––The performance of pavements depends to a large extent on the strength and stiffness of the subgrades. Subgrade strength (CBR) plays a major role in pavement design. Since determination of CBR value in field requires need of equipment and also time consuming alternatively one can be predict CBR value of subgrade in field from other soil support tests namely Dynamic Cone Penetrometer Index (DC...

We quantify mechanical processes common to soil penetration by earthworms and growing plant roots, including the energetic requirements for soil plastic displacement. The basic mechanical model considers cavity expansion into a plastic wet soil involving wedging by root tips or earthworms via cone-like penetration followed by cavity expansion due to pressurized earthworm hydroskeleton or root r...

We prove a number of results on the geometric complexity of special Lagrangian (SLG) T -cones in C. Every SLG T -cone has a fundamental integer invariant, its spectral curve genus. We prove that the spectral curve genus of an SLG T -cone gives a lower bound for its geometric complexity, i.e. the area, the stability index and the Legendrian index of any SLG T -cone are all bounded below by expli...

Soil compactibility which basically depends on soil texture, organic matter and soil water content during farm machinery traf®cking are major factors affecting soil conservation. In a ®eld experiment, cattle farmyard manure was applied to a silty clay loam soil (®ne-loamy, mixed, thermic Typic Haplargids, USDA; Calcaric Cambisols, FAO) in Isfahan, Iran. Three rates, 0, 50, 100 Mg haÿ1 (on oven ...

Dry density and water content are two important factors affecting the degree of soil compaction. Conventional methods such as the sand cone test and the plate load test are used to measure such properties for evaluating the degree of compaction and the stiffness of soil in the field. However, these tests are generally very time-consuming and are inherent with some errors depending on the operat...

crop yields are dependent on a number of factors such as soil type, weather conditions and farming practices. crop yield estimates in different soil types are required to meet the needs of farmers, land appraisers, and governmental agencies in iran as around the world. this study was conducted to model the wheat-grain yields [triticum aestivum l.]  by soil properties in khoy area, the north-wes...

Tractive efficiency is essential in tillage operations to optimise traction performance. In this field experiment, the tractor performance was measured under different resistance conditions. This study quantified soil stress, bulk density, moisture, cone index, surface disturbance, rolling and slip rate numbers of passes The actual power used conditions collected. Fuel consumption savings were ...

The purpose of this research was to developed a program in visual basic software for predicting tractor implement performance combination. A conventional tillage system with mounted mouldboard plough and three bottoms used collect data from Chery (Model RM750) four-wheel drive. soil texture class were determined laboratory. Soil cone index value measured using SpotOn digital compaction meter. o...