ABSTRACT
The impacts of agricultural mechanization and soil management on sugarcane activity may compromise the growth of plants. This study aimed to evaluate the initial growth of sugarcane (Saccharum officinarum) at soil densities under two salinity conditions, associated with the least limiting water range (LLWR), and obtain the critical density for the Spodosol. The treatments consisted of the use of five bulk densities (1.40; 1.50; 1.60; 1.70 and 1.80 Mg m-3) and two conditions of soil salinity (ECse = 0.5 and 3.0 dS m-1). Morphological variables and biomass of sugarcane plants were measured and, simultaneously, undisturbed soil samples were collected in the layers of 0.02-0.08 m to determine the water retention curve, soil resistance to penetration and the least limiting water range. In general, it was concluded that sugarcane plants has higher growth between the bulk densities of 1.50 and 1.60 Mg m-3. The salinized soil showed higher LLWR than the non-salinized soil, leading to higher shoot fresh mass at bulk densities between 1.49 and 1.66 Mg m-3. The critical bulk densities observed for the Spodosol were 1.70 Mg m-3 for the non-salinized soil and 1.77 Mg m-3 for the salinized soil.
Key words:
Saccharum officinarum; soil compaction; soil resistance to root penetration; soil physical quality
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PH = -261.671 + 320.232**Bd - 98.985**Bd2 +0.798**DAP -0.263*Bd DAP R2 = 0.91*, ** - Significant at p ≤ 0.05 and p ≤ 0.01, respectively, by F test
** - Significant at p ≤ 0.01 by F test
** - Significant at p ≤ 0.01 by F test
θFC - volumetric water content at field capacity, m3 m-3; θPWP - volumetric water content at permanent wilting point, m3 m-3; θRP - volumetric water content of the soil at which the penetration resistance reaches 2.0 MPa; θAP - volumetric water content of the soil at which the aeration porosity is 0.10 m3 m-3; Dashed line indicates the critical bulk density (Bdc)