Soil, Water and Plant Relationships
Hossein Beyrami; Hossein Parvizi; Amir Parnian; Hadis Hatami
Abstract
ABSTRACTIntroductionSoil and water salinization is a worldwide problem, especially in irrigated areas, causing decrease in crop yield and the continuous loss of arable fields. Halophytes are the natural genetic source of salt tolerance traits and can be used for revegetation and remediation of salt-affected ...
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ABSTRACTIntroductionSoil and water salinization is a worldwide problem, especially in irrigated areas, causing decrease in crop yield and the continuous loss of arable fields. Halophytes are the natural genetic source of salt tolerance traits and can be used for revegetation and remediation of salt-affected lands, and also as an alternative crop or biofuel. Due to the limited quality of water resources in the country and considering that the major regions of Iran's area are considered to be arid and semi-arid, it is important to cultivate plants with high tolerance to environmental stresses such as drought and salinity. The quinoa (Chenopodium quinoa Willd.) plant is important because of its ability to be cultivated in saline areas and irrigated with saline water. According to previous research, quinoa is an optional halophyte, and its irrigation is possible up to sea level salinity. Quinoa (Chenopodium quinoa Willd.) is one of the plants that has outstanding economic and agronomic advantages among the crops; it is particularly important in terms of forage production. There is no reliable and accurate information about the amount of water consumption by this plant in Iran. Considering the climatic characteristics and water shortages in the country, as well as the development plan for the cultivation of this plant due to its high nutritional value, attention to its water requirement becomes more important. For this reason, the importance of precise irrigation design and planning is needed in order to improve the performance of irrigation water usage in this region.Materials and MethodsThis research is conducted aim to determine the effects of different levels of moisture and salinity on the yield, some morphological traits, and some yield components of quinoa (Chenopodium quinoa Willd.) in field conditions during two growing seasons (2020-2022) in Yazd, Iran. The experiments were carried out in a factorial experiment in a randomized complete block design, which included two irrigation water salinity levels of 5 and 12 dS/m and four irrigation levels of 60, 80, 100, and 120% to provide the amount of allowable moisture depletion (MAD equal to 50%) in the root zone, in three replications. Experimental plots were designed with dimensions of 5×7 meters. Applying the amount of irrigation was done according to the determination of the field capacity levels and the permanent wilting point moisture measured (using a pressure plate device) before the start of the experiments. In this regard, according to this information, on the day of irrigation, the amount of soil moisture in each of the plots was measured at the root zone, and based on the treatments, the amount of water required was calculated, and irrigation was applied to the determined moisture level. Irrigation was carried out in the form of flooding, and the volume of irrigation water for each treatment was controlled by the volume contour and applied separately at each interval. At the end of the experiment, quinoa was harvested in a one-square-meter grid, and then plant height, panicle length and width, and stem diameter were measured. After the plant's drying, the weight of the seeds and the weight of the whole shoot were measured in different treatments.Results and DiscussionThe results showed that the different levels of salinity and soil moisture cause significant changes in biomass yield, seed yield, and harvest index. Also, the results indicated that changes in salinity levels and moisture levels caused significant differences in plant height, stem diameter and panicle length, panicle width, and 1000-seed weight (P<0.01), but their interaction was not significant. For two levels of salinity, the maximum biomass (9.28 tons/ha) was observed by supplying 100% of the depleted soil moisture based on MAD = 50%. According to the yield-water use function, the maximum seed yield for 5 and 12 dS/m irrigation water salinity was observed in treatments that supplied 115% and more than 120% of depleted soil moisture based on MAD = 50%, respectively. With the increase in salinity stress from 5 to 12 dS/m, biomass weight decreased by 23% and seed yield decreased by 17%. Based on the results, the average volume of applied water in fall cultivated quinoa under the 5 dS/m irrigation water salinity was 4900 m3/ha during the growth season (90 days).ConclusionIn the autumn planting of the Titicaca variety of quinoa, with a planting period of about 90 days in arid and semi-arid regions like Yazd, water consumption is about 450 to 550 mm. But in conditions of moisture deficiency, it is possible to grow this plant. Because it has a lower yield reduction slope than other plants under drought and salt stress conditions. Furthermore, the results indicated that the salinity of the soil profile increased in deficit irrigation conditions (60% and 80% of depleted soil moisture based on MAD = 50%) due to the lack of leaching requirements.
