Mutual shading as a factor limiting the yield response of rice to application of nitrogen, phosphorus and potassium fertilizers

Results are given from trials with the leafy rice Peta grown in nutrient culture and in pots in crowded or spaced arrangements at various NPK levels. At wide spacing, P and K levels of 5 and 10 ppm. limited yield only where N levels were above 40 ppm., whereas at high levels of P and K, yields increased as N levels increased up to 100 ppm.