Irrigation Regimes Research Articles

Index‐based selection of potato (Solanum tuberosum L.) genotypes for tolerance to soil moisture and ambient heat stress

AbstractDeveloping potato varieties that have enhanced tolerance to soil moisture and high‐temperature stress could improve household food and nutrition security in drought and heat prone areas. A field experiment was conducted at two locations in Ethiopia to evaluate the effectiveness of some stress tolerance indices for the identification of drought and heat tolerant potato genotypes. Treatments consisted of two irrigation regimes and 23 potato genotypes. The experiment was laid out as a split‐plot design in a factorial arrangement with three replications. Irrigation regimes were the main plot factor and genotypes were the sub‐plot factor. Stress tolerance indices were calculated based on the tuber yield under stress (Ys) and non‐stress (Yp) conditions of each genotype. To determine the most desirable stress tolerant genotypes, all indices mean rank (R) and standard deviation of the R were computed. Genotypes Cl‐12(CIP‐304371.67), Cl‐13(CIP‐304383.80), Cl‐2(CIP‐302499.30), Cl‐34(CIP‐397079.6), Cl‐15(CIP‐304394.56), and Cl‐14(CIP‐304387.39) were found to have had top mean ranks and higher tuber yield under drought and heat stress. Ranking methods using all indices best determined desirable drought, heat, and combined drought‐heat tolerant genotypes that consistently coincided with the yield rank of genotypes under a given stress condition. This implies that these indices (stress tolerance index, geometric mean productivity, mean productivity, yield stability index, and tolerance index) could be used in combination to differentiate stress tolerances and susceptible potato genotypes. It is recommended that genotypes that exhibited higher drought and/or heat stress tolerance in this study could be further evaluated in drought and heat prone areas for the development of tolerant potato varieties.

Influence of Hydrothermal Parameters on Potato Irrigation Regime

Background: The article presents the results of studies that allow us to calculate and predict the water consumption of cultivated vegetable crops depending on the moisture availability of the growing season. Hydrothermal indicators of the territory during the entire growing season have a significant impact on the irrigation regime and water consumption of cultivated crops. Methods: In the present study, the assessment of natural moisture during the growing season was determined by the hydrothermal coefficient (GTC) according to the criterion of T.G. Selyaninov. The irrigation rate was calculated according to the modified formula of A.N. Kostyakov. Biological productivity was taken into account by the method of meter sites in three-fold repetition. Result: The value of the irrigation norm varies depending on the intensity of atmospheric droughts when growing potatoes in the conditions of the dry-steppe zone of the Lower Volga region. To maintain a given pre-irrigation threshold of soil moisture, it is necessary to take into account the hydrothermal indicators of the territory during the entire growing season. The use of modern resource-saving irrigation methods, such as drip irrigation, makes it possible to ensure an uninterrupted supply of moisture to plants and, as a result, to obtain high-quality crop yields. Thus, in order to obtain high and stable yields of potatoes grown on drip irrigation, depending on the heat and moisture availability of the growing season, it took from 2,250 to 3,040 m3/ha of irrigation water.

Evaluation of moisture content of wheat (PBW 725) by using 766 keV thallium-204

The experiment was performed using beta radiation to estimate the water content (WC) of wheat (Triticum aestivum L.) having two nitrogen contents, i.e., 120 kgha−1 (N1) and 150 kgha−1 (N2), each at different irrigation regimes, i.e., irrigation at different stages of IW/CPE ratio 1.2 (I1), 0.9 (I2), and 0.6 (I3). Mass attenuation coefficient (μm) was used to evaluate WC and was more for dry leaves than for fresh leaves. The maximum WC was found in I2, followed by I1, and the minimum was in I3 for the both the nitrogen levels. It was shown that NI22 treatment would be the best management intervention for wheat crop because of the highest grain yield and minimal stress degree days. The radiation method is useful in WC estimation and can be effectively used in irrigation scheduling to conserve water.

