Depletion Of Available Soil Moisture Research Articles

RESPONSE OF SUNFLOWER CROP TO DIFFERENT LEVELS OF SOIL MOISTURE DEPLETION

The amount of water utilized by the plant has a significant impact on its yield. In this regard, yield response factor (Ky) permits measuring yield decline as a function of evapotranspiration. As a result, the purpose of this study was to calculate Ky for the sunflower crop grown in North Nile Delta, Egypt and to calculate economic water productivity. Seasons 2021 and 2022 were studied. The experiment used a complete randomized block design with three replicates. W1 (50-55%), W2 (55-60%), and W3 (60-65%) maximum allowable depletion of available soil moisture (MAD of ASW) treatments were used. In total, the average two seasons (0.52 and 0.61) found for sunflower crop under W2&W3, respectively, demonstrated its strong sociability to water deficit. Its yield is substantially impacted by water availability, with average 0.65 & 0.47% loss in yield for every 1% reduction in evapotranspiration with w2 and w3 treatments, respectively. The treatment without stress, w1 (50-55% MAD of ASW), yielded the highest grain yield. However, after considering water and irrigation costs, it could conclude that other stressed treatments, W2&W3, were more cost-effective.

Effect of limited irrigation and planting systems on yield and water productivity of maize (Zea mays)

A field experiment was conducted during the rainy (kharif) seasons of 2019 and 2020 at the research farm opf ICAR-Indian Agricultural Research Institute, New Delhi to study the effect of limited irrigation application and planting systems on yield and water productivity of maize (Zea mays L.). The experiment was laid out in factorial randomized complete block design with 3 replications. The experiment consisted of two crop establishment methods as one factor, viz. Narrow bed planting and broad bad planting and 5 irrigation levels, viz. 25% DASM (Depletion of available soil moisture); 25% DASM at tasselling, silking, grain filling and 50% during rest of time; 50% DASM at all growth stages; 50% DASM + KCl spray at 40 DAS and at pre-tasselling; and 50% DASM+2% Urea spray at 40 DAS and at pre-tasselling. Experimental results revealed that the broad bed system of planting during 2019 and 2020 recoded significantly higher grain yields (4.37 and 4.57 t/ha) compared to the narrow bed system (4.23 and 4.38 t/ha), respectively. Regarding different irrigation levels, the highest water productivity (91.26 and 199.76 kg/ ha-cm) was observed with irrigation at 50% DASM along with two sprays of urea at 40 DAS during both the years, respectively. It was concluded that broad bed along with irrigation at 50% DASM with two sprays of urea proved to be most effective approach to enhance water productivity and yield of maize crop.

Sensor-based precision nutrient and irrigation management enhances the physiological performance, water productivity, and yield of soybean under system of crop intensification.

Sensor-based decision tools provide a quick assessment of nutritional and physiological health status of crop, thereby enhancing the crop productivity. Therefore, a 2-year field study was undertaken with precision nutrient and irrigation management under system of crop intensification (SCI) to understand the applicability of sensor-based decision tools in improving the physiological performance, water productivity, and seed yield of soybean crop. The experiment consisted of three irrigation regimes [I1: standard flood irrigation at 50% depletion of available soil moisture (DASM) (FI), I2: sprinkler irrigation at 80% ETC (crop evapo-transpiration) (Spr 80% ETC), and I3: sprinkler irrigation at 60% ETC (Spr 60% ETC)] assigned in main plots, with five precision nutrient management (PNM) practices{PNM1-[SCI protocol], PNM2-[RDF, recommended dose of fertilizer: basal dose incorporated (50% N, full dose of P and K)], PNM3-[RDF: basal dose point placement (BDP) (50% N, full dose of P and K)], PNM4-[75% RDF: BDP (50% N, full dose of P and K)] and PNM5-[50% RDF: BDP (50% N, full P and K)]} assigned in sub-plots using a split-plot design with three replications. The remaining 50% N was top-dressed through SPAD assistance for all the PNM practices. Results showed that the adoption of Spr 80% ETC resulted in an increment of 25.6%, 17.6%, 35.4%, and 17.5% in net-photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), and intercellular CO2 concentration (Ci), respectively, over FI. Among PNM plots, adoption of PNM3 resulted in a significant (p=0.05) improvement in photosynthetic characters like Pn (15.69 µ mol CO2 m-2 s-1), Tr (7.03m mol H2O m-2 s-1), Gs (0.175 µmol CO2 mol-1 year-1), and Ci (271.7mol H2O m2 s-1). Enhancement in SPAD (27% and 30%) and normalized difference vegetation index (NDVI) (42% and 52%) values were observed with nitrogen (N) top dressing through SPAD-guided nutrient management, helped enhance crop growth indices, coupled with better dry matter partitioning and interception of sunlight. Canopy temperature depression (CTD) in soybean reduced by 3.09-4.66°C due to adoption of sprinkler irrigation. Likewise, Spr 60% ETc recorded highest irrigation water productivity (1.08kg ha-1 m-3). However, economic water productivity (27.5 INR ha-1 m-3) and water-use efficiency (7.6kg ha-1 mm-1 day-1) of soybean got enhanced under Spr 80% ETc over conventional cultivation. Multiple correlation and PCA showed a positive correlation between physiological, growth, and yield parameters of soybean. Concurrently, the adoption of Spr 80% ETC with PNM3 recorded significantly higher grain yield (2.63t ha-1) and biological yield (8.37t ha-1) over other combinations. Thus, the performance of SCI protocols under sprinkler irrigation was found to be superior over conventional practices. Hence, integrating SCI with sensor-based precision nutrient and irrigation management could be a viable option for enhancing the crop productivity and enhance the resource-use efficiency in soybean under similar agro-ecological regions.

