5
Alireza Karbasi; Toktam Mohtashami; Amin Alizadeh; Zahra Moghimi
Abstract
Agriculture in arid and semiarid areas is dependent on groundwater extraction. Utilization of groundwater resources in Zaveh-Torbath Haydarieh plain is more than the aquifer's renewable potential, therefore, these resources have a reservoir deficit. To this end, in this study, using the information obtained ...
Read More
Agriculture in arid and semiarid areas is dependent on groundwater extraction. Utilization of groundwater resources in Zaveh-Torbath Haydarieh plain is more than the aquifer's renewable potential, therefore, these resources have a reservoir deficit. To this end, in this study, using the information obtained from interviews with farmers in this plain, who were selected through cluster sampling in the year 2015-2016, and the use of the Tobit Model and the two-stage method of Hackman, factors influencing the extraction of groundwater resources were studied. The results of the two-stage Hackman model showed that, in the first stage, the explanatory variables including the dominant cultivation and personal and share ownership of water wells had a positive final effect of 0.35, 0.43 and 0.41, respectively, while variables of well depth, type of water transfer channel, and low yielding crops had a negative effect on overdraft of groundwater resources. In the second stage, the results showed that farm-to-well distance, farmer's annual income, and type of the dominant cultivation had a positive and significant effect at 5 percent on overdraft. Accordingly, paying more attention to the technical factors effective in water management, as well as raising farmers' awareness of their participation in improving cropping pattern, is an effective step in reducing overdraft of groundwater resources.
alireza vahidi; amin alizadeh; amin baghizadeh; Hossein Ansari
Abstract
In order to study the effect of biofertilizers, chemical fertilizers, and water deficit stress on biological yield, lawsone content, and root colonization with mycorrhiza in henna[1] an experiment was conducted at research greenhouse of Bam University in 2014 and 2015 growing seasons. The treatments ...
Read More
In order to study the effect of biofertilizers, chemical fertilizers, and water deficit stress on biological yield, lawsone content, and root colonization with mycorrhiza in henna[1] an experiment was conducted at research greenhouse of Bam University in 2014 and 2015 growing seasons. The treatments included fertilizers (without any fertilizer (), humic acid (), application of mycorrhizae and vermicompost (), vermicompost (), and chemical fertilizer () and water deficit levels (100% water requirement (I1), 80% W.R (I2), and 60% (I3). The treatments were arranged as factorial in a randomized complete blocks design with fifteen treatments and three replications. Results showed that the highest weight of dry leaf, no. of leaves, and biological yield were obtained with application of mycorrhizae and vermicompost treatment under full irrigation (). With increasing stress severity, the highest weight of dry leaf (0.153g), no. of leaves (171), and plant height (120.33 cm) were obtained in , largest number of nodules (63) in (), and maximum biological yield (5.21 g/plant), total lawsone content (69.6 mg/g), and colonization with roots (82.2%) was obtained with application of mycorrhizae and vermicompost treatment under 60% water requirement i.e. treatment. It seems that biofertilizers can be considered as a replacement for chemical fertilizers in henna medicinal plant production. [1]- Lawsonia inermis
h m; a a; h a; p r
Abstract
To study the effects of irrigation water (50%, 75%, and 100% of plant water requirement) and potassium fertilizer (0, 50%, and 100% required potassium fertilizer based on soil test) on the dynamics of root, yield, and shoots of sorghum varieties (Pegah, Karaj, and Speedfeed), a research was conducted ...
Read More
To study the effects of irrigation water (50%, 75%, and 100% of plant water requirement) and potassium fertilizer (0, 50%, and 100% required potassium fertilizer based on soil test) on the dynamics of root, yield, and shoots of sorghum varieties (Pegah, Karaj, and Speedfeed), a research was conducted in the Agricultural Research Center of Semnan province (Shahrood) in 2014. This research was conducted in pots and in field experiment. The experimental variables were irrigation water, potassium fertilizer, and varieties of forage sorghum. The treatments were arranged as split plots based on a randomized complete block design with three replications. In the pot experiment, 243 plastic pots with diameter of 30 and height of 60 cm were used. Irrigation water was calculated with Penman-Monteith method. Drip irrigation was used as irrigation system. Sampling was carried out from the roots in three phases during the season. The root volume was determined by immersion in water method. Shoots parameters such as leaf area, leaf dry weight, stem dry weight, and shoot weight were measured. The results showed that the effects of irrigation water, potassium fertilizer, and sorghum varieties were significant on the forage yield, root volume, and dry weight of roots and shoots of the plants. The highest yield was obtained from the W100K100 treatment (102.8 ton/ha). Pegha variety showed the maximum yield. The maximum water use efficiency was obtained from the W75K100 treatment (20.5 kg/m3/ha). The W75K100Vp < /sub> treatment was introduced as a superior treatment. Potassium fertilizer could compensate the loss of yield. The mathematical equations expressing root volume and dry weight with time were determined during the season. The relationships between some parameters of the shoots and roots were determined.
a f; h a; m k; a a; m m
Abstract
Almost all districts of the country are experiencing quantitative and qualitative decline of agricultural water resources. Considering the extensive expansion of greenhouse cultivation and importance of tomato production, and in order to evaluate the combined effect of salinity and drought stress on ...