Effect of Varying Irrigation Regimes and Cultivars on Growth, Yield, Water Use Efficiency and Economics of Rice (Oryza sativa) under Aerobic Condition

The present study was undertaken for standardization of irrigation interval and performances of medium duration selected rice varieties under the aerobic conditions in the westen Odisha. The field experiment was conducted at the Regional Research Technology and Transfer Station (RRTTS), Chiplima, Sambalpur, Odisha, during the summer season of 2019 and 2020 to see the performance of medium-duration rice varieties with varying irrigation regimes under aerobic conditions. The experiment was laid out in split plot design with three replications and consisted of four irrigation regimes (I1 = Irrigation at IW/CPE = 1.0, I2 = Irrigation at IW/CPE = 1.5, I3 = Irrigation at IW/CPE = 2.0, and I4 = Irrigation at IW/CPE = 2.5) in main plot treatments and four varieties (V1 = Naveen, V2 = MTU-1010, V3= CR Dhan-201 and V4 = CR Dhan-204 in subplot treatments. The result of the pooled mean of both years showed that growth and yield attributes significantly affect in regards to different irrigation regimes and cultivars. The maximum plant height (69.0 cm) and filled grains per panicle (80.98) leaf area index (LAI ) at 75DAS (3.940, dry matter accumulation of the shoot at 90 DAS ( 927 g m-2), number of effective panicles m-2 (287) and test weight (22.27 g) was maximum at irrigation regime IW/CPE = 2.5. In contrast, it was at par with the irrigation regime at IW/CPE = 2.0. The maximum plant height(67.1cm), filled grains per panicle (74.47), leaf area index (LAI ) at 75DAS (3.52), dry matter accumulation of the shoot at 90 DAS (901 g m-2 ), and a number of effective panicles m-2 (286) were recorded with CR Dhan 201 which was significantly higher as compared to other cultivars. The result of the pooled mean of both years showed that the highest grain yield was recorded at IW/CPE = 2.5, i.e., 4.07 t/ha, which was at par with IW/CPE = 2.0 (3.90 t/ha) and significantly superior to rest of other irrigation regimes. But in the case of cultivars, the highest grain yield was obtained with variety CR-Dhan 201 (3.54 t/ha), which was at par with variety Naveen (3.30t/ha) and significantly superior to the rest of other cultivars. The highest mean FWUE of 40.71kg/ ha-cm was observed with irrigation at IW/CPE 1.5, which was at par with other irrigation regimes except IW/CPE 2.5, whereas the highest B: C ratio (1.74) was observed with irrigation at IW,/CPE 2.0 which was at par with IW/CPE 2.5 (1.73) and significantly superior to other irrigation regimes. But in the case of cultivars, the highest mean FWUE of 41.60kg/ ha-cm and B: C ratio (1.62) was observed with variety CR Dhan 201 and significantly superior to the rest of the other cultivars. Hence, a variety like CR Dhan 201 needs to be irrigated at IW/CPE 2.0 to produce economically optimum yield and field water use efficiency on sandy loam soils of the western region of Odisha under aerobic conditions.

Biostimulant Application Alleviates the Negative Effects of Deficit Irrigation and Improves Growth Performance, Essential Oil Yield and Water-Use Efficiency of Mint Crop

The scarcity of water is limiting crop production and is one of the most important stressors that severely affects crop yield, and it may also decrease the quality of the final products. Most of the medicinal and aromatic plants are considered resilient to water stress and constitute a sustainable choice for crop production in arid and semiarid conditions. In the present study, we examined the effect of scheduled deficit irrigation (e.g., I1: 40% of field capacity); I2: 70% of field capacity; and I3: 100% of field capacity) combined with biostimulant application (four different products that consisted of nitrogenous compounds and carboxylic acids (M1); nitrogenous compounds and seaweed extracts (M2); humic and fulvic acids and seaweed extracts (M3); and CaO, SiO2, calcium mobilization and translocation factor and microminerals (M4)) on crop performance and essential oil production of mint plants (Mentha arvensis L.). Our aim was to define an irrigation regime that increases water-use efficiency and the biostimulant products that alleviate water stress effects. Our results indicate that moderate deficit irrigation (I2 treatment) and biostimulants that contained seaweed extracts and nitrogenous compounds and humic and fulvic acids (M2 and M3 treatments, respectively) significantly improved yield parameters in terms of fresh and dry herb yield and essential oil production. Moreover, the same biostimulant treatments significantly increased water-use efficiency of mint crops based on the various yield parameters tested in this study. In conclusion, our results indicate that selection of proper biostimulatory products may allow to apply deficit irrigation regimes in mint cultivation without compromising the crop performance in terms of both biomass production and essential oil yield. Therefore, the combination of these agronomic tools could facilitate water saving strategies in arid and semiarid regions and contribute to the sustainable management of water resources.

