Productive capacity of the maize for silage crop grown in disturbed irrigation regime

An experiment was conducted with maize for silage as a main irrigation culture in the experimental field of the Agricultural Institute - Stara Zagora. The following variations have been tested: variation 1 - no irrigation (sentinel); variation 2 - optimal irrigation, 80%-85% of FC (100% irrigation); variation 3 - Irrigation as variation 2 but with first irrigation cancelled; variation 4 - irrigation as variation 2 but with second irrigation cancelled; variation 5 - irrigation as variation 2, but with third irrigation cancelled. On the basis of a chemical analysis of the sudangrass forage for the raw protein content, FUM, FUG and PDI were defined. It was found that the highest yield of raw maize protein grown as the main crop was obtained from the optimal irrigation variation, both in the non-fertilized and the fertilized variation, respectively with 1023.5 kg / ha and 1303.5 kg / ha. The optimal water supply of maize provides the highest energy efficiency of the forage expressed in FUM -15022.8 kg / ha, FUG -15584.4 kg / da, PDI - 1060 kg / ha for non fertilized variations and FUM -16873.5 kg / ha, FUG -17516.3 kg / ha, PDI-1219 kg / ha with fertilizer applied.

Productivity and chemical composition of green biomass from Sudan grass, grown as a second crop, with optimal and insufficient water supply

The aim of the present study is to determine the impact of the disturbed irrigation regime on the yield and the chemical composition of Sudan grass, grown as a second crop. To accomplish this goal, a trial was conducted in the experimental field of the Agricultural Institute - Stara Zagora with Sudan grass on meadow-cinnamon soil under irrigated conditions. The following variants have been studied: 1 - without irrigation (control variant); variant 2 - optimal irrigation, 75-80% of field capacity (FC); variant 3 - irrigation as in variant 2, but with the removal of the first watering; variant 4 - irrigation as variant 2, but with the removal of the second irrigation; variant 5 - irrigation as variant 2, but with the removal of the third watering. It was found that when growing Sudan grass as a second crop with optimal irrigation and disturbed irrigation regime done by canceling successive watering, the highest yield of dry biomass is obtained with optimal irrigation including three irrigations. Its yield increased by 24.2% compared to the control treatment. Irrigation of Sudan grass with only the second and the third irrigation in a row, without the first irrigation provided, leads to the lowest yield of dry biomass - 11290 kg / ha. Among the chemical composition indicators, the most significant change is observed in the content of the crude fat, followed by that of the crude fiber and crude protein, depending on the method of growing Sudan grass (with or without irrigation).

Improving water deficit tolerance of Salvia officinalis L. using putrescine

To study the effects of foliar application of putrescine (distilled water (0), 0.75, 1.5, and 2.25 mM) and water deficit stress (20%, 40%, 60%, and 80% available soil water depletion (ASWD)) on the physiological, biochemical, and molecular attributes of Salvia officinalis L., a factorial experiment was performed in a completely randomized design with three replications in the growth chamber. The results of Real-Time quantitative polymerase chain reaction (qRT-PCR) analysis showed that putrescine concentration, irrigation regime, and the two-way interaction between irrigation regime and putrescine concentration significantly influenced cineole synthase (CS), sabinene synthase (SS), and bornyl diphosphate synthase (BPPS) relative expression. The highest concentration of 1,8-cineole, camphor, α-thujone, β-thujone, CS, SS, and BPPS were obtained in the irrigation regime of 80% ASWD with the application of 0.75 mM putrescine. There was high correlation between expression levels of the main monoterpenes synthase and the concentration of main monoterpenes. The observed correlation between the two enzyme activities of ascorbate peroxidase (APX) and catalase (CAT) strongly suggests they have coordinated action. On the other hand, the highest peroxidase (PO) and superoxide dismutase (SOD) concentrations were obtained with the application of 0.75 mM putrescine under the irrigation regime of 40% ASWD. Putrescine showed a significant increase in LAI and RWC under water deficit stress. There was an increasing trend in endogenous putrescine when putrescine concentration was increased in all irrigation regimes. Overall, the results suggest that putrescine may act directly as a stress-protecting compound and reduced H2O2 to moderate the capacity of the antioxidative system, maintain the membrane stability, and increase secondary metabolites under water deficit stress.

