A.R. Sepaskhah

Irrigation Department, Shiraz University, Shiraz, I.R. of Iran

[ 1 ] - Safflower model for simulation of growth and yield under various irrigation strategies, planting methods and nitrogen fertilization

Development and use of crop growth models is an effective tool for agricultural planningand decision making in agricultural industry. Besides, the drought and limited supplies of waterin many areas of the world has increased attention to favourable strategies in farm managementsuch as efficient irrigation and planting methods. The objective of this study was to develop acrop model for safflower...

[ 2 ] - Modification of transient state analytical model under different saline groundwater depths, irrigation water salinities and deficit irrigation for quinoa

Salinization of soil is primarily caused by capillary rise from saline shallow groundwater orapplication of saline irrigation water. In this investigation, the transient state analytical modelwas modified to predict water uptake from saline shallow groundwater, actual cropevapotranspiration, soil water content, dry matter, seed yield and soil salinity under differentsaline groundwater depths, i...

[ 3 ] - Effect of irrigation water salinity, manure application and planting method on qualitative compounds of saffron (Crocus sativus L.)

The objective of the present study is to investigate the effects of irrigation water salinity,cow manure levels and different planting methods on saffron quality compounds includingcrocin (coloring strength), picrocrocin (bitterness) and safranal (aromatic strength). A split-splitplot arrangement was conducted in complete randomized block design with irrigation watersalinity levels (0.45 (fresh...

[ 4 ] - Modification of the saffron model for growth and yield prediction under different irrigation water salinity, manure application and planting methods

The Saffron Yield Estimation Model (SYEM) was modified for salinity conditions, cowmanure application and planting methods using two-year experiments data in Badjgah region ofIran. A split-split plot arrangement was conducted in complete randomized block design duringtwo years with irrigation water salinity levels (0.45 (fresh water, S1), 1.0 (S2), 2.0 (S3) and 3.0(S4) dS m-1) as the main plot,...

[ 5 ] - Relationships between wheat yield, yield components and physico-chemical properties of soil under rain-fed conditions

This research was conducted to study and classify the physico-chemicalproperties of soil, yield components of wheat and to determine the significance ofthese parameters on the grain yield formation. In this research, seven statisticalmethods consisting of simple correlation analysis (SCA), multiple linear regression(MLR), stepwise regression (SR), factor analysis (FA), principal componentanalys...

[ 6 ] - Effect of irrigation interval and water salinity on growth of vetiver (Vetiveria zizanioides)

The purpose of the present study was to investigate the limits of irrigationwater salinity and soil water content for growth inhibition of vetiver. Moreover,different models were studied to describe the root water uptake and plant topgrowth under salinity and water stresses in a pot experiment. Irrigation treatmentsconsisted of three irrigation intervals (3, 6 and 9-day). The salinity levels of...

[ 7 ] - Effects of deficit irrigation and groundwater depth on root growth of direct seeding rice in a column experiment

Rice is an essential crop in Iran that is grown mostly in areas where depth to groundwater is low. Root growth and water uptake of rice under shallow groundwater has not been thoroughly studied. This experiment was conducted to determine the lowland rice (cv. Ghasrodashti) root distribution above shallow groundwater in relation to deficit irrigation and groundwater depth in cylindrical gre...

[ 8 ] - Maize response to different water, salinity and nitrogen levels: agronomic behavior

Soil water, salinity and nitrogen content are three major factors affecting crop production in arid and semi-arid areas. This study was performed in two years of 2009 and 2010 in a semi-arid area in order to investigate the effects of irrigation water quantity (as main plot), quality (saline water, as sub-plot), nitrogen fertilizer (as sub-sub plot) and their interactions on growth and yiel...

[ 9 ] - Maize response to water, salinity and nitrogen levels: physiological growth parameters and gas exchange

A split-split-plot design with three replications in two years of 2009 and 2010 was conducted to investigate the effect of different levels of irrigation water (main plot), salinity of irrigation water (sub-plot) and nitrogen fertilizer rate (sub-subplot) on maize growth rate and gas exchange. Irrigation treatments were I1 (1.0 crop evapotranspiration (ETc)+0.25ETc as leaching), I2 (0.75I1)...

