نتایج جستجو برای: yield production function

تعداد نتایج: 1911023  

ژورنال: علوم آب و خاک 2007
هانی رضائی, , همایون فرهنگ‌فر, ,

A total of 179,460 monthly test-day milk records (thrice a day milking) obtained from 17,946 Iranian Holstein heifers distributed in 287 herds and calved from 1986 to 2001 were used to predict breeding value of animals. Monthly test-day milk production was analysed by applying a covariance function in which the effects of herd-year-season of production (HYSOP), age at test day (covariate), addi...

Journal: :journal of agricultural science and technology 2010
s. f. mousavi b. mostafazadeh-fard a. farkhondeh m. feizi

high groundwater salinity, a high water table and secondary soil salinization are dominant conditions in eastern isfahan province, iran. this region has a low annual rainfall, high annual evaporation demand, saline soils and limited fresh water supplies. to investigate the effects of irrigation deficit and salinity on cantaloupe (cucumis melo l. var. cantalupensis) production, a field experimen...

Abstract In order to determine the best water production function (CWPF) for predicting grain yield of a soybean crop four models were evaluated. The four functions evaluated were Jensen (1968), Minhas et al (1974) and modified Stewart et al (1977) and modified Bras and Corodova (1981) models. Field experiments were carried out for evaluation of the models. The grain yields simulated by the c...

Journal: :پژوهش های تولید گیاهی 0

stomata are closed by moisture stress, reducing carbon assimilation and yield production with dry land agriculture. relative 13c to 12c molar ratio assimilation by a plant is a function of time stomata remain open during plant life time, itself a function of moisture stress. the purpose of this study was to test the existence of any relationship between stomatal conductance and assimilation rat...

Journal: :آب و خاک 0
وحیدرضا وردی نژاد تیمور سهرابی نادر حیدری شهاب عراقی نژاد محمد فیضی

abstract in this study, seven main field crops of the rudasht and abshar irrigation networks of esfahan (with 54,000 ha designed command area) such as wheat, barley, onion, sunflower, fodder mays and sugar beet were selected and swap model was calibrated by inverse modeling base on field experiments results in order to determine crop water salinity production functions. field experiments were c...

Journal: :journal of livestock science and technologies 2015
m. r. zare mehrjerdi m. ziaabadi a. ayatollahi mehrgardi o. dayani

to calculate partial and total productivity of production factors in broiler farms in yazd province, 72 manufacturing units were selected based on simple random sampling method and their information and statistics were collected for one production period in the second half of 2013. to measure productivity, the cobb-douglas production function was estimated using classic and fuzzy regression met...

Journal: :تحقیقات مهندسی کشاورزی 0
علیرضا توگلی عضو هیات علمی (استادیار پژوهش) بخش تحقیقات فنی و مهندسی مرکز تحقیقات کشاورزی استان سمنان (شاهرود)

this study investigated the effect of sowing date and limited water allocation management for single irrigation on the grain yield of rainfed barley. the experiment was a split-split plot arranged in a randomized complete block design with three replications from 2004 to 2006 at the main station of the dryland agricultural research institute at maragheh. the treatments comprised three sowing da...

A.A. Kamgar-Haghighi A.R. Sepaskhah, M. Amini-Nejad

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...

Journal: :علوم دامی ایران 0
سمیه لطفی دانشجوی دکتری تخصصی، دانشکدۀ علوم ریاضی دانشگاه گیلان رضا لطفی دانشجوی دکتری تخصصی، دانشکدۀ کشاورزی دانشگاه فردوسی مشهد علی وحیدیان کامیاد استاد گروه ریاضی کاربردی دانشکدۀ علوم ریاضی دانشگاه فردوسی مشهد همایون فرهنگ فر استاد گروه علوم دامی دانشکدۀ کشاورزی دانشگاه بیرجند

description of lactation curve were investigated using sine function, compare it with two functions (dijekstra and wood). the data contained 32233 dairy milk yield records from 93 first parity iranian holstein cows that had calving between aug. 2008 and jul. 2009. actual milk production per day and subsequently the actual production of each animal were available in the first lactation. lactatio...

Journal: :تحقیقات مهندسی کشاورزی 0
مجید دلاور دانشجوی دکتری منابع آب دانشگاه تربیت مدرس سعید مرید استاد گروه منابع آب دانشگاه تربیت مدرس مهنوش مقدسی استادیار دانشکده کشاورزی دانشگاه اراک

decreasing water resources has made optimum water allocation in agriculture essential. planning optimum irrigation and crop production function considering accessible water and growing stage is an efficient approach to increase water productivity. studies have applied this approach to maximize crop production using the fao crop production method introduced in 1979. however, the fao introduced a...

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