Using leaf regrowth stage to define defoliation interval for diverse pastures of complementary species (Lolium perenne L., Bromus valdivianus Phil., Dactylis glomerata L. and Trifolium repens L.)

Abstract

Diverse pastures of complementary species (DPCS) comprise species that fulfil different agroecological niches, resulting in growth asynchrony and complementarity of functional roles. It is expected that DPCS have a greater capability to tolerate and performunder increasingly extreme climate events, providing a potential alternative for New Zealand pastoral systems. In the present study, DPCS comprised Lolium perenne L., Bromus valdivianus Phil., Dactylis glomerata L., and Trifolium repens L. The leaf regrowth stage [LS; L. perenne (2.5-3.0LS), B. valdivianus (3.5-4.0LS) and D. glomerata (3.5-4.0LS)] is proposed to be an applicable method of defoliation management for DPCS due to a potential overlapping of the defoliation interval. The seasonal and annual herbage mass accumulation and botanical composition of DPCS and their respective single-grass and T. repens pastures under the LS criterion were assessed. The annual yield did not differ among pastures (average 20.26 t dry matter (DM) ha- 1). However, significant differences were found within seasons, with DPCS exhibiting asynchronous growth among species that reduced the seasonality of herbageaccumulation and invasion by volunteer species. Lolium perenne, B. valdivianus and D. glomerata were shown to be complementary grass species, presenting growth asynchrony and an overlapping defoliation interval that optimised production, indicating that defoliation based on LS criterion is a suitable management for DPCS.