Assessment of Crop-Water Requirement of Alfalfa Using FAO-CROPWAT Model-8.0

The current study was conducted at the Farming System Research Station, situated within the Department of Agronomy at the College of Agriculture, Junagadh Agricultural University in Junagadh, Gujarat, India. This research took place during the winter cycle (Rabi season) 2021 to 2022 and 2022 to 2023. In this study, the CROPWAT crop irrigation schedule provides an overall Evapotranspiration (ETc) value of 549.6 millimeters as the optimal water requirement for achieving maximum crop production with sufficient water supply. The actual water use by the crop during its growth period amounted to 544.2 millimeters and total net irrigation applied was 507.9 millimeters, while the gross irrigation amounted to 725.6 millimeters. The irrigation efficiency was 100%. Comparing this approach to irrigation scheduling based on the Irrigation Water to Crop Potential Evapotranspiration (IW/CPE) ratio, using CROPWAT enabled the precise management of irrigation water. It ensured that the alfalfa crop received the appropriate amount of water according to its specific growth stage requirements. The CROPWAT model data indicates that there was no yield reduction, even with a 100% critical depletion of available soil moisture. Additionally, the seasonal yield response factor was calculated to be 0.80%. These findings emphasize the effectiveness of the irrigation strategy employed, resulting in optimal crop yields without yield losses due to critical soil moisture depletion.

Assessment of Maize Crop Evapotranspiration Using Eddy Covariance Flux Tower Weather Data

The study conducted at the Maize Research Centre, Agriculture Research Institute, Professor Jayashankar Telangana State Agricultural University (PJTSAU), Rajendranagar, Hyderabad, from November, 2022 to March, 2023 aimed to compute the crop evapotranspiration (ETc) of maize crop under two different irrigation treatments using the weather data generated from the Eddy Covariance (EC) flux tower. The two treatments comprise of scheduling irrigation at certain Depletion of Available Soil Moisture (DASM) viz., T1: 20% DASM and T2: 40% DASM. The maize crop was sown and cultivated as per the recommended practices. The bio-physical parameters like plant height and LAI were recorded at 15 days interval. These parameters were statistically analysed by two sample T-test with equal variance. The plant height increased from 35 to 198 cm in 20% DASM and 36 to 180 cm in 40% DASM during the crop growth period (30 to 100 DAS). Similarly, LAI increased from 0.72 to 3.9 and 0.77 to 3.2 in 20 and 40 % DASM treatments till 90 DAS, respectively and later on decreased till harvest. The findings emphasize a positive influence of optimum moisture availability in the root zone on plant growth parameters. The amount of irrigation given was measured to compute ETc using Soil Water Balance (SWB) method and the crop parameters like plant height, LAI, stomatal resistance values etc., were used for computing the Penman-Monteith equation using the weather parameters generated from the EC flux tower. Seasonal ETc estimated from the Soil Water Balance (SWB) method (340 & 280 mm) and FAO Penman-Monteith method (350 & 295 mm) in 20 and 40% DASM treatments showed a deviation of +10 and +15 mm, respectively. Furthermore, the study concludes that FAO Penman-Monteith method can accurately estimate ET by using EC flux tower measured weather data, with minor deviations from the SWB method.

