Mohammad Jolaini; mohammad karimi
Abstract
Introduction: After wheat, rice and corn, potato is the fourth most important food plant in the world. In comparison with other species, potato is very sensitive to water stress because of its shallow root system: approximately 85% of the root length is concentrated in the upper 0.3-0.4 m of the soil. ...
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Introduction: After wheat, rice and corn, potato is the fourth most important food plant in the world. In comparison with other species, potato is very sensitive to water stress because of its shallow root system: approximately 85% of the root length is concentrated in the upper 0.3-0.4 m of the soil. Several studies showed that drip irrigation is an effective method for enhancing potato yield. Fabeiro et al. (2001) concluded that tuber bulking and ripening stages were found to be the most sensitive stages of water stress with drip irrigation. Water deficit occurring in these two growth stages could result in yield reductions. Wang et al. (2006) investigated the effects of drip irrigation frequency on soil wetting pattern and potato yield. The results indicated that potato roots were not limited in wetted soil volume even when the crop was irrigated at the highest frequency while high frequency irrigation enhanced potato tuber growth and water use efficiency (WUE). Though information about irrigation and N management of this crop is often conflicting in the literature, it is accepted generally that production and quality are highly influenced by both N and irrigation amounts and these requirements are related to the cropping technique. Researches revealed that nitrogen fertilizers play a special role in the growth, production and quality of potatoes.
Materials and Methods: A factorial experiment in randomized complete block design with three replications was carried out during two growing seasons. Studied factors were irrigation frequency (I1:2 and I2:4 days interval) and nitrogen fertilizer levels (applying 100 (N1), 75 (N2) and 50 (N3) % of the recommended amount). Nitrogen fertilizer was applied through irrigation water. In each plot two rows with within-and between-row spacing of 45 and 105 cm and 20 m length. The amount of nitrogen fertilizer for the control treatment was determined by soil analysis (N1). In all treatments, nitrogen fertilizer applied in 5 times until flowering stage. Potassium, phosphorus and microelements applied according to the soil analysis results. The subsurface drip tape was used for irrigation. Tapes with 300 µm thickness, 30 cm dripper spacing and 4 lit/hour discharge were applied. Tapes buried at 20 cm soil depth before planting. Water amount was measured by the volume meter at each irrigation treatment. Water amount calculated based on crop water requirement and plot area and irrigation frequency. On maturity stage, 8 m of two central rows of each plot harvested for determining tuber yields. Water use efficiency was calculated as the ratio of the tuber yield to the total consumed water volume. Statistical analysis was performed using MSTAT-C software. Means were compared by Duncan's multiple range tests at 0.05 and 0.01 significant levels.
Results Discussion: Results of combined analysis showed that yield and water use efficiency (WUE) did not affected by irrigation frequency. Yield and water use efficiency affected by nitrogen level (p
J. Givi
Abstract
In addition to qualitative and quantitative land suitability evaluation, economical evaluation can be carried out as well, based on net or gross benefit per surface area unit. The present research was done to evaluate land suitability, qualitatively and economically,, by different methods for irrigated ...
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In addition to qualitative and quantitative land suitability evaluation, economical evaluation can be carried out as well, based on net or gross benefit per surface area unit. The present research was done to evaluate land suitability, qualitatively and economically,, by different methods for irrigated maize, wheat, potato and barley in Shahrekord area. In this regards, qualitative land suitability class was determined by matching land characteristics with the studied crops growth requirements, using simple limitation method and ALES program. Economical land suitability evaluation was carried out, using "internal rate of return", "gross profit", "net present value" and "benefit/cost ratio" methods which are included in the ALES program. The results showed that qualitative suitability class in all of the studied land units for irrigated maize, wheat and barley is S2 and for irrigated potato in 73% of the units is S2 and in 27% of them is S3. As the "net present value" method is used, % 73 and % 27 of the land units are classified as S2 and S1, respectively for all of the studied crops. For wheat and maize, all of the land units are classified as S1, as gross profit, benefit/cost ratio and internal rate of return methods are used. For potato and barley, using gross profit and internal rate of return methods, % 73 and % 27 of the land units are classified as S2 and S1, respectively and as the benefit/cost ratio method is used, economical land suitability class in all of the land units is S1.
Z. Lotfi Arpachaei; Abazar Esmali; kazem hashemimajd; n n
Abstract
In modern agriculture, the preparation of soil fertility map seems to be necessary to plan for appropriate using of fertilizers for crops. This study was conducted to prepare a distinct map for evaluating soil fertility according to soil chemical properties in 136 soil samples of Ardabil plain in Ardabil ...
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In modern agriculture, the preparation of soil fertility map seems to be necessary to plan for appropriate using of fertilizers for crops. This study was conducted to prepare a distinct map for evaluating soil fertility according to soil chemical properties in 136 soil samples of Ardabil plain in Ardabil province. To achieve this purpose, the available K and P, total N, EC, pH and organic matter of soil were mapped using geostatistical Kriging estimator into Geographic Information System (GIS) by ArcGIS9.3 software. The Analytical Hierarchy Process (AHP) was used for weighting soil fertility factors as the input data. Then a membership functions was defined for each factor by factorial scoring and the map of soil fertility was prepared and classified for wheat and potato by using AHP technique into GIS program. The results showed that 74.84, 3.59, 19.3 and 2.32 percentage of lands for wheat cropping were classified based on soil fertility into groups of weak, moderate and suitable, respectively while for potato it was 24.88, 27.57, 7.19 and 40.34 percentage, respectively. As a final result, this type of distinct soil fertility map for different crops could assist us to manage the appropriate using of lands and fertilizers.
