If the VP spot is vacant, the president selects a new VP who must then be confirmed by the House and Senate; per the 25th amendment:
Whenever there is a vacancy in the office of the Vice President, the President shall nominate a Vice President who shall take office upon confirmation by a majority vote of both Houses of Congress.
Just jumping in to say that red soils are not very fertile. They are nutrient-poor in the necessary macro-nutrients (nitrogen, potassium, and phosphorus) and have a very poor ability to retain water. They are very rocky - little organic matter content - which limits both water retention and cationic exchange capacity (affecting N+ and K+ bioavailability), and tend to be acidic.
Cultivation is possible, but it requires large amounts of fertilizers and soil conditioning agents (liming to raise pH and add calcium, addition of organic matter). In effect, recreating an artificial soil that is closer in nutrient availability to the black soils present in the world's most fertile regions (which today are also heavily fertilized).