Spatial variability of phosphorus in soil from irrigated perimeter Engenheiro Arcoverde, PB.

Abstract

This work was conducted at the Engenheiro Arcoverde Irrigated Perimeter located in Condado-Paraiba, Brazil, aiming to evaluate the phosphorus spatial variability in a Fluvic Neosolo. The 42 ha area was sampled on an irregular grid with 53 randomized distributed soil spots, separated by 100m. The soil samples were extracted at 0-20, 20-40 and 40-60 cm depth intervals and then they were carried to the laboratory and analyzed with respect to phosphorus. The data was analyzed using descriptive and geostatistic procedures. The contour maps were obtained by interpolation and kriging. In general, the phosphorus levels of the area were high. The variation coefficients showed medium phosphorus variability at the three soil depth intervals studied. Strong spatial dependence for the phosphorus was found. The spatial dependence range was lower at the 0-20 and 20-40cm than in de 40-60 cm depth interval. The geoestatistical analyses showed a high spatial variability discontinuity at the surface layer, due to the soil and water management in the area.