Interaction Effect Of Irrigation Research Articles

Performance of okra (Abelmoschus esculentus) to different irrigation levels and mulches under drip irrigation system

The present study was carried out at Lovely Professional university, Phagwara, Punjab during 2019 to study the performance of okra under irrigation levels and mulching methods under drip irrigation. The treatment comprised of 3 irrigation levels (1.0 ETc, 0.8 ETc and 0.6 ETc) and 5 mulch methods (black plastic mulch, silver plastic mulch, straw mulch, soil mulch and no mulch) laid out in split plot design replicated thrice. The growth and yield attributes were significantly influenced by irrigation levels and mulching methods. The irrigation level I2 (0.8 ETc) significantly exhibited maximum plant height (100.45 cm), number of branches per plant (1.77), and yield per plant (216.59 g) whereas irrigation level I1 (1.0 ETc) recorded maximum pod yield (15.59 tonnes/ha) which is at par with irrigation level I2 (15.36 tonnes/ha). The black plastic mulch was found significantly superior over no mulch treatments in terms plant height, number of branches, pod yield per plant, pod yield (19.09 tonnes/ha). The maximum water use efficiency (0.41 tonnes/ha-cm) was recorded in irrigation treatment I3 and in black plastic mulch (0.46 tonnes/ha-cm). The interaction effect of irrigation and mulching not showed significant difference on pod yield but significantly affected water use efficiency. At interaction effect, the maximum water use efficiency (0.56 tonnes/ha-cm) in combination of I3 and M1. Maximum B:C ratio was recorded in irrigation level I1 (3.49) which is at par with I2 (3.40). Black plastic mulch recorded higher B:C ratio (3.40). The interaction effect did not showed significant effect on B:C ratio. Looking the higher yield of crop, water use efficiency and higher B:C ratio, it can be recommended that okra crop showed good performance under irrigation level I2 and black plastic mulch.

Interaction effects of irrigation and nitrogen on the coordination between crop water productivity and nitrogen use efficiency in wheat production on the North China Plain

Improving nitrogen use efficiency-yield (NUEYield) and crop water productivity (CWP) simultaneously has been a focus for sustainable wheat production, especially for the North China Plain, which faces challenges with limited water resources and low fertilizer use efficiency. With three-year wheat field experiments with two irrigation levels (rainfed, and irrigated at jointing and anthesis) and three N rates (0, 180, and 270 kg ha−1), we systematically investigated the effect of irrigation and nitrogen management on wheat water consumption at different growth stages, and further determined on the relationship between CWP and NUEYield simultaneously under different irrigation and nitrogen interactions. The results showed that N application and irrigation increased the total crop water consumption (1.2%−3.6% and 42.4%−44.4%, respectively). Increasing the N rate improved the soil water use (7.5%−10.3%) and reduced crop dependence on irrigation and precipitation, whereas irrigation reduced soil water utilization (54.4%−57.8%). Both irrigation and N application significantly increased the amount, percentage, and intensity of water consumption, especially during the grain filling period. There was a significant positive synergistic relationship between CWP and NUEYield under different irrigation and nitrogen treatments. For every 1 kg m−3 increase in CWP, NUEYield increased by 2.71–11.37 kg kg−1, depending on the N rate and water conditions. Increasing the N rate reduced the positive response of NUEYield to increasing CWP, while irrigation increased the positive response of NUEYield to increasing CWP. After decomposing NUEYield into nitrogen uptake efficiency (NuptE) and nitrogen utilization efficiency for yield (NutEYield), we found that the positive synergistic relationship between CWP and NUEYield was mainly due to the positive response of NuptE but not NutEYield to CWP. Irrigation increased the grain nitrogen accumulation efficiency by simultaneously increasing both pre-anthesis N translocation (GNAT) and post-anthesis N assimilation (GNAA) but increased GNAT more significantly than GNAA. Our results provide a theoretical basis for the efficient management of water and fertilizer in wheat production on the North China Plain and offer critical insights for improving the modeling of water-nitrogen relationships in wheat.

