Soil moisture is a key state variable of the hydrologic cycle. It plays a significant role in many hydrological, meteorological and other natural processes in the land-atmosphere continuum. In the past two decades we have conducted several field campaigns to better understand the underlying processes controlling the spatio-temporal variations of soil moisture using multiple ground, air, and spa...

This study demonstrates the spatial and temporal variations of streambed vertical hydraulic conductivity Kv from October 2011 to November 2014 along the Weihe River, the largest tributary of the Yellow River. The streambed Kv values of a total number of 385 locations from five test sites were estimated on the basis of in situ falling-head standpipe permeameter tests. The difference of Kv values...

The microbial community structure in various microaggregates in a loamy sand soil was investigated. The microaggregates were separated into outer and inner aggregates using a series of soil washes. Further physical fractionation of inner aggregates was achieved by separation into coarse and fine sand as macroaggregate fractions, coarse and fine silt as microaggregate fractions, and clay. Resear...

Methods to predict soil hydraulic properties frequently require information on the particle size distribution (PSD). The objectives of this study were to investigate various protocols for rapidly measuring PSD using the laser diffraction technique, compare the obtained PSD with those determined using the traditional hydrometer-and-sieves method (HSM), and assess the accuracy of soil hydraulic p...

forests are an important economic source for human and have key role in nutrient cycle, hydrology and ecosystem performance, any interference in this vital ecosystem causes to damage to forests. mechanical logging and road construction in forest areas have led to much soil compaction. soil physical and chemical properties were studied in parts of road and non-road in the darabkola forest of ira...

The objectives of this research were to: (i) develop hyperspectral narrow-band models to determine soil variables such as organic matter content (OM), sum of cations (SC = Ca + Mg + K), aluminum saturation (m%), cations saturation (V%), cations exchangeable capacity (CEC), silt, sand and clay content using visible-near infrared (Vis-NIR) diffuse reflectance spectra; (ii) compare the variations ...

Mathematical descriptions of classical particle size distribution (PSD) data are often used to estimate soil hydraulic properties. Laser diffraction methods (LDM) now provide more detailed PSD measurements, but deriving a function to characterize the entire range of particle sizes is a major challenge. The aim of this study was to compare the performance of eighteen PSD functions for fitting LD...

The erosion threshold, beyond which bed sediments start to move, is a key parameter describing sediment transport processes. For silt-dominated mixtures, in the grain size between sand and clay, existing experimental studies exhibit contradictory observations. That is, was either sand-like or clay-like, suggesting transitional behavior. To explore underlying mechanism of behavior silt-sized sed...

nineteen irrigated farms of canola from six cities of khorasan selected to assess the seedling emergence one month after sowing in 2009. soil texture of each farm determined using the hydrometer method. the results showed that weather conditions of sowing areas had no significant effect on emergence of oilseed rape. with increasing the temperature (within the range of 19.5 to 21.5 ˚c) emergence...