Controlling seal formation and improving seedling emergence using polyacrylamide polymers
Soils from arid and semiairid regions are often structurally unstable and seal. This surface sealing phenomenon negatively effects many components of the soil-plant system, thereby limiting crop production. Delayed or erratic plant emergence are direct effects of the surface sealing and subsequent crusting phase of the soU. Increased water runoff loss, decreased water infiltration, and enhanced wind erosion are all negative indirect effects of surface seals. Since the 1980's, there has been renewed interest in the use of water soluble polymers for enhancing soil physical properties. Several factors contributing to this use are more efficient application strategies, availability of inexpensive and, more effective polymers. Better understanding of the beneficial effects of using polymers on surface sealing (increased infiltration and reduced surface strength and hardening) and on the emergence and development of various crops will make crop growing more economical and profitable in soils susceptible to seal formation. Subsequently, farmers (especially from the Southern High Plains of Texas) will benefit from a wider range of crops that they could grow and thus improve productivity and profits.
This project investigated polymer addition to the soil surface to (i) decrease soil sealing and (ii) enhance seedling emergence. Polymers of differing charges and molecular weight were sprayed on the soil surface at several rates.