Thanks for another great read!

I had learned about soils in much the same manner. I went for N, P, K, C, Ca, ... the major elements. I then discovered other elements like Fe, I, Mg, ... the minor but 'catalystic' or 'control' elements. These are often 'in small quantities' and often ignored (as decimal points). They are as essential as the 'bulk raw elements (C, Ca, N, P, K)' because without these 'trace elements, major (bio-chemical) 'reactions' (processes) cannot occur in soil, plants and micro-organisms.

Elements may already be in the soil or deposited by plants, insects, animals (human included), winds, (flood/rain) waters. Energy is also needed to make 'gardens' grow. Lucky that plants can use solar-energy to maintain tempaerature for reactions and processes.

I insist that we call farmers 'supreme engineers'. They must, dig, build, organize, transport, lanscape, water, air, sunlight, wind, ... just about 'all engineering disciplines on earth' ;-)

Happy planting.