Değişen Sulama Suyu Seviyeleriyle Toprağa Farklı Oranlarda Biyoçar Uygulanarak Yetiştirilen Kıvırcık Marulun Fiziksel ve Fizyolojik Özellikleri ile Mineral Madde İçeriği

The crisis experienced from the water supply causes food production to be adversely affected in the agriculture sector, which is the biggest consumer of water. The deficit irrigation strategy ensures the continuity of food production as well as using water effectively. However, since the plant grown in this strategy is exposed to abiotic stress, it experiences significant yield and quality losses. For this reason, it is necessary to develop approaches to improve yield and quality losses of the plant grown with deficit irrigation. In this study, the physical and physiological properties and mineral content of curly lettuce (Lactuca sativa L. var. Crispa) grown by applying different rates of biochar to the soil (0%, 1%, 2%, 3%) with varying irrigation water levels (100%, 67%, 33%) researched. The study determined that decreasing irrigation water level decreased plant height, stem diameter, number of leaves, root wet and dry weights, plant weight, chlorophyll and leaf relative water contents, stomatal conductivity and N, P, K, Ca, Mg, Na, Fe, Cu, Mn and Zn contents of curly lettuce, while increasing the membrane damage index, but the physical and physiological properties and mineral content affecting the yield and quality of curly lettuce improved with increasing biochar rates. In the study, as a result of the emergence of the highest stress factor in irrigation at 33% level, it was observed that physical and physiological properties and mineral content of curly lettuce were affected at the highest level, and the dose of biochar, which managed the stress most effectively, was 3%. As a result, considering that biochar has an important potential to improve yield and quality losses of curly lettuce grown under deficit irrigation conditions, the use of biochar in the deficit irrigation regime were found to be recommendable.

Effects of acid modified biochar on potassium uptake, leaching and balance in an alternate wetting and drying paddy ecosystem

Straw biochar amended soils reduce fertilizer losses and alleviate soil K-exhaustion, while decrease grain yield due to its high pH. H2SO4-modified biochar has been studied as a means to enhance the advantages of biochar and address yield decrease. However, little information is available on its effects on aboveground K uptake, soil K fixation, K leaching, and utilization in paddy rice systems, especially under water stress. A 3-year field experiment was conducted with two irrigation regimes (continuously flooded irrigation, ICF and alternate wetting and drying irrigation, IAWD) as main plots and 0 (control), 20 t ha−1 biochar (B20), and 20 t ha−1 acid-modified biochar (B20A-M) as subplots. The results showed that IAWD significantly decreased water percolation by 9.26 %–14.74 % but increased K leaching by 10.84 %–15.66 %. Compared to B0, B20 and B20A-M significantly increased K leaching by 32.40 % and 30.42 % in 2019, while decreased it by 11.60 %–14.01 % in 2020 and 2021. Both B20 and B20A-M significantly improved aboveground K uptake by 3.45 %–6.71 % throughout the three years. B20 reduced grain yield in 2019 and increased it in 2020 and 2021, while B20A-M increased grain yield throughout the three years. Apparent K balance (AKB) from pre-transplanting to post-harvest over the three years suggested that IAWD significantly increased the risk of soil K depletion but B20 and B20A-M significantly increased AKB, thereby addressing the depletion of it. IAWDB20A-M have a comparable AKB with ICFB20A-M, but had up to 18.3 % and 21.61 % higher AKB than IAWDB20 and ICFB20. Therefore, the use of H2SO4 modified biochar could produce higher grain yield with lower K leaching for addition in IAWD paddy systems, which is beneficial to mitigate soil K depletion and ensure a sustainable agricultural production.

Melatonin-mediated alleviation of drought stress by modulation of physio-biochemical and metabolic status in Dracocephalum kotschyi Boiss. (Lamiaceae)

