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

Abstract

A major challenge in agricultural production systems is the maximization of resources used to promote the development of crops with a minimum of environmental impact. In this sense, the use of fertilizers of animal origin has great potential to promote the improvement of soil properties. In southern Brazil, swine manure (SM) is widely used in agricultural areas, allowing nutrient cycling within pig units and reducing costs for chemical fertilizers. Much of this manure is applied in liquid form (PS), but other strategies are often used, such as PS compost and swine bedding (DL). The use of these SMs improves the chemical, biological, and physical attributes of the soil, contributing to increased fertility and productivity of crops. However, prolonged use or applications with high doses of SM can result in the accumulation of metals and phosphorus in soils, representing a risk of contamination of soils and surface water resources, mainly due to losses by runoff, and subsurface, by leaching. Therefore, the adoption of criteria and the rational use of PMs need to be adopted to avoid dangerous effects on the environment, such as plant toxicity and water contamination. The potentialities and risks of SM applications are discussed in this chapter.

Aggregation Index and Carbon and Nitrogen Contents in Aggregates of Pasture Soils under Successive Applications of Pig Slurry in Southern Brazil

“…Some studies have shown divergent results for the effect of PS application to the soil surface on C and N contents and soil aggregation [19,26,27,29,37,66,71,72], which were probably due to differences in PS rates, initial soil characteristic, tillage system, and evaluation time. Moreover, according to Benedet et al [25] long-term application of high PS rates can be a risk of contamination to soils and surface waters, mainly due to losses by runoff, and subsurface, by leaching. Basso et al [73] reported that the use of low PS rates (20 and 40 m 3 ha −1 ) minimizes N losses by volatilization; and N-NO 3 − leachate, despite little being expressed when compared to the amounts added by PS applications, can surpass the concentration limits for groundwater quality [74].…”

“…Changes in soil chemical [24,25], physical [16,26,27], and biological [28][29][30] attributes have been found with application of PS, with positive effects on soil quality, and crop yields [10,31,32]. These benefits are mainly due to increases in organic matter contents, which favor soil aggregation and availability of nutrients to plants.…”

Repeated Manure Application for Eleven Years Stimulates Enzymatic Activities and Improves Soil Attributes in a Typic Hapludalf

“…Recently, several meta-analyses have emphasized the benefits of animal manure application on crop yields and chemical, physical and biological soil attributes [7][8][9][10][11][12][13]. Animal manure of many kinds are expected to improve soil quality and crop yields on organic production systems, where mineral fertilizers are avoided, but also in intensive agricultural production systems [14][15][16][17][18].…”

“…The use of animal manure as fertilizer for annual crops is not always a viable option in agricultural production areas because collection, preparation and distribution of manure can be expensive when transporting over long distances is necessary [3,15,24,25]. However, in cattle, swine and poultry producing regions, accumulated manure is a reality that has to be managed [24].…”

“…However, in cattle, swine and poultry producing regions, accumulated manure is a reality that has to be managed [24]. Several studies have shown that the excessive accumulation of manure in a single location can have serious environmental impacts, mainly due to the displacement of nutrients and eutrophication of water bodies [15,24,25]. However, measuring and understanding the benefits of incorporating organic manures even in conventional intensive systems may give subsidies for the development of public policies, which may change the scenario of discouragement and support more sustainable development.…”