Skip the Ammonium nitrate! Use cotton seed meal, blood meal, or high nitrogen bat guano, well,... basically
anything high N (nitrogen). Straw is carboniferous, anything high nitrogen activates the descomposition processes, creating heat which is something you will want for heat loving plants; tomatoes, eggplants, peppers, squashes, beans even, etc. Peas, lettuces, and cool weather plants will not enjoy warm roots.