Read More
Almost all districts of the country are experiencing quantitative and qualitative decline of agricultural water resources. Considering the extensive expansion of greenhouse cultivation and importance of tomato production, and in order to evaluate the combined effect of salinity and drought stress on growth and yield of tomato plant (Lycopersiconesculentum Mill. Cv. Oriental), four levels of irrigation (125% ETc, 100% ETc, 75% ETc and 50% ETc) and six levels of salinity (0.1, 1.3, 3, 5, 7 and 9 dS/m) were factorially combined in a completely randomized design with 3 replication in a greenhouse soilless culture. Yield and its indexes were measured during the crop growing season. As expected, results indicated that salinity of the nutrient solution and drought stress had significant negative effects on yield and growth indexes of plant. Yield data were fitted on different production functions (simple linear, logarithmic linear, quadratic, and transcendental). The results indicated that the simple linear form was the optimum form. The S1W4 treatment (EC= 0.1 dS/m, and 50% ETc) with 34.6 kg/m3 and S5W1 treatment (EC= 7 dS/m, and 125% ETc) with 6.4 kg/m3 had the highest and lowest water use efficiency, respectively. The iso-yield curves showed that by increasing irrigation water amounts, water with higher salinity can be applied without changing the yield.
n s; a a; h a; j h
Abstract
To study the effects of using plastic mulch on soil moisture and salinity changes under drip irrigation system in mature pistachio trees (Ohadi cultivar), a research was conducted in a randomized complete block design in two orchards with different treatments in terms of water consumption (4100 and 6170 ...
Read More
To study the effects of using plastic mulch on soil moisture and salinity changes under drip irrigation system in mature pistachio trees (Ohadi cultivar), a research was conducted in a randomized complete block design in two orchards with different treatments in terms of water consumption (4100 and 6170 m3/ha), irrigation frequency (8 and 12 days), and trees growth. The study was carried out in the western suburbs of Rafsanjan, Iran. In each of the orchards, three mulch treatments including: without mulch (treatment C), black-and-white plastic mulch (treatments MB, MW), with three replications were used. At the end of the season, data on growth characteristics, quality and quantity of the product, and water use productivity (WUP), were averaged and compared using Duncan multiple range test to determine the effects of using plastic mulch on these traits. The results showed significant effect of plastic mulch on all growth factors, quantity and quality of yield, and water use productivity. Moreover, in most cases, the color of mulch did not affect these traits. Overall, using plastic mulch in orchard 1 increased the dry product up to 271 g per tree, reduced blanking to 10.6 percent, increased splitting by 11.2 percent, reduced the number of grains per ounce of pistachios by 2.3 units, and increased the water use productivity by 100 percent compared to the control. Also, in orchard 2, plastic mulch increased the dry product upto 1090 g per tree and increased the water use productivity by 36 percent compared to the control. Measurement of soil moisture changes in between two consecutive irrigations indicated significant effect of mulching on conserving soil moisture in comparison with the control. Considering the Permanent Wilting Point (PWP) and Readily Available Water (RAW) of the experimental soils, proper irrigation frequency for pistachio trees in uncovered loamy sand to sandy loam soils under drip irrigation is 5 to 9 days, and in the use of plastic mulch, it is 11 to 15 days.
a f; h a; m k; a a; m m
Abstract
In order to investigate the economics of simultaneous effect of salinity anddrought stress on growth and yield of tomato plant (LycopersiconesculentumMill.Cv. Oriental), four levels of irrigation (125% ET, 100%ET, 75%ET and 50%ET)and six levels of salinity (0.1, 1.3, 3, 5, 7, and 9 dS/m) were combined ...
Read More
In order to investigate the economics of simultaneous effect of salinity anddrought stress on growth and yield of tomato plant (LycopersiconesculentumMill.Cv. Oriental), four levels of irrigation (125% ET, 100%ET, 75%ET and 50%ET)and six levels of salinity (0.1, 1.3, 3, 5, 7, and 9 dS/m) were combined in afactorial and completely randomized design with 3 replication in a greenhousesoilless culture. Economic model of deficit irrigation optimization was extractedand used for growing tomato in a greenhouse under salinity and drought stresses.The results of this model showed that the net profit of full irrigation of tomato insoilless culture in greenhouse using water of 0.1, 1.3, and 3 dS/m was equal to thenet profit of deficit irrigation at 36%, 21%, and 24%, respectively. Thus,considering the large number of tomato greenhouses with soilless production andvery high price of chemical fertilizers and other costs related to plant nutrition andirrigation, applying approximately 25% deficit irrigation will cause acorresponding reduction in total costs of production, which is economicallysignificant.
n k; a a; k d
Abstract
Plant yield is a function of root distribution and its activity. Under limited water conditions, adequate root growth and efficiency are essential for crop productivity. To study the relationship between the dynamics of corn (Zea Maize L., variety single cross 704) root growth and soil available water ...
