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Autonomous self-burying seed carriers for aerial seeding


Aerial seeding can quickly cover large and physically inaccessible areas1 to improve soil quality and scavenge residual nitrogen in agriculture2, and for postfire reforestation3,4,5 and wildland restoration6,7. However, it suffers from low germination rates, due to the direct exposure of unburied seeds to harsh sunlight, wind and granivorous birds, as well as undesirable air humidity and temperature1,8,9. Here, inspired by Erodium seeds10,11,12,13,14, we design and fabricate self-drilling seed carriers, turning wood veneer into highly stiff (about 4.9 GPa when dry, and about 1.3 GPa when wet) and hygromorphic bending or coiling actuators with an extremely large bending curvature (1,854 m−1), 45 times larger than the values in the literature15,16,17,18. Our three-tailed carrier has an 80% drilling success rate on flat land after two triggering cycles, due to the beneficial resting angle (25°–30°) of its tail anchoring, whereas the natural Erodium seed’s success rate is 0%. Our carriers can carry payloads of various sizes and contents including biofertilizers and plant seeds as large as those of whitebark pine, which are about 11 mm in length and about 72 mg. We compare data from experiments and numerical simulation to elucidate the curvature transformation and actuation mechanisms to guide the design and optimization of the seed carriers. Our system will improve the effectiveness of aerial seeding to relieve agricultural and environmental stresses, and has potential applications in energy harvesting, soft robotics and sustainable buildings.

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Fig. 1: Bioinspired design of the autonomous self-drilling seed carrier.
Fig. 2: The curvature formation mechanism and hygromorphic actuation.
Fig. 3: Geometrical parameters of the seed carrier design.
Fig. 4: Tailored designs of self-drilling carriers.

Data availability

Data generated and analysed during the study is available at Digital models, processing protocols and datasets are available on request from L.Y.

Code availability

Code used for the finite-element analysis to simulate coil extension and drilling is available at Further information on code and models used is available on request from T.Z.


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Download references


We thank C. Y. Wei for processing suggestions, E. Sharon for mechanism discussions, and L. B. Hu, J. Z. Gu and J. Forman for helpful insights. We also thank J. Y. Zhu and N. Z. Plaza from the US Department of Agriculture Forest Products Laboratory for discussions and characterization through X-ray diffraction. We acknowledge funding support from the US National Science Foundation, including IIS-CAREER-1847149 (L.Y.), CMMI-2020476 (T.Z.) and the Future Eco Manufacturing Research Grant, no. CMMI 2037097 (S.Y.). Simulations were carried out at the Triton Shared Computing Cluster at the San Diego Supercomputer Center and the Expanse cluster (TG-MSS170004, T.Z.) in the Extreme Science and Engineering Discovery Environment. We also acknowledge the use of the Materials Characterization Facility at Carnegie Mellon University (MCF-677785, L.Y.), the National Natural Science Foundation of China (62002321, G.W.) and a gift to Carnegie Mellon University (L.Y.) from Accenture Labs.

Author information

Authors and Affiliations



L.Y. and D.L. conceived the initial concept. A.M. and A.D. conceived two application contexts. L.Y., T.Z., S.Y. and G.W. supervised the project. L.Y., D.L., T.Z. and S.Y. wrote the manuscript. D.L., L.Y. and G.W. carried out fabrication and peak force measurements. D.L., L.Y., G.W., J.L., Y.Y., Y.T. and L.S. carried out drilling and germination tests. D.L., L.Y. and Y.Y. carried out bending angle and coil pitch measurements. D.L., L.Y. and D.K.P. carried out scanning electron microscopy and micrograph analysis. D.K.P. and L.Y. conducted tensile tests. T.Z. and L.Y. carried out curvature analysis. T.Z. carried out mechanical modelling and simulation. S.Y., T.Z. and L.Y. provided scientific and experimental advice. L.Y. and D.L. created the videos.

Corresponding authors

Correspondence to Guanyun Wang, Shu Yang, Teng Zhang or Lining Yao.

Ethics declarations

Competing interests

A US patent application (application no. 17/718,232) on the methods and devices for the biomimetic composite has been filed by Carnegie Mellon University (assignors: L.Y., G.W., J. Gu, D.L. and F. Qin.). The other authors declare no competing interests.

Peer review

Peer review information

Nature thanks Barbara Mazzolai, Naomi Nakayama and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.

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Extended data figures and tables

Extended Data Fig. 1 SEM images of partially delignified wood veneer.

a, Chemically washed and moulded wood veneer (0.5 mm thick, 0.8 mm mandrel diameter). Wrinkled cell walls are caused by mechanical moulding on the longitudinal cells on the inner side. The outer side cells show no obvious signs of deformation. b, The chemically washed but not moulded wood veneer, showing uniform cell structure throughout the sample.

Extended Data Fig. 2 Performance of the engineered moisture-driven actuators.

a, Reversible curvature changes of a bending actuator during three actuation cycles. b, Reversible actuation of a moulded coiling actuator with seven coils in three consecutive hydration-dehydration cycles, showing the angular changes relative to the initial position of the top end of the helix (θ-θdry). Both actuators are 3 mm in width and 0.5 mm in thickness, moulded with a mandrel, with a 0.8 mm diameter. The length is 3 mm in (a) and 40 mm in (b).