Irrigation regime and fertilization rates for vegetable corn varieties in the Samarkand region

Цель исследований – изучить рост, развитие и урожайность сортов сахарной (овощной) кукурузы Шерзод и Замон при различных режимах орошения и нормах удобрений и установить оптимальные параметры режима орошения и нормы удобрений, обеспечивающих получение устойчивого высокого урожая (не менее 8,5–9,0 т/га). Исследования проведены в 2017–2020 годах на орошаемых лугово-сероземных почвах Самаркандской научно-опытной станции Научно-исследовательского института овощебахчевых культур и картофеля. Почвы – среднесуглинистые с залеганием грунтовых вод на глубину 4–5 м. В опытах изучали два режима орошения по предполивной влажности почвы не ниже 65–70 и 70–80% ППВ. В каждом режиме орошения изучали следующие нормы удобрений: 1. N150P120K75, 2. N200P160K100, 3. 30 т/га навоза + N150P120K75, 4. 30 т/га навоза + N200P160K100 кг/га. При режиме орошения по предполивной влажности почвы не ниже 65–70% ППВ проводили шесть поливов по схеме 2–4 с интервалом 18–16–14–12–10–10 дней. Оросительная норма – 5696–5734 м3/га, при этом поливная норма – 827–1185 м3/га. При режиме орошения по предполивной влажности почвы не ниже 70–80% ППВ растения поливали восемь раз по схеме 3–5, то есть в фазах всходов – образования метелки – три раза, а в фазах образования метелки – полной спелости – пять раз, через каждые 15–13–10–9–8–7–7–9 дней с оросительной нормой 5451–5500 м3/га, при поливной норме 536–918 м3/га. Высокий и гарантированный урожай сортов сахарной (овощной) кукурузы Шерзод и Замон (8,6–10 т/га) можно получить при выращивании их при режиме орошения по предполивной влажности почвы не ниже 70–80% ППВ или при 8 поливах по схеме 3–5, то есть в период фазы всходов – образования метелки – 3 поливов, а во второй период в фазах образования метелки – полной спелости – 5 поливов с поливной нормой 536–918 м3/га и совместном внесении органоминеральных удобрений в норме 30 т/га навоза + N200P160K100 кг/га. The purpose of the research is to study the growth, development and yield of varieties of sugar (vegetable) corn Sherzod and Zamon under various irrigation regimes and fertilizer rates and to establish the optimal parameters of the irrigation regime and fertilizer rates that ensure a stable high yield (at least 8.5–9.0 t/ha). The research was carried out in 2017–2020 on irrigated meadow-gray-earth soils of the Samarkand Science and Research Station of Scientific Research Institute of Vegetables Crops, Melons and Potatoes. The soils are medium loamy with the occurrence of groundwater to a depth of 4–5 m. In the experiments, two irrigation modes were studied for pre-irrigation soil moisture not lower than 65–70 and 70–80% PPV. In each irrigation regime, the following fertilizer standards were studied: 1. N150P120K75, 2. N200P160K100, 3. 30 t/ha of manure + N150P120K75, 4. 30 t/ha of manure + N200P160K100 kg/ha. Under the irrigation regime, according to the pre-irrigation soil moisture not lower than 65–70% of the PISM, six irrigations were carried out according to the 2–4 scheme with an interval of 18–16–14–12–10–10 days. The irrigation rate is 5696–5734 m3/ha, while the irrigation rate is 827–1185 m3/ha. Under the irrigation regime for pre-irrigation soil moisture not lower than 70–80% PISM, the plants were watered eight times according to the scheme 3–5, that is, in the phases of germination – panicle formation – three times, and in the phases of panicle formation – full ripeness – five times every 15–13–10–9–8–7–7–9 days with an irrigation norm of 5451–5500 m3/ha, with an irrigation norm of 536–918 m3/ha. A high and guaranteed yield of varieties of sugar (vegetable) corn Sherzod and Zamon (8,6–10 t/ha) can be obtained when growing them under the irrigation regime for pre – irrigation soil moisture not lower than 70–80% PISM or with 8 watering according to the scheme 3–5, that is, during the germination phase – the formation of a panicle –3 watering, and in the second period in the phases of the formation of a panicle – full ripeness – 5 watering with a watering norm of 536–918 m3/ha and joint application organomineral fertilizers in the norm of 30 t/ha of manure + N200P160K100kg/ha.

