for optimum planning, utilization, and management of lands, recognition of spatial variability of soil properties is necessary. this research was conducted to evaluate spatial variability of soil properties in 5000 ha of arsenjan plain in fars province. for this purpose, soil salinity, ph, particle size percentage, sodium, potassium, and organic carbon (oc) were measured on a systematic squared...

Seed was collected from a sweetgum tree in Washington County, Miss., in the fall of 1964 and stored at 35° to 40° F. for 4 months. Prior to sowing, the seed was stratified moist for 30 days at the same temperature. About 4 inches of loose silt loam was placed in 4inch clay pots. The soil was settled by sprinkling lightly with water and then leveled. Fifty seeds were placed in each pot and cover...

B et te r C ro ps /V ol . 9 7 (2 01 3, N o. 4 ) Silicon is a major component of sand, silt and clay minerals. Because of this abundance, it typically has not been considered as a limiting factor in soil fertility. However numerous fi eld studies have shown that supplying crops with adequate plant-available Si can suppress plant disease, reduce insect attack, improve environmental stress toleran...

The models that were analyzed using FLAC version 4.0 (FLAC, 2000) are shown on Figure 5.1. The models have different soil types: loose silty sand with 20% fines content (Figures 5.1a and 5.1b), soft clay (Figure 5.1c), and silt (Figure 5.1d). Hence, the determination of the parameters is different for each model. The following sections discuss the determination of the parameters used in the ana...

Various soil texture schemes are in current use. These differ in the size ranges of their particle fractions. There is a need to establish simple methods to correlate these conventional schemes. Therefore I have defined closed-form exponential and power law functions to fit models to cumulative particle-size distribution data. I have tested the functions for their suitability (i) to represent c...