Dracocephalum kotschyi Boiss., a fragrant perennial plant belonging to the Lamiaceae family, contains many bioactive substances, including essential oil, terpenoids, phenolics, and flavonoids that possess a wide range of biological and pharmaceutical properties. Due to the importance of plant exploitation in dry and low-yield lands, the present study was conducted to explore the effect of the exogenous application of melatonin (0, 50, 100, 150, and 200 μM) on physiological, biochemical, and phytochemical traits of the plant subjected to different levels of water deficit stress (80 %, 60 %, and 40 % of field capacity). The results showed that the application of 150 μM melatonin caused the highest content in the relative growth rate (1.84 g/g d), chlorophyll content (14.55 mg/g FW), relative water content (93 %), and chlorophyll fluorescence (0.9) at different irrigation regimes. Reduced irrigation significantly reduced chlorophyll content and fluorescence, while exogenously applied melatonin enhanced their contents at all levels. Reduced irrigation caused a significant increase in the levels of malondialdehyde (7.47 µmol/g FW) and hydrogen peroxide (51.86 nmol/g). Total phenol content, antioxidant activity, and antioxidant power were increased by applying of melatonin up to 200 μM, while the irrigation rate decreased. The essential oil content was increased by reducing irrigation, so the highest content (3.0 % w/w) was observed at 40 % FC and 150 μM melatonin. Geranyl acetate (44.6–60.4 %), α-pinene (9.0–19.1 %), and geranial (6.2–16.2 %) were the major essential oil components of the treated plants. Reduced irrigation and application of melatonin up to 150 μM caused an increase in coumaric acid, rosmarinic acid, and rutin despite a decrease in the content of chicoric acid and apigenin. The highest oleanolic acid content (52.69 mg/g DW) was measured in the plants subjected to 40 % FC. The highest (132 mg/g DW) and lowest (43.58 mg/g DW) ursolic acid content was measured in 40 % FC with 200 μM melatonin and 80 % FC without melatonin treatment, respectively.

The Response Characteristics of Sugarcane Yield, ET and WUE to Meteorological Drought Based on DSSAT-Canegro Model in Lai-bin, China

Crop water use efficiency is an important indicator of the scientific and rational nature of agricultural water use. Studying the response characteristics of sugarcane yield accumulation and water use efficiency to meteorological drought scenarios is a key scientific issue to promote smart management and sustainable development of China's sugarcane industry. In this paper, based on SPEI index, different meteorological drought scenarios were set and the DSSAT-Canegro model was used to simulate the response mechanisms of sugarcane yield accumulation and canopy evapotranspiration to irrigation regime scenarios under different meteorological drought scenarios. Furtherly, in this study, the total on-farm water use efficiency (WUEg), field water use efficiency (WP), true irrigation water use efficiency (WUEti), and irrigation water use efficiency (WUEi) of sugarcane in the study area were evaluated quantitatively to screen the optimal irrigation regime. Specific studies have shown that the stem extension stage is the most sensitive growth stage for sugarcane response to irrigation. Soil evapotranspiration and crop transpiration in sugarcane fields in Laibin varied with irrigation quotas, and that reducing soil evapotranspiration could improve sugarcane water use efficiency. In meteorological drought scenarios with longer and more intense droughts, irrigation has a stronger stimulating effect on sugarcane growth and is more favourable to its yield accumulation.The correlations between WUEg index and WP, WUEi) and WUEti indicators of sugarcane in the study area were all significant, which can be used as key analytical indicators for the optimization of sugarcane irrigation regimes in Laibin. The results of this study can provide important scientific support for the accurate quantification of water demand and consumption of sugarcane in southern China and their coupled and coordinated intelligent management.

Effects of five-year field aged zeolite on grain yield and reactive gaseous N losses in alternate wetting and drying paddy system

Clinoptilolite zeolite has been widely used in agricultural production systems for enhancing water and fertilizer savings, mitigating greenhouse gas emissions, and increasing yield. However, there is little information on field-aged effects of zeolite on reactive gaseous N losses under alternate wetting and drying irrigation (AWD). We conducted a five-year field experiment to investigate field-aged effect of natural zeolite addition at 0 (Z0), 5 (Z5), and 10 (Z10) t ha−1 on reactive gaseous N losses (NH3, N2O), N-related global warming potential (GWPN), soil properties and grain yield under two irrigation regimes (CF: continuous flooding irrigation; AWD) in the 4th (2020) and 5th (2021) years since its initial application in 2017. As compared with CF, AWD did not significantly affect grain yield and NH3 volatilization but increased seasonal N2O emissions by 46 %–71 % over two years. Zeolite increased rice yield for five consecutive years. Z10 reduced averaged cumulative NH3 volatilization and GWPN by 23 % and 26 %, compared to zeolite-free treatment, respectively, in the 4th and 5th years. Soil NH4+-N was increased with the increased rate of Z application under both CF and AWD. Z10 increased soil NH4+-N by 27 %–38 % and NO3−-N by 14 %–22 % in five years, compared to Z0, respectively. Compared to AWD without zeolite, the addition of 10 t ha−1 zeolite under AWD lowered NH3 volatilization, cumulative N2O emissions, and GWPN by an average of 28 %, 29 %, and 30 % in two years, respectively. IAWDZ10 did not differ from ICFZ0 on reactive gaseous N losses but significantly lowered reactive gaseous losses relative to IAWDZ0. Therefore, zeolite addition could mitigate the reactive gaseous N losses and GWPN for at least five years after initial application, which is beneficial to promoting zeolite application and ensuring sustainable agriculture.

