Water levels and defoliation frequencies on the behavior of Lotus corniculatus L.

Abstract

Birdsfoot trefoil (L.corniculatus L.) is affected by root-crown rot diseases and by summer water deficits. The objective of this work was to study the effect of two defoliation frequeny (F: frequent and A: sparse), under three levels of soil water stress (E0, E1 and E2), on the birdsfoot trefoil behavoir and water use. Without water deficit the A management yielded 46% more total forage than F. Plant persistence was affected only by water deficits. The response to A management on forage yield decreased as water stress increased. When water stress was more intense, the positive response of A management on the root growth characteristics was mantained but it could did not affect summer forage production. Therefore, at severe water stress the A management lost more water by evapotranspiration (ET) as a consequence of higher soil root density (2l.41cm/cm3 ). The water uptake rate per unit of root lenght resulted lower for A (23.3mg/cm.day), than F management rate (120.1mg/ cm.day).Despite its lower water loss by ET it had a higher water uptake rate because their low soil root density (0.61cm/cm3).