Soil samples from the Jakara irrigation project site were evaluated with respect to possible degradation caused by irrigation. Most of the soils were neutral to alkaline with pH values ranging between 6.58 + 0.04 and 10.45 + 0.03. The electrical conductivity ranged from 0.3 + 0.01 to 75.2 + 0.06 dSm-1 which implies low to very high salinity. The concentrations of the exchangeable cations in the...

For 5 yr we monitored the fertility of a volcanic-ash derived Inceptisol at a site in the humid tropics of Costa Rica. After forest felling and burning, we established four treatments in a randomized block design with six blocks: a sequence of monocultures (two crops of maize [Zea mays] followed by cassava [Manihot esculenta], then the tree species Cordia alliodora), successional vegetation, a ...

Leaf lifespan varies widely among plant species, from a few weeks to >40 years. This variation is associated with differences in plant form and function, and the distribution of species along resource gradients. Longer leaf lifespans increase the residence time of nutrients and are one mechanism by which plants conserve nutrients; consequently, leaf lifespan should increase within species with ...

One of the most important micro engineers of the terrestrial ecosystems, especially in the arid areas is the harvester ants due to their activity in the soil through nest building; they can make major changes while influencing the surface and subsurface in the rangeland soil. The purpose of this study was to investigate the effects of harvester ants (Messor spp.) on some soil properties in Rood...

This paper aims to study the influence of soil-structure interaction on plastic energy demand spectra directly derived from the energy-balance equations of soil-shallow-foundation structure with respect to an ensemble of far-field strong ground motions obtained from Pacific Earthquake Engineering Research (PEER) database and recorded on alluvium soil. The superstructure is modeled as a single-d...

Beans require adequate amounts of all essential plant nutrients for optimum growth but only a few nutrients are documented to be needed for southern Idaho soils. These nutrients include phosphorus (P), nitrogen (N), zinc (Zn), potassium (K), sulfur (S), and to a much less extent B, Cu, Mn and Fe. University of Idaho Agricultural Experiment Station research as well as research from throughout th...

In the present study, a biofertilizer on the basis of Streptomyces fumanus gn-2 was used for the treatment of wheat and soybean seeds (dose 104 spore/ml) before planting them in soil with low fertility in order to determine the effect of this biological agent on germination rate; the growth of seedlings, shoots, and the maturation phase of plants; the rhizosphere’s functional biodiversity; and ...