[ 10 ] - Developing a dynamic yield and growth model for saffron under different irrigation regimes

Better irrigation management and more efficient management of crop production require modeling of plant growth and crop yield. More applicable models are usually simple and requires less and accessible inputs. The objective of this study was to develop a model for growth and yield prediction of saffron under various irrigation regimes. In this modeling soil water budget and other simple rel...

[ 11 ] - Growth and physiologic response of rapeseed (Brassica napus L.) to deficit irrigation, water salinity and planting method

Salinity and water stress reduces the ability of plant to take up water and decrease growth rate, photosynthesis rate (An) and stomatal conductance (gs) of plants. In this study, effects of deficit irrigation with different salinity levels and planting method (in-furrow and on-ridge) as strategies for coping with water and salinity stress on physiologic properties of rapeseed was investigat...

[ 12 ] - Effects of salinity and irrigation water management on soil and tomato in drip irrigation

In this research, the effects of irrigation with saline and fresh water through drip irrigation method and using two irrigation management strategies: M1, M2 (M1 is irrigation with fresh water in alternative with saline water, M2 is saline water in first half time of each irrigation event and fresh water in the second half), on the yield, water productivity (WP), soil salinity, plant height...

[ 13 ] - Responses of agronomic components of rapeseed (Brassica napus L.) as influenced by deficit irrigation, water salinity and planting method

Shortage and salinity of irrigation water are two major constraints that influence rapeseed production in arid and semi-arid regions of central and southern Iran. In this study, effects of deficit irrigation with different salinity levels and planting methods (in-furrow and on-ridge) as strategies for coping with water and salinity stresses on yield and yield quality of rapeseed were invest...

[ 14 ] - Yield and nitrogen leaching in maize field under different nitrogen rates and partial root drying irrigation

Irrigation water is limiting for crop production in arid and semi-arid areas. Furthermore, excess nitrogen (N) application is a source of groundwater contamination. Partial root drying irrigation (PRD) can be used as water saving technique and a controlling measure of groundwater N contamination. The objectives of this investigation were to evaluate the effect of ordinary furrow irrigation (OFI...

[ 15 ] - Interaction of different irrigation strategies and soil textures on the nitrogen uptake of field grown potatoes

Nitrogen (N) uptake (kg ha-1) of field-grown potatoes was measured in 4.32 m2 lysimeters that were filled with coarse sand, loamy sand, and sandy loam and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. PRD and DI as water-saving irrigation treatments received 65% of FI after tuber bulking and lasted for six weeks until final harvest. Results show...

[ 16 ] - Effects of water-saving irrigations on different rice cultivars (Oryza sativa L.) in field conditions

A more efficient water use system is needed for agriculture. This is more evidence for rice production with a higher water use for economical production. A large cultivar×water regime interaction exists for grain yield in rice. Therefore, information is required to adopt new rice cultivars with high yield potential under water-saving conditions. The objectives of this study were to analyze the ...

[ 17 ] - Response of different rice cultivars (Oryza sativa L.) to water-saving irrigation in greenhouse conditions

Due to increasing water and growing demand for food a more efficient water use system is needed for agriculture. This is more evidence for rice production with a higher water use for economical production. A large cultivar×water regime interaction exists for grain yield in rice. Therefore, information is required to adopt new rice cultivars with high yield potential under water-saving condition...

[ 18 ] - A review on partial root-zone drying irrigation

Available fresh water resources are subjected to an ever-increasing pressure due to extensive agricultural water demand for irrigated lands. A long-term perspective in shortage of fresh water resources, especially in arid and semi-arid area, highlights an urgent solution for innovative irrigation strategy and agricultural water management. This paper is a review on the wide applications of the ...

[ 19 ] - Evaluation of macroscopic water extraction model for salinity and water stress in saffron yield production

Water scarcity and salinity are important limitations for saffron (Crocus sativus L.) production in arid and semi-arid regions. The purpose of this research was to study the interaction effects of water salinity and deficit irrigation on the macroscopic water extraction model for saffron. The effect of salinity and water stress on root-water uptake coefficient was determined by additive and mul...