The role of LAI and leaf chlorophyll on NDVI estimated by UAV in grapevine canopies

Despite the wide use of the Normalized Difference Vegetation Index (NDVI) in precision viticulture, there are no studies aimed at discriminating the contribution of plant biomass from that of leaf chlorophyll on canopy NDVI. Leaf area index (LAI) and leaf chlorophyll (Chl) were concomitantly monitored by ground measurements and projected canopy area (PCA), canopy volume (CV) and NDVI by high resolution UAV multispectral images in fully productive “Sangiovese” grapevines either grown in containers or in the field and subjected to different irrigation regimes over two consecutive years. NDVI values calculated from only vine canopy pixels (NDVIUAV) and NDVI obtained from mixed ground-canopy pixels (simulated Satellite NDVI, NDVISAT) were both evaluated as potential predictor of LAI and leaf Chl concentration.The seasonal patterns of LAI and leaf Chl concentration were affected by irrigation, showing differences depending on field vs container-grown conditions. In situations where a decoupling between LAI and leaf Chl occurred, NDVIUAV and NDVISAT showed different responses: NDVIUAV patterns strictly followed the leaf Chl ones, whereas NDVISAT was more affected by LAI. The coefficient of determination between NDVIUAV and leaf Chl ranged between 0.51 and 0.78, that between NDVIUAV and leaf Chl from 0.01 to 0.76, depending on the irrigation-growing conditions combination. NDVISAT was a better predictor of LAI (R2=0.69) than NDVIUAV (R2=0.42). In field-grown vines the relationships between NDVI (both UAV and SAT) and LAI was stronger than in potted ones. The relationships between LAI and PCA (R2=0.44) or LAI and canopy volume (R2=0.77) were both significant. The results allowed to confirm the two main hypotheses behind this experiment: i) leaf Chl concentration had a greater impact than LAI on NDVI values obtained from vine canopy pixels (NDVIUAV), whereas NDVISAT was more affected by LAI; ii) The canopy volume from UAV images was a better predictor of LAI than NDVI and the resulting relationship showed a better temporal stability.

Assessment of Shelf life of Chrysanthemum (Dendranthema x grandiflora Tzelev.) var. Marigold Flowers as Influenced by Phenophase Based Irrigation and Nutrition Schedule

The present investigation was conducted in the Division of Flower and Medicinal Crops at the ICAR-Indian Institute of Horticultural Research, Bengaluru, to evaluate the influence of phenophase based irrigation and fertigation schedules on shelf life of chrysanthemum (Dendranthema x grandiflora Tzelev.) var. Marigold. The experiment comprised of three main plots (irrigation regimes) and five sub plots (nutrient regimes) and was laid out in split plot design with three replications. Irrigation regime at 0.8, 1.0 and 1.2 ER at vegetative, bud and flowering phases, respectively along with weekly fertigation of NPK @ 75:112.5:75 kg /ha (75% RDF) in three split doses of 40:20:20 % NPK during vegetative phase, 30:40:40 % NPK during bud phase and 30:40:40% NPK during flowering phase, recorded the maximum shelf life of flowers (12.15 days) whereas, the minimum shelf life (7.60 days) was observed in the irrigation regime at 0.6,0.8 and 1.0 ER at vegetative, bud and flowering phases, respectively along with conventional method soil application of recommended dose of fertilizer (100:150:100 Kg NPK/ha).The shelf life of flowers had significantly high positive association with the physiological parameters of the plant viz., relative water content (0.728), transpiration rate (0.201), single flower weight (0.559) and stomatal conductance rate (0.492). Whereas, the photosynthetic rate (0.214), diameter of the flower head (0.269) and estimated flower yield (0.047) were significantly and positively correlated with shelf life of flowers. However, the days taken for bud appearance (-0.250) was negatively associated with shelf life of flowers.

