considers full vegetation cover, was larger by 21-28% than the SWL and SWP models, which consider the partial plant cover. Irrigation doses were deduced from ET multiplied by crop coefficients derived in a previous study for the same crop and structures. Using average data of the two seasons, we found that seasonal irrigation based on the two SW models was lower by 5-15% than that based on PMrb, and by 35-42% than the commercial irrigation. The water use efficiency of the commercial treatment was the lowest, while for the other treatments it was about 0.02 ton m-3 and higher by about 40% than the commercial. We conclude that irrigation of annual crops based on partitioning ET into evaporation and transpiration based on crop coverage and using internal climatic conditions allows water-savings without significant yield loss.

Effect of deficit irrigation and soil fertility management on wheat production and water productivity in the Upper Blue Nile Basin, Ethiopia

In the Ethiopian Upper Blue Nile Basin, like in other regions in the world, agricultural productivity is declining due to water scarcity owing to longer dry seasons coupled with soil acidity−induced fertility problems. Wheat is one of the major food security crops in Ethiopia but its productivity is reduced due to water scarcity, especially during the irrigation season. Addressing these problems might be essential to increase productivity. This study explores the effect of deficit irrigation (DI) combined with lime, manure and inorganic fertilizer on wheat production and water productivity (WP) in the Koga irrigation scheme, Ethiopia. Four levels of DI strategies (100% ETc or 0% deficit as a control, 80%, 60% and 50% ETc) were applied for two irrigated seasons. Five levels of soil fertility management were applied for four consecutive cropping seasons: (i) 0.86 t ha−1 lime combined with 3 t ha−1 manure and full dose urea and NPS−B (hereafter referred to as inorganic fertilizer) (L3); (ii) 1.15 t ha−1 lime combined with 3 t ha−1 manure and full-dose inorganic fertilizer (L2); (iii) 1.43 t ha−1 lime combined with 3 t ha−1 manure and full dose inorganic fertilizer (L1); (iv) 3 t ha−1 manure combined with full dose inorganic fertilizer (M); and (v) full dose inorganic fertilizer alone (C). The grain yield and biomass data were collected at harvest from a sample area of 2 m × 3 m from each plot with three replicates. The effect of DI and liming, as well as manuring on average grain yield and biomass, were highly significant. Under all irrigation scenarios, higher grain yield and biomass were found at L1, L2, L3 and M (in that order), compared with C. The highest WP was obtained at 50% ETc irrigation dose, compared with 60%, 80% and 100% ETc (in that order). Yet, the lowest WP was found at C under all irrigation scenarios compared with L1, L2, L3 and M. The WP increased when the amount of water supply decreased and liming doses increased. The application of full dose lime and manure combined with 50% ETc DI resulted in comparable grain yield, biomass and WP as 100% ETc full irrigation at L3 and M. It could be concluded that liming and manuring could be used to mitigate the yield penalty effect of DI in the study area. In scenarios where farmers have to pay for water, profitability rises as the irrigation water supply reduces. Thus, under such conditions, a 50% ETc irrigation scenario is more profitable than scenarios with 60%, 80% and 100% ETc irrigation.

Vegetative growth, yield, and crop water productivity response to different irrigation regimes in high density walnut orchards (Juglans regia L.) in a semi-arid environment in Argentina

The area dedicated to walnut orchards has recently expanded in central-western Argentina. Nevertheless, studies on crop water demand are scarce and fundamental in semi-arid environments. This work aims to evaluate the effects on stem water potential (SWP) and stomatal conductance (gs), vegetative growth (trunk cross-sectional area, canopy volume, and canopy porosity), and water productivity in terms of yield of four water irrigation regimes T50, T75, T100, and T125. The plants were irrigated at 50%, 75%, 100%, and 125%, of crop evapotranspiration, respectively over two consecutive seasons (2018–2019 and 2019–2020). The experiment was carried out in a young walnut orchard cv. Chandler in a semiarid environment in La Rioja province, Argentina. SWP and gs had similar seasonal behavior in both seasons. T100 SWP remained between 0.5 and 0.8 MPa, like T75, while T50 reached minimum values of − 1.0 MPa. Stomatal conductance was less responsive than SWP to water deficit, showing significant differences only at 100 days after bloom. Vegetative growth and yield components did not differ among treatments. Compared to T100 and T50, crop water productivity (CWP) increased from 4.30 to 5.29 dry yield mm−1 ha−1 in 2018–2019 and from 5.25 to 7.28 kg dry yield mm−1 ha−1 in 2019–2020; while T75 CWP did not differ from the CWP of T100. Irrigation doses greater than crop requirements (T125) have no effect on yield if compared with T100, and in terms of the water productivity function, irrigation at 90% of T100 would have allowed for maximum productivity in both seasons.

Growth Characteristics of Five Plum Varieties on Six Different Rootstocks Grown in Containers at Different Irrigation Levels

In contrast to other European countries, the nurseries in Hungary mainly use Myrobalan seedlings as rootstock for plum trees; no experience with other rootstocks is available yet. The aim of our research was to gather experience and recommend rootstocks to growers that are adapted to the climatic conditions and can be used in high-density intensive orchards. In the experiment, six rootstocks (Myrobalan seedlings, ‘St. Julien GF655/2’, ‘St. Julien A’, ‘Fereley’, ‘Wangenheim’ and ‘WaVit’) and five varieties (‘Topper’, ‘Toptaste’, ‘Topfive’, ‘Čačanska lepotica’ and ‘Jojo’) were tested. The experimental plantation was established in Kecskemét, in the lowland region of Hungary, which is characterised by low humus content and dry climatic conditions. The trees received two different irrigation doses from 2012 onwards, one for each half of the trees (six trees) of a combination. The first irrigation dose was 2 L and the second was 4 L per hour. Trees with the highest trunk cross-sectional area (TCSA) and canopy volume were ‘Topper’, ‘Toptaste’ and ‘Topfive’ on the ‘Fereley’ rootstock, but this rootstock showed lower survival, with only 33–50% of trees surviving the 2× dose irrigation. The average TCSA values of the rootstocks showed that ‘Wangenheim’ and ‘WaVit’ rootstocks resulted in too poor growth. In contrast, the Myrobalan seedling (Sdlg) and ‘St. Julien GF655/2’ provided strong growth to the trees based on the TCSA and canopy volume data. The results of the analysis of shoot growth showed that irrigation did not significantly affect shoot length, except for ‘Jojo’. The plum trees developed fruit trees typical of the cultivars after fruiting, with little influence of the rootstocks. ‘Topper’ and ‘Čačanska lepotica’ were dominated by bunched and bunched shoots, while ‘Topfive’ was dominated by short shoots and ‘Toptaste’ developed the highest proportion of long shoots.