جستجوی مقالات مرتبط با کلیدواژه « nirs » در نشریات گروه « آبخیزداری، بیابان، محیط زیست، مرتع »

Information on forage quality could help rangeland managers to select suitable grazing method to achieve higher animal performance without damage to vegetation. The aim of this study was to determine and compare the forage quality of S. yazdiana and S. tomentosa, which are the most important species of saline rangelands in Ardakan in Yazd province, Iran. These two species are grazed by goats and camels. The edible biomass of both species was sampled in three phenological stages during 2015-2016. Forage quality indices such as Crude Protein (CP), Dry Matter Digestibility (DMD), Metabolizable Energy (ME), Acid Detergent Fiber (ADF), Crude Fiber (CF), and Water Soluble Carbohydrate (WSC) were measured using Near Infrared Spectroscopy (NIRS). Data were analyzed using a factorial experiment in a completely randomized design. Means comparison was conducted using Duncan's Multiple Range test. According to the results, phenological stages showed significant differences for DMD, CP, WSC, ASH, ADF (P<0.01) CF and ME (P<0.05). Moreover, results showed significant differences between species for DMD, WSC, ASH, ADF (P<0.01) and CP (P<0.05). However, interactions (species × stage) showed significant differences only for DMD and ASH (P<0.05). In both species, forage quality based on positive indicators such as DMD (72.83, 63.91), CP (11.18, 10.12), and ME (7.7, 7.44) for both S. yazdiana and S. tomentosa had the highest values at the vegetative stage. By the progress of growth stages in both species, these indices were decreased. In comparison, S. tomentosa had higher forage quality than that of S. yazdiana. Although the grazing season for goat and camel in these rangelands is in fall and winter, the suitable time for grazing by these livestock is the late winter and early spring at the vegetative stage. Thus, by considering the grazing time of goat and camel from these species, supplementary feeding is required.

Chemical assessments of forage clearly determine the forage quality; however, traditional methods of analysis are somehow time consuming, costly, and technically demanding. Near Infrared Reflectance Spectroscopy (NIRS) has been reported as a method for evaluating chemical composition of agriculture products, food, and forage and has several advantages over chemical analyses such as conducting cost-effective and rapid analyses with non-destructive sampling and small number of samples. This study aims to estimate Nitrogen (N) and Acid Detergent Fiber (ADF) content of grass species using NIRS.A total of 171 samples of grasses (Poaceae) at vegetative, flowering, and seeding stages were collected from different regions in Iran. The samples were scanned in a NIRS DA 7200 (Perten instruments, Sweden) in a range of 950-1650 nm. The sample set consisted of 110 samples for calibration and 61 samples for validation was used to predict N and ADF. Samples were previously analyzed chemically for Nitrogen (N) and Acid Detergent Fiber (ADF) and then were scanned by NIRS. Calibration models between chemical data and NIRS were developed using partial least squares regression with the internal cross validation. The coefficients of determination (r2) of linear regression between chemical analyses and NIRS were 0.90 and 0.94 for N and ADF, respectively. The standard errors of prediction were 0.30% and 3.10% for N and ADF, respectively. The results achieved from this study indicated that NIRS has a potential to be used in the measurement of N and ADF contents regarding the forage samples.