1990 Volume 61 Issue 5 Pages 439-446
In order to investigate the effect of the macronutrient deficiencies on the utilization and the allocation of nitrogen in wheat, maize, soybean, and potato, an experiment was conducted in the field where treatments (1) with application of nitrogen, phosphorus, and potassium, (2) without nitrogen, (3) without phosphorus, and (4) without potassium have been maintained for 74 years. The following results were obtained. 1. The relative dry weight of the harvest organs in the treatment without N, P, or K application, compared with the control treatment, was 28, 88, and 91, respectively, in wheat; 40, 81, and 38 in maize; 106, 82, and 57 in soybean; and 25, 70, and 46 in potato. 2. The absorption of N, P, and K was considerably lower in the treatment without N, P, or K application, the photosynthetic activity should be more important than the N use efficiency and the harvest index of N. The decomposition of nitrogen compounds, translocation, and reconstruction might be kept quite stable under deficiency of each macronutrient.