[ 20 ] - Physiological and morphological responses of rice (Oryza sativa L.) to varying water stress management strategies

Sustainability of rice production under limited water conditions is threatened by increasing irrigation water scarcity. Therefore, physiological and morphological responses of rice to varying water stress management strategies should be determined. The physiological and morphological responses of a semi dwarf rice (Hashemi cultivar) to water stress intensities (mild and severe, i.e., short-dura...

[ 21 ] - Effect of irrigation interval and water salinity on growth of madder (Rubina tinctorum L.)

Madder (Rubina tinctorum L.) is mainly cultivated in central part of I.R. of Iran that is an arid and desert area with scarce and saline water resources. Its root is used as herbal medicine and food additives and its shoot (top) is used as forage crop. However, little is known about its salinity tolerance and soil water limits for growth. The objectives of the present study were to investigate ...

[ 22 ] - Optimization of performance measures in Doroodzan Irrigation Network

Abstract- In this research, the performance measures of water equity and productivity have been optimizedin the entire DoroodzanIrrigation Network by using genetic algorithms. Results indicated thatirrigation water management improvement at field scale[increasing irrigation application efficiency (Ea) and water reduction fraction (WRF)] has much more impressive impact on raising the performance...

[ 23 ] - Effect of 10-year continuous saffron cultivation on physical and chemical properties of soil

The effect of 10-year continuous saffron cultivation on physical and chemical properties of a silty clay loam soil was investigated in a research farm of College of Agriculture, Shiraz University, Shiraz (52 º 33ʹ E Longitude and 29º 36ʹ N latitude), Iran. This farm was irrigated with different regimes (100% of saffron's potential evapotranspiration (ETp), 75%ETp, 50%ETp) including rain fed tre...

[ 24 ] - روش جدید برآورد پارامترهای هیدرولیکی با اندازه‌گیری رطوبت خاک در مزرعه

In this study, the values of moisture and soil temperature were estimated at different depths and times under unsteady conditions by solving the Richards’ equation in an explicit finite difference method provided in Visual Studio C#. For the estimation of soil hydraulic parameters, including av and nv (coefficients of van Genuchten’s equation) and Ks (saturated hydraulic conductivit...

[ 25 ] - اثر مدیریت بقایای گیاهی بر ویژگی‌های فیزیکی و بیولوژیکی خاک و عملکرد ذرت علوفه ای و جو

The objective of this study was to evaluate the effects of crop residues management on soil physical and biological properties. The impacts of residue management on yield of forage corn and barley and soil micro-organisms population were also studied. The results showed that application of crop residues increased soil organic matter (22.2 %), saturated hydraulic conductivity (51.9 %), porosity ...

[ 26 ] - تأثیر بیوچار و شوری آب آبیاری بر خصوصیات شیمیایی خاک تحت کشت باقلا

امروزه با توجه به محدود بودن منابع آب و حاصلخیزی کم خاک‌ها، به‌ ویژه در مناطق خشک و نیمه خشک، نیاز به استفاده از آب با کیفیت نا مطلوب (مانند آب شور) و استفاده از اصلاح‌کننده‌های خاک مانند بیوچار ضروری به نظر می‌رسد. بیوچار نوعی زغال تهیه شده از زیست توده‌‌های گیاهی و حیوانی است که به‌دلیل ساختار متخلخلی که دارد سبب بهبود شرایط فیزیکی و شیمیایی خاک می‌شود. لذا تحقیق حاضر به منظور بررسی اثر سطوح ...

[ 27 ] - کاربرد تلفیقی شبکه عصبی و روش های محاسباتی جهت تخمین دقیق تر تبخیر-تعرق مرجع

در بسیاری از مسائل آبیاری و زهکشی، هیدرولوژی، محیط زیستی، فرسایش خاک و منابع آب تخمین دقیق تر تبخیر-تعرق اهمیت زیادی دارد. استفاده از شبکه عصبی مصنوعی یکی از روش های تخمین تبخیر-تعرق مرجع می‌باشد. تاکنون در بیشتر مقالات منتشر شده داده های اقلیمی به عنوان ورودی شبکه عصبی جهت تخمین تبخیر-تعرق مرجع مورد استفاده قرار گرفته است. در این تحقیق از تبخیر-تعرق محاسبه شده بوسیله روش های محاسباتی هارگریوز ...