Water productivity of summer mungbean (Vigna radiata) in relation to irrigation, tillage and mulch in sandy loam and loamy sand soils

There is a growing interest among the farmers of the state to take an additional crop, i.e. summer mungbean (Vigna radiata L.) in the window period of rice (Oryza sativa L.)-wheat (Triticum aestivum L.) system with a little emphasis on the water productivity of summer mungbean. The present study was aimed to assess the water productivity of summer mungbean under differential irrigation regimes, tillage and mulch in sandy loam and loamy sand soils. A field experiment was conducted during the summer 2021 and 2022 with three irrigation regimes (based on irrigation water to PAN-E ratio of 0.75 (I0.75), 0.50 (I0.50), 0.25 (I0.25) in sandy loam and 0.8 (I0.8), 0.6 (I0.6) and 0.4 (I0.4) in loamy sand soils, two tillage systems, viz. deep tillage and conventional tillage; and two mulch rates (no mulch and application of rice straw mulch @6 t/ha). Irrigation regime, I0.75 and I0.8 resulted in higher crop biomass, however the seed yield and water productivity were highest under I0.50 and I0.6. Deep tillage with mulch resulted in higher seed yield and water productivity in comparison to conventional tillage with no mulch. Medium irrigated regime (I0.50 and I0.6) coupled with deep tillage and rice straw mulch was found to be effective in improving the seed yield of mung bean in loamy sand soils in north-west India.

Doubling Farmer Income through Cultivating Headed Broccoli (Brassica oleracea var. Itilica) under Different Irrigation Regimes and Water Saving Techniques

Doubling Farmer Income through application of precious irrigation and water saving techniques in vegetable crops may be possible under change in climatic and water scarcity conditions by proper inclusive adaptation of the results of present field experiment investigation. Significantly higher, net returns and benefit cost ratio Was observed in IR treatment I1.00. Total cost of cultivation and benefit cost ratio were significantly higher in IR treatment I0.75. The net returns and benefit cost ratio were significantly higher in WST treatment MK and benefit cost ratio were in MC. The treatment combination I1.00 x MK had given higher returns followed by followed by the treatment I0.75 x MBP among all the treatments. However, based on the IWM aspect to overcome the problem of irrigation water scarcity, adaptation and mitigation of changed climate as well as projected future climate change through precision farming, increasing leaf area, decreasing ambient temperature and economic profitability factor i.e. net returns from the cultivation of headed broccoli, the treatment combination I0.75 x MBP and I0.50 x MBP were observed significantly superior amongst all the treatments.

Influence of irrigation regime and seasonal temperatures on nut quality and the oil fatty acid profile of walnuts (Juglans regia L.)

Walnut production is expanding worldwide due to the high demand for natural products with proven nutraceutical properties. This expansion includes new growing areas, such as central–western Argentina, where crop water requirements have yet to be determined and little is known about the response in terms of production quality to the water regime. The aim of this study was to assess the effects of four irrigation regimes (at 50, 75, 100, and 125 % of crop evapotranspiration) and the weather conditions over two consecutive seasons in a young Chandler walnut orchard in terms of in–shell and kernel caliber, kernel color, oil concentration, and fatty acid profile. Quality production characteristics were not significantly affected by irrigation regimes within each season. In contrast, the quality parameters achieved were significantly different between seasons. The first season (S1) was wetter (462 mm) and cooler (17.05 °C mean air temperature in the oil accumulation period) and produced more extra–light kernels (92%). The second season (S2) was drier (326 mm) and warmer (19.02 °C) and produced a lower proportion of extra–light kernels (82.2%). In addition, during the second season, walnuts produced larger kernels with a higher oil concentration (62.7%; +3.5% of S1) and a better omega–6/omega–3 ratio (3.25 in S2 vs. 3.70 in S1). These results suggest that kernel quality was more sensitive to the seasonal temperature than the irrigation studied regimes. The nutritional quality of walnuts may increase significantly in warmer seasons/environments despite the deterioration of kernel color.

Drip irrigation and sulphur fertilization influenced fodder yield, quality and water use efficiency of groundnut in arid region.

