| Popis: |
Aims This study evaluated the optimal herbage level from both plant and animal perspectives, through the adjustment of instantaneous herbage accumulation rate as estimed by the Gompertz curve model and short-term intake rate of sheep. Schedonorus arundinaceus (tall fescue) was used as an experimental model. Methods Weekly tall fescue herbage accumulation was measured during seven growth periods initiated on monthly intervals (October, November, and December 2015, and March, April, August and September 2016) with the initiation dates arranged in a randomized complete block design with four replicates. Total herbage mass, leaf lamina mass, pseudo-stem + sheath mass, senescent mass, and sward surface height were measured each week. Results We demonstrated that a pre-grazing sward surface height of 22.3 cm of tall fescue promoted concomitantly the maximum short-term intake rate of sheep and the instantaneous herbage accumulation rate in the spring and autumn periods. In general, the convergent point occurred after the maximum instantaneous leaf lamina accumulation rate and before the maximum instantaneous accumulation rate of pseudo-stem + sheath and senescent material. Conclusions We suggest the existence of a convergent point in which both primary and secondary production of pastoral ecosystems could be fostered, potentially reconciling the fundamental ecological dilemma of grazing systems. |
