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...

This paper investigates the effects of wheat production risk and other socio-economic factors on the probability of adopting new seed technologies. Also, the effects of production inputs and production conditions are examined on wheat production yield and risk. Moreover, the relative risk of new seed varieties will be examined under different scenarios. To carry out the study, farm-level data ...

This study was conducted to investigate the genetic diversity of alfalfa genotypes by multivariate analyses using agronomic and morphological traits. For this purpose, 20 alfalfa genotypes with local control Baghdadi was considered as the first factor and three harvest was used as the second factor. This experiment was performed to split plot at the time in randomized complete block design with...

Irrigation water Scarcity is the major limiting factor for crop production in irrigated farming. Therefore, optimal use of water is influenced by seasonal rainfall especially where the water price is high. Nitrogen also plays a key role in plant nutrition. In this study, wheat grain yield production as a function of applied water (irrigation plus seasonal rainfall) and nitrogen fertilizer (appl...

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...

The purpose of this research is the simulation of the maize function to scenario of climate change to the present and future. So to survey the region climate, daily data, maximum and minimum temperature, precipitation and radiation have been utilized during the period of (1987-2016). In order to simulating of climate in future, firstly the date of IPCM4 model under scenario and 30’s and 50’s wi...