نتایج جستجو برای: soil sampling was done from 0
تعداد نتایج: 7793518 فیلتر نتایج به سال:
some of arid regions problems of iran are saline and sodic soils. in improvement and reclamation of iranian arid rangelands, some foreign species of atriplex had been imported and adapted for many years ago. the most adapted species was atriplex canescens. at the present research, some environmental factors, vegetative characteristics (na, ca, mg and k), soil properties (moisture, ec, ph, solut...
Miller, Richard E.; Hazard, John; Howes, Steven. 2001. Precision, accuracy, and efficiency of four tools for measuring soil bulk density or strength. Res. Pap. PNWRP-532. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 16 p. Monitoring soil compaction is time consuming. A desire for speed and lower costs, however, must be balanced with the appro...
β-glucosidase (E.C. 3.2.1.21), an enzyme involved in cellulose degradation, plays an important role in the soil organic carbon cycle. Cellulose is the most abundant organic compound in the biosphere so a product of its enzymatic hydrolysis is important as an energy source for soil microorganisms. Since β-glucosidase is very sensitive to different factors, determination of its activity might be ...
the purpose of this study was to examine the english language needs of medical students at tehran university of medical sciences . analysis of the needs took place for three groups: 320 undergraduate students, 30 postgraduate students and 20 university instructors. a triangulation approach to collect data was used in which a combination of the quantitative (using the questionnaires) and qualita...
Water soluble anionic polyacrylamide (PAM) is a highly effective erosion preventing and infiltration enhancing polymer, when applied at rates of 1–10 g m 3 in furrow irrigation water. PAM greatly reduces sediment, nutrients, pesticides and coliform bacteria in irrigation runoff. There has been some concern about the potential for PAM accumulation to affect microbial ecology. We ran a long-term ...
The depth of sampling is an important factor for evaluating soil stability. The objective of this study was to test soil aggregate particle-size fractions and soil organic carbon (SOC) in water-stable aggregate by vegetation restoration through 0–60 cm soil profile. We collected soil samples in 30 years old Robinia psendoacacia (Rr); Platycladus orientalis (Po); Pinus tabulaeformis (Pt); abando...
Objective: Soil organic carbon has been the most important soil quality measurement factors and has intense relation with soil physical, chemical and biological characteristics. Organic matter and its components are important factors of soil aggregates constitution and stability and play significant role in its structure. So, this research has been done for achieving this purpose. Methods: This...
this study was intended to analyze the listening tapescripts of the elementary and pre-intermediate levels of total english textbooks from the pragmatic dimension of language functions and speech acts in order to see whether the listening tasks are pragmatically informative or not. for this purpose, 8 conversations from the two books were selected randomly, and then, the two pragmatic models of...
this study attempts to investigate the effect of peers’ revision in comparison to that of the teacher, and whether peers’ comments and teachers’ comments facilitate students’ revision? if yes, which one is more effective? also attempts have been made to see which aspects of language are more highlighted by peers versus teachers when commenting. besides, it is investigating the student’s attitud...
A strategy for sampling soil from intact monolith lysimeters was established based on measurements of spatial heterogeneity within the lysimeter area. This was part of an ongoing study to determine relationships between soil microbial diversity and nutrient loss by leaching. The sampling protocol had to allow for collection of soil on a regular basis (as opposed to destructive sampling) and ens...
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