Energy and carbon budgeting in a soybean–wheat system in different tillage, irrigation and fertilizer management practices in South-Asian semi-arid agroecology

The sustainability of agricultural production systems is significantly threatened due to climate change and land degradation. Agricultural practices like conventional tillage with imbalanced fertilizers, and indiscriminate irrigation have serious environmental implications like higher greenhouse gas (GHG) emissions. Therefore, we assessed the three-year productivity, effectiveness of energy, and carbon (C) footprint of soybean–wheat system under different tillage techniques [zero-till flat beds (ZTFB), conventional till-raised beds (CTRB), and conventional till- flat beds (CTFB)], irrigation regimes [irrigation at 25%, 50%, and 75% depletion of available soil moisture (DASM)] and fertilizer rates [50% and 100% recommended rates of fertilizers (RRF). The study was conducted for three years in a fixed-field plots using split-split plot design with three replications. The results show that conventional till-raised bed (CTRB) recorded higher system crop productivity (9.5–15.2%), energy-efficiency (17.3), C-output (6424), C-efficiency (11.7), C-sustainability index (9.73), net-returns (1035 US$ ha−1) and the least C-footprints (0.19) over conventional till-flat beds (CTFB) and zero till-flat beds (ZTFB). Whereas, residue mulched ZTFB plots exhibited ∼24.2% higher system water productivity and consumed less energy (∼77.0%) over others. Irrigation applied at 25% depletion of available soil moisture (DASM25%) led to higher system productivity (5.96 Mg ha−1), energy output (232.6 GJ ha−1), energy-efficiency (13.4) and C-output (6657.4 kg CE ha−1) compared to DASM75% and DASM50%. Interestingly, C-footprints increased with ZTFB while least C-footprints were found under CTRB and CTFB. Consequently, the adaptation of CTRB with optimal irrigation and fertilizers will be a viable alternative for achieving improved system production, energy efficiency with a lower C-footprint under semi-arid regions.

Comprehensive Selection Criteria for Some Barley Genotypes under Different Water Stress Treatments

Nowadays, water scarcity is a great danger to agriculture development, in semiarid and arid regions beside climate change risks. Egypt is suffering from scarce water resources for agriculture; it is of high priority to rationalize irrigation water use. During two seasons, 2019/2020 and 2020/2021 the experimental were carried out to investigate the effect of three different irrigation water treatments (I1 at 45, I2 at 60 and I3 at 75% depletion of available soil moisture) on some photosynthetic, agronomical, grain quality parameters, water productivity for eight barley genotypes. Also, classify them on the SSR molecular level. The results showed that there were high genetic variations found among the eight genotypes with significant responses to irrigation water treatments. Rationalize irrigation water from I1 to I3 had a negative effect on all studied phenotypic traits, whereas had an appositive effect on leaf diffusive resistance and cured protein content and inducement all genotypes to flower early by average increasing (27.7, 12.7 and 7.08%) respectively. Giza 138, Giza 131, and Line 4 gave high mean performance values of the measured characters besides, attaining high WP values were 1.14, 1.08, and 0.89 kg grain/m3 applied water I1, I2, and I3 irrigation treatments, respectively. While, WUE values increased with increasing water availability. Water use efficiency values were 1.92, 1.71, and 1.34 kg grain/m3 consumed water for I1, I2, and I3 irrigation treatments, respectively. Twenty-six alleles were generated using ten SSR primers with a mean value of 2.6 alleles per locus. The Polymorphism Information Content (PIC) value of each SSRs marker ranged from 0.33 (Bmag 0387) to 0.47 (Bmac 0167) with an average value of 0.34. Cluster analysis clustered the eight barley genotypes into two major clusters divided according to their response to water stress tolerance. The genetic information about eight barley genotypes for water stress tolerance was established, for use them in breeding programs in Egypt.

Co-implementation of tillage, irrigation, and fertilizers in soybean: Impact on crop productivity, soil moisture, and soil microbial dynamics

