Irrigation Water Levels Research Articles

Effect of Levels Water Salinity and Inoculation With Azospirillum and Bacillus on Some Growth and Yield Characters of Wheat (Triticum aestivum L.)

A field experiment has been conducted at the College of Agriculture - University of Al-Muthanna (Al Bandar station 2 km from the center of Al-Muthanna Governorate), during seasons 2019-2020 and 2020-2021, to study the effect of four salinity levels of irrigation water (S1, S2, S3, S4) and four treatments. of Bio Fertilization (A, B, AB, C), and knowing its effect on some characteristics of growth and yield of wheat, result showed that levels of water salinity was significant effect on growth characters, the level S1 was superior in high plant, No. tellers, leaf flag area was reached 76.03 and 82.08 cm, 358.5 and 357.2 tellers m2, 40.08 cm2 for both season on sequences. The treat of salinity S3 was superior in seed of spikes and total yields and give high means 32 and 34.42 seed spike−1, 3.850 and 4.13 ton h−1 in both season. The inoculation treatment was high significant in growth characters and the treat A was superior in plant high reached 77.78 and 77.76 cm, in tellers treat A was superior in No. tellers reached 352.4 tellers m2, the treatment AB was superior in flag leaf area and reached 40.17 cm2. The result showed superior treat AB in seeds spikes−1 reached 32.58 and 34.67 seeds spike−1 for both season, in 1000 seed weight was treat B was superior and give 33.83 and 35.08 gm in both season, the treat AB was superior in total yield its reached 3.52 and 3.82 ton h−1.

Investigating effects of deficit irrigation levels and fertilizer rates on water use efficiency and productivity based on field observations and modeling approaches

Investigating the effects of optimized fertilizer and irrigation levels on water use efficiency and productivity of wheat crop at small farms is of great importance for precise and sustainable agriculture in Pakistan's irrigated areas. However, traditional farmer practices for wheat production are inefficient and unsustainable. This study aimed to investigate the effects of deficit irrigation and nitrophos fertilizer levels on bread wheat grain yield, yield parameters, nutrient use and water use efficiencies in bed planting wheat compared to traditional farmers' practices in the flat sowing method. The two-year field experiment followed a randomized complete block design of three replications, taking three irrigation treatments according to the requirement of crop estimated by CROPWAT model (100% of ETC), deficit irrigation (80% of ETC), and deficit irrigation 60% of ETC and three nitrophos fertilizer treatments (farmer practice 120 kg N ha-1, optimized 96 kg N ha-1, and 84 kg N ha-1) at different growth stages. Crop ETC was calculated using the FAO CROPWAT 8.0 model from the last ten years (2003-2013) average climate data of the experimental station. The traditional farmer practice treatment was included as a control treatment with a flat sowing method compared with other sown-by-bed planter treatments. All treatments were provided with an equivalent amount of fertilizer at the basal dose. Before the first and second irrigation, top-dressing fertilizer was used in traditional farmers' treatment at the third leaf and tillering stages. It was applied in optimized treatments before the first, second, and third irrigation at the third leaf, tillering and shooting stages, respectively, under the bed planting method. The deficit level of irrigation (80% of ETc) and optimized fertilizer (96 kg N ha-1) showed the optimum grain yield, nutrient use, and water use efficiencies, with 20% reduced irrigation water and fertilizer levels than traditional farming practice. The results suggest that bread wheat should be irrigated with 80% of ETC and applied 96 kg N ha-1 nitrophos fertilizer at the third leaf, tillering, and shooting stages to achieve higher grain yield and water and nutrient use efficiencies under bed planting.

Autogation: An Alternate Wetting and Drying-Based Automatic Irrigation and Paddy Water Level Control System through Internet of Things

This study aims to create an automated watering system that can adapt with network-based irrigation monitoring and a safe alternate wetting and drying or AWD. A secure AWD irrigation method is one in which the rice paddy is alternately subsided and immersed with a critical level of 100mm below the ground and a maximum irrigation level of 150 mm above the ground. The designed methodology automates irrigation by considering the needed water level in the field and its present level. It determines and controls the watering schedule based on the data collected by the sensors and then acts on it. It regulates the irrigation delivery gate to close or open the counterweight-designed water gate valve following the smart timetable that it has established. This approach conserved around 20% of the water used in a two-hectare area with four weirs compared to the traditional irrigation method in three weeks.