An Empirical Assessment of the Interactive Impacts of Irrigation and Climate on Farm Productivity in Samarkand region, Uzbekistan

Analyzing climate change's consequences is more complex for irrigated agriculture compared to rainfed. There are still limited researches that has considered the interactive effects of irrigation and climate variables regardless the fact that a broad range of climate studies was already involved in international literature. In this view, this study aimed at exploring the cross effects of irrigation with climate on farm output using ex-post assessment technique in Uzbekistan, where agriculture contributes for a large portion of the national GDP and irrigation water is becoming scarce. We applied a Stochastic Frontier Approach (SFA) with panel data from the central-eastern part of Uzbekistan for the period of 2013-2018, which includes a sample of 2,135 wheat and 1,141 cotton growers. The analysis revealed that climate factors have diverse influence by crop types across the region. Increased warming would be harmful for wheat farmers: a one-degree Celsius rise in average temperature between March and June could lead to up to 60% losses of total yields on wheat-growing farms, although precipitation has a positive significant effect. In contrast, increased temperatures are beneficial for cotton-growing farmers but excessive rainfall during the months of May-September could lead to 3% losses of total yields on cotton-growing farms. It's expected that both wheat and cotton growing farmers will suffer from temperature increases and excessive precipitation on their farms in the near future. More importantly, the interaction effects of irrigation and climate variables show that the cross effects of applied irrigation and mean temperature have highly significant positive impacts on the total yields of both wheat and cotton growing farmers in the study region. Thus, productivity in the region could be improved when enough water is available and more efficient irrigation techniques are used, otherwise declines in productivity could be witnessed.

Evaluation crop indices of canola spring genotypes in terminal drought stress conditions and foliar application of Potassium silicate

Introduction Drought is a restriction in crop production in arid and semiarid regions. It is forecast that climate change may cause droughts shortly. After oxygen, silicon (Si) is the second most common element in the soil. In reducing both biotic stress (e.g., plant diseases and pest damage) and abiotic stresses such as salinity, drought, aluminum toxicity, heavy metal toxicity, nutrient imbalance, lodging, radiation, high temperature, wounding, and freezing. Materials and Methods In order to study the effects of terminal drought stress and foliar application of potassium silicate on yield and canola spring genotypes components, a factorial split-plot test was conducted in Karaj, Iran in a full randomized block configuration with three replications for two years of cultivation (2016-2018). The irrigation was performed at two levels in this study, including routine irrigation (control) and interruption of irrigation from the pod formation stage. Potassium silicate foliar application at two levels comprised of 0 and 4 g liter-1 in factorial status in main plots and five Brassica napus L. genotypes including OG × AL, RGS × SLM, DALGAN, RGS003 and RGS × Okapi in subplots. SAS Ver 9.1 statistical analysis was used for variance analysis. Results Combined variance analysis showed that the impact of the year on some characteristics seed number in silique, silique length and seed yield was significant. Also, the effect of irrigation was significant on seed yield. The effect of genotype on plant height was significant indicating that the genotypes had different reactions. The interaction effect of irrigation × genotype on Harvest index was significant. The interaction effect of Irrigation × Potassium Silicate × Genotype on branch number, silique number, silique length, seed number in silique, seed weight, biological yield, seed yield, oil content and oil yield was significant. The mean comparison of irrigation and Potassium silicate interaction demonstrated that the most grain yield was observed in normal irrigation and the least value related to cut off irrigation at pod formation stage. The results indicated that, irrigation, foliar application of Potassium silicate and their interaction had significant effect on growth and agronomic traits and increased them. Conclusions Finally, our study showed the beneficial effects of Potassium Silicate in improving the drought tolerance of canola plants, especially at the end of the season. This can provide a basis for attempting new strategies to reduce the damage from drought and create a functional link between the role of silicon, physiological response and tolerance to drought stress in canola plants. According to the results, in the case of application of Potassium Silicate and normal irrigation, the promising genotype of OG×AL, with the highest seed and oil yield, is recommended as standard. Also, in the case of application of Potassium Silicate and late-season drought stress (restricted irrigation from the pod formation stages), RGS × SLM and DALGAN with the highest seed yield, is recommended.

Canola Quality and Fatty Acids Composition as Influenced by Delayed Cropping and Late Season Drought Stress

To investigate the effects of drought stress and delayed planting on oil quality and fatty ‎acids composition of canola cultivars, a factorial split-plot test was conducted in a ‎randomized complete blocks design with three replications at Seed and Plant Improvement ‎Institute, Karaj, Iran for two years (‎2015-2017) ‎.Planting date at two levels of timely ‎planting (Oct. 27) and late planting (Nov. 27) and irrigation at two levels of normal ‎irrigation (control) and restricted irrigation from pod formation stage onwards were ‎considered the main factors. Canola cultivars including Kodiak, Traviata, Compass, ‎Diffusion, Mehr2, Elvise and Tassilo were the variables. The simple effects of planting date, ‎irrigation, and cultivar on all research parameters were significant. The interaction effect of ‎planting date × irrigation was significant on oil yield and oil content at the level of 5% and ‎in terms of linoleic and palmitic acids, and stomatal resistance, it was significant at the level ‎of 1%. The interaction effect of irrigation × cultivar was significant on palmitic acid, ‎glucosinolate and stomatal resistance at the level of 1%. Late season drought stress and late ‎planting dramatically reduced oil yield (58%), oil content (8%) and qualitative ‎characteristics of canola cultivars. Among the studied cultivars, Tassilo cultivar was ‎recommended for all conditions of this research with the seed yield (4407 kg ha-1), oil yield ‎‎(2007 kg ha-1), chlorophyll content (1.43 mg g-1fw), high oleic and linoleic fatty acids, as ‎well as low and standard erucic acid (0.41%) and glucosinolate (22.8 μmol g-1).‎

