1 --- 20-0-0 2 3 --- --- 16-0-4 16-4-0 4 5 6 --- --- --- 12-0-8 12-4-4 12-8-0 7 8 9 10 --- --- --- --- 8-0-12 8-4-8 8-8-4 8-12-0 11 12 13 14 15 --- --- --- --- --- 4-0-16 4-4-12 4-8-8 4-12-4 4-16-0 16 17 18 19 20 21 --- --- --- --- --- --- 0-0-20 0-4-16 0-8-12 0-12-8 0-16-4 0-20-0 It is quite apparent that in this scheme the entire field of fertilizer formulas is covered in a regular way. In addition to this formula plan other experiments are also under way to determine the influence of the different fertilizing materials, carrying the phosphate, ammonia and potash, and the influence of lime, rock phosphate, various green manuring crops, etc. The experiments are carried out in commercial orchards on several soil types and in several localities.