Soil phosphorus fractions in sandy soils amended with cattle manure for long periods

Abstract

Phosphorus fractions were determined in soil samples from areas fertilized or not with farmyard cattle manure (FYM) and in samples of FYM used in the semi-arid region of Paraiba state, Brazil. Soil samples were taken from the 0-20; 20-40 and 40-60 cm layers of 18 cultivated areas, which, according to interviews with farmers, had been treated with 12 to 20 t ha-1 FYM annually, for the past 2 to 40 years. Soil samples were also collected from four unfertilized pasture areas as controls. Phosphorus in the soil samples was sequentially extracted with water (Pw), resin (Pres), NaHCO3 (Pi bic and Po bic), NaOH (Pi hid and Po hid), H2SO4 (Pacid) and, finally, by digestion with H2SO4/H2O2 (Presd). Nine FYM samples were extracted with water, resin, Mehlich-1, H2SO4, NaOH or digestion with H2SO4/H2O2, not sequentially, and the extracts analyzed for P. The sampled areas had homogeneous, sandy and P-deficient soils; increases in total soil P (Pt) above the mean value of the control areas (up to 274 mg kg-1 in the 0-20 cm layer of the most P-enriched samples) were therefore attributed to FYM applications, which was the only external P input in the region. Regression analysis was used to study the relationship between soil P fractions and Pt. The Pacid fraction, related to Ca-P forms, showed the greatest increases (p < 0.01) as a result of FYM applications, rising from 8.4 mg kg-1 in a non-fertilized sample to 43.8 mg kg-1 in the sample with the highest Pt content. The sum of Pw, Pres and Pi bic, considered as labile P, showed comparable increases with Pacid, while Pi hid showed the smallest increase due to FYM applications. Organic P forms also increased, more so the fraction Po hid, considered less labile, than the more labile one, Po bic. The residual P fraction was practically half of Pt, independently of the Pt value. Increases in labile P, Pacid and organic P were justified by the high average concentration of Pw (36 %), Pacid (34 %), and Po hid (30 %) in the FYM. Significant changes in the proportion of P forms among soil layers indicated the downward movement of P in organic forms.

Use of Organic Compost Containing Waste from Small Ruminants in Corn Production

“…Results similar to those found in this study for the P variable were obtained by Galvão and Salcedo (2009) in a study with cattle manure applied regularly in a rural region of the state of Paraíba in areas cultivated with potato, common bean, corn, cassava, cowpea, and fava bean. In addition, the effect of adding organic byproducts and compost on P retention by the soil depends on the concentration of P in the organic fertilizer.…”

Decomposição e liberação de N, P e K de esterco bovino e de cama de frango isolados ou misturados

“…A liberação mais rápida de P pelo EB em relação à CF deve-se ao maior teor de P, aos menores valores da relação C/P e possivelmente ao predomínio de fosfatos solúveis em água e fracamente ligados à matriz sólida do EB (Cassol et al, 2001;Galvão & Salcedo, 2009), em comparação à prevalência de frações de P orgânico (fosfatos monoésteres) de menor labilidade na CF (Pitta et al, 2012;Souza et al, 2012). A liberação mais lenta de P no EM pode ter sido propiciada pela imobilização de P na biomassa microbiana por causa do aumento do número de microrganismos totais na mistura (Moreira & Siqueira, 2006;Tiago et al, 2008).…”

Evaluation of composting performance of mixtures of chicken blood and maize stover in Harare, Zimbabwe

“…The analysis was determined: pH in water 1:10 (m/v); electric conductivity (EC) 1:10 (m/v); total P (P t ) obtained by digestion with H 2 SO 4 and H 2 O 2 (Thomas et al 1967); P extracted with Mehlich-1 solution (MEP); P extracted with water (WEP) and the extracts determined by the method of Murphy and Riley (1962); WEC determined by the method of Mendonça and Matos (2005) adapted from Bartlett and Ross (1988); TOC obtained by wet oxidation-diffusion (Snyder and Trofymow 1984); and ash obtained by the method of EMBRAPA (2011) ( Table 4). The manure dose was calculated based on the content of P t in the cattle manure, considering the application of 16 Mg ha −1 in the first 20 cm of soil, which is the mean annual dose applied in the region (Galvão and Salcedo 2009;Oliveira et al 2011). However, we decided to apply 8 Mg ha −1 of cattle manure to the 0-10 cm layer to better observe P displacement.…”

“…In Brazil, annual applications of manure in areas with Dystric Xeropsamments of sandy texture in sub-humid region in the northeastern Brazil (Agreste) have caused accumulation of nutrients in the surface layer (Silva and Menezes 2007;Galvão et al 2008;Oliveira et al 2011). Consequently, these nutrients move down the soil profile, including phosphorus (Galvão and Salcedo 2009;Xavier et al 2009), which has little mobility in clayey soils. The accumulation of P in the topsoil increases the risk of its vertical displacement beyond the reach of the roots.…”