Nutritional evaluation of nitrogen and potassium fertilization of carob tree under dry-farming conditions

Correia, P. J.; Correia, Maribela Pestana; Domingos, I.; Martins Loução, M. A.

http://hdl.handle.net/10400.1/7416

Use this identifier to reference this record.

Name:	Description:	Size:	Format:
Nutritional Evaluation of Nitrogen and Potassium Fertilization of Carob Tree under Dry Farming Conditions.pdf		370.67 KB	Adobe PDF	Download

Send Feedback

Authors

Correia, P. J.

Correia, Maribela Pestana

Domingos, I.

Martins Loução, M. A.

Abstract(s)

The aim of this work was to assess how potassium (K) and nitrogen (N) fertilization might affect the variation of leaf and fruit nutrient concentrations in carob tree (Ceratonia siliqua L.) under low precipitation. A field study was conducted in 1997, 1998, and 1999 in a calcareous soil. Four fertilization treatments were tested: no fertilizer (C), 0.8kg N tree(-1) (N treatment), 0.83kg K tree(-1) (K treatment), and 0.80kg N tree(-1) plus 0.83kg K tree(-1) (NK treatment). During the hydrological cycle 1998/1999, only 250mm of rain were recorded. Because of this, from 1998 to 1999 a decrease in the concentrations of mobile nutrients N, phosphorus (P), and K and an increase in calcium (Ca), iron (Fe), and manganese (Mn) were observed in leaves. The application of N led to higher leaf N concentration compared with other treatments. This response allowed the establishment of a linear model that relates soil plant analysis development (SPAD) readings with leaf N concentrations (r(2)=0.55; P < 0.05). Compared with leaves, fruits showed similar amounts of N and P; less Ca, Mg, Fe, and Mn; and high concentrations of K. Fertilization did not change considerably the mineral composition of fruits, and because of large variation among trees, yield was similar for all treatments.