Effects of plantbac panels on seedling establishment and plant growth of Calligonum comosum L’Herit. in desert areas of Iran

Today, application of superabsorbent material as plantbac panels to overcome water shortages is considered for improving plant vegetation cover in arid areas. This research was aimed to investigate the effects of plantbac panels on plant establishment and growth of Calligonum comosum L’Herit. in the Kashan Arid and Desert Research Station over three years from 2017 to 2020. The experiment was conducted as a split plot design based on randomized complete blocks in four replications, in which the duration of irrigation (2 and 4 weeks) was considered as the main plot, and the amount of water (10 and 20 liters) and treatment (plantbac and control) as sub subplots. The seedlings were planted in the soils with and without plantbac panels. For each plant, the irrigation was conducted using 10 and 20 l water for two- and four-week intervals. Data were collected and analyzed in terms of plant height, canopy diameter, collar diameter, and survival rate. The results showed that the use of plantback plates increased the examined growth criteria of seedlings. When comparing interactions between treatments, the height, collar diameter and crown diameter of the Plantback treated seedlings showed average 11, 11, and 14.8% superiority to their controls. Furthermore, the interaction effect of irrigation by water consumption was significant for canopy diameter (p < 0.05), while interaction effect of irrigation by plantbac was significant for plant height (p < 0.05). The average higher and lower crown diameters of 83 cm and 39 cm were observed by 10 l water in two- and four-week irrigations, respectively.

Effect of potassium sulfate on the physiological characteristics of canola cultivars in late season drought stress conditions

In order to reduce the damage caused by the late-season drought stress of canola, a factorial split-plot experiment was performed based on the randomized complete blocks design with three replications in Karaj, Iran. The treatments were Potassium sulfate in two levels, including application and non-application of potassium sulfate, irrigation at three levels including normal irrigation (control), restricted irrigation from the flowering and pod formation stage, as factorial were in main plots and winter canola cultivars including Opera, L72, KR1, GKH3705, GKH0224 were in subplots. The simple effect of irrigation and potassium sulfate on all of the studied traits and the simple effect of cultivar on all traits except chlorophyll b were significant. The interaction effect of irrigation × cultivar on soluble carbohydrate, stomatal resistance, proline content, chlorophyll a and total chlorophyll content was significant. The interaction effect of irrigation × potassium sulfate on the amount of soluble carbohydrates, stomatal resistance and proline content of leaves was significant. In irrigation interruption from the pod formation stage, the promising line of L72, and in irrigation interruption from the flowering stage, the Neptune cultivar exhibited the most positive effect of potassium application on the studied traits. As a result, the application of potassium sulfate in addition to the L72 and Neptune cultivars is recommended in areas similar to the tested area encountering the late-season drought stress.

Response of Haricot Bean (&amp;lt;i&amp;gt;Phaseolus vulgaris&amp;lt;/i&amp;gt; L.) to Irrigation Frequency and Intra Row Spacing at Arba Minch, Ethiopia

Optimizing irrigation frequency and intra row spacing for specific environment is one the major agronomic practices to improve productivity of haricot bean. Hence, a field experiment was conducted to evaluate the effect of irrigation frequency and intra row spacing on growth, nodulation and agronomic performance of haricot bean at Arba Minch during dry season of 2018/19. The treatments consisted of three levels of irrigation frequency based on IW/CPE ratio (0.5, 0.67 and 1.0) with irrigation depth of 60 mm and three intra row spacing (6, 10 and 14 cm) which were factorially arranged in split plot design with three replications. Data were collected on phenological, nodulation, growth, yield and yield related parameters of the crop. The measured parameters were subjected to analysis of variance using SAS software version 9.0. Among the measured parameters, plant height, pod number per plant, dry matter and seed yield were significantly influenced by interaction effect of the treatments. The maximum seed yield (2873.7 kg ha−1) was recorded with interaction effect of irrigation at IW/CPE of 1 and intra row spacing of 10 cm. As for economic analysis, the same treatment combination also resulted in the highest net benefit (11254.1 Ethiopian Birr ha−1) and marginal rate of return (422.1%). Therefore, it could be concluded that irrigating haricot bean at IW/CPE ratio of 1 and planting at 10 cm intra row spacing could maximize both seed yield and economic benefit of the crop in the study area.

