Tomato plant leaf curl possibly due to manure infection
When this first occurs what can one do?
Certified GKH Gardening Expert
If the manure is not well composted, then this is certainly the cause. It contains way too much raw nitrogen in a form that is not useful to plants. This will cause nutrient burn. You will have to remove the manure, and replace with compost, or composted manure.
The rest of that nitrogen will have to leach out of the soil naturally. It may take some time, but it will happen naturally.
This article will help you to grow tomatoes properly: https://www.gardeningknowhow.com/edible/vegetables/tomato/growing-tomatoes-guide.htm