Salt Leaching with Brackish Water during Growing Season Improves Cotton Growth and Productivity, Water Use Efficiency and Soil Sustainability in Southern Xinjiang

Low water use efficiency and soil salinization are two main factors limiting cotton production in southern Xinjiang. A field experiment was conducted to investigate the effects of brackish water irrigation levels on cotton growth, yield and soil water–salt dynamics in southern Xinjiang, so as to provide a theoretical and experimental basis for the development and utilization of brackish water. There were three irrigation levels: W1 (75 mm + 80%ETc), W2 (150 mm + 80%ETc) and W3 (240 mm + 80%ETc) at the seeding stage (S1), seeding stage + budding stage (S2) and seeding stage + budding stage + flowering stage (S3), with an irrigation amount of 450 mm during spring as the CK (the local reference level) (10 treatments in total). The salt of the local brackish water used was 3 g·L−1. Film-mulched drip irrigation experiments were conducted to observe cotton growth, aboveground dry matter, cotton yield, soil water and salt distribution, as well as other indicators. The results showed that the irrigation applications of S3 can improve the soil moisture and salt distribution of the root zone. The salt accumulation at the harvest stage of W3S3 was reduced by 39.5% and 2.8% compared with W3S1 and W3S2, respectively. More frequent irrigation applications can reduce a soil’s total dissolved solids (TDS), avoid exceeding the salt tolerance threshold of 4.8 g kg−1 and lead to higher aboveground dry matter and cotton yields. W3S3 obtained the highest yield of 5685 kg ha−1, which was increased by 39.59%, 7.85% and 11.25% compared with W3S1, W3S2 and CK, respectively. The higher the irrigation amount, the less water use efficiency (WUE), following the order of S3 > S2 > S1 > CK at various growth stages. W3S1 obtained the lowest WUE of 0.64 kg·m−3. Comprehensively considering the effects of soil moisture retention and salt suppression, cotton growth, yield and water use efficiency, an irrigation amount of 240 mm brackish water at three growth stages, with 80%ETc for irrigation, is recommended for the sustainable production of cotton in southern Xinjiang.

Yield and Water Use of Eggplants (Solanum melongena L.) Under Different Irrigation Regimes and Fertilizers

This study was conducted ın Bandırma (Balıkesir, Turkey) during the growing season of the plant in 2017 and 2018 to determine the effect of four levels of irrigation water and three kinds of fertilizer on yield and water use of field-grown eggplant (solanum melongena). Treatments included four irrigation regimes, which were 100% (I100, control), 80% (I80), 60% (I60), and 40% (I40) of evaporation from Class A Pan and three different fertilizers, which were chemical fertilizer CHF; N, P, K (20-20-20+15 SO3) added as 40 kg da-1 organic fertilizer (OF) added as 2000 kg da-1 and developed organic fertilizer (DOF) added as 2000 kg da-1. Total irrigation water of 305 mm and 360 mm were applied to I100 irrigation treatment, in which water use was determined as 447 mm and 436 mm, respectively. In both experiment years, the effect of irrigation level on fruit yield was found to be significant statistically (p<0.05) but the effect of fertilizers treatments and irrigation x fertilizer interaction was insignificant (p>0.05). The highest yield with 3681and 4515 kg da-1 was harvested from I100 irrigation treatment, and the lowest yield with 3021 and 2792 kg da-1 from I40 irrigation treatment, respectively. As for fertilizer, the highest yield with 3462 and 3878 kg da-1 was harvested from DOF, while the lowest yield with 3258 and 3629 kg da-1 from OF, respectively. Water use efficiency (WUE) ranged from 8.26 to 12.54 kg mm-1 and irrigation water use efficiency (IWUE) from 11.9 to 25.68 kg mm-1 in the experimental years. Thus, in irrigation programming, the Kcp3: 0.80 plant-pan coefficient and in fertilizer application, DOF is recommended for field-grown eggplant.