[ 28 ] - تحلیل سیستمی بازده پروژه آبیاری تک کشتی برنج

مقدار دقیق بازده پروژه‌های آبیاری در دست نیست. بنابراین برنامه‌ریزی و طراحی شبکه‌های آبیاری بر اساس مقادیر غیر دقیق انجام می‌شود که منجر به نتایج مأیوس کننده می‌گردد. هدف این پژوهش تحلیل داده‌های ارزیابی پروژه شبکه آبیاری پاشاکلا در مازندران می‌باشد که دارای سطح ایستابی کم عمق است. در این پژوهش از روشهای سیستمی و غیرسیستمی استفاده شده است. در روش سیستمی نفوذ عمقی و رواناب سطحی بعنوان اتلاف آب م...

[ 29 ] - مقایسه دو روش کم‌آبیاری سورگم

کمبود آب مهم ترین عامل محدود کننده تولیدات زراعی در مناطق خشک و نیمه خشک ایران است. کاربرد کم آبیاری موجب بازده بالای مصرف آب با منابع آبی موجود می‌شود. در این مقاله روشهای فصلی و درون فصلی برای کم آبیاری سورگم (نوعی ذرت علوفه‌ای) مقایسه شدند. داده‌های کم آبیاری برای این پژوهش در منطقه باجگاه با شرایط نیمه خشک واقع در 16 کیلومتری شمال شیراز (جنوب جمهوری اسلامی ایران) جمع آوری شد. توزیع زمانی آب...

[ 30 ] - ارائه مدلی جهت تخمین بارندگی سالانه در استان کرمان

پیش‌ دید میزان بارش، موفقیت در کشت دیم و مدیریت بهتر مراتع را تا حد زیادی تضمین می‌کند. در این تحقیق با تجزیه و تحلیل آمار بارندگی روزانه ایستگاه‏های مختلف هواشناسی استان کرمان که دارای آمار بارندگی روزانه طولانی مدت (حداقل 28 ساله ) بودند، مشاهده گردید که فاصلة زمانی وقوع 5/47 میلی‌متر باران تجمعی از ابتدای پاییز (t47.5 ، حسب روز) با میزان بارندگی سالانه (Pa ، حسب mm) را...

[ 31 ] - مدیریت بهره برداری از مخازن سدها

متغیر بودن رژیم‌های بارندگی و جریان رودخانه در سال‌های مختلف، در عین حالی که تاییدی بر تکرار پدیده خشکسالی است، اتخاذ یک راه‌کار مناسب را ایجاب می‌کند. در این مقاله یک مدل برنامه‏ریزی ریاضی که تلفیقی از برنامه ریزی غیر خطی (به عنوان زیر مدل 1) و برنامه ریزی پویای استوکاستیکی (به عنوان زیر مدل 2) برای یک سد یک منظوره جهت مصارف کشاورزی است،. تدوین گردید. در زیر مدل 1، با توجه به مقادیر مشخصی از ...

[ 32 ] - ارزیابی و واسنجی سه معادله تبخیر تعرق در منطقه ای نیمه خشک

در این مقاله سه روش مختلف برای تخمین تبخیر تعرق بالقوه سطوح گیاهی (ET0) در منطقه باجگاه ( استان فارس, ایران) ارزیابی می شود. با استفاده از میانگین داده های هواشناسی در سال‏های 2002- 1986 در (17 سال) , مقادیر ماهانه ET0 با معادله‏های پن من - فائو , پن من - مانتیث و هارگریوز تخمین زده شد. معادله‏های پن من - مانتیث و هارگریوز بر اساس روش پن‏من- فائو که در مطالعات قبلی مناسب ...