Due to depleting water supplies and the cultivation of high water-demanding crops like rice, water deficit in crop production has become a major concern, especially in semi-arid regions of South Asia. Soybean has been considered a possible substitution for high-water-demand crops with improved water productivity and nutrient quality. However, due to inefficient and injudicious water and fertilizer management, the overall productivity and profitability of soybean is quite low. Hence, a three-year field investigation was carried out using strip-strip plot design with three replications to study the individual and combined effects of tillage, irrigation, and fertilizer levels on crop yield and quality, soil moisture and soil microbial dynamics. Results revealed that zero tilled-flat beds (ZTFB) and conventional tilled-raised beds (CTRB) reduced the irrigation water requirement by 5.15–5.45 and 3.12–3.49 cm ha −1 , respectively, compared to conventional tilled-flat beds (CTFB). Moreover, CTRB enhanced seed yield by 8.1–31.5 %, biomass yield by 6.5–34.1 %, crop water productivity (CWP) by 27.2–30.9 %, and irrigation water productivity (IWP) by 55.2–57.5 % over CTFB. Similarly, in 2016 and 2017, CTRB had higher SPAD-chlorophyll content (34.3 and 33.2 in the top leaves) and normalized difference vegetation index (NDVI) (0.51 and 0.71) values than CTFB and ZTFB. At 0.0–0.30 m soil depth, ZTFB showed the highest soil moisture content of 11.2 % and 22.5 %, respectively, leading to the highest relative water content (RWC) of 76.7–78.7 % in soybean leaves. As a result, ZTFB took 4–8 days longer to mature than CTFB, delaying the sowing of the following wheat crop. During the 2016–2018 growing seasons, irrigation applied at the depletion of available soil moisture (DASM) by 25 % and 100 % rate of recommended fertilizer (RRF) achieved significantly higher crop, biomass yields, protein yield, SPAD, NDVI, and CWP than irrigation at lower levels. Interaction effects revealed that combinations of CTRB and ZTFB + 25 % DASM + 100 % RRF strategies generated significantly (P ≤ 0.05) higher seed yield, biomass yield, and CWP. At the same time, ZTFB had significantly higher alkaline and acid phosphatase activity than CTRB, whereas the latter had significantly higher soil microbial biomass carbon. In comparison to individual use of these crop management methods, the results of this study showed planning soybean either in CTRB or ZTFB, irrigating at 25 % DASM, and fertilizing crops with 100 % RRF could help achieve higher crop and water productivity, thus sustaining soybean production in India and adjoining regions with similar agro-ecology. • Tillage, irrigation and fertilizer rates on soybean growth were studied in three years. • CTRB+DASM 25 % + 100 % fertilizer rate enhanced soybean yield and resource use efficiency. • Due to higher soil moisture content, a soybean grown in ZT-flat beds matures later.

Co-Implementation of Tillage, Precision Nitrogen, and Water Management Enhances Water Productivity, Economic Returns, and Energy-Use Efficiency of Direct-Seeded Rice

The sustainability of conventional rice (Oryza sativa L.) production systems is often questioned due to the over-mining of groundwater and environmental degradation. This has led to the development of cost-effective, resource-efficient, and environmentally clean rice production systems by optimizing water and nitrogen (N) use. Hence, a 2-year field study (2019 and 2020) was conducted at the ICAR–Indian Agricultural Research Institute, New Delhi, to assess the effect of precision N and water management strategies on growth, land, and water productivity, as well as energy-use efficiency in scented direct-seeded rice (DSR). Two crop establishment methods, conventional-till DSR (CT-DSR) and zero-till DSR (ZT-DSR) along with three irrigation scenarios (assured irrigation (irrigation after 72 h of the drying of surface water), irrigation at 20% depletion of available soil moisture (DASM), and 40% DASM+Si (80 kg ha−1)) were assigned to the main plots; three N management options, a 100% recommended dose of N (RDN): 150 kg ha−1; Nutrient Expert® (NE®)+leaf color chart (LCC) and NE®+soil plant analysis development (SPAD) meter-based N management were allocated to sub-plots in a three-time replicated split-plot design. The CT-DSR produced 1.4, 11.8, and 89.4, and 2.4, 18.8, and 152.8% more grain yields, net returns, and net energy in 2019 and 2020, respectively, over ZT-DSR. However, ZT-DSR recorded 8.3 and 10.7% higher water productivity (WP) than CT-DSR. Assured irrigation resulted in 10.6, 16.1 16.9, and 8.1 and 12.3, 21.8 20.6, and 6.7% higher grain yields, net returns, net energy, and WP in 2019 and 2020, respectively, over irrigation at 20% DASM. Further, NE®+SPAD meter-based N management saved 27.1% N and recorded 9.6, 18.3, 16.8, and 8.3, and 8.8, 21.7, 19.9, and 10.7% greater grain yields, net returns, net energy, and WP over RDN in 2019 and 2020, respectively. Thus, the study suggested that the NE®+SPAD-based N application is beneficial over RDN for productivity, resource-use efficiency, and N-saving (~32 kg ha−1) both in CA-based and conventionally cultivated DSR. This study also suggests irrigating DSR after 72 h of the drying of surface water; however, under obviously limited water supplies, irrigation can be delayed until 20% DASM, thus saving two irrigations, which can be diverted to additional DSR areas.