Availability of ample and nutritious fodder for livestock is always a challenge in arid region. Choice of crops such as groundnut that can fulfil the requirement of fodder with its crop residues along with human needs can be a viable option to bridge the gap between availability and requirement of fodder. The fodder yield and quality largely depend on soil moisture and nutrient supply especially sulphur (S), a key nutrient for improving groundnut fodder quality. However, no researchers have given emphasis on coupling effect of drip irrigation (DI) and sulphur on fodder yield, quality, digestibility and water use efficiency (WUE). Therefore, the study was conducted to determine the effects of different regimes of DI and S on productivity and quality of fodder. Results revealed that higher regimes of DI i.e. 0.8 +1.0 PE(pan evaporation) and 1.0 PE level of irrigation along with 40 kg S ha-1 significantly improved the yield, primary quality traits (crude protein, ether extract and ash), digestibility indices and significant reduction in Fibers which indicates improvement in quality of fodder. Fodder productivity was 27.0 and 25.6% higher in 1.0 PE and 0.8+1.0 PE level of irrigation, respectively, as compared to 0.6 PE level (lower water regime) of irrigation, although 0.6 PE level of irrigation recorded higher WUE and was at par with 0.8 PE and 0.6 +1.0 PE level of DI. By changing the levels of DI from 1.0 PE to 0.8+1.0 PE, considerable water can be saved without affecting the yield and quality of fodder. Similarly, crop responded to S up to 60 kg ha-1 but at par with 40 kg S ha-1 indicating that application of extra S after 40 kg did not warrant any extra benefit in terms of fodder yield, WUE and quality of fodder. Thus, adjusting the PE levels of DI for water saving and optimal S application can be a sustainable strategy to improve the productivity and quality of groundnut fodder in arid region.

Investigating high throughput phenotyping based morpho-physiological and biochemical adaptations of indian pennywort (Centella asiatica L. urban) in response to different irrigation regimes

Indian pennywort (Centella asiatica L. Urban; Apiaceae) is a herbaceous plant used as traditional medicine in several regions worldwide. An adequate supply of fresh water in accordance with crop requirements is an important tool for maintaining the productivity and quality of medicinal plants. The objective of this study was to find a suitable irrigation schedule for improving the morphological and physiological characteristics, and crop productivity of Indian pennywort using high-throughput phenotyping. Four treatments were considered based on irrigation schedules (100, 75, 50, and 25% of field capacity denoted by I100 [control], I75, I50, and I25, respectively). The number of leaves, plant perimeter, plant volume, and shoot dry weight were sustained in I75 irrigated plants, whereas adverse effects on plant growth parameters were observed when plants were subjected to I25 irrigation for 21 days. Leaf temperature (Tleaf) was also retained in I75 irrigated plants, when compared with control. An increase of 2.0 °C temperature was detected in the Tleaf of plants under I25 irrigation treatment when compared with control. The increase in Tleaf was attributed to a decreased transpiration rate (R2 = 0.93), leading to an elevated crop water stress index. Green reflectance and leaf greenness remained unchanged in plants under I75 irrigation, while significantly decreased under I50 and I25 irrigation. These decreases were attributed to declined leaf osmotic potential, increased non-photochemical quenching, and inhibition of net photosynthetic rate (Pn). The asiatic acid and total centellosides in the leaf tissues, and centellosides yield of plants under I75 irrigation were retained when compared with control, while these parameters were regulated to maximal when exposed to I50 irrigation. Based on the results, I75 irrigation treatment was identified as the optimum irrigation schedule for Indian pennywort in terms of sustained biomass and a stable total centellosides. However, further validation in the field trials at multiple locations and involving different crop rotations is recommended to confirm these findings.

Особенности формирования саженцев малины при капельном орошении в условиях дерново-подзолистых почв Центрального Нечерноземья

Practically no studies on drip irrigation of raspberries in the conditions of the Moscow region have been carried out, in particular, the patterns of the production process of plants under drip irrigation have not been identified. In this regard, the purpose of the research was to study the effect of drip irrigation regimes on the formation of raspberry seedlings in the conditions of soddy-podzolic soils in the Central region of the Non-Chernozem zone of Russia. The studies were carried out on the lands of the educational and experimental farm of the laboratory of fruit growing "Michurinskiy Sad" of the Russian State Agrarian University - Moscow Timiryazev Agricultural Academy in 2020-2022. The two-factor field experience included regimes as the first factor, and varietal characteristics as the second. As a result of the research, it was revealed that drip irrigation contributes to the saving of irrigation water and the creation of an optimal water-air regime of the soil during the entire growing season. In the variant of drip irrigation with maintaining moisture in the root layer in the range of 80-100% of the lowest moisture capacity, the saving of irrigation water compared to furrow irrigation averaged 65%, and in the variant of 60-80% of the lowest moisture capacity - 78%. Drip irrigation contributes to the formation of seedlings with the highest values of biometric indicators (stem diameter, plant height, leaf surface area and volume, length, mass of the root system) and increase productivity. An analysis of the experimental data on the biometric indicators of raspberries and its yield allows us to recommend irrigation regimes with maintaining the moisture content of the root layer of the soil in the range of 70-90% of the lowest moisture capacity and 80-100% of the lowest moisture capacity as optimal.