Emergence, photosynthesis, and seedling growth of bean genotypes, as affected by salt sources and salinity levels

ABSTRACT The type and amount of salt present in water determine the suitability of water for irrigation. The aim of this study was to determine the effects of different salt sources (SS) and different salinity levels (SLs) in irrigation water on photosynthetic capacity, emergence and seedling growth parameters of eight bean (Phaseolus vulgaris L.) genotypes (G). The experiment was designed as a three-factorial split–split plot under a rain-out shelter. The G × SS × SL interaction for all investigated parameters was statistically significant. In general, GV-51, VN-50 and ML-34 genotypes were not adversely affected by increasing SL with respect to CaCl2, MgCl2 and CaSO4 salts. However, compared to the control, VN-8 and TR-64995 genotypes showed the lowest percent emergence from 2 and 3 dS m−1 with all salt sources, except VN-8 with CaSO4 salt. None of the genotypes showed significant differences for mean emergence time with increasing SL of CaSO4 salt. The highest shoot length was obtained for Helda genotype under control SL. Considering all genotypes, the values ranged from 0.533 to 0.740 for Fv/Fm ratio, 3.36 to 3.38 g for biomass weight, 1.82 to 4.75 g for shoot weight, and 1.42 to 4.50 g for root weight. Genotypic differences existed for salinity tolerance for emergence and early seedling growth, and the effects of salinity depended not only on the amount of salt but also on the kind of salt present in the irrigation water.

Evaluation of Deficit Irrigation Effect on Water Use Efficiency and Yield Response for Onion and Potato at Ketar Scheme

In the situation of improving water productivity, there is increasing interest in deficit irrigation practice whereby water supply is reduced below maximum levels and mild stress is allowed with minimal effects on yield. For this authorize, the study was conducted during the dry season for three years from December 2017 to May 2019 to study the effect of deficit on application efficacy, storage efficiency, distribution uniformity and irrigation water use efficiency of potato and onion. The deficit water level used were 75 and 50% CWR lined with full irrigation 100%. From the result, average of application efficiency (Ea), storage efficiency (Es) and distribution uniformity (DU) of the three water levels (100%, 75% and 50%) were 60.97%, 70.27%, 75.4%, 55.45%, 62.84%, 88.68%, 88.24%, 87.61% and 89.89% for potato and 60.06%, 70.81%, 85.64%, 65.03%, 60.24%, 66.02%, 88.49%, 87.89% and 86.24% for onion respectively. The highest Ky of 0.98 and 0.85 was attained at 50% CWR for potato and onion respectively and the lowest was 100% CWR for both crops. This show the highest yield reduction was registered under 50% CWR. The application efficiency, storage efficiency, distribution uniformity and yield response of 75% CWR is slightly low from full irrigation water level. So it is recommended to use 75% CWR for both crops in saving water as it has low yield reduction. Therefore, to implement deficit irrigation on farm participatory training should be given for application of right amount of water.

The Effects of Different Irrigation Scheduling Approaches on Seed Yield and Water Use Efficiencies of Cotton

This study was conducted in the Aegean region conditions of Turkey in 2020. It was carried out on May-505, a local cotton variety. The study examined the variation of seed yield, water use efficiency (WUE), and irrigation water use efficiency (IWUE) of cotton with different irrigation programs and water levels. The field trial, which was designed as two factors and three replications, was designed according to the randomized complete block trial design. Four different irrigation levels (IL) (100%, 67%, 33%, and 0%) and two different irrigation scheduling approaches (gravimetric and pan evaporation) were investigated in the study. Seasonal water use values in treatments varied between 215 (0%) and 746 (100% - Pan evaporation approach) mm during the production period. The average yield values obtained with irrigation levels, which have essential effects on cotton seed yield, are listed as follows; 2057 kg ha-1 (IL-0%), 3471 kg ha-1 (IL-33%), 3771 kg ha-1 (IL-67%), and 5083 kg ha-1 (IL-100%). It was determined pan evaporation applications performed higher yields than gravimetric applications. WUE values were between 0.63 – 1.04 kg m-3. The gravimetric method’s yield response factor (ky) was 0.73, and the pan evaporation method’s yield response factor (ky) was 0.89. These results show that cotton is tolerant of water stress. In conclusion, although the pan evaporation approach with 100% treatment is suggested for cotton production in the parts of the Aegean region within the semi-arid climate zone, while water resources are sufficient. When the results are evaluated in terms of seed cotton yield for a deficit irrigation strategy, IL-67% treatment with a gravimetric approach can be used.