Effect of GreenSeeker based nitrogen management and its interaction with water on growth and productivity of maize (Zea mays L.) under conservation agriculture

A field experiment was conducted during kharif season of 2019 at research farm of ICAR–Indian Agricultural Research Institute, New Delhi, India, to study the effect of GreenSeeker(GS) based nitrogen management and its interaction with water on growth and productivity of maize (Zea mays L.) var. PMH-1 under conservation agriculture. The experiment was laid out in split-split plot design withtwo crop establishment techniques (CET) viz. conservation agriculture (CA) and conventional tillage (CT) in main plots three irrigation regime (IR) in sub-plotsirrigation at critical growth stages, irrigation at 25% depletion of available soil moisture (DASM) and irrigation at 50% DASM, and four levels of nitrogen (N) in sub-sub plots; no-N applied, 33% N as basal, 33% N at knee high stage and 34% N at silking stage, 50% basal + rest N as guided by Green Seeker (GS) and 75% as basal + rest N as guided by GS. The results showed that GS based N application outperformed over farmers fertilizer practices in terms of growth and productivity, and its interactionalso significantly differed with irrigation scheduling. The maximum value of grain yield (6.9 tha-1 ), plant height at tasseling (173 cm) and harvest (235 cm), leaf area index at knee high stage (2.11) and silking (4.10), crop growth rate (8.4 and 9.2 gm-2 day-1 ) at 0-30 and 30-60 days after sowing, respectively and NDVI (0.748), were recorded under75% as basal + rest N as guided by GS, over other practices and interaction effect with irrigation at 25% depletion of available soil moisture.

Effect of GreenSeeker based nitrogen management and its interaction with water on growth and productivity of maize (Zea mays L.) under conservation agriculture

A field experiment was conducted during kharif season of 2019 at research farm of ICAR–Indian Agricultural Research Institute, New Delhi, India, to study the effect of GreenSeeker(GS) based nitrogen management and its interaction with water on growth and productivity of maize (Zea mays L.) var. PMH-1 under conservation agriculture. The experiment was laid out in split-split plot design withtwo crop establishment techniques (CET) viz. conservation agriculture (CA) and conventional tillage (CT) in main plots three irrigation regime (IR) in sub-plotsirrigation at critical growth stages, irrigation at 25% depletion of available soil moisture (DASM) and irrigation at 50% DASM, and four levels of nitrogen (N) in sub-sub plots; no-N applied, 33% N as basal, 33% N at knee high stage and 34% N at silking stage, 50% basal + rest N as guided by Green Seeker (GS) and 75% as basal + rest N as guided by GS. The results showed that GS based N application outperformed over farmers fertilizer practices in terms of growth and productivity, and its interactionalso significantly differed with irrigation scheduling. The maximum value of grain yield (6.9 tha-1), plant height at tasseling (173 cm) and harvest (235 cm), leaf area index at knee high stage (2.11) and silking (4.10), crop growth rate (8.4 and 9.2 gm-2day-1) at 0-30 and 30-60 days after sowing, respectively and NDVI (0.748), were recorded under75% as basal + rest N as guided by GS, over other practices and interaction effect with irrigation at 25% depletion of available soil moisture.

Determination of optimum irrigation scheduling for sorghum in Benna-Tsemay Woreda, Southern Ethiopia

Scarcity of water is the most severe constraint for sustainable development of agriculture in arid and semi-arid areas. Hence, novel irrigation water application systems need to be developed so that high crop yield and water productivity per unit of land can be increased. Thus, the field experiment was conducted with the objective of determining the effect of different soil moisture depletion levels on yield and water use efficiency of sorghum crop in Benna-Tsemay woreda at Enchete kebele, Southern Ethiopia. The experiment was conducted for two consecutive years (2019-2020). It was arranged in RCBD with three replications and treatment was rated for five levels of available soil moisture depletion (ASMD), where T1 = 60%, T2 = 80%, T3 = 100%, T4 = 120%, and T5 = 140% of ASMD. Analysis of variance has shown that yield and water use efficiency of sorghum crop was significantly (P < 0.05) affected by irrigation scheduling. As observed in this study, the most economically attractive and environmentally accepted for small scale farmers with tolerable cost of production and higher net benefit was obtained by application of T3 (100% ASMD) under conventional furrow irrigation system. Therefore, for this particular sorghum crop (teshale variety), it could be concluded that increased water saving and water productivity through irrigation at 100% ASMD under conventional furrow irrigation system can solve the problem of water shortage and would ensure the opportunity of further irrigation development in the study area and similar agro-ecology. Int. J. Agril. Res. Innov. Tech. 11(2): 95-102, Dec 2021

