With no-till cropping systems, fertilizers and animal-waste nutrients are applied to the soil surface or surface residue and remain there until water infiltration carries them into the soil. The rate of microbial decomposition will be slower than with the conventional practice of incorporating animal waste, and this delays the availability of nutrients. As a result, nutrient losses due to surface runoff or volatilization may increase. Consider these factors when developing a farm nutrient-management plan.
In North Carolina’s waste-management guidelines it is assumed that more of the nitrogen from animal wastes becomes available for uptake by the first crop if the waste is injected or incorporated into the soil rather than left on the surface (Table 10.5) [8]. In contrast, research from Alabama [27] and Nebraska [13] suggests similar nitrogen availability from animal wastes in conventional and no-till systems. In practice, follow BMPs developed for your area, realizing that the nutrient supply from organic sources is less predictable than nutrients from inorganic sources.