Effect of Drip Lateral Spacing and Water Levels on Yield and Water Use Efficiency of Onion ( allium cepa l. ) Under Awash Melkassa Climatic Condition

Water being scarce resources, irrigation water is the most limiting factor for vegetable production in the central rift valley of Ethiopia. Drip irrigation technique together with deficit irrigation application improves crop yield and water use efficiency. Hence, the objective of this study was to enhance onion production and WUE through the application of drip irrigation technology and deficit irrigation application. Field experiment was conducted at Melkassa agricultural research center during the cool cropping season of 2019/2020 to investigate the effects of drip lateral spacing and irrigation levels on onion yield, water use efficiency and net return. Two levels of drip lateral spacing viz., lateral placed in every row and between two rows, and three levels of deficit irrigation viz., 80% ETc, 70% ETc and 55% ETc, and one-full irrigation (100% ETc). The treatments were arranged in split plot with three replications. Data were analyzed using statistical package appropriate to split plot with the help of SAS software. The result showed that onion yield, yield parameters and water use efficiency was affected by the effects of drip lateral spacing and irrigation water levels but not affected by their interaction effect. Onion bulb yield decreased with increased levels of water deficit. In contrast, both water use efficiency and irrigation water use efficiency increased with increase in water deficit level. Maximum onion bulb yield of 41.43 t ha-1 were obtained from lateral spacing in every row and full irrigation application level of 100% ETc and has no a significant difference with every row lateral spacing, and 85% and 70% ETc irrigation application levels. The highest water use efficiency of 13.33 Kgm-3 was recorded from every row drip lateral spacing and irrigation application of 70% ETc. Therefore, onion could be irrigated every row drip lateral spacing with 70% ETc application to increase water use efficiency without a significant total bulb yield reduction.

Comparison of different irrigation methods for onion by means of water and nitrogen response functions

ABSTRACT Considering the cost of two common agriculture inputs, water and nitrogen as well as their effects on the environment, optimum use of them is necessary. In this way, the production functions are applying to achieve maximum profits and environmental protection. Therefore, spilt-plot experiments were conducted on onion (Allium cepa L.) in a completely randomised block design for two years (2014/15-2015/16) in an arid region of Iran. The treatments included three irrigation methods (subsurface drip irrigation (SDI), drip irrigation (DI) and furrow irrigation (FI)), four levels of irrigation water (50(I1), 75(I2), 100(I3) and 120(I4) % of crop water requirement) and four levels of nitrogen fertiliser (25(N1), 50(N2), 75(N3), and 100(N4) % of crop nitrogen requirement). Regression analyses were done by linear, Cobb-Douglas, Quadratic and Transcendental functional forms of onion production. Results showed that the quadratic fits the data best, for the given local condition. The onion reached the highest increase in yield rise by increasing a unit of I (irrigation water) and N (nitrogen fertiliser) in SDI and the lowest in FI. Moreover, the pressurised irrigation methods are found to be advantageous to the substitution of N by I. The marginal rate of technical substitution demonstrates that in comparison to FI, more amounts of I and N are required to achieve equal yield in the pressurised irrigation methods.

Effects of water and fertilizer coupling on the physiological characteristics and growth of rabbiteye blueberry.

Understanding the impact of irrigation and fertilizer on rabbiteye blueberry (Vaccinium virgatum) physiology is necessary for its precision planting. Here, we applied varied irrigation and fertilizer under completely randomized experimental design to see its impact on the physiological characteristics and bush growth of rabbiteye blueberries. A comprehensive evaluation of the membership function was used to establish the best water-fertilizer coupling regimes. Rabbiteye blueberry enhanced the net photosynthetic rate, stomatal conductance and transpiration rate of leaf and improved its photosynthetic capacity at maximum level of irrigation water and fertilizer application (F3W4). The high fertilizer-medium water treatment (F3W3) increased leaf-soluble protein contents. The medium fertilizer-medium water treatment (F2W3, F2W2) increased leaf- soluble sugar, superoxide dismutase, and chlorophyll contents; decreased the malondialdehyde content; and enhanced leaf resistance and metabolism. It also promoted the growth of flower buds and new shoots. Combined membership function and cluster analyses revealed that the optimal water and fertilizer conditions for promoting rabbiteye blueberry plant growth were the medium fertilizer-medium water [(NH4)2SO4:Ca(H2PO4)2:K2SO4 at 59:10:20 g plant-1; 2.5 L water plant-1], medium fertilizer-medium-high water [(NH4)2SO4:Ca(H2PO4)2:K2SO4 at 59:10:20 g plant-1; 3.75 L water plant-1], and high fertilizer-medium-high water [(NH4)2SO4:Ca(H2PO4)2:K2SO4 at 118:20:40 g plant-1; 3.75 L water plant-1] treatments. The findings of this study could be used in improving the precision and efficacy of rabbiteye blueberry planting in Guizhou, China. Such an approach can increase the productivity and profitability for local fruit farmers.