Dry Matter Production and Nitrogen Uptake as Influenced by Irrigation and Nitrogen Levels in Maize

A field experiment was conducted at Agro Climate Research Center, Agricultural Research Institute, P.J.T.S Agricultural University, Rajendranagar, Hyderabad, India during rabi 2019-20. The field experiment was laid out in a split plot design with three replications. The treatments comprising of three irrigation scheduling based on (Depletion of Available Soil Moisture) at 60% DASM, 40% DASM and 20% DASM as main plots and three nitrogen levels viz., 90, 180 and 240 kg N ha-1 as sub-plots. The experiment was laid out in split plot design. The results indicated that, among the different treatment combinations, the crop irrigation scheduled at 20 % DASM in conjunction with 240 kg N ha-1 accumulated significantly more dry matter of 34.2 g, 149.2 g, 233.7 g and 284.8 g plant-1, at 6th leaf, silking, dough and physiological maturity stages, respectively. The nitrogen uptake was found to be more when the crop was irrigated at 20 % DASM in conjunction with 240 kg N ha-1 (67.1 g, 231.8 g, 294.7 g and 305.3 g plant-1) at 6th leaf, silking, dough and physiological maturity stages, respectively.

Effect of Different Irrigation Levels and Methods of Humic Acid Addition on Growth, Yield and Storability of Garlic

A field experiment was carried out to study the effect of different levels of irrigation at 40%, 60% and 80% of available soil moisture depletion (ASMD) and humic acid application methods (without, soil application, foliar application and soil application + foliar) on growth, productivity and storability of garlic cv. Sids-40. Results indicated that highest values of irrigation water applied (IWA),were found to be 3359 and 3162 m3/fed due to 40% ASMD comparison with other two irrigation treatments in both seasons respectively. Also, results reveal that 80% ASMD irrigation treatments could save about 31.0% and 29.8% of the applied water, compared with 40% ASMD in both seasons respectively. Furthermore, the irrigation after depletion of 40%, 60% ASMD with applying soil conditioner and foliar application of humic acid increased the plant length, leaves number, neck diameter, bulb diameter, bulb fresh weight, fresh and dray weight of plant as well as the yield of bulbs, cloves fresh weight/bulb, cloves number/bulb, bulb diameter, neck diameter, average clove weight, nitrogen, phosphors, potassium and carbohydrates content. While, the proline and total pungency of garlic increased significantly and the percentage of weight loss (%) after two, four and seven months of the storage as a result of irrigation decreased after 80% ASMD with soil application plus spraying with humic acid. Also, average water utilization efficiency, increased by using 60% ASMD with soil and foliar application of humic acid (HS+ HF) followed by 80% ASMD with HS+ HF then 40% ASMD treatments with HS+ HF in both seasons.

Changes in growth and quality performance of Roselle (Hibiscus sabdariffa L.) in response to soil amendments with hydrogel and compost under drought stress

Drought and low organic carbon content are two main problems for agriculture in arid and semiarid regions. Application of hydrogels and compost may decrease adverse effects of drought on plants. A factorial experiment with a randomized complete block design with three replicates was conducted to evaluate the effect of hydrogels and compost application on yield and growth parameters of Roselle (Hibiscus sabdariffa L.) under drought stress (DS). These factors manipulated with seven treatments of soil amendments with 0, 150 (H1) and 300 (H2) kg ha−1 hydrogel, 10 (C1) and 20 (C2) ton ha−1 compost, 150 kg ha−1 hydrogel + 10 ton ha−1 compost (H1C1), and 150 kg ha−1 hydrogel + 20 ton ha−1 compost (H1C2) upon three DS levels (D1: 25% depletion of available soil moisture (DASM) as no-stress condition, D2: 50% DASM as mild-stress and D3: 75% DASM as severe-stress treatment). Results showed that drought stress significantly decreased growth parameters and relative water content (RWC) while increased ion leakage (IL), antioxidant activity (AA), and total phenolic content (TPC). H1, H1C1, and H1C2 Treatments significantly increased chlorophyll content index (CCI), leaf area (LA), leaf water potential (LWP), RWC, AA, and TPC compared to control under mild and severe stress conditions. In addition, only H1C2 treatment significantly increased calyx yield (CY) under mild and severe drought conditions. Interaction between 150 kg.h−1 hydrogel and 20 ton ha−1 compost compared to the each treatment alone led to the highest SDW, LA, and CY amounts under severe DS treatment. The CCI showed a strong positive correlation with CY (R2 = 0.61, p = 0.01), while revealed a negative correlation with TPC (R2 = -0.72, p = 0.01) and AA (R2 = -0.68, p = 0.01). These results confirm that hydrogel and compost could be suitable for agricultural use under DS conditions. The amount of hydrogel and compost application is very important on plant performance under DS.

