Functional contribution of two perennial grasses to enhance pasture production and drought resistance under a leaf regrowth stage defoliation criterion

作者：Javier García‐Favre, Ignacio F. López, Lydia M. Cranston, D. J. Donaghy, Peter Kemp, Iván Ordóñez · 发表于：Journal of Agronomy and Crop Science · 年份：2022 · DOI：10.1111/jac.12602 · 被引用次数：19 · 研究领域：Pasture and Agricultural Systems、Ruminant Nutrition and Digestive Physiology、Soil Carbon and Nitrogen Dynamics

Abstract Lolium perenne L. (Lp) is the main pasture species in New Zealand, but climate change increases the likelihood of drought during summer and consequently lowers its growth rates. Bromus valdivianus Phil. (Bv) tolerates better the summer soil water restriction, but its competitiveness in a diverse pasture relates to the defoliation management and soil moisture levels. The performance of both species in terms of production, persistence and feed quality across seasons under different defoliation regimens was evaluated when the species were mixed and in monoculture. The treatments were applied in a randomised complete block design with three blocks. Bromus valdivianus and Lp monocultures and the 50/50 mixture (Mx) were grazed at low and high defoliation frequencies (i.e. based on Bv and Lp optimal leaf regrowth stage [LS], respectively). Herbage mass production was 15% higher in the Mx, mainly due to an increase in production in spring and summer. In spring, there was complementarity growth between the species, while during summer/early autumn, the Mx production relayed in the higher participation of Bv. Root biomass at depth (31–70 cm) was 38% greater for Bv monoculture and the Mx compared with Lp monoculture, which demonstrated the contribution of Bv to a better production of the mixture during and following the dry periods. In addition, the maintenance of the Bv tiller population and the higher growth rate during dry periods demonstrated its better fitness to low soil ...