Socio-Spatial Analysis of Exposure and Susceptibility to Irrigation Water Quality Risk

Climate variability and population growth has increased irrigation water usage in Ghana. The study compared microbial levels of irrigation water, differences in exposure, and perceptions of microbial contamination in a peri-urban and rural community. A mixed method approach was used to collect and analyse primary data. Water samples were collected and tested for faecal coliform and E. coli counts. Further, a survey, focus group discussion, and observation were used to understand the demographics of irrigation water use. Results show widespread irrigation water contamination with levels higher than the World Health Organization (WHO) acceptable threshold. The survey, focus group discussion, and observation also reveal that majority of the users of irrigation water uses their water untreated and may be vulnerable to water-borne diseases. Also, the exposure to these contaminants were location specific and correlated with level of education, years of farming experience, and agronomic practices. The study recommends education to improve the irrigation water quality and agronomic practices.

Stress markers and physiochemical responses of the Mediterranean shrub Phillyrea angustifolia under current and future drought and ozone scenarios

Mediterranean plants are particularly threatened by the exacerbation of prolonged periods of summer drought and increasing concentrations of ground-level ozone (O3). The aims of the present study were to (i) test if selected markers (i.e., reactive oxygen species, ROS; malondialdehyde, MDA; photosynthetic pigments) are able to discriminate the oxidative pressure due to single and combined stress conditions, and (ii) elucidate the physiochemical adjustments adopted by Phillyrea angustifolia (evergreen woody species representative of the maquis, also known as narrow-leaved mock privet) to perceive and counter to drought and/or O3. Plants were grown from May to October under the combination of two levels of water irrigation [i.e., well-watered (WW) and water-stressed (WS)] and three levels of O3 [i.e., 1.0, 1.5 and 2.0 times the ambient air concentrations, i.e. AA (current O3 scenario), 1.5 × AA and 2.0 × AA (future O3 scenarios), respectively], using a new-generation O3 Free Air Controlled Exposure (FACE) system. Overall, this species appeared relatively sensitive to drought (e.g., net CO2 assimilation rate and stomatal conductance significantly decreased, as well as total chlorophyll and carotenoid contents), and tolerant to O3 (e.g., as confirmed by the absence of visible foliar injury, the unchanged values of total carotenoids, and the detrimental effects on stomatal conductance, total chlorophylls and terpene emission only under elevated O3 concentrations). The combination of both stressors led to harsher oxidative stress. Only when evaluated together (i.e., combining the information provided by the analysis of each stress marker), ROS, MDA and photosynthetic pigments, were suitable stress markers to discriminate the differential oxidative stress induced by drought and increasing O3 concentrations applied singly or in combination: (i) all these stress markers were affected under drought per se; (ii) hydrogen peroxide (H2O2) and MDA increased under O3per se, following the gradient of O3 concentrations (H2O2: about 2- and 4-fold higher; MDA: +22 and + 91%; in 1.5 × AA_WW and 2.0 × AA_WW, respectively); (iii) joining together the ROS it was possible to report harsher effects under 2.0 × AA_WS and 1.5 × AA_WS (both anion superoxide and H2O2 increased) than under 2.0 × AA_WW (only H2O2 increased); and (iv) MDA showed harsher effects under 2.0 × AA_WS than under 1.5 × AA_WS (increased by 49 and 18%, respectively). Plants activated physiological and biochemical adjustments in order to partially avoid (e.g., stomatal closure) and tolerate (e.g., increased terpene emission) the effects of drought when combined with increasing O3 concentrations, suggesting that the water use strategy (isohydric) and the sclerophyllous habit can further increase the plant tolerance to environmental constraints in the Mediterranean area.

