Agglomerating seeds to enhance native seedling emergence and growth.
Abstract
Restoration in rangelands is constrained by low establishment of species sown from seed. Non-biotic soil-surface crust is one of the major factors limiting reseeding success by acting as a barrier to seedling emergence. The objective of this study was to determine whether seedling emergence could be improved by agglomerating multiple seeds into a single pellet, so that the seedlings growing from the pellet will collectively generate sufficient force to penetrate the soil crust. To evaluate this technology, we compared seedling emergence and biomass production from agglomerated, single and non-coated seed (control) of Pseudoroegneria spicata. In the greenhouse, seeds were sown in either crust-forming clay or non-crusting sandy soil and studied for a 25-day period. Starting seed density was constant across treatments. In the clay soil, seedling emergence from the agglomeration treatment was 1.3 and 1.9 times higher than the single seed coating and control, respectively. In the sandy soil, the agglomeration and single seed coating responded similarly, producing 1.4 times more seedlings than the control. Biomass production followed a similar trend as plant density. In the clay soil, increased biomass of the agglomeration treatment was not only because of higher plant densities but was also a product of having greater biomass per plant. Synthesis and applications. This short-duration 'proof-of-concept' study indicates that both the seed coating materials used to form the agglomerates and the act of agglomerating the seeds together improve P. spicata emergence and plant growth. These results also demonstrate that in the early seedling stage, facilitation outweighs competition in agglomeration plantings. Additional research is needed to verify these results in the field.