rasoul asadi; farzad hasanpour; mitra mehrabani; Amin Baghizadeh; Fateme karandish
Abstract
Introduction: In arid and semi-arid areas, water can be a limiting factor for plant growth and agricultural yields. Considering limited water resources in arid and semi-arid climate of Iran, deficit irrigation is one of the strategies for efficient use of water and increasing water use efficiency ...
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Introduction: In arid and semi-arid areas, water can be a limiting factor for plant growth and agricultural yields. Considering limited water resources in arid and semi-arid climate of Iran, deficit irrigation is one of the strategies for efficient use of water and increasing water use efficiency in agricultural lands. Deficit irrigation (DI) is a suitable solution to gain acceptable and economic performance by using minimum amount of water. The Partial Root- zone Drying (PRD) irrigation is a new improvement in deficit irrigation in which the half of the root zone is irrigated alternatively in scheduled irrigation events. The plants with PRD irrigation method can, therefore, have different root system in comparison with other irrigation methods. At this method the plant’s condition would be OK by withdrawing water from wet side, and the roots at the dry side can release abscisic acid hormone which decrease the stomatal conductance and consequently the water use efficiency would increase. Also, by using proper irrigation management in farm, we are able to utilize water, soil and fertilizer to produce high yield and quality products. Drip irrigation is considered one of the most efficient irrigation methods. One of the major advantages is its ability to apply water to the soil as often as desired and in smaller quantity than the other irrigation methods. Drip irrigation has been practiced for many years for its effectiveness in reducing soil surface evaporation and it has been widely used in horticultural crops in both greenhouse and open field.
Materials and Methods: In order to compare two deficit irrigation methods on plant growth characteristics of Rosmarinus officinalis L., a field experiment was carried out during 2016 growing season at an experimental farm in Kerman Municipality seedling production station. The experimental treatments were arranged as randomized complete block design with three replications. The irrigation regimes consisted of full irrigation (FI-100), regulated deficit (RDI75 and RDI55) and partial root zone drying irrigation (PRD75 and PRD55). In this study, drip lines were placed on the soil surface at a distance of 15 cm from the plant and plant rows were placed between drip lines. The irrigation interval was 4 days for all treatments. In the full irrigation and regulated deficit irrigation treatments, the plants were irrigated from two sides for every irrigation. In the PRD, one of two neighboring drip line was alternatively used for irrigation. The irrigation interval was 4 days for all treatments. Dry weight, leaf area index (LAI), number of shoots, plant height, water productivity, root fresh weight, root depth and root volume were measured. Since the highest essential oil of rosemary is at 50 percent of flowering time, the above-mentioned indices were measured at the middle of flowering (190 days after planting) by removing the side rows in each replicate and half a meter from the beginning and end of each row. As a marginal effect, 10 plants were randomly selected and sampled from two middle rows, each replicate of each treatment. The harvested bushes were dried at 25 °C for three weeks and then the dried weight of the vegetative organs was measured. Moreover, the number of 10 plants selected from each treatment was accurately counted to determine the number of shoots. Data were analyzed statistically using SAS Statistical software. Treatment means were compared using LSD test.
Results and Discussion: The results showed that highest herbage dry weight (145.3 g) and leaf area index in different stages of growth were under full irrigation treatment in which no significant difference between this treatment and 75 percent water replacement in partial root zone drying was observed. The highest number of shoots (128.7) and plant height (68.4 cm) were also obtained by full irrigation treatment and there was significant difference between this treatment and other treatments. However, the highest water productivity (2.06 kg/m3), root fresh weight (3.8 g), root depth (16.4 cm) and root volume (2.4 cm3) were found in 75 percent water replacement in partial root zone drying.
Conclusion: According to the results, 75 percent water replacement in partial root zone drying irrigation treatments, in addition to saving water consumption, provides better use of soil moisture and sunlight. Thus, this treatment can be considered as a suitable approach to cope with the water crisis and achieve a sustainable agriculture.
Keywords: Drip irrigation, Drought stress, Leaf area index, Medicinal plant, Rosmarinus officinalis, Water productivity
shekoofe najafabadi; mohammad reza Nori Emamzadeie; Mehdi Ghobadinia; Abdolrazagh Danesh shahraki
Abstract
Introduction: Water scarcity is the most important limiting factor in the production of crops in arid and semi-arid regions. Thus, actions for increasing the efficiency and productivity of farm water is inevitable. A large proportion of the water, used in irrigation, evaporates, so an effective solution ...
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Introduction: Water scarcity is the most important limiting factor in the production of crops in arid and semi-arid regions. Thus, actions for increasing the efficiency and productivity of farm water is inevitable. A large proportion of the water, used in irrigation, evaporates, so an effective solution for conserving water is to control the evaporation on arable lands. Nowadays using mulch or plastic mulch is common and it makes efficient use of water in furrow irrigation possible by conserving and storing soil moisture. Mulch does not let dry air contact topsoil and it also prevents topsoil from solar irradiance and reduces evaporation and maintain soil moisture. Recent research in order to economize on water use and irrigation efficiency and water use efficiency has led. Thus, regarding the problem of water scarcity, the objective of this research is to investigate the effects of evaporation suppressing monolayers on the efficiency of water consumption and growth indices of seed corn single cross SC 704 in an arid and semi-arid region.
Materials and Methods: This research was conducted in Shahrekord University during 2015. The experimental design was randomized complete block design with 6 treatments and 3 replications. The treatments include control treatment (uncovering) and transparent plastic wrap, black plastic, cotton gunny and white and blue pp woven fabric. Planting and growing operations were conducted due to agronomic principles. Changes in soil moisture within the root-zone during the season were measured by using thetaprobe and all operations by measuring the amount of irrigation water used in all experimental plots of each treatment were applied separately using flow measurement and the amount and time of each irrigation was determined and applied based on MAD=50 by supplying required water.
