“…However, it was not until the 1950s and 1960s that extensive field trials by Lobb, Walker, Ludecke, and others established the widespread extent of S deficiencies in the mainly hilly inland regions of Marlborough, Canterbury, and Otago, on soils derived from greywacke and schist, or from loess, alluvium, and colluvium of similar origins (Lobb 1954(Lobb , 1959Lobb & Reynolds 1956;Lobb & Bennetts 1958;Walker 1955Walker , 1957. Walker et al , 1956Walker & Adams 1958a;During 1956;Ludecke 1960Ludecke , 1962Ludecke , 1965Ludecke , 1966O'Connor 1962;Vartha 1963). The soils concerned were mainly zonal soils (Taylor & Pohlen 1968) at the weakly to moderately weathered end of the sequence (brown-grey earths, southern yellow-grey earths, high country yellow-brown earths).…”