Open Access

ARTICLE

Use of diammonium phosphate on wheat grown in southwestern Buenos Aires (Argentina)

Ron MM, T Loewy

Departamento de Agronomía, Universidad Nacional del Sur, Altos del Palihue, 8000, Bahía Blanca, Argentina.

Address correspondence to: María de las Mercedes Ron, Fax 054-0291-4595127; Phone 054-0291-4595126, e-mail:

Phyton-International Journal of Experimental Botany 2016, 85(all), 15-20. https://doi.org/10.32604/phyton.2016.85.015

Abstract

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. Yield response variables were derived from the equation. Measured site variables were pH, organic matter (OM) and soil extractable phosphorus (Bray-P). Categorical variables of soil texture, wheat cycle and previous soil use were also included. Regressions were developed between dependent and site variables. The set of equations constituted a model that explained 31 to 75% of the variation in the yield response variables. Agronomic efficiency of N-urea for soils with agricultural use was around 12 kg wheat/kg N for both times of application. Response to DAP and TSP was related to Bray-P and soil texture. The bridging experiments between these two P sources estimated a superiority of DAP of around 180 and 90 kg wheat/ 80 kg of fertilizer on coarse and medium textured soils, respectively. Although it is physically impossible to isolate N-P effects in a binary fertilizer, this may be attributed to additional N. The data also suggested synergism between DAP and urea applied at sowing after their interaction in the soil.

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