Predawn plant water potential (Psi(w)) is used to estimate soil moisture available to plants because plants are expected to equilibrate with the root-zone Psi(w). Although this equilibrium assumption provides the basis for interpreting many physiological and ecological parameters, much work suggests predawn plant Psi(w) is often more negative than root-zone soil Psi(w). For many halophytes even...

One of the main European agricultural problems is the decline in soil fertility due to the reduction of the natural soil harmony. When natural soil composition is altered, few cultivated plants replace spontaneous populations of numerous species. Man becomes the only regulator of a new fragile equilibrium between the simplified biocenosis elements. Agronomic techniques (fertilisation, irrigatio...

Scientific and policy interest in the biological diversity of agriculture (agrobiodiversity) is expanding amid global socioeconomic and environmental changes and sustainability interests. The majority of global agrobiodiversity is produced in smallholder food-growing. We use meta-analyses in an integrated framework to examine the interactions of smallholder agrobiodiversity with: (1) livelihood...

The comparative effects of different concentrations of saline soil and saline irrigation water were investigated on growth of canola (cv. Ganyou-5). Plants were subjected to control (non-saline), 0.2% (EC 2.5 dS.m-1), 0.4% (EC 4.5 dS.m-1) and 0.6% (EC 6.5 dS.m-1) of sea salt concentrations in soil as well as saline irrigation water. Vegetative growth parameters recorded were plant height, numbe...

Mechanical mastication is increasingly prescribed for wildfire mitigation, yet little is known about the ecological impacts of this fuels treatment. Mastication shreds trees into woodchips as an alternative to tree thinning and burning the resulting slash, which can create soil disturbances that favor exotic plants. Previous research on mastication has not simultaneously considered both the res...

Determination of the pile capacity is always a major concern for the safe geotechnical engineering design. Different direct and indirect methods have been proposed for determining pile bearing capacity such as static and dynamic approaches. Each method depends on the condition of the soil and type of pile as well as accessibility to necessary information. In this study bearing capacity of drive...

We evaluated the effects of livestock grazing on C content of the plant-soil system (to 60 cm) of two semi-arid grasslands: a mixed-grass prairie (grazed 12 years), and a short-grass steppe (grazed 56 years). Grazing treatments included season-long grazing at heavy and light stocking rates, and non-grazed exclosures. Significantly higher soil C (0-30cm) was measured in grazed pastures compared ...

We used a continuous labeling method of naturally C-depleted CO2 in a growth chamber to test for rhizosphere effects on soil organic matter (SOM) decomposition. Two C3 plant species, soybean (Glycine max) and sunflower (Helianthus annus), were grown in two previously differently managed soils, an organically farmed soil and a soil from an annual grassland. We maintained a constant atmospheric C...

It is well established that plant species influence ecosystem processes, but we have little ability to predict which vegetation changes will alter ecosystems, or how the effects of a given species might vary seasonally. We established monocultures of eight plant species in a California grassland in order to determine the plant traits that account for species impacts on nitrogen and phosphorus c...

The magnitude and direction of water transport by the roots of eight dominant Brazilian savanna (Cerrado) woody species were determined with a heat pulse system that allowed bidirectional measurements of sap flow. The patterns of sap flow observed during the dry season in species with dimorphic root systems were consistent with the occurrence of hydraulic redistribution of soil water, the movem...