Read More
Plant yield is a function of root distribution and its activity. Under limited water conditions, adequate root growth and efficiency are essential for crop productivity. To study the relationship between the dynamics of corn (Zea Maize L., variety single cross 704) root growth and soil available water uptake under drip-tape irrigation system, an experiment was conducted in a randomized complete block design with three replications. Experimental variables were three irrigation treatments including: 100% (I1), 80% (I2), and 60% (I3) of the actual plant water requirement calculated by the Penman–Monteith formula using meteorological data. The roots were collected from the beginning to the end of the growing season at four stages including: 25, 55, 85 and 115 days after planting. Samples were taken from 5 depths: 0-10, 10-20, 20-30, 30-40, and 40-50 cm. The results showed that irrigation treatments had significant effect (p=0.01) on root length density at different depths. About 60% of the corn root length density was up to the depth of 20 cm. On the other hand, the surface layers of the soil at this depth lost their moisture rapidly and, therefore, the plant needed to absorb water from the lower layers (below 20 cm) to survive. In low irrigation treatment (60% water requirement) up to the depth of 40 cm, root growth was low and, as a result, water absorption was also low. Higher irrigation had a positive effect on corn yield as the highest yield (7769 kg/ha) was obtained with the irrigation treatment of 100% water requirement.
H D; A A; K E; H N
Abstract
Drought stress is one of the main problems regarding agricultural productions throughout the world, especially in arid and semi-arid regions like Iran. Manyresearchers studies various effects of drough stress on root and shoot parts of crop. But, there is not more information about root growth of tomato. ...
Read More
Drought stress is one of the main problems regarding agricultural productions throughout the world, especially in arid and semi-arid regions like Iran. Manyresearchers studies various effects of drough stress on root and shoot parts of crop. But, there is not more information about root growth of tomato. In this study, the effect of drought stress on root growth, yield and yield components of tomato was investigated under greenhouse conditions. The experimental design was a randomized block design with four irrigation treatments comprising 100%, 80%, 60% and 40% of water requirement in three replications. Fruit weight, diameter and quantity, dry weight of shoot part, root volume, wet weight of root, dry weight of root and root length were measured at the end of growing season. Generally, drought stress had significant effect (p<0.01) on yield, yield components and root attributes of tomato. Themaximum fruit weight (602.53 g), fruit quantity (9.33), diameter (4.86 cm), dry weight of shoot part (127.64 g), root volume (0.38 L), wet weight of root (268.97 g), dry weight of root (24.25 g), root length (239386 cm) and root area (33860 cm2) was corresponded to 100% water requirement treatment. In general, the results showed . The root volumehadmaximum correlated with yield and yield components of tomato.
Alireza Tavakoli; Abdolmajid Liaghat; Amin Alizadeh
Abstract
Crops growth and production in rainfed systems is a function of changes in climatic parameters. Identification of the effective parameters and planning for their management and/or adapting agronomic practices to those changes will result in improving production baseline and yield prediction. In order ...
Read More
Crops growth and production in rainfed systems is a function of changes in climatic parameters. Identification of the effective parameters and planning for their management and/or adapting agronomic practices to those changes will result in improving production baseline and yield prediction. In order to estimate climate-yield production functions, we analyzed eight crop seasons data (1998-2006) of 25 climate parameters and rainfed wheat grain yields of four cold and semi-cold regions of Lorestan province including Aleshtar, Khoram-Abad, Aligodarz, and Boroujerd. Correlation coefficients of linear and non-linear regressions were established between each weather parameter, as the independent variable, and wheat grain yield. By path analysis method, correlation coefficients were separated into direct and indirect effects. Results showed that, in local models of production functions, the role of vapor pressure deficit during crop growth was very important. Rain water productivity of all regions determined for eight crop seasons, and the amounts of maximum, minimum, and average rain water productivity were 0.341, 0.132, and 0.234 kg per cubic meter precipitation, with the average being 20 percent lower than the national average (0.292 kg.m-3). The maximum temperature of Oct-Nov, sunshine hours,, autumn precipitation, and maximum seasonal temperature were the most sensitive parameters with respect to grain yield prediction. Determination of the effective climatic factors and the degree of their effects will help farmers in adopting improved agronomic practices (such as proper planting dates, suitable cultivars, and improving soil water holding capacity), thereby controlling the negative factors affecting criop growth and yield and improving the effectiveness of the positive factors.