Deep tillage and residue mulch effects on productivity and water and nitrogen economy of spring maize in north-west India

Alarming decline of groundwater levels in last two decades in Punjab state of north-west India has limited the scope of high water-requiring, but otherwise profitable spring maize crop. This water limitation also calls for optimizing use of fertilizer nitrogen (N). Interventions like tillage and residue management help to address these constraints. This study examined the effects of deep tillage, irrigation, residue mulch and N regimes on root growth, water use, N uptake and productivity of spring maize in a sub-tropical environment. Combinations of two tillage systems viz., deep tillage (DT) and conventional tillage (CT), with two irrigation regimes viz., irrigation water to pan evaporation ratio of 1.0 (I1.0) and 0.5 (I0.5) in main plots; and combinations of four N rates viz., 0 (N0), 50 (N1), 100 (N2) and 150 (N3) kg ha−1 with two mulch rates viz., 0 (M0) and 6 t ha−1 (M) in subplots were randomized with three replications.Deep tillage reduced soil penetration resistance and caused denser rooting than CT. Residue mulch decreased maximum soil temperature by 3.5–8.5 °C resulting in better root growth. Root mass at silking in CTI1.0MN3 (1.46 t ha−1) was comparable to that in DTI1.0M0N3 (1.48 t ha−1) suggesting that deep tillage and mulch had similar effects. Interaction effects of irrigation and N on grain yield were significant. Mean yield increased from 4.3 t ha−1 in N0 to 7.0 t ha−1 in N3 in I1.0 regime; while in I0.5 regime, yield increased from 3.9 t ha−1 in N0 to 5.5 t ha−1 in N2 and declined thereafter. Deep tillage and mulch modified this synergism by causing greater yield increase in I0.5N3 than in I1.0N3 regime. Comparable grain yield in CTM0I1.0N3 (6.3 t ha−1) and DTM0I0.5N2 (6.2 t ha−1) indicate that same yield could be realized with less water and N in DT than in CT regime.

Coupling effects of irrigation and nitrogen levels on yield, water and nitrogen use efficiency of surge-root irrigated jujube in a semiarid region

Jujube (Ziziphus jujuba Mill.) is one of the most optimal fruit trees for economy and ecology in many semiarid regions. However, with water as a scarce resource, the strategy for irrigation and applied nitrogen (Napp) management need to be identified. The goal of this project was to determine the effects of irrigation and Napp on jujube yield, water use efficiency (WUE) and agronomic nitrogen use efficiency (ANUE), and the optimal level of soil water content (SWC) and Napp for jujube under surge-root irrigation (SRI) in a semiarid region. Experiments were conducted during the jujube growing seasons (May–October) of 2014 and 2015 in northern Shaanxi in China that included three levels of SWC, i.e. 60–85%θ (I1) (mass water content, simplified as %θ), 50–75%θ (I2), 40–65%θ (I3), and four levels of Napp, i.e. 0.75 (N1), 0.50 (N2), 0.25 (N3) and 0.00 kg N plant−1 (N4). The treatments were arranged in a strip-plot design with complete randomized blocks with three replications. For both years, irrigation and Napp had significant (P < 0.05) effects on yield, WUE and ANUE, while the interaction effect of irrigation and Napp on WUE and ANUE was significant (P < 0.05), and significant on yield in 2014 but not in 2015. In both years, maximum yield (10.16 and 9.81 kg plant−1, respectively) occurred in 60–85%θ and 0.50 kg N plant−1, maximum WUE were 3.75, 4.43kg m−3 when SWC level and Napp were 40–65%θ and 0.50 kg N plant−1, while maximum ANUE were 2.21, 2.88 kg kg−1 when SWC level and Napp rate were 50–75%θ and 0.25 kg N plant−1, respectively. The dualistic and quadric regression equations of irrigation amount and rate of Napp indicate that the yield, WUE and ANUE of jujube cannot reach the maximum at the same time. Irrigation−Napp input optimization model shows that three combinations of likelihood functions can all be used for the comprehensive management of SRI for jujube. Considering the coupling effects of irrigation and Napp on yield, WUE and ANUE in 2014 and 2015, the SWC level shall be controlled in 50–75%θ and the Napp rate is 0.42 kg N plant−1, which can be as the suitable strategy of irrigation and Napp management for the maximum comprehensive benefits of yield, WUE and ANUE for jujube under SRI in a semiarid region.

Irrigation and nutritional effect on growth and seed yield of coriander (Coriandrum sativum L.)

