urine will bring the nitrogen level up, and lime will bring the ph level up. it takes time for plants to break down the manure and be able to absorb the nitrogen from the aged horse manure. don't give up just be patient and you can bet next years garden will improve and each year you add manure,wood chips,lawn clippings as long as you don't use any herbicides on your lawn. The herbicides stay in the grass clippings and can make your garden wilt or be puny over all and just not produce. The same goes for where you get the manure if the hay the horses ate was sprayed it will affect the garden in a negative way.