نتایج جستجو برای: soil depth

تعداد نتایج: 333035  

2016
Galibjon Sharipov Dimitris Paraforos Hans W. Griepentrog

In direct seeding systems, soil strength variability and crop residues increase the difficulty of seeding operation. Especially when trying to achieve uniform seeding depth that will result in reliable seed germination and plant emergence. An advanced improvement has been accomplished using direct seeding systems. However, some problems still exist in soil-machine interaction due to various rea...

2017

Subseasonal-to-seasonal (S2S) weather forecasting has improved in recent years, thanks partly to better representation of physical variables in models. For instance, realistic initializations of snow and soil moisture in models yield enhanced predictability on S2S time scales. Snow depth and soil moisture also mediate month-to-month persistence of near-surface air temperature. Here the role of ...

2010
Ramin Naghdi Majid Lotfalian Iraj Bagheri Aghil Moradmand Jalali

Nacrtak Extracting logs from stump to landings causes extensive damages to forest stand and soil. In this research two parcels adjacent to each other were selected in order to assess the effect of traditional and mechanized methods of logging on regeneration and soil compaction. A skid trail and a mule trail with similar longitudinal slope, skidding direction and total volume of extracted wood ...

2017
Huimei Wang Wenjie Wang Scott X. Chang

We currently have a poor understanding of how different soil sampling methods (pedogenetic horizon versus fixed-depth) influence the evaluation of soil properties. Here, 159 soil profiles were sampled from larch (Larix gmelinii) plantations in northeast China using both the pedogenetic horizon and fixed-depth sampling methods. Analysis of variance was used to determine how sampling method influ...

Journal: :ماشین های کشاورزی 0
احمد شریفی مالواجردی محمد یونسی الموتی احمد محسنی منش

soil compaction can occur as a result of a number of factors. one of the most important factors is soil response to pressures imposed by wheels and soil engaging tools. this research investigated the effect of tyre load and inflation pressure on soil compaction-related factors. these factors include rut width, rut depth, cone index and horizontal force in different layers of soil profile. in th...

2017
Craig Anderson Mike Beare Hannah L. Buckley Gavin Lear

In arable cropping systems, reduced or conservation tillage practices are linked with improved soil quality, C retention and higher microbial biomass, but most long-term studies rarely focus on depths greater than 15 cm nor allow comparison of microbial community responses to agricultural practices. We investigated microbial community structure in a long-term field trial (12-years, Lincoln, New...

Journal: :مرتع و آبخیزداری 0
پریا کمالی دانشجوی کارشناسی ارشد رشتة مرتع داری، دانشکدة منابع طبیعی دانشگاه تربیت مدرس رضا عرفانزاده استادیار گروه مرتع داری دانشکدة منابع طبیعی دانشگاه تربیت مدرس حسن قلیچ نیا استادیار پژوهشی مرکز تحقیقات کشاورزی و منابع طبیعی ساری

this study aimed to investigate the effect of animal grazing on soil seed bank characteristics in the northern slopes of alborz. for this purpose, soil seed bank characteristics were compared between grazed and ungrazed areas. therefore, four transects perpendicular to the sides of exclosure inside and outside of it were established. then soil samples were collected within 28 plots inside and 2...

2014
Bei-xiao Shi Cheng-feng Zheng Jin-kun Wu

Engineering problems shunned previously rise to the surface gradually with the activities of reforming the natural world in depth, the problem of expansive soil crack under the changing environment becoming a control factor of expansive soil slope stability. The problem of expansive soil crack has gradually become a research hotspot, elaborates the occurrence and development of cracks from the ...

2010
Whendee L. Silver Rebecca Ryals Valerie Eviner

Rangeland ecosystems cover approximately one-third of the land area in the United States and half of the land area of California. This large land area, coupled with the propensity of grasses to allocate a considerable proportion of their photosynthate belowground, leads to high soil carbon (C) sequestration potential. Annual grasslands typical of the Mediterranean climates of the western United...

2016
Yuanxin Liu Wenwu Zhao Lixin Wang Xiao Zhang Stefani Daryanto Xuening Fang Eric J. Jokela

Soil moisture scarcity has become the major limiting factor of vegetation restoration in the Loess Plateau of China. The aim of this study is: (i) to compare the spatial distribution of deep (up to 5 m) soil moisture content (SMC) beneath the introduced shrub Caragana korshinskii Kom. under different precipitation zones in the Loess Plateau and (ii) to investigate the impacts of environmental f...

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