Irrigation Regime for Protection on Root Intrusion for Subsurface Drip Irrigation

Root intrusion into emitters poses a threat to the service lives of subsurface drip irrigation systems. In an attempt to address this problem, an experiment was conducted on spring wheat grown in soil columns installed in a greenhouse to study the effects of irrigation regimes in protecting against root intrusion into emitters. Spring wheat was planted in soil columns. The specifications of the soil column were 15-cm width, 60-cm length and 100-cm depth. Drip tapes were buried manually in the center of the soil columns at a -40-cm depth. The soil matrix potential at a 20-cm depth immediately over the drip emitters was used to schedule the subsurface drip irrigation regime. Five different irrigation arrangements, with targeted soil matrix potentials of -10, -20, -30, -40 and -50 kPa, were maintained. The soil matrix potential influenced the spring wheat root distribution, emitter flow rate, root intrusion, and spring wheat yield and quality. The total root dry weight increased as the soil matrix potential decreased. Root length density at 35-45-cm increased as the soil matrix potential increased. The decrease in the emitter flow rate increased along with the soil matrix potential. All the treatments had root intrusion, but its severity was correlated with the soil matrix potential. Root intrusion first decreased as the soil matrix potential decreased but then increased as the soil matrix potential continued to decrease. The lowest root intrusion rate (22.22%), as well as the greatest relative yield and relative thousand-grain weight values, were achieved with a soil matrix potential of -40 kPa.

Irrigation Rationalization Boosts Wheat (Triticum aestivum L.) Yield and Reduces Rust Incidence under Arid Conditions

Under changing climate, water scarcity and frequent incidence of diseases like stripe rust pose the biggest threat to sustainable crop production which jeopardizes nutritional security. A study was executed to rationalize crop water requirement and evaluate wheat (Triticum aestivum L. cv. Bohoth 3) yield losses by stripe rust infection under irrigated conditions. Seven water treatments included three irrigations in three stages/season ( S 3 ), four irrigations ( S 4 ), and five irrigations ( S 5 ) at the different sensitive growth stages, full ( F ), and two deficit irrigation levels including D 1 = 80 % of field capacity (FC) and D 2 = 70 % (FC) along with farmers’ practice of irrigation as control ( C ). Results revealed that F and D 1 boosted grain yield by 31 and 14%. Overall, F irrigation regime resulted in the highest grain production (2.93 ton/ha) as well as biomass yield (13.2 ton/ha). However, D 2 had the highest value of grain protein (15.9%) and achieved the highest application efficiency (AE) at midseason (54.6%) and end season (59.6%), and the lowest AE was under S 3 . Also, halting irrigation at the milky stage ( S 5 ) led to a significant decrease in irrigation water use efficiency as compared to D 1 . However, cutting irrigation at the end of seedling, heading, and milky stages ( S 3 ) caused a significant reduction in E a , crop water use (ETa), and 1000 grain weight in comparison with all other treatments. Regarding yellow rust, S 3 irrigation regime resulted in the lowest incidence of yellow rust infection. The highest irrigation and water use efficiency values were recorded under D 1 (0.79 and 0.59 kg/m3), and the lowest values were obtained for control. Hence, the deficit irrigation treatment D 1 could be recommended as the best appropriate strategy to save more water and to improve the water productivity under Yemeni agroclimatic conditions.