ABSTRACTOptimum quantity of fertilizers and irrigation water to minimize the cost and increase the production is need of the day. Consequently, an experiment was conducted at CCS Haryana Agricultural University, Hisar during the winter season of 2014–15 and 2015–16 to study the effect of irrigation schedules and fertilizer levels on coriander. Irrigation at 25, 50, 75, and 100 days after sowing (DAS) gave higher growth and yield attributing characters, seed yield (16.48 q/ha), biological yield (50.79 q/ha), net return (Rs. 138,950.6), and benefit to cost ratio (2.36), which resulted in 40.9% and 15.3% increase in seed and biological yield over two irrigations, respectively. The application of fertilizers, i.e., N60 and P50 kg/ha, registered higher growth, seed yield attributes, consumptive use of water, whereas, net return and benefit to cost ratio was recorded maximum under fertilizers, i.e., N75 and P62.5 kg/ha. The interaction effect of irrigation and fertilizer on seeds per umbellet and seed yield was also found to be significantly positive. Hence, in Northern Plains of India four irrigations at 25, 50, 75, and 100 DAS in association with nitrogen 75 kg/ha and phosphorus 62.5 kg/ha is more profitable in coriander crop.

Influence of Irrigation Scheduling with Levels and Times of Nitrogen Application on Root Growth of Aerobic Rice

Aerobic rice is one of the alternative methods for saving water, energy, labour, time and reduced methane gas in rice production ecosystem. The field experimental trial was conducted during summer 2018 at Agricultural College and Research Institute, Madurai. Irrigation scheduling based on different IW/CPE (Irrigation Water/Cumulative Pan Evaporation) ratios and different doses along with various spilt applications of nitrogen were experimented. Results of field experiment indicated that irrigation scheduling at IW/CPE of 0.8 up to panicle initiation stage and thereafter IW/CPE of 1.0 up to dough stage recorded the highest root length of 13.0 cm at active tillering and 18.8 cm at flowering stage. But, irrigating the aerobic rice at IW/CPE of 1.0 up to panicle initiation stage and thereafter IW/CPE of 1.2 up to dough stage recorded the highest root volume (16.9, 27.1 cc·hill-1) and root dry weight (6.1, 12.9 g·hill-1) at active tillering and flowering stage. Application of nitrogen at 150 kg·ha-1 in 5 equal splits at 20, 35, 50, 65 and 80 DAS (Days after sowing) recorded the highest root length of 13.5 cm, root volume of 17.6 cc·hill-1 and root dry weight of 6.4 g·hill-1 at active tillering stage and root length of 19.4 cm, root volume of 27.6 cc·hill-1 and root dry weight of 14.4 g·hill-1 at flowering stage. The interaction effect of irrigation and nitrogen significantly influenced the root growth. Irrigation at IW/CPE of 0.8 up to panicle initiation stage and thereafter IW/CPE of 1.0 up to dough stage along with 150 kg N ha-1 in 5 equal splits at 20, 35, 50, 65 and 80 DAS significantly enhanced the root length (15.7, 23.6 cm) at active tillering and flowering stage. However, irrigation scheduling at IW/CPE of 1.0 up to panicle initiation stage and thereafter IW/CPE of 1.2 up to dough stage along with application of N 150 kg·ha-1 in 5 equal splits at 20, 35, 50, 65 and 80 DAS registered the highest root volume (20.3, 32.8 cc·hill-1) and root dry weight (8.3, 16.4 g·hill-1) at active tillering and flowering stage.

Effect of foliar application of zinc on yield of wheat grown by avoiding irrigation at different growth stages

A field experiment was carried out at micronutrient experimental field of Soil Science Division, BARI, Joydebpur, Gazipur to study the effect of foliar application of zinc on yield of wheat (BARI gom-25) grown by skipping irrigation at different growth stages of the crop. The experiment was designed in a split plot design on sixteen treatments comprising four irrigation treatments (regular irrigation, skipped irrigation at crown root initiation, skipped irrigation at booting stage and skipped irrigation at grain filling stages of wheat growth) and four foliar application of zinc (0.0%, 0.02%, 0.04% and 0.06% of zinc). Zinc Sulphate Monohydrate (ZnSO4. H2O) was used as a source of Zn. The interaction effect of irrigation and foliar application of zinc significantly influenced the yield and yield components of wheat. The highest yield (5.59 t ha-1) was recorded in normal irrigation which was identical with skipping irrigation at flowering and heading stage with 0.06% foliar application of zinc. Skipping irrigation at crown root initiation stage had the most negative effect on growth and yield. Skipping irrigation at flowering and heading stage of wheat with 0.04% foliar application of zinc gave the identical yield in regular irrigation with 0.04% and 0.06% foliar application of zinc. Thus, foliar application of zinc played a major role on yield and yield components of wheat at later stages of growth. The response of foliar application of Zn was positive and quadrate in nature. The optimum dose was appeared as 0.04% foliar application of zinc for grain yield of wheat in the study area of Joydebpur, Gazipur (AEZ-28).Bangladesh J. Agril. Res. 41(2): 323-334, June 2016

Effect of crop geometry, drip irrigation and bio-regulator on growth, yield and water use efficiency of wheat (Triticum aestivum L.)