Extended Data Fig. 3 Design of a remote-controlled device that can be attached to a drone to carry and deploy seeds.

a, Photograph of the customized seed deployment mechanism attached to a drone. bd, Top view of the device with a sliding cover to prevent turbulence caused by the wings of the drone from affecting the deployment. ef, Bottom view of the device, with a magnetic double-side door that can be opened with a remote-controlled pulling mechanism, shown in (g). hj, A field test of the aerial delivery with examination of the landing pose of the seed carriers. kl, a portion of the seed carriers for the aerial delivery test. The tails are dyed with bright colors for easy identification. Scale bar: 10 mm.

Extended Data Fig. 4 Photos of the fabrication and assembly of the seed carrier prototypes.

af, The process of turning a white oak log into a wood veneer with a specified thickness and fiber orientation. gh, The process of laser cutting, chemical washing and manual moulding of the wood strips. i, The chemical washing process. jn, The mechanical moulding process. o-q, Adding two additional tails for three-tailed seed carriers. rw, The tip manufacturing process adapted from the literature24 with additional seeds embedding. x, The process of moulding a double-coiled body. Scale bar is 10 mm unless otherwise specified.

Extended Data Fig. 5 Comparison of the self-drilling depth between a double-coiled and a single-coiled seed carrier.

ab, Photographs of four cycles of a double-coiled seed carrier (a) and a single-coiled seed carrier (b) at each hydration and dehydration state.

Extended Data Fig. 6 Tracking of the living nematodes extracted from the soil.

a, Representative images of nematodes extracted from the soil (Methods). b, The total number of living nematodes identified in the soil samples. Data are means ± s.d. n = 3 soil samples each day.

Extended Data Fig. 7 Selective field drilling and germination test results (more details in Supplementary Table 5).

a, Drilling test 1 from Table S5, with 22 three-tailed seed carriers under natural conditions for two consecutive days. b, A rain-anchored seed continues to drill after the sun emerges, as shown in drilling test 3 of Table S5. c, Established seed carriers tend to germinate more easily than non-established seed carriers after five days with four periods of rain. The established and exposed seeds had a 100% and 19% germination rate, respectively, in drilling test 1 of Supplementary Table 5.

Extended Data Fig. 8 Optimizing the material choice and processing method.

a, Comparison of the mouldability and actuation range of bending actuators made of different types of wood. The wood strip is ~0.5 mm thick and the moulding diameter is 0.8 mm. Data are means ± s.d. n = 3 samples for each type of wood. b, Comparison of the mouldability of the seed body made of various types of wood. The wood strip is ~0.5 mm thick. c, Effect of the chemical washing durations on the curvature changes. For both (a) and (c), data are means ± s.d. n = 3 with a thickness of ~0.5 mm, length of ~3 mm and width of ~3 mm, moulded with a mandrel with a 0.8 mm diameter. d, Moulding quality comparison on wood veneer of different thickness, moulded on mandrels of different diameters, with a washing duration of 10 min.

Extended Data Fig. 9 Experiments and simulations for seed carrier drilling on a surface that is hard and smooth.

a, Simulation (top) and experimental (bottom) snapshots of the drilling process of the single-tailed design seed carrier. b, Simulation (top) and experimental (bottom) snapshots of the drilling process of the three-tailed design seed carrier.

Supplementary information

Supplementary Information

This file contains Supplementary Tables 1–5, Notes 1–12 including Figs. 1–26, and References.

Reporting Summary

Supplementary Video 1

The natural Erodium seed has an inevitable crevice-searching phase that can negatively impact the drilling efficiency especially in the case of relatively flat land.

Supplementary Video 2

Dropping test of both natural and engineered seed carriers. Compared to Erodium seeds thath have an 80% chance of landing flat, this three-tailed carrier has a 90% chance of landing with a guaranteed angle between its body and the ground to increase the drilling success.

Supplementary Video 3

Comparing the self-drilling success of the engineered three-tailed seed carrier and the natural single-tailed Erodium seed.

Supplementary Video 4

Experiment and finite-element simulation of the self-drilling processes of both three-tailed and single-tailed designs. The three-tailed design generates a larger force, as multiple tail tips and bodies can generate effective torques simultaneously.

Supplementary Video 5

Self-drilling processes of three seed carrier design variations, including three-tailed, double-coiled and large-sized systems, tailored to different use cases. The tests were conducted in an indoor controlled environment.

Supplementary Video 6

Fabrication process of the seed carriers.

Supplementary Video 7

Germination experiment using the three-tailed seed carrier, with embedded symbiotic cherry belle radish seeds and beneficial fungi, captured for a duration of 190 h.

Supplementary Video 8

Living nematodes captured in the soil after 9 days of seed burial.

Supplementary Video 9

Successful self-drilling and germination under natural conditions outdoors for 7 continuous days, with 2 periods of intermittent light rain on the first day and 1 thunderstorm and heavy rain, which lasted for more than 6 h on the second day.

Peer Review File

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Luo, D., Maheshwari, A., Danielescu, A. et al. Autonomous self-burying seed carriers for aerial seeding. Nature 614, 463–470 (2023).

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