نتایج جستجو برای: soil ratio

تعداد نتایج: 674745  

Journal: :Ecology letters 2008
Robert L Sinsabaugh Christian L Lauber Michael N Weintraub Bony Ahmed Steven D Allison Chelsea Crenshaw Alexandra R Contosta Daniela Cusack Serita Frey Marcy E Gallo Tracy B Gartner Sarah E Hobbie Keri Holland Bonnie L Keeler Jennifer S Powers Martina Stursova Cristina Takacs-Vesbach Mark P Waldrop Matthew D Wallenstein Donald R Zak Lydia H Zeglin

Extracellular enzymes are the proximate agents of organic matter decomposition and measures of these activities can be used as indicators of microbial nutrient demand. We conducted a global-scale meta-analysis of the seven-most widely measured soil enzyme activities, using data from 40 ecosystems. The activities of beta-1,4-glucosidase, cellobiohydrolase, beta-1,4-N-acetylglucosaminidase and ph...

Journal: :علوم گیاهان زراعی ایران 0
محمدرضا چایی چی روزبه فرهودی ناصر مجنون حسینی غلامرضا ثواقبی

residue management has a direct impact on soil physical and chemical characteristics which in turn have identical effects on sustainability of crop production in agroecosystems. the effects of wheat residual management practices (burning, plowing under and removal) on soil physical and chemical characteristics were investigated in this research. treatments were compared in a complete block desi...

Journal: :Plant physiology 2017
Tino Colombi Norbert Kirchgessner Achim Walter Thomas Keller

Increased soil strength due to soil compaction or soil drying is a major limitation to root growth and crop productivity. Roots need to exert higher penetration force, resulting in increased penetration stress when elongating in soils of greater strength. This study aimed to quantify how the genotypic diversity of root tip geometry and root diameter influences root elongation under different le...

ژورنال: علوم آب و خاک 2021

The present study was intended to improve the chemical properties of a saline-sodic soil using the individual application of alfalfa residue and two biochars produced from sugarcane bagasse and walnut shell, at the weighting ratio of 5%; their concomitant application with gypsum, aluminum sulfate and the mixture of these two chemical amendments was considered. The experiment was conducted in th...

ژورنال: علوم آب و خاک 2017

Soil organic matter is the largest source of organic carbon in the soil surface which played an enormous role in restoring balance, environmental sustainability, soil elements and climatic conditions. Organic materials influence physical, chemical and biological properties of soil and thus soil fertility directly and indirectly. The amount, type and composition of organic matter are different i...

2002
A. J. Franzluebbers

Soil quality is a concept based on the premise that management can deteriorate, stabilize, or improve soil ecosystem functions. It is hypothesized that the degree of stratification of soil organic C and N pools with soil depth, expressed as a ratio, could indicate soil quality or soil ecosystem functioning, because surface organic matter is essential to erosion control, water infiltration, and ...

2011
Yuanhe Yang Yiqi Luo

Results The C : N ratio in plant tissue, litter, forest floor and mineral soil exhibited large variation across various sequences, with an average of 145.8 9.4 (mean SE), 49.9 3.0, 38.2 3.1 and 18.5 0.9, respectively. In most sequences, the plant tissue C : N ratio increased significantly with stand age, while the C : N ratio in litter, forest floor and mineral soil remained relatively constant...

2016
Ahmed M. Eltohamy

In this paper, an experimental and numerical study was adopted to investigate the effect geogrid soil reinforcement prestressing on the pressure settlement relation of sand bed supporting a strip foundation. The studied parameters include foundation depth and pre-stress ratio for the cases of one and two pre-stressed reinforcement layers. The study reflected that pre-stressing of soil reinforce...

Journal: :Environmental pollution 2002
A J Franzluebbers J A Stuedemann

Pasture management can be effective at sequestering soil organic C. We determined the depth distribution of particulate organic C (POC), non-particulate organic C (NPOC), particulate-to-total organic C (POC-to-TOC) ratio, and particulate organic C-to-N (POC-to-N) ratio under pastures near Watkinsville, GA, USA. POC was highly related with total organic C (TOC), but became an increasingly larger...

2010
Robert A. Patterson

Septic tank effluent is inherently high in sodium ions relative to divalent cations (high sodium adsorption ratio). The disposal of septic tank effluent to the soil will cause the sodium ions to disperse the clay colloids, resulting in a physical blocking of the soil pores. Hydraulic conductivity will be reduced and the effluent will fail to dissipate into the soil profile. In designing the dis...

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