Characterization of soil properties is a key step in understanding the source of spatial variability in the productivity across agricultural fields. A study on a 16 ha field located in the eastern region of Saudi Arabia was undertaken to investigate the spatial variability of selected soil properties, such as soil compaction ‘SC’, electrical conductivity ‘EC’, pH (acidity or alkalinity of soil) and soil texture and its impact on the productivity of Rhodes grass ( Chloris gayana L.). The productivity of Rhodes grass was investigated using the Cumulative Normalized Difference Vegetation Index (CNDVI), which was determined from Landsat-8 (OLI) images. The statistical analysis showed high spatial variability across the experimental field based on SC, clay and silt; indicated by values of the coefficient of variation (CV) of 22.08%, 21.89% and 21.02%, respectively. However, low to very low variability was observed for soil EC, sand and pH; with CV values of 13.94%, 7.20% and 0.53%, respectively. Results of the CNDVI of two successive harvests showed a relatively similar trend of Rhodes grass productivity across the experimental area ( r = 0.74, p = 0.0001).

Soil physicochemical layers of a considerable spatial variability (SC, clay, silt and EC) were utilized to delineate the experimental field into three management zones (MZ-1, MZ-2 and MZ-3); which covered 30.23%, 33.85% and 35.92% of the total area, respectively. The results of CNDVI indicated that the MZ-1 was the most productive zone, as its major areas of 50.28% and 45.09% were occupied by the highest CNDVI classes of 0.97–1.08 and 4.26–4.72, for the first and second harvests, respectively. 1. Introduction Farming systems have various types of soils, habitats, microclimatic features, and crop varieties, which result in wide variations in soil fertility, water retention and crop productivity (). Crop yield variability can be caused by many factors, including spatial variability of soil type, landscape position, crop history, soil physical and chemical properties and nutrient availability (). Understanding the spatial variability of soil physicochemical characteristics, in both its static (e.g. Texture and mineralogy) and dynamic (e.g.

Water content, compaction, electrical conductivity and carbon content) forms is necessary for site-specific management of agricultural practices, as it is directly contributing to variability in crop yields and quality (, ). Site-specific practices could help significantly in managing the spatial variability in the productivity of agricultural soils by tailoring the agricultural inputs to fit the spatial requirements of soil and crop (). Spatial variations of soil properties across agricultural fields have been reported by many scientists as a major source of variability in crop yields (). Therefore, determination of the major sources of variation in productivity is a key parameter in achieving efficient site-specific management practices (). Variability in agricultural soils is a function of both soil structure and the imposed management practices for crop production (). Corporate Seal Stamp Template Designs.

Soil Physicochemical properties that are important in crop production are characterized as those that directly affect crop growth, such as water, oxygen, temperature and soil resistance, and others, such as bulk density, texture, aggregation and pore size distribution, that indirectly affect crop growth (). Pavement Wowee Zowee Sordid Sentinels Edition Rar more. Soil compaction risk occurs when soil density reaches a critical value, beyond which soil performance is affected considerably.

Magicdraw 16 6 Keygen Download. Such critical soil densities are different for different crops in different soils and different climatic regions (). Soil compaction negatively affects essential soil properties and functions, such as hydraulic properties and gas-phase transport or root growth; hence, it is associated with various environmental and agronomic problems, such as erosion, leaching of agrochemicals to water bodies, emissions of greenhouse gases and crop yield losses (). The susceptibility of agricultural soils to soil compaction depends mainly on soil type and moisture status. In general, for moist soils, soil compaction increases with the decrease in soil particle size (). Spectral vegetation indices are being successfully used as effective measures of vegetation activity and are considered as useful parameters to characterize differences in crop canopy characteristics; hence, for the assessment of spatial variability in agricultural fields (, ). The Normalized Difference Vegetation Index (NDVI) is considered by many scientists and researchers as one of the most important vegetation indices utilized for the prediction of crop production, because of its strong relationship with crop yield (,,, ).