My pasture grass is short and thin, and weeds have almost taken over. I sprayed them, but most of them are still there. I want to reseed a pasture.
Plants take up nitrates from the soil to make plant proteins for growth.
When growth is slowed by lack of water, these nitrates accumulate. Once rains begin coming, the plant rapidly takes up even more nitrates trying to compensate for the slowed growth. When too many nitrates are eaten by the grazing animal, the excess nitrates become nitrites which are absorbed into the blood stream where they decrease the blood's ability to transport oxygen. The animal can suffocate. The whole process can be quite rapid.