this study was carried out to determine nitrogen, phosphorus, and potassium contents of rangeland plants using spectral reflectance value. the measurements were made in 1 m2 area of different parts of a rangeland. a portable spectroradiometer capable of measuring the wavelength range of 325-1,075 nm of the electromagnetic spectrum was used to collect spectral data. spectral measurements were ma...

A question that frequently arises in connection with elements regarded necessary for plant growth is whether or not a particular element is an essential plant food or merely a stimulating substance. Is its role that of a catalyzer, or is it actually incorporated into the tissues as an integral part of the plant? These questions are more applicable to such elements as manganese, copper, zinc and...

Major sedimentary nutrient cycles Phosphorus cycle Sulphur cycle Major gaseous cycles Nitrogen Cycle Carbon Cycle Ammonification Nitrification Nitrogen fixation Symbiotic nitrogen fixation Non-symbiotic nitrogen fixation Photosynthesis Light reaction Dark reaction Carbon dioxide cycle Micronutrients Plant uptake of trace elements (essential and non-essential) Factors influencing micronutrient u...

Mycorrhizas are the chief organ for plant mineral nutrient acquisition. In temperate, mixed forests, ash roots (Fraxinus excelsior) are colonized by arbuscular mycorrhizal fungi (AM) and beech roots (Fagus sylvatica) by ectomycorrhizal fungi (EcM). Knowledge on the functions of different mycorrhizal species that coexist in the same environment is scarce. The concentrations of nutrient elements ...

One criterion of the effectiveness of nutritional sprays is the rate at which the foliar applied nutrients are absorbed by the leaf and translocated to other plant parts including the roots. Two distinct but not easily separated processes, absorption and transport, are involved. Initial penetration most likely involves passage through the cuticle and epidermal cells (17, 20); stomata may also p...

Ecological stoichiometry postulates that differential nutrient recycling of elements such as nitrogen and phosphorus by consumers can shift the element that limits plant growth. However, this hypothesis has so far considered the effect of consumers, mostly herbivores, out of their food-web context. Microbial decomposers are important components of food webs, and might prove as important as cons...