Influence of Planting and Irrigation Levels as Physical Methods on Maize Root Morphological Traits, Grain Yield and Water Productivity in Semi-Arid Region

Assessing the impact of planting methods and irrigation levels is needed to determine the effects on maize root morphological traits, grain yield, and water productivity in semi-arid regions. A study was initiated on maize (Zea mays L.) from 2015 to 2016, including three planting methods [i.e. broad bed and furrow (BBF), shallow and narrow furrow (SNF) and deep and wider furrow (DWF)] and four irrigation levels [i.e. irrigation once in ten days (I10D), irrigation at 40% depletion of available soil moisture (DASM, I40), irrigation at 50% DASM (I50) and irrigation at 60% DASM (I60)] arranged in a split-plot design with three replications. Results reveal that the DWF method has increased root length, root volume, root surface area and root dry weight compared to SNF and BBF (p < 0.05). DWF and SNF resulted in higher grain yield than BBF, although the DWF grain yield was non-significant with SNF but resulted in 22.40% higher irrigation application. Irrigation at I50 had a significant effect on root length, root surface area, and grain yield, regardless of planting methods. Therefore, where irrigation has been a costly and limited farm input, the practice of SNF and deficit irrigation (I50) could be a viable option for greater water saving and higher grain yields of maize.

A Study on Sensor Based Irrigation and Nitrogen Management in Maize Zea Mays L

Maize is widely called as the "Queen of Cereals” owing to its great producing capacity among the cereal crop. The ever-increasing demand combined with the ever-increasing expenses of water and energy has made it imperative to create new technologies for the appropriately managing of water resources. The conventional method of farming is no longer viable because of the increasing shortage of water; as a result, it is no longer possible to satisfy the needs of ever-increasing populations. During the Kharif-2019 growing season, the field experiment entitled "Sensor and SMI based irrigation management in Maize [Zea mays (L.)] to enhance growth, yield, and water use efficiency" was carried out at the 'L' Block, ZARS, University of Agricultural Sciences, GKVK, Bangalore 560065. The experiment included seven different treatments: T1 was surface irrigation, T2 was drip irrigation at three-day intervals, T3 was green soil moisture indicator (GSMI) based drip irrigation, T4 was yellow soil moisture indicator based drip irrigation (YSMI), T5 was sensor based drip irrigation at 25% depletion of available soil moisture (DASM), T6 was sensor based drip irrigation at 50% DASM, and T7 was sensor based drip irrigation at 75% DASM. These were arranged in RCBD, and three copies were made of them. According to the findings, sensor-based drip irrigation with a concentration of 25% DASM resulted in considerably better growth metrics, kernel yield, and Stover yield. However, GSMI-based drip irrigation reported a yield that was on par with that of conventional irrigation. Additionally, greater water usage efficiency was obtained with the same treatment. In contrast, surface irrigation resulted in a grain yield of 6551 kilogrammes per hectare, a stover yield of 8007 kilogrammes per hectare, and a water usage efficiency of 131.8 kilogrammes per cubic metre per hectare.

Effect of Soil Moisture Content and Rate of Potassium Fertilizer on Soil Potassium Content and Growth of Cowpea (Vigna unguiculata l.) Grown in Sandy Regosol in Sri Lanka

