Adjusting spatial use to establish productive and stable Elymus nutans monocultures and mixed sowing systems

Abstract

Community arrangement plays a critical role in maintaining forage community production and stability. To explore reasonable management for efficient community production in alpine regions, three monoculture communities composed of Elymus nutans, Cross row (S_C), Double row (S_D), and Single Row (S_R), and three mixed communities consisting of Elymus nutans and Onobrychis viciifolia, Broadcast(M_B), Dependent row (M_D) and Independent row (M_I) were established in Tianzhu County on the Qinghai Tibetan Plateau during 2018–2019. The results showed S_C was the most productive monoculture community, with less intraspecific competitiveness and higher population density after establishment, which could reduce the influence of lodging on yield loss. The maximum forage yield was attained at the end of 2018 (5187.6 kg·ha−1) and August 2019 (26190.9 kg·ha−1). In mixed communities, the relationship of natural height between E. nutans and O. viciifolia was relatively stable, but growth rate displayed asynchronous traits. Besides, mixed communities had higher lodging resistance compared with monoculture communities; E. nutans showed higher competitiveness than O. viciifolia, but O. viciifolia competivity when the community natural height decreased. M_B (3015.3 kg·ha−1 in 2018; 4804.6 kg·ha−1 at the flowering of 2019), and M_D (7686.2 kg·ha−1 in 2019) had better performance in forage yield. Our study has demonstrated the feasibility of adjusting plant spatial arrangements as a means to enhance forage production in alpine regions. It is crucial to consider the interaction of growth rates, as this factor determines the optimal utilization time for monocultural and mixed communities. Additionally, this study highlights the influence of changes in sowing patterns on forage growth and yield, while enriching the grassland establishment mode, thus supporting the development of sustainable livestock systems in the Qinghai Tibet Plateau.