جستجوی مقالات مرتبط با کلیدواژه "nir" در نشریات گروه "آبخیزداری، بیابان، محیط زیست، مرتع"

The most important factor affecting forage quality is phenological stage, that recognizing it be determined the appropriate time grazing in pasture. In this study, four species including Artemisia sieberi, Salsola kerneri, Aelienia subaphylla and Eurotia ceratoides were sampled in different phenological stages (vegetative, flowering and seedling). Samples were taken from the rangelands of Nodooshan-Yazd in 1389 and 1390. At each stage, five replicates for each plant species were selected at least five vegetable base from different locations of vegetation type in the region for each replicates Year growth of shrub species were harvested. Samples grinding after drying and to separate the different parts (Flower, leaf and stem) and were analyzed using infrared spectroscopy in the laboratory. important indicators of quality such as crude protein (CP), acid detergent fiber (ADF), dry matter digestibility (DMD) and metabolic energy (ME) were determined. Results showed that the highest percentage of crude protein is related to in leaves of A. subaphylla and in vegetative stage (9.19%), highest percentage of ADF in shoot of and in seedling stage (53.42%) and highest percentage of DMD (48.13%) and highest amount of metabolic energy (6.18 MJ/KgDM) in leaves of A. sieberi and in vegetative stage. The end of the vegetative period can be considered the best time for grazing.

The aim of this research is to describe the development of a methodology based on present knowledge and available data for evaluation of water erosion behavior and risk as well as modeling and estimation of soil erosion، which is compatible for other similar areas of Iran. Accordingly، the conducted research was based on four major types of water erosions including: sheet، rill، channel and riverbank which have considerable role on sediment yields of Baleghli Chay Watershed، Ardebil Province، were separately and spatially studied. In order to determine the inter-effects of effective factors، the study was conducted using stepwise multivariate statistical tests. For each erosion type، an individual model was then presented. In the next step، after determining of relations between sediment yield and environmental factors (fixed & variable) through statistical analyses and selecting of effective factors on erosion and sediment yields، was created an empirical structure for modeling erosion and sediment yields based on MPSIAC erosion model. In formulation of the new model، were used of eight effective factors on erosion in the area. These factors are susceptibility of geological formation، soil erodibility، rainfall erosivity، runoff erosivity، topography، hydrographic drainage، Normalized Difference of Vegetation Index (NDVI) and field conditions of erosion features. In the presented model، with summation of the scores of mentioned eight factors، obtains the M value، which can estimate the amount of erosion and sediment yields of the area، using exponential formula between sediment yield and M values. In addition، in order to obtain the confidence of presented model، it was used in «Nir» catchment for evaluation the precision. The results showed 11 percent difference. With accepting of this error value، the water erosion hazard map of the area was provided and presented using new model.