Fun？？es de pedotransferência para as curvas de reten？？o de água e de resistência do solo à penetra？？o em sistemas de manejo com plantas de cobertura permanente em citros

the soil quality in management systems can be assessed by simple indicators or pedrotransfer functions. this study was aimed at obtaining pedotransfer function (ptf's) such as the soil water retention curve (swrc) and the soil resistance to penetration curve (srpc), under interrows groundcover management systems of the 'pêra' orange. three treatments were evaluated: bahiagrass mowed paspalum notatum, perennial peanut arachis pintoi and spontaneous vegetation with herbicide, in a typic paleudult, northwestern paraná, brazil. in may 2003, two hundred and sixteen undisturbed soil samples were collected under beneath and between the whell tracks at 0.05-0.10m depth. soil bulk density (db), organic carbon (oc), water content and soil resistance to penetration (pr) were determined to fit the swrc and srpc in differents water potential. the db and oc contributed to fit the swrc and srpc under groundcover management systems in the interrows. ptf's were depended db, oc and treatment to fit swrc (r2=0.94) and srpc (r2=0.87). management on spontaneous vegetation using herbicide enhance soil compaction, decrease water retention and increase pr. perennial peanut decrease soil water retention and increase pr, and bahiagrass groundcover enhance the soil physical and hydarulic quality in the interrows. alternatively, ptf's required only to the determinations of the water content and db to the srpc and swrc.