نتایج جستجو برای: soil penetration resistances

تعداد نتایج: 220610  

2017
Jean-François Ponge

Observed on a 5 x 5 cm small surface of litter in a 35-years-old Scots pine stand with bracken and the moss Pseudoscleropodium purum, the F1 layer is extensively invaded by a mycelial mat made of several mycorrhizal fungi. Observations under a light microscope gave circumstantial evidence of the role of these fungi in advanced stages of decomposition: they seem to protect the partly decayed pla...

2002
Wallace Wilhelm L. N. Mielke C. R. Fenster W. W. Wilhelm

Tillage practices can influence crop root development. Root distributions were determined for wheat (Tdicum aestivum L.) grown in a wheat-fallow rotation during the 1977-1978 winter wheat crop year on an Alliance silt loam (Aridic Argiustoll). The fallow tillage treatments were plow, subtillage, and chemical (no tillage). Each tillage treatment was split into subplots for N application of 0 or ...

2007
R. Giraldo P. Delicado J. Mateu

We present a methodology to perform spatial prediction when measured data are curves. In particular, we propose both an estimator of the spatial correlation and a functional kriging predictor. We adapt an optimization criterium used in multivariable spatial prediction in order to estimate the kriging parameters. A real data example on soil penetration resistences illustrates our proposals.

2013
D. Yanase A. Andoh M. Chiba S. Yoshida

Five photosynthesis inhibiting herbicides were com pared for their mobility in soil colum ns used as the penetration m odel. The vertical m ovem ent o f these com pounds in soil was an a ­ lyzed by a newly developed technique in which herbicide distribution was determ ined by the intensity o f chlorophyll fluorescence in Chlorella cells suspended in aqueous extracts o f soil samples from variou...

Journal: :تحقیقات مهندسی کشاورزی 0
مجتبی نادری بلداجی دانشجوی دکتری پردیس کشاورزی و منابع طبیعی دانشگاه تهران رضا علیمردانی استاد دانشکده مهندسی بیوسیستم پردیس کشاورزی و منابع طبیعی دانشگاه تهران احمد طباطبایی فر استاد دانشکده مهندسی بیوسیستم پردیس کشاورزی و منابع طبیعی دانشگاه تهران احمد شریفی استادیار پژوهش مؤسسه تحقیقات فنی و مهندسی کشاورزی

soil compaction is an important aspect of agriculture and different methods are available to measure this parameter. one method is called the cone index; measuring the force required per unit area for penetration of a standard steel cone into the ground. cone penetrometers are used for cone index measurement. in this study, a tractor mounted, hydraulically-operated penetrometer was designed, bu...

2017
Yosuke Yanai Yukiyoshi Iwata Tomoyoshi Hirota

On-farm soil frost control has been used for the management of volunteer potatoes (Solanum tuberosum L.), a serious weed problem caused by climate change, in northern Japan. Deep soil frost penetration is necessary for the effective eradication of unharvested small potato tubers; however, this process can delay soil thaw and increase soil wetting in spring, thereby delaying agricultural activit...

2010
TUSHAR SINHA KEITH A. CHERKAUER VIMAL MISHRA

The present study examines the effects of historic climate variability on cold-season processes, including soil temperature, frost depth, and the number of frost days and freeze–thaw cycles. Considering the importance of spatial and temporal variability in cold-season processes, the study was conducted in the midwestern United States using both observations and model simulations. Model simulati...

2012
Endla Reintam Jaan Kuht

Soil compaction first affects physical properties, as compaction occurs when soil particles are pressed together, reducing pore space between them and increasing the soil bulk density (Lipiec & Hatano, 2003; Raper, 2005; Reintam, 2006; Reintam et al., 2009). Soil compaction also influences chemical and biological processes, such as decreasing organic carbon (C) and N mineralization, the concent...

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