Abstract Crop yield improvement during the last decades has relied on increasing ratio of economic organ to total aboveground biomass, known as harvest index (HI). In most crop models, HI is set a parameter; this empirical approach does not consider that only depends plant genotype, but also affected by environment. An alternative simulate allocation mechanistically, in LPJ-GUESS model, which s...

to study the effect of nitrogen form and ph of nutrient solution on the uptake and concentration of fe, zn, cu and mn in roots and shoots of spinach plant, a factorial experiment was conducted with two factors including nutrient solution ph in three levels (4.5, 6.5 and 8.0) and nitrate to ammonium ratio of nutrient solution in five levels (100:0, 75:25, 50:50, 25:75 and 0:100). the experiment ...

Background: Qual2k is a stream water quality model and was used to evaluate the water quality of the Kine-Vars River and assess the response of the river to nutrient management strategies. Methods: For that purpose, 7 sample stations were selected and surface water samples were collected in the winter and summer of 2012 and were analyzed for temperature, dissolved oxygen, biological oxygen dem...

background: qual2k is a stream water quality model and was used to evaluate the water quality of the kine-vars river and assess the response of the river to nutrient management strategies. methods: for that purpose, 7 sample stations were selected and surface water samples were collected in the winter and summer of 2012 and were analyzed for temperature, dissolved oxygen, biological oxygen dema...

re-vegetation of bare soil is believed to increase, or at least maintain the organic matter levels of soil. the aim of this study was to investigate the soil characteristics changes, nutrient pool sizes and their availability under mid canopy, and canopy gap positions of saltbush in an area re-vegetated with atriplex lentiformis. some of the physical and chemical soil characteristics (the parti...

some factors affecting crude protein balance (cpb), as a measure of efficiency, were studied using 2824 records of 501 lactating holstein cows. the cpb (kg d-1) was calculated as crude protein (cp) intake (kg) minus cp yield (kg). two different statistical methods including principal components (pcs) and general linear model analyses were used to study the effects of different factors. crude pr...

citric acid has been reported to increase utilization efficiency of dietary phytate-bound phosphorus and protein. objective of this study was to determine the effects of citric acid on growth performance and nutrient retention of broiler chickens fed diets having two levels of non-phytate phosphorus and rice bran. giving a completely randomize design in 2 × 2 × 2 factorial arrangement, 144 broi...

one hundred and eighty 28-days-old arbor acres broiler birds were utilized in a 28 day experiment to investigate the effect of replacing bone ash with eggshell meal in the diet of broiler birds on their nutrient digestibility and blood parameters. five experimental diets tagged t1, t2, t3, t4 and t5 were formulated to be isocaloric (2865.53 kcal me/kg) and isonitrogenous (20% crude protein) suc...

The spatial distribution of plant-available mineral nutrients in forest soils is often highly heterogeneous. To test the hypothesis that local nutrient enrichment of soil leads to increased root proliferation in the nutrient-rich soil zone, we studied the effects of nutrient enrichment on the growth and nutrient concentrations of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), Scots pine (P...