Nitrogen fertilization and irrigation types do not affect the overall N2O production potential of a sandy soil, but the microbial community structure and the quantity of functional genes related to the N cycle

Nitrous oxide (N2O), one of the major greenhouse gases, features a 273-fold higher global warming potential compared to carbon dioxide (CO2). Soil-born N2O emissions are based on microbial processes, while the microbial processes are affected by environmental factors and agronomic management measures. The objective of this study was the exploration of the effects of different irrigation and nitrogen (N) fertilization regimes on N2O emissions in relation to the microbial community structure and the quantities of genes involved in the N cycle. The following four treatments were investigated in a sandy soil during the potato cropping season in 2019 in Brandenburg, Germany: drip irrigation without N fertilization (DI-ZN), drip irrigation with broadcasted N fertilization (DI-N), simultaneous application of dissolved N in irrigation water, the so-called fertigation (F), and fertigation without crops (F-ZC). N2O fluxes were measured with the closed chamber method. Microbial biomass was analyzed using phospholipid fatty acids (PLFAs). The bacterial functional genes amoA (ammonium monooxygenase), nxrB (nitrite oxidoreductase), narG (nitrate reductase), nirS/nirK (nitrite reductase), and nosZ (N2O reductase) were determined using quantitative real-time polymerase chain reaction (qPCR). N2O fluxes varied over the season and could mainly be explained by temperature changes. The fertilized treatments showed slightly higher area-related cumulative N2O emissions (DI-ZN: 1.13 kg N2O-N ha−1, DI-N: 1.28 N2O-N ha−1, F: 1.26 N2O-N ha−1, median values). Additionally, N2O flux rates as well as the area- and yield-related N2O emissions of DI-N and F were approximately at the same level, even though the quantities and correlation patterns of the investigated functional genes differed. Highest seasonal median flux rates were detected under DI-N (15.0–100.1 μg N2O-N m−2 h−1), where a greater influence of a nirS/nosZ harboring microbial community was found. In contrast, under F more diverse correlation patterns were found, especially regarding a predominance of nirK and nirS/nosZ harboring microbial community. F-ZC showed the lowest N2O flux rates (−8.7–44.2 μg N2O-N m−2 h−1), which might be explained by the lack of plant carbon sources, particularly root exudates. To conclude, the applied treatments affected the microbial community structure and their genetically determined potential for N2O production, whereby the overall N2O flux rates and hence N2O emissions remained unaffected. Although fertigation is considered to be more demand-based particularly in terms of N fertilization, this study indicates that agronomic management measures according to good faming practice might feature an oversupply of N, neglecting the real N demand of cultivated crops and hence hindering the mitigation of N2O emissions.

The application of nanoparticles on the yield and nutritional quality of rice under different irrigation regimes

Abstract The amino acid profile in rice serves as an indicator of its nutritional worth, playing a significant role in evaluating its overall nutritional quality. However, there has been limited research on how nanoparticles (NPs) and various irrigation regimes affect the nutritional value and overall quality of rice. In the present study, the effects of different irrigation regimes and foliar spray of NPs on the yield, nutrient concentration, and amino acid profile of milled rice in two rice cultivars were evaluated. The results showed that the Shirodi cultivar had a higher yield and nutrients compared to the Hashemi cultivar. Reducing irrigation significantly lowered the grain yield, nutrient elements, and some amino acids (asparagine, glutamic acid, serine, alanine, histidine, and arginine) in milled rice while increasing other amino acids. However, NPs treatments, especially ZnONPs + SiO2NPs treatment, increased grain yield and amino acids in milled rice. Regarding mineral nutrients, SiO2NPs and ZnONPs + SiO2NPs treatments decreased mineral nutrients in milled rice, while ZnONPs treatment increased Ca, Fe, Mg, and N and decreased the content of other elements in milled rice. Therefore, our findings showed that SiO2NPs and ZnONPs are promising NPs that can improve the yield and nutritional quality of milled rice, especially in water-deficient conditions.