Effect of placement of liquid and solid fertilizer on the growth and yield of potatoes

Abstract

SUMMARYThree field experiments in 1963–5 compared the effects of three methods of fertilizer application, each at four rates, on the growth and yield of main-crop potatoes. Solid fertilizer was broadcast over the furrows and then concentrated round the seed tubers by splitting the ridges during machine planting. Liquid fertilizer was injected immediately after planting either 2 in below and 2 in to the side (shallow placement), or 6 in below and 2 in to the side of the seed tubers (deep placement). Solid and liquid supplied the same quantity of nutrients.In two years deep placement of liquid gave larger yields than the solid fertilizer and in all three years larger yields than shallow placement of liquid. Results from growth analysis of the 1963 crop indicated that deep placement of liquid gave the largest yield after a dry period. Growth analysis on an additional experiment in 1964 showed that when the soil moisture deficit was limited by irrigation to 1-6 in, both the yield and nitrogen uptake from shallowly and from deeply placed liquids were similar. However, without irrigation deep placement gave a larger yield and nitrogen uptake than shallow placement. An artificial 'dry climate' emphasized that the magnitude of the response to deep placement was related to the soil-moisture regime. It is concluded that the deepplaced fertilizer was in a region of the soil which remained moist, whereas the shallower fertilizer was in drier soil where it was less available to the potato roots.