EFFECT OF 6-BAP GROWTH REGULATOR ON SEED PRIMING OF SEVERAL BREAD WHEAT VARIETIES UNDER WATER IRRIGATION SALINITY STRESS

Two experiments were carried out under greenhouse conditions at the College of Agriculture - University of Anbar for the spring season 2018, using plastic seedlings containers on sandy soil to study the effect of 6 Benzylaminopurine growth regulator and used at a concentration of 250 mg l-1 on seedlings performance of six varieties of wheat, namely; IBA 99, Bohooth 10, Bohooth 22, Abu Ghraib, Bohooth 158 and Ezz under four levels of saline irrigation water 3.00, 4.50, 6.00 and 7.50 dS m-1 in addition to the comparison treatment distilled water 0 dS m-1. The results of the experiment showed that the low concentrations of salts in the nutrient medium activate the radicle growth in the wheat plant. The seeds of wheat germinated in the irrigated medium were outperformed with salty water 3.00 dS m-1 with the highest averages of the studied traits. Ezz cultivar was the most tolerant category of salinity of irrigation water compared to other cultivars. The results of the experiment also showed that soaking the seeds of wheat with a growth regulator solution 6-Benzylaminopurine contributed to reducing the negative effect resulting from the increase in saline stress in the germination medium which improved the seed germination and seed growth characteristics under saline stress. The research recommends using the Ezz variety in the event of high salinity in irrigation water, as well as treating the seeds with the 6-BAP growth regulator to increase the tolerance of seeds to the stress of irrigation water salinity.

Study on Okra (Abelmoschus esculentus L.) Response to Salt Stress Environment under Kabul Climatic Conditions, Afghanistan

Abstract − The research was conducted to examine the effects of saline-irrigation water on growth and fresh pod weight of okra (Abelmoschus esculentus L.) under climatic conditions of Kabul province, Af-ghanistan. This study consisted of four treatments having different salinity levels of irrigation water, (T1:0.0mM, T2:5mM, T3:10mM, and T4:20mM), which were applied throughout the growing season of okra in plastic pots with a randomized complete block design. Results showed that saline irrigation water caused a significant reduction in germination of seeds (in T1:98% germination, T4: 53% germination), leaf length (in T1:9.17 cm, T4:6.8cm leaf length), shoot height (in T1:15.43cm, T4: 13.87cm Shoot height) and root length (in T1:15.37cm, T4:8.7cm root length). Okra plants grown under salt stress conditions showed a significantly decline in yield as compared to control treatment. While 6904kg/ha yield was obtained in control treatment (T1), 6696kg/ha, 4772kg/ha, 3100kg/ha yield were obtained in T2, T3 and T4 applications, respectively. Water use efficiency was maximum in the control treatment and minimum in treatment level 20mM. A maximum value of 13.08kg/ha/mm was computed for control treatment and minimum value of 5.87kg/ha/mm for treatment level 20mM, the water use efficiency value for treatment level 5mM and 10mM were 12.68kg/ha/mm and 9.04kg/ha/mm respectively. As a result, okra growth parameters were decreased significantly with the increasing concentration of ECiw (electrical conductivity of irrigation water). Salinity adversely affected morphological and physiological characteristics of okra.

Long-Term Irrigation with Treated Municipal Wastewater from the Wadi-Musa Region: Soil Heavy Metal Accumulation, Uptake and Partitioning in Olive Trees

Utilization of treated wastewater (TWW) for agricultural purposes has grown over the past few years because of limited available water resources. This study was performed to assess the long-term irrigation of treated wastewater from the Wadi-Musa region on the accumulation of heavy metals in soil and their uptake and translocation to various parts of olive trees. Fifteen year old trees that had been grown and irrigated with treated wastewater resources since their establishment were used in this study. Irrigation water, soil, and plant samples (root, stem bark, leaves, fruits) were collected and chemically analyzed for their heavy metal content. Accumulation of heavy metals in irrigation water and soil were found to be within the acceptable range for the safe use of treated wastewater according to the standards of the WHO. However, long-term and continuous irrigation with TWW resulted in significant accumulation of heavy metals in plant parts when compared to their levels in irrigation water and soil. Uptake of metals was consistent among plant parts with the highest concentrations for Fe, Mn, Pb and Zn, and the lowest concentrations for Ni, Cr and Cd. Assessment of the bioaccumulation factor (BFC) and translocation factors (TF) of heavy metals into different plant parts indicated selective absorption and partitioning of these heavy metals into different plant parts. High BCF values were observed for Fe, Cu and Ni in roots and fruits, and Fe, Mn, Cd and Pb in leaves. Translocation factors of metal ions were variable among plant parts. Fruits had the highest TF for Cu, Cd and Zn metals, and the lowest for Mn and Fe, while leaves have the highest TF for Fe, Zn and Mn and the lowest for Cd and Pb. The results of this study indicate that olive trees are heavy metal accumulators, caution should be considered in long-term use of TWW and periodic assessment of possible hazards, especially on fruits and oil quality is required.

