Soil compaction is one of the forms of physical change of soil structure which has positive and negative effects, in agriculture considered to make soil degradation. The undisciplined use of heavy load traffic or machinery in modern agriculture causes substantial soil compaction, counteracted by soil tillage that loosens the soil. Higher soil bulk densities affect resistance to root penetration, soil pore volume and permeability to air, and thus, finally the pore space habitable for soil organisms. In contrarily for some soils, controlled soil compaction can improve the water holding capacity. Through a combination of these factors, soil compaction will affect crop growth. Soil compaction reduces total pore space of a soil and makes water and air flow through soil more difficult. Low soil oxygen levels caused by soil compaction are the primary factor limiting plant growth. Rectifying compacted soil is very costly process and involves again the use of machinery. Precision agriculture is a farming management concept based on observing and responding to intra-field variations. Precision agriculture is proven to be successful and very cost effective in fertilizer and planting/seeding application rates and, another promising area could be in the primary tillage operations leading to irrigation management.

  

In this research conducted under arid-zone crop cultivation in Oman, a penetrologger was used to measure soil penetration resistance and moisture contents in a selected farm field plots grown with Rhoades Grass and Sweet Corn. The main objective of this study was to investigate the effects of soil compaction level due to vehicle traffic indicated in the cone penetration resistance and irrigation patterns on the growth of grass and corn grown. The selected field plot area was approximately 1.8 ha. Based on the layout of the sprinkle irrigation system used, the field was subdivided into 84 subplots (each 12×12 m). One control condition and six compaction treatments were given to filed strips (24×12 m)  having three replications from each arranged under randomized block design. The penetrologger device utilized in the experiments recorded GPS and moisture content readings simultaneously. The experiments were conducted for more than two years, completing three corn crops and seven grass crops. The results were analyzed and used for planning irrigation applications and tillage management.

The mapping of soil compaction levels and  moisture status were successfully done through integrating data obtained into GIS maps. Result indicated that there was a trend for significant reduction in the growth of Rhoades grass in areas of higher soil compaction level due to traffic. In part of the field a hard pan (penetration resistance higher than 5 MPa) was clearly visible at 6-10 cm depth soil layer. Water logging observed on the fields was correlated with high soil compaction at the soil surface layer (1-5 cm deep). However, significant correlation could not be obtained for corn due to the fact that deeper root zone, soil type and other climatic factors specific to the country. Based on the result of this study, operational costs, schedules for tillage management practices could be optimized.