| In the southwest of Buenos Aires Province (Argentina), nitrogen (N) and phosphorus (P) deficiencies are important wheat yield limiting factors. There is an information gap regarding differences between single element and binary N-P sources. The objective of this paper was to develop a general model for N-P fertilization in the area that also quantified diammonium phosphate (DAP) effect and its interactions with N-urea, applied at sowing or tillering, as compared with triple superphosphate (TSP). Between 1984 and 1985, 13 experiments were carried out in farmer’s fields N. With the yield data for each experiment, a yield function was fitted which included terms for single effects of urea (0, 30 and 60 kg N/ha) and 80 kg/ha of either DAP or TSP.... |