A research study was conducted to identify the effect of potassium rate and drought stress on the post-harvest soil potassium content and growth parameters of cowpea (Vigna unguiculata L.). The experiment was arranged in a Completely Randomized Design (CRD) in a factorial manner with 8 treatments (4 different rates of fertilizer potassium as muriate of potash (MOP (i) 100% of recommended level (75 kgha-1), (ii) 125% of recommended level (93.75.kgha-1), (iii) 150% of recommended level (112.5 kgha-1), and (iv) 175% of recommended level (131.25.kgha-1) at 2 different soil moisture conditions as 25% depletion and 75% depletion of available soil moisture as optimal and sub-optimal moisture condition respectively and was replicated 3 times. The post-harvest soil potassium content, chlorophyll content of leaves and cowpea growth parameters such as, dry weight of root and dry weight of shoot were recorded at vegetative and harvesting stages. The results reveal that there was a significant influence (p<0.05) of potassium rate and soil moisture on the growth parameters, leaf chlorophyll content and available soil potassium content after harvest. In overall terms potassium promoted growth of cowpea when subject to sub-optimal soil moisture. Further, it was found that the increased application of potassium fertilizer up to 175% of recommended level can be considered as a significant factor in overcoming soil moisture stress in cowpea.

Effect of Water Regimes and Polyvinyl Alcohol on Faba Bean Yield, Chemical Composition and Water Use Efficiency

Quantifying local crop response to irrigation is important for establishing proper irrigation management approaches.To apply that, a field experiment was carried out to evaluate the effect of three available soil moisture depletion(ASMD) levels, 25 %, 50 %, and 75% applied using solid set sprinkler irrigation system in combination with four concentrations (0.00%, 0.05%, 0.1% and 0.2 %)of poly vinyl alcohol soil conditioner. The combined effect of water regimes and different concentrations of soil conditioner was studied on faba bean (Vicia faba cvGiza 843), The experiment was carried out in the semiarid climate of northeast Farm of El-Ismailia Agricultural Research Station, El-Ismailia Governorate Egypt during two successive seasons(2012/2013 and 2013/2014).Evapotranspiration (ETa), yield productivity of faba bean, water use efficiency and macronutrients uptake were also evaluated. Results showed that the actual seasonal crop evapotranspiration (ETa) for ASMD treatments varied between (1605.36 –2482.45m3 fed-1.) in the first season (2012/2013) and (1439.26 – 2457.01m3 fed-1.) in the second season (2013/2014). There are three options to calculate seasonal ETc for faba bean crop in Ismailia condition. So, it can be use FAO-24RD, PMd or Droogers and Allen (2002)methods. Moreover,obtained data reveal that application of polyvinyl alcohol(PVA)synthetic soil conditioners (with high concentration), decreased available soil moisture depletion (ASMD) in sandy soil and caused a significant increase in faba bean yield, water use efficiency (WUE) and improved the macronutrient uptake by faba bean yield. Finally, the results clearly showed that the significant effect of PVA at (0.1or 0.2 %) concentration was most observed at 50% ASMD.

Differences in Physiological and Biochemical Attributes of Wheat in Response to Single and Combined Salicylic Acid and Biochar Subjected to Limited Water Irrigation in Saline Sodic Soil.

Given the expectancy of the water supply becoming scarce in the future and more expensive, water conservation during wheat production processes has become very crucial especially in saline sodic soil. Biochar and salicylic acid (SA) were used to assess the potential to alleviate the influences of depletion of available soil moisture (DAM) on physicochemical, physiological, biochemical attributes, as well as wheat production absorption (Triticum aestivum L. cv. Misr 1) and macro-elements. Two seasons (2018/2019 and 2019/2020) of field trials were investigated using twelve combinations of three water treatments (50%, 70%, and 90% DAM) and foliar- and soil-applied treatments (control, biochar, salicylic acid, and biochar + SA). Biochar treated plots amplified soil physicochemical attributes, leading to improved physiological traits and antioxidant enzymes, as well as yield related traits under water limitation conditions in both years. Similarly, synergistic use of biochar and salicylic acid greatly augmented the designed characteristics such as chlorophyll a, b, K+ content, relative water content (RWC), stomatal conductance, photosynthetic rate, and intrinsic water use efficiency, whilst exhibited inhibitory effects on proline content, electrolyte leakage, Na+ content SOD, POX, CAT, and MDA, consequently increased 1000-grain weight, number of grains spike−1, grain yield, as well nutrient uptake (N, P, K) under water limitation condition in both years, followed by treatment of sole biochar or SA compared to unamended plots treatment (control). Wheat productivity achieved further increasing at 70% DAM alongside synergistic use of biochar and SA which was on par with 50% DAM under unamended plots (control). It is concluded from the findings that coupled application of biochar alongside salicylic acid accomplished an efficient approach to mitigate the injurious influences of water limitation, along with further improvement of the soil, physiology, biochemical attributes, and wheat yield, as well nutrient uptake, under saline sodic soil.