Available content, surface runoff and leaching of phosphorus forms in a typic hapludalf treated with organic and mineral nutrient sources

Abstract

The application of animal manure to soil can increase phosphorus availability to plants and enhance transfer of the nutrient solution drained from the soil surface or leached into the soil profile. The aim of this study was to evaluate the effect of successive applications of organic and mineral nutrient sources on the available content, surface runoff and leaching of P forms in a Typic Hapludalf in no-tillage systems. Experiment 1 was set up in 2004 in the experimental area of UFSM, in Santa Maria (RS, Brazil). The treatments consisted of: control (without nutrient application) and application of pig slurry (PS), pig deep-litter (PL), cattle slurry (CS), and mineral fertilizers (NPK). The rates were determined to meet the N crop requirements of no-tillage black oat and maize, grown in the 2010/2011 growing season. The soil solution was collected after each event (rain + runoff or leaching) and the soluble, particulate and total P contents were measured. In November 2008, soil was collected in 2 cm intervals to a depth of 20 cm, in 5 cm intervals to a depth of 40 cm, and in 10 cm intervals to a depth of 70 cm. The soil was dried and ground, and P determined after extraction by anion exchange resin (AER). In experiment 2, samples collected from the Typic Hapludalf near experiment 1 were incubated for 20, 35, 58, 73 and 123 days after applying the following treatments: soil, soil + PS, soil + PL, soil + CS and soil + NPK. Thereafter, the soil was sampled and P was analyzed by AER. The applications of nutrient sources over the years led to an increase in available P and its migration in the soil profile. This led to P transfer via surface runoff and leaching, with the largest transfer being observed in PS and PL treatments, in which most P was applied. The soil available P and P transfer via surface runoff were correlated with the amounts applied, regardless of the P source. However, P transfer by leaching was not correlated with the applied nutrient amount, but rather with the solution amount leached in the soil profile.

Effects of Pig Slurry Application and Crops on Phosphorus Content in Soil and the Chemical Species in Solution

“…But, although to a lesser degree, the migration of P in particulate form and by bioturbation may also have occurred, which is the movement of particles in biopores (Ceretta et al, 2010a). The migration of P in the profile, especially in soils with sandy texture, as in the Typic Hapludalf of this study, the risk of subsurface water contamination is greater, especially in soils where the water table is shallower, making the water unfit for human consumption (Sorensen and Rubaek, 2012;Girotto et al, 2013;Lourenzi et al, 2014).…”

“…Approximately 38,000 m 3 of pig slurry (PS) is generated daily (Fepam, 2008), which is applied repeatedly in the same areas of cultivation, especially because the land distribution in the main producing regions in the North and Northwest of the State consists of mostly small farms. The PS is applied as organic nutrient source, including P for plants (Guardini et al, 2012;Lourenzi et al, 2014), which is one of the most limiting macronutrients for crop productivity in the weathered soils of tropical and subtropical regions (Gatiboni et al, 2008).…”

“…However, when P is added successively and at high rates to the soil, for example by PS application in crop conservation systems such as no-tillage (NT), where the soil is not tilled, the total P content may increase (Berwanger et al, 2008;Lourenzi et al, 2014), and especially the content available to plants, which can be diagnosed by the method of Mehlich-1 (Gatiboni et al, 2008;Guardini et al, 2012). Thus, the saturation of the most avid adsorption sites and a reduction in adsorption energy between phosphate oxygen and functional groups of the surface of oxides and clay minerals are expected, increasing the P concentration in the solution (Guardini et al, 2012;Schmitt et al, 2014); consequently, the P transfer in surface runoff solution to surface waters increases, but also migration in the soil profile by water flow, raising the risk of contamination of subsurface waters, especially in soils with sandy surface texture (Berwanger et al, 2008;Ceretta et al, 2010b;Wang et al, 2013).…”

Effects of Substrate Material on Plant Growth and Nutrient Loss

“…Furthermore, plant type is an important factor that affects nutrient runoff, absorption of nutrients, permeability and porosity of the substrate material, and the effects of plant roots on the soil microbial community [44]. In the second year, plant biomass of A. fruticosa becomes relatively stable, the plant's demand for nutrients is reduced, and the major elements accumulated in the substrate are gradually released in the runoff [45].…”

Fertilización organomineral y NPK en el cultivo maíz (Zea mays L.)

“…É sabido que as fontes de elevada solubilidade apresentam maior eficiência em menor espaço de tempo em relação aos fosfatos naturais. No entanto, os solos tropicais, com elevada capacidade de adsorção de P, o nutriente oriundo da fonte solúvel é rapidamente convertido a formas menos disponíveis reduzindo assim sua eficiência (Lourenzi et al, 2014). Este elemento desempenha um importante papel nas plantas, uma vez que está fortemente ligado a inúmeros processos metabólicos, atuando também na constituição do ATP, do DNA e de enzimas, como a fosforilase.…”