This research is a study on the relationship of irrigation water treatments and soil moisture distribution uniformity (DU). Soil moisture distribution was based on long-term data sets that were collected during wet and dry soil conditions (from permanent wilting point to field capacity) using a novel electromagnetic sensor-based platform moving inside subsurface horizontal access-tubes. The irr...

Analysis of heavy metals in top soil samples from Nzoia sugarcane farms in Western Kenya found elevated levels of heavy metals in the soils with mean concentrations (mg kg⁻¹ dry weight) of 142.38, 59.12, 73.35, 116.27, 409.84 (dry season) and 144.22, 50.29, 72.14, 158.81, 368.83 (wet season) for Cr, Pb, Cu, Zn and Fe, respectively, compared with a control soil sample from an adjacent field wher...

How soil microbes assimilate carbon-C, nitrogen-N, phosphorus-P, and sulfur-S is fundamental for understanding nutrient cycling in terrestrial ecosystems. We compiled a global database of C, N, P, and S concentrations in soils and microbes and developed relationships between them by using a power function model. The C:N:P:S was estimated to be 287:17:1:0.8 for soils, and 42:6:1:0.4 for microbes...

-Compaction is one of the efficient ways to improve the strength and stiffness properties of soils, such as elasticity modulus and shear modulus. Moreover, compaction decreases soil settlement, improves bearing capacity and the stability of sloped embankments. An optimum water content is required to provide the best path to enter energy into soil and compact it. A constant value of energy appli...

Vertical wind shear and concentration gradients of viable, airborne bacteria were used to calculate the upward flux of viable cells above bare soil and canopies of several crops. Concentrations at soil or canopy height varied from 46 colony-forming units per m over young corn and wet soil to 663 colony-forming units per m over dry soil and 6,500 colony-forming units per m over a closed wheat ca...

We studied controls on nitrification in an undisturbed water-limited ecosystem by inhibiting autotrophic nitrifying bacteria in soils with varying levels of vegetative cover. The activity of nitrifying bacteria was disrupted using nitrapyrin, 2-chloro-6-(trichloromethyl)-pyridine, under field conditions in three microenvironments (underneath shrubs, next to grasses and in bare soil). Ammonia-ox...

Three terrestrial plant species, oat (Avena sativa ), Chinese cabbage (Brassica campestris cv. chinensis) and lettuce (Lactuca sativa), were exposed to different concentrations of herbicide TCA (sodium trichloroacetate) in a growth test according to guideline OECD # 208. Classical (i.e. germination and biomass) and biochemical (i.e., antioxydant enzyme activities) endpoints were investigated. G...

The effect of barriers of dry soil on the ability of Formosan subterranean termites, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), to construct tunnels and find food was evaluated. Termite movement and wood consumption in a three-chambered apparatus were compared between treatments with dry soil in the center container and treatments where the soil in the center container was mois...

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...

Soil thermal conductivity is significantly influenced by saturation and dry density. In this paper, a family of empirical correlations are presented which relate soil thermal conductivity to saturation for five soil types, namely, gravel, sand, silt, clay and peat, in both the frozen and unfrozen states. These correlations were developed from a soil thermal conductivity database which was const...