1. Keep rates low. Because high rates of salt and nitrogen products can negatively impact plant, “care should be taken to keep rates low to reduce the risk for damage but maintain a potential for positive benefits from seed placed fertilizer application,” says Kaiser.
2. Account for nutrients in the starter. If applying a starter fertilizer to corn, those should be accounted for in the overall fertility program.
3. Watch soil test values. “Previous knowledge of soil tests will allow for reduction of seed-placed fertilizer rates in areas where there may be no benefit,” says Kaiser.
4. Choose a product that fits your goals. “Choosing a product that will meet your goals with the least cost can help ensure the cost of the product can be recovered with additional grain yield,” he says.
5. Don’t fall for debates. “Early in the growing season, the amount of phosphorus needed y plants is low,” says Kaiser. “Therefore, there’s no difference in performance of fertilizer sources containing phosphorus relative to their content of ortho- or poly-phosphate.”
(Source – http://cornandsoybeandigest.com/fertilizer/5-tips-when-using-furrow-starter-fertilizer-corn)