Using Rice Hulls As a Soil Amendment
Since rice hulls are comprised of mostly silica, they can be of great use as a soil amendment. Silica helps to strengthen your plants cell walls, and build up their immunity to things like drought and heat.
By mixing in rice hulls to your soil, they will provide aeration similar to how perlite, or pumice would do in potting soil. In a garden, or field situation, you would typically do this every 2 or 3 seasons, as the aeration benefits should last multiple years. Depending on the microbial life in your soil, temps, humidity, crops being grown, etc.. you may be able to extend the length of time between incorporating rice hulls into your fields.
When used in potting soil, rice hulls are the perfect alternative to other aeration amendments like perlite. Unlike perlite, it will break down eventually, but again, I have seen it last 5+ years in living soil containers. We use it as part of our solution for long term aeration in our no-till living soil, and it has served us well for many years. If you are mixing your own soil for the season, rice hulls would be a great option for a single use soil. The reason I like it for single use soils, is that when you are done with the season you can compost the remaining soil, and there won't be any issues with perlite, pumice, lava rock, etc.. being in your compost. Then the next season you can use your old soil as compost for your new soil, and continue the cycle indefinitely.
(I have no affiliation with redbudsoilcompany, they just had good info on some of the benefits rice hulls provide for gardening!)