Data from: Developing extruded seed pellets to overcome soil hydrophobicity and seedling emergence barriers

Globally soil water repellency is a major constraint to plant establishment, restricting water infiltration and moisture retention in the seed zone, resulting in poor germination and seedling emergence. To address this problem within an ecosystem restoration context, we investigated the use of a surfactant in extruded seed pellets to improve native plant recruitment in water repellent topsoils of two proteaceous woodland species, Banksia menziesii R.Br (glasshouse trial) and Lambertia inermis R.Br (field trial). In this two-part study, we first examined B. menziesii seedling performance in detail under glasshouse conditions for differences in survival between the extruded pelleting formulations after an induced drought at 12 weeks. We demonstrated that there was no difference in seedling emergence, amongst control seed and pellet treatments in B. menziesii. Initially B. menziesii seedlings emerged faster in the control treatment (non-pelleted control seeds) and had greater initial plant growth (leaf and root production), however by week 12, seedlings generated from pellets were not significantly different from the control seeds, and pellets + surfactant had the greatest number of leaf establishment. Survival after drought of B. menziesii seedlings ranged from 14 to 31 days with pellet + surfactant surviving approximately 2.6 days (11.8%) longer than the control seeds. For the second species, L. inermis, seedling emergence under field conditions was approximately 24% greater in seedlings derived from extruded pellets, however there was no difference in overall survival due to post-emergence predation. This study provides a proof of concept that seedling emergence in water repellent soils can be enhanced with extruded pellets containing surfactants. Our demonstration under in situ and ex situ conditions confirms the prospective use of seed enhancement technologies with future development and field-testing warranted.全球范围内，土壤斥水性（soil water repellency）是制约植物定植的核心限制因素，其会阻碍种子微区的水分入渗与水分留存，进而导致发芽率低下与幼苗出苗受阻。为在生态系统修复的背景下解决该问题，本研究针对两种山龙眼科（Proteaceae）林地物种——班克木（Banksia menziesii R.Br，温室试验（glasshouse trial））和平滑Lambertia（Lambertia inermis R.Br，田间试验（field trial））的斥水性表层土壤，探究了将表面活性剂（surfactant）添加至挤压型种子丸粒（extruded seed pellets）中以提升本土植物种群补充效果的可行性。本研究分为两个部分：首先在温室条件下详细探究班克木的幼苗表现，对比12周诱导干旱后不同挤压丸粒配方间的幼苗存活率差异。研究结果显示，班克木的对照组种子与丸粒处理组之间的幼苗出苗率并无显著差异。初始阶段，对照组（未丸粒化的对照种子）的班克木幼苗出苗更快，初始植株生长（叶片与根系生成量）更为旺盛，但至第12周时，丸粒处理组的幼苗与对照种子组已无显著差异，且添加表面活性剂的丸粒组幼苗的叶片建成数量最多。班克木幼苗在干旱胁迫后的存活时长介于14至31天，添加表面活性剂的丸粒组幼苗存活时长较对照种子组延长约2.6天（增幅11.8%）。针对第二个物种平滑Lambertia，田间条件下挤压丸粒处理组的幼苗出苗率较对照组提升约24%，但由于出苗后捕食危害，整体存活率并无显著差异。本研究证实了在斥水性土壤中，添加表面活性剂的挤压型种子丸粒可提升幼苗出苗率这一概念的可行性。我们在原位（in situ）与迁地（ex situ）条件下的验证结果表明，种子增强技术具有应用前景，未来需开展进一步开发与田间试验。