[PureHarvest]

Horse manure has 10 pounds of organic nitrogen per ton of manure. Organic nutrients are unavailable until microbes (when temperatures are warm, like during the growing season) are present to move it into the available (called inorganic) form. This process is called mineralization. You will only get 20% of that 10 pounds in the first year, so you crop will get 2 pounds of actual Nitrogen for every 2,000 lbs you apply. If you do not work the manure in within 12 hours of applying it, you will lose about 4lbs of N per ton to volatilization (gassing off). You will still have to 10 lbs. of organic N though.
As far as N requirements for tomatoes, you need about 0.5 pounds of total N to grow a 4'x50' row. So, that would be 500 lbs of horse manure in that row to supply the needed N for one season, just using horse manure to supply your total N needs.
P and K are about 70-80% available in the first year, and that might more than cover those requirements depending on the starting levels of your soil.
Now, picturing 500 lbs. of manure on a 4'x50' area is probably way too much volume.
Probably best to add a fraction of that for some nutrients, the organic matter contribution, and microbial life. Add the rest through some other organic or inorganic fertilizer form that is more concentrated. Tell me what you want to use and I can tell you how much. Can be any combo of manure and fert.