Variable rate application of fertilizer has the potential to improve nutrient use efficiency, improve economic returns, and reduce negative environmental impacts. The objective of this study was to evaluate the variable rate application of potassium fertilizer to soybean crop in a no-till system. The study was conducted on a 13-ha soybean grain field in Carambeí, State of Paraná, Brazil in a Ty...

0305-7364/0 * For corre bcgn.grignon. There is still disagreement about whether crop growth rate or soil nitrate concentration control nitrogen absorption by crops under ®eld conditions. The in ̄uence of these factors on the control of N uptake rate was examined in the absence of water stress, using data on dry matter production, above-ground nitrogen accumulation and soil nitrate concentration ...

in order to determine the best traits related to indirect increasing of grain yield, five wheat genotypes (zagros, tajan, durum cul., kohdasht and n-81-18 line) were evaluated by using randomized complete block design (rcbd) with 4 replications in research field of gorgan university of agricultural sciences and natural recourses. the studied traits included leaf area index (lai), crop growth ra...

in order to study the effects of nitrogen fertilizer on yield and growth of soybean (glycine max l.) an experiment as factorial in rcb design with three replications was conducted during 2006 and 2007 years at north khorasan. factors were cultivar (hobbit, l.w.k., and williams), and nitrogen fertilizer (0, 50, 100, and 150 kg n/ha from urea source). results indicated that cultivar and n fertili...

The paper describes a model of cauliflower (Brassica oleracea L. botrytis) growth and development under conditions where water and nutrients are not limiting. The model consists of four linked processes: crop development, leaf area expansion, increase in curd diameter and growth of dry matter. The model aims to describe variability between plants in time of curd initiation and harvest. Crop dev...

A water simulation model (WaSim) to simulate the growth and development of Amaranthus cruentus as well as the components of water balance for a typical sandy-clay-loam soil of Akure has been described. Dry season experiments were carried between January and March of 2005 and 2006. Amaranthus seeds were established on the field and three irrigation water managements were imposed on the crop to d...

Protein deficiency is the most crucial factor that affects physical growth and development and that increases morbidity and mortality especially in developing countries. Efforts have been made to improve protein quality and quantity in crop plants but with limited success. Here, we report the development of transgenic potatoes with enhanced nutritive value by tuber-specific expression of a seed...