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...

Invariably, many agricultural soils of the world are deficient in one or more of the essential nutrients needed to support healthy plants. Acidity, alkalinity, salinity, anthropogenic processes, nature of farming, and erosion can lead to soil degradation. Additions of fertilizers and/or amendments are essential for a proper nutrient supply and maximum yields. Estimates of overall efficiency of ...

recently, biological fertilizers extensively recommended because of over application of chemical fertilizer and their effects on environment and production resources. in order to study the effect of inoculate phosphate solubilization microorganisms (psm) and plant growth promoting rhizobacteria (pgpr) on nutrient use efficiency in corn [zea mays (l.) cv. sc 604] an experiment was conducted in 2...

background and objectives: the quefts model is using for optimizing fertilizer managements in crops, but it has not been used in iran yet. quefts accounts for interactions among npk affecting the ie of n, p and k and allows differentiation according to different yield levels targeted. it is necessary to determine crops parameters before application the model in the studying area. the first step...

We measured nutrient use efficiency (NPP/nutrient uptake) in three species of tropical trees, Hyeronima alchorneoides, Cedrela odorata, and Cordia alliodora. We tested the prediction that on fertile soils species with very different biomass and nutrient allocation and turnover would converge on a common value of nutrient use efficiency. Due to high soil fertility, nutrient use efficiencies of t...

Differences in nutrient-use efficiency have been attributed to differences in leaf habit. It has been suggested that evergreens, with their longer-lived leaves, and therefore longer nutrient retention, are more efficient than deciduous species in their use of nutrients. In tropical trees, however, leaf life span is not always a function of whole-tree deciduousness, leading to the proposal that ...