Critical limits of the soil physical properties for cotton

Abstract

The objective of this study was to establish the relation between the soil physical properties and the cotton crop development in order to determine the critical limits. For this, an experiment was performed in a randomized block design in a dystrophic Red Oxisol typical of a clayey texture. The treatments consisted of five compaction states as a function of the different passages numbers of an agricultural tractor, with C0: no additional traffic; C1: one tractor passage; C2: three tractor passages; C3: six tractor passages and C4: eleven tractor passages. The soil physical properties, root distribution in its layers, vegetative and reproductive characteristics, and root anatomy were all evaluated. Cotton crop has been shown to be sensitive to compacted soils. Compaction promoted the arrangement of the soil solid particles, and it was possible to establish that the productivity is reduced with values of 0.26 m3 m-3, 0.27 m3 m-3 and 0.90 MPa of macroporosity, microporosity and soil resistance to penetration, respectively. Soil compaction causes changes in the root system, with a reduction in the explored volume and increased root diameter, reflecting a yield drop.