Effects of long term raw pig slurry inputs on nutrient and metal contamination of tropical volcanogenic soils, Uvéa Island (South Pacific)

Abstract

In small Polynesian islands, family pig breeding is usually conducted without recovery of pig slurry. Raw pig slurry is spread onto the soil without any treatment. So far, most of the studies were carried out in temperate climate and for industrial digested pig slurry applications on agricultural lands. In the present case study, conducted in Uvéa Island, the aim is to determine if long term application of raw pig slurry on tropical soils, naturally rich in heavy metals has a significant influence on elements concentrations and mobility. Two types of tropical soils and two pig breeding systems, pig enclosure on small concrete pens or pig enclosure in large land pens, were investigated. Here we demonstrate that raw pig slurry inputs on soils can lead to an increase of total nitrogen and phosphorus content with high Contamination Factors. The Pollution Load Index values (1.3; 5.3; 2.5; 2.3) were indicative of multi-heavy metals pollution (Fe, Mn, Al, Cu, Zn, Cr and Ni) in mixed calcareous soils of the coastal area and they are exchangeable while they are immobilized or less mobile in inland pure ferralitic soils. For mixed calcareous soils of the coastal area, family pig breeding represents a drainage risk of soluble species (phosphorus, inorganic nitrogen, Fe, Mn, Al, Cu, Zn, Cr and Ni). For inland ferralitic soils, family pig breeding is more compatible with a sustainable management of the environment in Uvéa Island and by extension in volcanic tropical islands with respect to the investigated chemical elements.

Use of nutrient-enriched zeolite (NEZ) from urban wastewaters in amended soils: Evaluation of plant availability of mineral elements

“…The clay soil (SC), with pH 8.4 ± 0.3, is described as mixed calcareous soil due to its high contents of calcium, aluminium, iron and magnesium with high contents of quartz and illite (Gunkel-Grillon et al, 2015). It contains 27% of CaCO3, a medium content of organic matter (8%) from agricultural practices leaving harvest residues on the topsoil, a silty-clay texture and a Ca-dominated cation exchange complex with values of 25 cmol(+) kg -1 .…”

Nutrient Status and Contamination Risks from Digested Pig Slurry Applied on a Vegetable Crops Field

“…Considering the large amount of total N in digested pig slurry ( Table 1 ), the accumulation of total N in the fertilized soil was inconspicuous, and only 14% higher than control soil. This could have resulted from a loss of NH 4 + -N by volatilization, N uptake by crops and nitrification/denitrification [ 24 ]. Available N in soils mainly consists of NH 4 + -N and NO 3 − -N. Compared with control soil, a slight increase of NH 4 + -N content while a decrease of NO 3 − -N content (by 33.7%) in the fertilized soil were found.…”

Impact of pig slurry application on soil and water losses: Comparison with a historical series

“…The use of pig slurry (PS) as fertilizer is an alternative practice used in agriculture. Therefore, this practice should be studied, taking into account the effects of PS on the soil, the benefits in erosion reduction, the influence on crop productivity, and possible environmental contamination outside the place of erosion (Gunkel-Grillon et al, 2015).…”