A field experiment was conducted during Rabi season, 2011-12 at Niche Area Excellence Farm, Bikaner to study the effect of crop geometry, drip irrigation and bio-regulator on growth, water use efficiency and yield of wheat ( Triticum aestivum L.). The experiment was conducted in Randomized Block Design with three irrigation schedules viz. , 60, 80 and 100 per cent ETc, two crop geometry levels viz. , 22cm paired row spacing-4 rows (120 cm lateral spacing) and 22 cm normal spacing sowing (60 cm lateral spacing) and two levels of bioregulator viz. , control (water spray) and thiourea (500 ppm) foliar spray twice at vegetative stage and flowering stage. The study indicated that there was increase in dry matter accumulation, plant height, grain yield and biological yield with increase in irrigation level from 60 per cent ETc to 100 per cent ETc. The study further indicated that dry matter accumulation and plant height was maximum in paired row as compared to normal planting whereas grain yield, biological yield and harvest index were maximum in normal planting as compared to paired row planting. The study indicated that dry matter accumulation significantly increase only 60 and 120 DAS and plant height at only 120 DAS with the thiourea (500 ppm) as compared to control. The study also indicated that the interaction effect of irrigation and geometry gave maximum grain yield, biological yield and WUE at 100 per cent ETc +60 cm drip line spacing, maximum harvest index at 60 per cent ETc + 60 cm drip line spacing whereas maximum WUE at 80 per cent ETc + 60 cm drip line spacing.

Effects of vermicompost on growth parameters, water use efficiency and quality of Zinnia bedding plants (Zinnia elegance 'Dreamland Red') under different irrigation regimes.

The drastic decline of precipitation over the past decade along with overuse of chemical inputs and consequent soil fertility reduction are the most important problems in the approach to agricultural expansion, particularly in urban landscaping. Therefore, an experiment was designed to examine the effects of different irrigation levels (40, 70 and 100 % of field capacity, or FC) and different vermicompost (VC) levels (0, 2.5 and 5 %) on the morphophysiological parameters of Zinnia elegance ‘Dreamland Red’ in a factorial experiment based on completely randomized design with three replications. Results indicated a significant reduction in root/shoot ratio, flower diameter, flower longevity, water use efficiency (WUE), photosynthetic pigments and nutrient uptake, along with reduction in the FC, while VC application improved these features. Based on the results, the highest electrolyte leakage and free radicals were observed in the 40 % of FC level without VC treatment, while the highest antiradical property and phenolic compounds were obtained at the same FC level along with 2.5% VC. Moreover, the highest WUE was observed at 2.5% VC with 70% FC, compared to 40% FC with no VC application. The flower diameter and longevity, as the most important indicators of the zinnias’ quality, were significantly affected by the interaction effects of irrigation and organic fertilizers.

Effect of Drip Fertigation Scheduling on Fertilizer Use Efficiency, Leaf Nutrient Status, Yield and Quality of ‘Shweta’ Guava (Psidium guajava L.) Under Meadow Orcharding

To find out the effect of drip fertigation scheduling on fertilizer use efficiency, leaf nutrient status, yield and quality of 3-year-old ‘Shweta’ guava (Psidium guajava L.) under meadow orcharding, 16 treatment combinations were tried. Treatments comprises with four irrigation [(basin (I0), 50 % (I1), 75 % (I2) and 100 % (I3) irrigation of irrigation water/cumulative pan evaporation)] and four fertigation levels [basal dose (F0), 50 % (F1), 75 % (F2) and 100 % (F3) water soluble fertilizers]. The experiments were laid out in factorial randomized block design. Seventy five percentage irrigation of irrigation water/cumulative pan evaporation through drip resulted in maximum yield with quality fruits, leaf nutrient status and fertilizer use efficiency with highest net return (Rs. 2,12,372.17). Use of 45, 20, 20 g NPK/plant/year produced fruit yield (29.81 t/ha), quality of fruits with maximum net return (Rs. 2,12,550.62). However, F1 (30, 10, 10 g NPK/plant/year) exhibited highest fertilizer use efficiency (101.97 kg/ha). Interaction effect of irrigation and fertigation levels showed that 75 % irrigation of irrigation water/cumulative pan evaporation +75 % water soluble fertilizer produced maximum fruit yield (32.79 t/ha) with quality fruits and highest net returns (Rs. 2,44,073.07). However, maximum fertilizer use efficiency (103.23 kg/ha) was obtained in 75 % irrigation of irrigation water/cumulative pan evaporation + 30, 10, 10 g NPK/plant/year water soluble fertilizer.