Amir Parnian; Hossein Beyrami; Kianoush Behrahi
Abstract
Introduction lack of water and soil salinization are two main threats to the sustainability of agriculture, especially in arid and semi-arid areas same as most parts of Iran. High evaporation in arid and semi-arid regions drive the down-to-up salt movement into the soil profiles and led the soil to salinization. ...
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Introduction lack of water and soil salinization are two main threats to the sustainability of agriculture, especially in arid and semi-arid areas same as most parts of Iran. High evaporation in arid and semi-arid regions drive the down-to-up salt movement into the soil profiles and led the soil to salinization. Soil salinity reduces plant production through many ways like reducing water and nutrient uptake, ion toxicity, change in soil microbial activity, carbon and nitrogen ecological cycle disruption, etc. There are many ways to control the soil salinity and preserve soil water by application of mulch is one of them. Actually the use of mulch on soil in agriculture is mainly to limit evaporation, improve water use efficiency, and weed control. Many tupes of mulch are using to control the soil evaporation such as tephra, sand, plastic, wheat straw, geotextile, etc. Organic mulches have two main disadvantages, the ecological problem and, biological pollution for agricultural areas. More than one million tons of sugarcane bagasse produce in the Khuzestan province of Iran as the agricultural waste. And composting is a proper way to reduce the bad effects of raw organic material. This study examined a soil organic mulch, produced by composted sugarcane bagasse, in Jofeir area haloculture pilot in Khuzestan province. Materials and Methods. This study, conducted in the southwest of Khuzestan province, Iran. The mean temperature during the experiment was 44 ± 2 ᵒC and the relative humidity was 65 ± 3%. The composted sugarcane mulch in 4 different thicknesses of 0.5, 1, 2 and, 0 (control) cm with 3 replicas applied on 2.5 liters of the local silt-clay-loam soil. The micro-lysimeters were 3 liters PVC pots which have heat-insulated and fill with the soil in 25 cm depth. In addition, The weight of the pots were measured at 10:00, 12:00, 14:00, 16:00, and 18:00 houres after the soil saturation. Before and after the experiment soil EC (1:2), bioavailable B concentration, saturation extracts Na concentration, and exchangeable sodium percentage (ESP) of the top 5 cm of the pots was examined. The experiment re-conducted in 5 continuous days and Identification of significant differences was performed using one-way ANOVA, in which p < 0.05 is considered significant in differences. Statistical analysis was performed with the Microsoft Excel 2010 and SPSS Version 16.Results and DiscussionResults showed the significant difference between treatments with and without soil mulch in available water loss. The lowest water loss was belonging to the treatment with 2 cm (198.6 g of water/pot) of sugarcane composted mulch. The non-mulched soil had the highest evaporation amount (407.7 g of water/pot). water loss percentage showed the same trend and reduction with increasing in the sugarcane composted mulch thickness. Which with 2 cm of the mulch the moisture loss percentage calculated about 9.8 % and it near half of the value for the control (no-mulched soil) one. This mulch able to increase the available water for plant uses. Salts, B, and Na accumulation in surface soil appeared due to the evaporation process and mulch prevents it. As the results represented, with increasing the sugarcane composted mulch thickness, EC rising was slow. The EC increase in surface section of the non-mulched soil was high (20.5 dS/m) and the final EC were 41, 32, 25.5, 22 dS/m respectively in 0, 0.5, 1, and 2 cm of the mulch thickness treatments. This effect of sugarcane composted mulch could save the plant roots from salinity effects such as high Na, B and ESP. Also, it may play a positive role in water preservation in horticulture and green space. According to the composting process, this mulch has less ecological adverse effect than other organic raw materials. On the other hand, it able to release carbon and nutrients to enhance soil biological activity which would help plants to grow well.Conclusion Results showed increasing in the water losses and salinity accumulation in the soil surface of the treatments with decresing the mulch thickness. Also, the same trend was observed for bioavailable B concentration, saturation extract Na concentration, and ESP of the soil surface. Evaporation and, as the result salinization of the soil surface, decreased by the time but, the salt transport was very fast and the high considerable amount moved to the top
