The effects of tillage systems on soil bulk density and penetrometer resistance of a sandy clay loam soil

Abstract

Standard triaxial compression tests were carried out on an agricultural sandy loam soil to assess the effect of soil dry bulk density and moisture content on soil mechanical properties, namely, cohesion, internal friction angle, Young's modulus of elasticity and Poisson's ratio. Regression analyses were performed to establish mathematical relationships for simulating the variation in these mechanical properties as a function of dry bulk density and moisture content. These relationships were developed for six typical field moisture contents ranging from 3 to 22% d.b., and various dry bulk density levels ranging from 1Á15 to 1Á82 Mg m À3. Results showed that all mechanical properties increased with dry bulk density, except the internal friction angle that was an independent property. Cohesion, Young's modulus of elasticity and Poisson's ratio decreased with moisture content, except that the Poisson's ratio increased after the moisture content exceeded 17% d.b. However, the internal friction angle was also independent of moisture content. The regression equations developed to relate the soil cohesion, Young's modulus of elasticity and Poisson's ratio with moisture content and dry bulk density were quite simple, and had high determination coefficients ranging from 0Á92 to 0Á96. The regression equations indicated that the three mechanical properties varied linearly with moisture content and non-linearly with dry bulk density. Quadratic relationships were detected for the variations in properties studied and dry bulk density. These equations may be used for prediction of the variation in the mechanical properties (except internal friction angle) of sandy loam soils for any combination of moisture content and dry bulk density. Establishing these equations can be considered an advantage from an economical point of view because of avoiding the need of carrying out the costly triaxial compression test. #

Hardpan and maize root distribution under conservation and conventional tillage in agro-ecological zone IIa, Zambia

“…6) is consistent with data presented by Steyn et al (1995), which showed higher penetration resistance in the top 20 cm of soils under minimum tillage, compared to conventional tillage. The current data are also consistent with Steyn et al (1995) in that the differences in penetration resistance between the tillage methods were not large enough to influence root growth significantly. The penetrometer measurements did not capture potential surface crusting.…”

Tillage and Irrigation Requirements of Sorghum (<i>Sorghum bicolor</i> L.) at Hamelmalo, Anseba Region of Eritrea

“…The effect was lowest in NT and RT plots and maximum in conventional tillage farmers practice (CTf) plots followed by CTm plots. Lower effects in NT and RT plots might be due to lesser degradation of organic matter compared to CTm and CTf plots [6] [27] [34]. Presence of high exchangeable Ca 2+ and Mg 2+ in soil ( Table 1) might have also contributed to formation of denser structure due to series of wetting and drying cycles before harvesting.…”

Analysis of Flora and Vegetation in Forest Road Slopes Along to Constructions Age

“…는 임도는 절성토 비탈면의 녹화에 시간이 오래 걸리는 문제가 심화되고 있으며 (Steyn and Tolmay, 1995) (Chun and Oh, 1993;Jung, 2001;Lee et al, 2003). …”