Analyzing potato response to irrigation and nitrogen regimes in a sub-tropical environment using SUBSTOR-Potato model

Increasing water scarcity and rising fertilizer cost warrant their judicious use in the world agriculture. It implies that management interventions should synchronize crop needs with soil supplies of these resources in the root zone to reduce probability of water and nutrient stresses and yield loss. This study examines the applicability of SUBSTOR-Potato model in analyzing potato response to irrigation and nitrogen regimes in a semi-arid sub-tropical environment of Punjab. In order to evaluate the model, database was generated by establishing a field experiment on potato (cv. Kufri Badshah) planted in mid-October on a sandy loam soil. Combinations of three irrigation regimes viz., irrigation water (IW) to pan evaporation (Ep) ratios of 0.8, 1.4 and 2.0 and four N rates viz., 0, 135, 180 and 225kgha−1 were randomized in a split-plot design with three replications. Half dose of N for a given rate was applied at planting and the rest half with a common irrigation 4 weeks after planting. The crop was managed for pest control by adopting local recommendations and harvested in end-January.Irrigation and fertilizer N had significant effects on tuber fresh yield, water use and N uptake. Performance of the SUBSTOR-Potato model was reasonable as indicated by close agreement of simulated crop phenology, biomass, water use, tuber yield and N uptake with the measured data. The normalized root mean square of deviations (RMSD) between simulated and measured values for harvest-time dry biomass and fresh tuber yield was 7.3 and 12.6%, while normalized RSMD for seasonal water use (ET+drainage) and total (tuber+haulm)N uptake was 12.4 and 19%. Simulation of tuber yield for independent data (2008–2009) was as good as for calibration data (2010–2011) giving confidence in the model. Scenario analysis based on historical weather data showed that mean potential tuber yield was 50.8tha−1 for October 1 planting that reduced to 41.8 and 37.8tha−1 for later (October 16 and October 31) plantings. The analysis also demonstrated that yield and ET-based water productivity (WPET) were greater on a sandy loam than a loamy sand soil for comparable irrigation and N regime. Interaction effects of irrigation and N on yield and ET indicated that irrigation response was greater in the presence of N. Greater initial soil water status reduced irrigation and N needs than with lower initial soil water for comparable tuber yield. Initial soil mineral-N also affected N and irrigation regime to achieve a given yield.

تأثیر تنش خشکی و مقادیر نیتروژن بر عملکرد و راندمان مصرف آب رازیانه (Foenicolum vulgare Mill.)

به منظور بررسی تأثیر تنش خشکی در مراحل مختلف دوره رشد زایشی و مقادیر نیتروژن بر عملکرد و راندمان مصرف آب رازیانه، آزمایشی به صورت کرت‌های خرد شده در قالب طرح بلوک‌های کامل تصادفی با سه تکرار در سال زراعی 89-1388 در مزرعه تحقیقاتی دانشگاه آزاد اسلامی واحد بیرجند اجرا گردید. سه سطح آبیاری (آبیاری کامل، قطع آبیاری در مرحله گلدهی و مرحله پر شدن دانه) به عنوان فاکتور اصلی و مقادیر نیتروژن در چهار سطح ( 0، 60، 120 و 180 کیلوگرم نیتروژن در هکتار) به عنوان فاکتور فرعی مورد مطالعه قرار گرفت. نتایج نشان داد با اعمال تنش خشکی در مرحله گلدهی و پر شدن دانه نسبت به تیمار آبیاری مطلوب، تعداد چتر در بوته به ترتیب 48/2 و 28/8 درصد، تعداد دانه در چتر به ترتیب 39/4 و 22/4 درصد، عملکرد دانه به ترتیب 69/7 و 52/6 درصد، شاخص برداشت به ترتیب 5/4 و 21/5 درصد و راندمان مصرف آب برای تولید دانه به ترتیب 65/6 و 65/9 درصد کاهش یافت. همچنین با افزایش مصرف نیتروژن از صفر به 120 کیلوگرم نیتروژن در هکتار، تعداد چتر در بوته، عملکرد دانه، عملکرد بیولوژیک و راندمان مصرف آب برای تولید دانه و بیومس به ترتیب 22/1، 24/3، 21/8، 34/5 و 20/4 درصد افزایش یافت. اثر متقابل آبیاری و نیتروژن نیز تنها بر تعداد چتر در بوته و عملکرد دانه رازیانه معنی‌دار بود. بر اساس نتایج این تحقیق می‌توان تیمار آبیاری مطلوب و کاربرد 60 کیلوگرم نیتروژن در هکتار را به علت رعایت مسائل زیست محیطی و داشتن عملکرد و راندمان مصرف آب مطلوب برای زراعت رازیانه در منطقه توصیه نمود.

