Physiological Changes in Maize Grown in Soil with Copper and Zinc Accumulation Resulting from the Addition of Pig Slurry and Deep Litter over 10 Years

Use of Swine Manure in Agriculture in Southern Brazil: Fertility or Potential Contamination?

“…SM applications promote nutrients added to the soil, increasing its contents and, consequently, its availability to plants [6,[32][33][34][35][36][37]. Naturally, SM applications allow a more complete nutrients fertilization, not limited to N, K, and P, present in high concentrations in the manure, but also adding other macro and micronutrients, such as Ca, Mg, Cu, Zn, and Mn [7,9,12]. In a study conducted by Pessotto et al [34] in the municipality of Três Passos, RS, in a Entisol, PS applications (150 m 3 ha −1 ) for four and 16 years in pasture areas (Cynodon spp.)…”

“…The different diets offered, the animal ages, the volume of water used to clean slatted floor stalls, and the shape and time of storage, for example, are components that promote variation in the levels of nutrients present in manure [33]. Additionally, the breeding systems and the SM stabilization processes, such as the deep litter system, composting, and anaerobic digestion, promote changes in the structure and composition of manure and in its soil dynamics [5,7,8]. Admittedly, the incorporation of substrates with high lignification, such as rice husks, shavings, and sawdust, in the preparation of deep litter and compost increases its C/N ratio.…”

“…In addition to nutrients, SM applications also promote changes in the SOM contents, through the addition of organic compounds present in the manure, but mainly by increasing the crops biomass production [7,9,26,36]. The maintenance of these residues in the soil, along with soil conservation systems, such as no-till system and integrated crop-livestock-forest (ICLF), favors the accumulation of MOS [34,37].…”

“…However, it is important to notice that both studies found greater effects on soil superficial layers, promoting changes up to 10 and 4 cm, respectively. Additionally, the addition of solid material, such as PS compost or DL, tends to promote the greater accumulation of organic C than PS applications, due to the higher C content in these solid manures [6,7]. The increase in SOM contents in soils fertilized by SM is a factor of great importance in increasing soil fertility, contributing to its CEC, microbiological activity, and soil structure, also is an attribute associated with soil quality [11,12].…”

“…These strategies allow pig slurry (PS) transformation into a more stable material, with a higher concentration of nutrients and in a solid form, such as the PS compound and the deep litter (DL). SM transformation also has the advantage of allowing the waste transport and commercialization, becoming another source of income in the swine units [5][6][7][8].…”