Multiobjective land–water allocation model for sustainable agriculture with predictive stochastic yield response

AbstractConsider an agricultural land–water resource allocation problem in which yields are spatial dependent and stochastically correlated. To achieve sustainability, we formulate a multiobjective (MO) optimization problem, in which the decision maker determines the cultivation areas and the supplemental irrigation water levels at different locations, with social, economic, and environmental goals in mind. For the social goal, we minimize the root mean squared difference of incomes among locations. For the economic goal, we minimize the production risk. We show that minimizing production risk is equivalent to maximizing the service level, when demand is normally distributed. For the environmental goal, we minimize the resource utilization. Assume that the yield vector at different locations follows a multivariate normal distribution. We formulate the MO optimization problem using a weight global criterion method, and we provide a sufficient condition for convex quadratic programming. We demonstrate the applicability of our proposed framework in the case study of sugarcane production in Thailand. To capture yield response to water, we propose several models including linear and nonlinear regressions, and we obtain the closed‐form expression for the linear and probit yield response models. The numerical experiment reveals that our solution significantly improves the social and economic goals, compared to the current policy. Finally, we illustrate how to apply our model to quantify the monetary value from reducing yield variability, which could be resulted from smart irrigation or precision agriculture.

Using EPIC to simulate the effects of different irrigation and fertilizer levels on maize yield in the Eastern Cape, South Africa

Growing water scarcity and increasing Nitrogen (N) fertiliser prices in South Africa require more prudent N fertiliser and irrigation water use approaches. If the goal of sustainable agricultural intensification is to be realised, it is vital to develop location-specific agricultural land management strategies that promote increased crop productivity while minimising negative environmental impacts. In this study, a calibrated and validated Environmental Policy Integrated Climate (EPIC) model was used to simulate a range of N fertiliser and irrigation water levels on maize (Zea mays L.) yield in the Eastern Cape of South Africa. Results showed that a fertiliser and irrigation water management schedule combining approximately 200 kg N ha-1 and 580 mm irrigation water per maize growing season provided the highest average maize yield of 12.2 Mg ha-1 (an increase of +69% above farmers’ current maize yield levels). Nitrogen fertiliser application levels greater than 160 kg N ha-1 resulted in potential N fertiliser leaching losses of more than 35 kg N ha-1. The EPIC model can be considered a valuable tool to aid decision-makers in identifying optimal, site-specific irrigation water and N fertiliser application levels that contribute to increased maize crop productivity while maximising water use.

Impacts of different irrigation water levels on the yield, water use efficiency, and fiber quality properties of cotton (Gossypium hirsutum L.) irrigated by drip systems

Impacts of different irrigation water levels on the yield, water use efficiency, and fiber quality properties of cotton (Gossypium hirsutum L.) irrigated by drip systems

Growth of forage palm cultivars irrigated with saline waters

Forage palm (Cactaceae) is considered an important resource in the semiarid region of Brazil. This study aimed to analyze the effect of different levels of salinity in irrigation water on the growth of three forage palm cultivars. The study was conducted at the Federal University of Campina Grande (7° 12’ 52.6’’ S; 35° 54’ 22.3’’ W) in 120 L pots open to the sky. The experiment was a complete randomized block, with four replications and a 4 × 3 factorial arrangement. The treatments consisted of four levels of salinity in irrigation water with electrical conductivity of 0.2, 2.0, 3.8, and 5.6 dS m–1, and three forage palm cultivars: Miúda or Doce (Nopalea cochenillifera Salm Dyck), Orelha de Elefante (Opuntia stricta), and Baiana or IPA–Sertânia (Nopalea cochenillifera Salm Dyck). At 150 days after treatments, it was evaluated: length, width and perimeter of primary and secondary cladodes and total number of cladodes. Variance analysis was performed using an F-test (p < 0.05); significant effects were subjected to quadratic regression analysis for the quantitative variable, and the Tukey test (p < 0.05) for the qualitative variable. Salinity levels in irrigation water did not affect the growth variables. There was a significant difference in the growth of forage palm as a function of its cultivar. The Baiana cultivar showed the highest vegetative growth of length and perimeter of primary and secondary cladodes, while Miúda and Orelha de Elefante presented the greatest cladode numbers for plant and cladode widths, respectively.