Micromorphometric analysis of porosity changes in the surface crusts of three soils in the Piracicaba region, São Paulo State, Brazil

The aim of this study was to micromorphologically analyze modifications in soil porosity due to the occurrence of erosive rainfall events. Three types of soils, Typic Hapludox, Typic Hapludult and Rhodic Kandiudalf, were analyzed to determine their total porosity and the distribution and number of pores. The soils were tilled with a heavy disk and leveling harrow to ensure homogeneity of surface conditions at the beginning of the trial period and to simulate cropping conditions. The soils were kept uncovered during the trial period, and rainfall events with intensities greater than 25 mm h-1were recorded. The results showed that all of the soils presented crust formation, influenced by the soil texture. NVef showed significant changes in total porosity, pore numbers and pore morphology, while LVAd and PVAd did not display marked modifications in these attributes.本研究旨在通过微观形态学分析，探究侵蚀性降雨事件引发的土壤孔隙度变化。本研究选取典型强发育湿润老成土（Typic Hapludox）、典型弱发育湿润老成土（Typic Hapludult）与红化强发育湿润干润淋溶土（Rhodic Kandiudalf）三种供试土壤，测定其总孔隙度、孔隙分布及孔隙数量。试验初期，采用重型圆盘耙与平地耙对供试土壤进行耕作处理，以保证地表条件均一，并模拟大田耕作环境。试验期间，供试土壤全程保持裸露状态，并记录强度大于25 mm·h⁻¹的降雨事件。结果表明，所有供试土壤均出现结皮现象，且该现象受土壤质地影响。其中NVef的总孔隙度、孔隙数量及孔隙形态均发生显著变化，而LVAd与PVAd在上述指标上未出现明显改变。