Results and Discussion: The measurement results showed that variance analysis of relative water content (RWC) and water efficiency under the impact of different coverings had a significance difference with p-value of 0.01. Also the amount of the dry matter and harvest index of corn showed significance with p-value of 0.05. Results showed that mulch at all stages of measuring the impact of increasing the leaf relative water content it could originate from growing trend of air temperature during the period. Under these treatments the plants are expected to experience more desirable conditions regarding maintaining and distributing of soil moisture in comparison with other treatments and the indicator. The highest amount of dry matter calculated is for the blue pp woven fabric treatment that shows the ideal growth conditions and appropriate performance of the plant under the impact of this covering and the lowest amount is for the cotton gunny treatment. Leaf area index (LAI) is one of the important growth indices. In flowering (anthesis) stage, the maximum amount of LAI is 5.08 for the blue pp woven fabric treatment. The minimum amount of LAI is 2.5 for the cotton gunny treatment and it is because of There macroporous coating that weed growth has been hindering plant growth. On the basis of the hundred seed weight, the heaviest weight is 18.18 for the white plastic treatment and the lowest weight is 13.46 for the indicator treatment. The highest amount of harvesting index (HI) is 53.97 for the transparent plastic treatment and the lowest amount is 41.12 for the black plastic treatment.The corresponding amount is an increase of 32 percent compared to control treatment. The reason of reduction of HI is the reduction of seed performance than biological performance in water scarcity. One of the indices for evaluating irrigation management is water efficiency. The highest amount of water efficiency is 2.6 and 2.7 kg/m3for the blue pp woven fabric and white pp woven fabric covering and it reduces water wastage in form of evaporation and causes water conservation. And it protects the top soil from solar irradiance.
Conclusion: This research was conducted at Shahrekord University to investigate the effects of various coverings on water efficiency and corn seed performance. Using covering causes temperature growth in the soil under the covering and it also causes further and fast plant growth. It reduces evaporation from topsoil. As a result, it causes soil moisture to be invariable and because of lack of light under the coverings, photosynthesis is impossible, thus, weeds could not grow. Blue pp woven fabric of mulch to mulch increased 42% dry matter was cotton sack. Mulches effect of the corn harvest index showed a clear plastic mulch to increase 32 percent harvest index compared to the control. Mulches blue pp woven fabric, white pp woven fabric, cotton gunny, black plastic and transparent plastic, respectively, increases of 92, 85, 28, 14 and 78 percent of water use efficiency were compared to control.Therefore, plants under the impact of blue pp woven fabric and white pp woven fabric coverings access more water and nutrients than the indicator treatment, so water efficiency increases. Using coverings has conserved moisture more in the top layers of soil by reducing evaporation form topsoil.
Nader Naderi; Ramin Fazl Oula; Mirkhaleg Ziatabar Ahmadi; Ali Shahnazari; Saeed Khavari Khorasani
Abstract
Introduction: Water shortage is the most important factor affecting crop production in the world. The deficit irrigation is a way to reduce water consumption in farming. The Partial Root- zone Drying (PRD) irrigation is a new improvement in deficit irrigation in which the half of the root zone is irrigated ...
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Introduction: Water shortage is the most important factor affecting crop production in the world. The deficit irrigation is a way to reduce water consumption in farming. The Partial Root- zone Drying (PRD) irrigation is a new improvement in deficit irrigation in which the half of the root zone is irrigated alternatively in scheduled irrigation events. In the fixed partial root zone drying (FPRD) the irrigation is fixed to one side of the root zone in the growing season. Maize is a drought sensitive crop. In maize, secondary traits related to drought resistance are considered in producing tolerate cultivars.
Materials and Methods: An experiment was conducted in order to investigate the effects of regulated deficit irrigation, variable partial root zone drying (PRD) and fixed partial root zone drying (FPRD) on the yield, physiological and photosynthetic parameters of forage maize (KSC 704) during the growing seasons of 2014 in Mashhad region. A factorial experiment based on randomized complete block design with four replications was carried out. The treatments included the full irrigation (FI) and the deficit irrigations (regulated deficit irrigation (DI) and the replacements of 80 % (DI80) and 60 % (DI60) of total water requirement, fixed PRD (FPRD) at 100% (FPRD100), 80% (FPRD80) and 60%(FPRD60) of water requirement, and variable PRD at 100% (PRD100), 80% (PRD80) and 60% (PRD60) of water requirement). Drip irrigation tapes were placed between plant rows. In the full irrigation and regulated deficit irrigation treatments, the plants were irrigated from two sides for every irrigation. In the PRD, one of two neighboring tapes was alternatively used for irrigation. In FPRD, a drip tape was used for two plant rows and irrigation was fixed to one side of the root. The irrigation interval was 3 days for all treatments. Dry and fresh forage yield, leaf area index (LAI), stomatal conductance, leaf relative water content (RWC) and chlorophyll content were measured.
Results and Discussions: All the measured traits were affected by the deficit irrigation. The highest fresh forage yield (72099 kg/ha) was produced by the full irrigation treatment. The statistical comparison showed that there was no significant difference between regulated deficit irrigation and PRD method for the fresh forage yield. But the FPRD treatment reduced the fresh forage yield. There was no significant difference between the fresh forage yield of FI and PRD80 treatments. The dry forage yield was affected by the different irrigation methods, irrigation levels and the interaction effects of the treatments (p