English

&nbsp; A study was conducted during 2009 to 2010 and 2010 to 2011 to find out the effect of irrigation and fertigation scheduling on growth and yield of guava&nbsp;(Psidium guajava&nbsp;L.). The experiments were laid out in factorial randomized block design with sixteen treatment combinations which included four irrigation levels (basin, 50,&nbsp;75 and 100%&nbsp;irrigation of irrigation water/cumulative pan evaporation) along with four fertigation levels, including, basal dose, 50, 75 and 100% water soluble fertilizers and replicated thrice. The nitrogen, phosphorus and potassium (NPK) fertilizers were applied through fertigation as well as soil application to test various attributes of 3-years-old guava cv. Shweta under meadow (ultra high density) orcharding. The investigation indicated that 100% irrigation of irrigation water/cumulative pan evaporation (I3) through drip resulted in maximum plant height (1.97 m), canopy volume (0.98 m3), girth of primary branches (2.41 cm), leaf area (62.94 cm2) and fruit weight (163.71 g). However, I2&nbsp;(75% irrigation of irrigation water/cumulative pan evaporation) resulted in maximum plant spread east west-north south (1.91 to 1.79 m), fruit yield/plant (5.87 kg) with benefit:cost ratio of 2.62. Use of 60, 30 and 30 g NPK/plant/year produced maximum leaf area (63.39 cm2), fruit weight (162.43 g) and fruit yield/plant (6.01 kg). Interaction effect of irrigation and fertigation levels showed that 100% irrigation of irrigation water/cumulative pan evaporation + 100% water soluble fertilizers gave maximum plant height (2.07 m), canopy volume (1.24 m3), girth of primary branches (2.48 cm), leaf area (66.08 cm2), fruit diameter 6.69 cm (polar) and 5.97 cm (equatorial), fruit weight (182.17 g), yield/plant (6.59 kg). However, maximum benefit:cost ratio of (2.91) was obtained as 75% irrigation of irrigation water/cumulative pan evaporation + 75% water soluble fertilizers. &nbsp; Key words: Guava, irrigation, fertigation, meadow orchard, yield.

Interaction effects of irrigation by municipal wastewater and inorganic fertilisers on wheat cultivation in Bangladesh

The interaction effects of five irrigation water qualities formed with municipal wastewater (hereafter called wastewater) and two inorganic fertiliser levels on the growth and yield of wheat (Triticum aestivum L. cv Shatabdi) were explored in three consecutive growing seasons during 2007–2010. The experiment was set in a split-plot design with two factors and three replications. The five irrigation treatments – I1: freshwater (groundwater extracted by tubewell) as control, I2–I4: diluted wastewater (having wastewater fraction of 0.25, 0.50 and 0.75, respectively) and I5: raw/undiluted wastewater – were allocated to the main plots, and the two fertiliser levels – F0: no fertiliser and F1: recommended standard dose – were allocated to the sub-plots. The wastewater contained nitrogen (N), phosphorus (P) and potassium (K) at concentrations of 17.5, 3.7 and 10.3mgL−1, respectively, which correspondingly contributed 4.8–19.1, 3.8–15.1 and 5.4–21.7% of the recommended N, P and K. Wastewater exerted a significant (α=0.05) positive impact on most growth and yield variables and grain and biomass yields of wheat irrespective of the applied fertiliser dose. The highest values of the crop variables and yields were generally obtained in I4F1 (irrigation water containing 75% wastewater under the fertilised condition) and I5F0 (irrigation by raw wastewater under the non-fertilised condition). On average, over three years, the treatments that received 50–100% wastewater in irrigation (I3F1–I5F1) provided statistically identical results. Although wastewater always promoted leaf growth, its effectiveness in improving the leaf area index (LAI) decreased with its elevated quantity in irrigation. Raw wastewater promoted the highest leaf growth at 65 days after sowing (DAS) and provided the maximum LAI under both fertility treatments. The significantly different above-ground dry matters (ADM) among the irrigation treatments obtained at the later growth stages (95–110 DAS) exposed a delayed effectiveness of wastewater in the accumulation of shoot biomass. The raw wastewater contributed to producing the highest ADM under both fertility treatments. The most extensive root proliferation was in I4F1, which produced the highest grain and biomass yields; the grain yield increased in this treatment by 14% over I1F1. Both the grain and biomass yields in I3F1–I5F1 treatments were statistically similar. The highest water use efficiencies obtained in I4F1 and I5F0 depicted the most effective utilisation of irrigation water in these treatments.