[ 33 ] - اثر بیوچار و شوری آب آبیاری بر ویژگی‌های شیمیایی خاک پس از برداشت گندم

سابقه و هدف: شوری از مهم‌ترین و جدی‌ترین تنش‌های محیطی بوده که عاملی تعیین کننده در کاهش محصول گیاهان زراعی به شمار می‌رود. خاک‌هایی که تحت تاثیر شوری قرار می‌گیرند معمولا به دلیل کمبود ماده آلی، ساختمان ضعیفی دارند. از این رو افزودن مواد آلی می‌تواند سبب بهبود پایداری خاکدانه‌های خاک، افزایش تخلخل خاک و بهبود ظرفیت نگهداری آب خاک شود. بیوچار نوعی ماده آلی غنی از کربن می‌باشد که از سوزاندن بقای...

[ 34 ] - کاربرد سطوح مختلف بیوچار و آبیاری بر رشد، محصول و اجزای محصول گیاه باقلا

در یک آزمایش گلخانه‌ای تاثیر 4 سطح (صفر، 25، 50 و 75 تن در هکتار) بیوچار تولید شده از کاه و کلش گندم و 3 سطح آبیاری (100، 75 و 50 درصد نیاز آبی گیاه) در قالب طرح کاملاً تصادفی بر رشد و محصول گیاه باقلا مورد بررسی قرار گرفت. نتایج نشان داد که زمانی که گیاه باقلا رشد کامل خود را کرده، بیشترین مقدار ارتفاع گیاه و شاخص سطح برگ در تیمار بیوچار 25 تن در هکتار مشاهده شده است. همچنین، بیشترین مقدار محصو...

[ 35 ] - تأثیر آبیاری تکمیلی بر رطوبت خاک، محصول و درآمد باغداران در شرایط خشکسالی در باغ‌های انجیر دیم

در این پژوهش، تأثیر زمان و مقادیر مختلف آبیاری تکمیلی در فواصل مختلف از تنه درخت بر رطوبت خاک، محصول و درآمد باغداران انجیر در شرایط خشکسالی بررسی شد. آزمایشها طی دو سال (1392و 1393) در منطقه استهبان بر روی انجیر خوراکی دیم رقم سبز، انجام شد. تیمارهای آبیاری تکمیلی شامل فاصله آبیاری از درخت: نزدیک تنه درخت، در سایهاند...

[ 36 ] - بررسی رشد و محصول گندم تحت سطوح مختلف بیوچار و کم آبیاری در شرایط گلخانه ای

با توجه به میزان گندم تولیدی در استان فارس و همچنین وقوع خشکسالی، استفاده از بقایای محصول گندم بر روی زمین‌های زراعی به فرم بیوچار میتواند سبب بهبود باروری خاک و افزایش محصول گردد. لذا، در تحقیق حاضر به بررسی اثر سطوح مختلف بیوچار تولید شده از کاه و کلش گندم و کمآبیاری بر رشد و محصول گندم در شرایط گلخانهای پرداخته شد. تیمارها شامل چهار سطح بیوچار (صفر، 25/1، 50/2 و 75/3 درصد وزنی) و سه سطح آبیا...

[ 37 ] - Maize response to water, salinity and nitrogen levels: soil and plant ions accumulation

In the present study, some nutritional imbalances, specific ion toxicity and yield-ion concentration relationships in maize under water, nitrogen (N) and salinity stresses were assessed. Effect of different levels of irrigation water (I1=1.0ETc+0.25ETc as leaching, I2 =0.75I1 and I3 =0.5I1) as main plot, salinity of irrigation water (S1=0.6, S2= 2.0 and S3=4.0 dS m-1) as sub-plot and N fertiliz...

[ 38 ] - Effects of wheat straw biochar and irrigation water on hydraulic and chemical properties of a sandy loam soil after faba bean cultivation

Nowadays, applying soil amendments is one of the most important ways to cope with water shortages and improve soil physical properties. In this regard, a greenhouse experiment was conducted to study the effect of different levels of irrigation water and wheat straw biochar on physical and chemical properties of a sandy loam soil, after harvesting faba bean. The experiment was performed with 5 b...

[ 39 ] - The Effect of Deficit Irrigation, Planting Method and Mulch on the Yield and Water Productivity of Mungbean

In the present study, the effects of different levels of irrigation, organic mulch and planting method on the mungbean yield in Badjgah were investigated. The experimental plan in the first year was full randomized block, while in the second year, it was full randomized split-split plot block design, in three repetitions. The results showed that in the FI treatments, the yield was increased up ...