Composted Sewage Sludge Enhances Soybean Production and Agronomic Performance in Naturally Infertile Soils (Cerrado Region, Brazil)

Abstract

Naturally infertile soils require large amounts of mineral fertilizers to obtain the desired crop yield. In the Cerrado region of Brazil, there is a need to investigate the potential of organic fertilizers to sustainably increase crop productivity and food security. A field study was conducted over two experimental seasons to evaluate the agronomic effectiveness of composted sewage sludge (CSS) as a fertilizer for soybean cultivation in infertile tropical soils. A 4 × 2 + 2 factorial randomized complete block design was applied with the following treatments: (i) CSS: 5.0, 7.5, 10.0, and 12.5 Mg ha−1 on a wet basis applied according to two different methods: whole area (WA) or between rows (BR); (ii) comparison with two alternative treatments: a control with no CSS and mineral fertilizer application, and an area treated with conventional fertilizers only. All the treatments were compared in terms of micronutrient concentrations in surface soil and plant leaves, plant development, crop productivity, and yield. Bi- (ANOVA, correlation matrix, and polynomial regression analysis) and multivariate (PCA, principal factor analysis) statistics were applied to determine statistical differences and relationships/observed variability among the treatments. Results showed that at higher CSS-WA rates: (i) soil and leaf micronutrient concentrations increased; (ii) there was an increase in soybean yield by 12 and 20%, respectively, as compared to control and conventional fertilization; (iii) soybean yield was 67% higher than the mean soybean yields for Brazil. Research outcomes confirm the benefits of CSS application on infertile agricultural soils in the Cerrado region, representing a strong alternative source of micronutrients in the CSS with respect to conventional fertilizers.

Composted Sewage Sludge Application Reduces Mineral Fertilization Requirements and Improves Soil Fertility in Sugarcane Seedling Nurseries

“…This increase was due to the addition of exchangeable cations such as Ca and Mg with CSS application (Table 2). Bonini et al [35] and Prates et al [13] also reported that sewage sludge positively influenced SB in a degraded Rhodic Hapludox, treated with the same CSS doses applied in our study.…”

“…Additionally, this technique stabilizes organic matter, resulting in a product that can be used safely and classified by national and international regulations as an organic fertilizer (vide infra). As a matter of fact, CSS contains large amounts of organic matter and plant nutrients, including N, P, and micronutrients [13]. Several studies have reported on the benefits that CSS can have on soil physical, chemical, and biological properties [14][15][16].…”

Independent or Combinational Application of Sheep Manure and Litter from Indigenous Field Vegetation of Quercus sp. Influences Nutrient Uptake, Photosynthesis, Intrinsic Water Use Efficiency, and Foliar Sugar Concentrations in Olive Plants (Olea europaea L., cv. “Koroneiki”)

“…Apart from the beneficial impact of organic fertilizers at reducing production costs, other beneficial roles of organic fertilizers are as follows: (i) increasing soil organic C and matter [4][5][6]; (ii) enhancing soil microbial activities and improving soil quality [7,8]; (iii) boosting yields [8][9][10]; (iv) ameliorating fruit quality [8,11]; (v) increasing root production [12]. Different kinds of organic materials and agricultural/food industry bio-products (e.g., olive mill waste composts and pomace, other kinds of composts, municipal wastes, and recycled pruning materials) are used as soil amendments and bio-fertilizers for crops [13][14][15][16][17][18]. In other cases, in order to support organic farming and ecosystem services, decrease fertilizer inputs, and enhance the sustainable management of agricultural ecosystems, the integration of laying hens with orchards and the use of cover crops were suggested [15,19].…”

Sewage sludge as a pedotechnomaterial for the recovery of soils compacted by heavy machinery on Eucalyptus commercial plantation

“…3h) showed higher concentrations during the final investigated periods (18 and 36 months) for all lower SS doses (<10 Mg ha − 1 ); also, in this case, it did not show any increase with to SS dose. Previous studies have observed similar strong variability in exchangeable-cation behavior and concentration in SS-treated soils (Guerrini et al, 2017;Abreu-Junior et al, 2019;Prates et al, 2020). Explanations for this behavior include: i) competitive adsorption processes among cations towards soil organic and mineral colloidal fractions; ii) soil leaching processes; iii) kinetic aspects as a consequence of both (i) and (ii) (Guerrini et al, 2017).…”

“…F2 (30%) showed SOM, total P, CEC, Ca, and all micronutrients (B excluded) as positively concordant while negatively correlated with pH. Such a factor showed that at increasing SOM content (related to an increase in applied SS doses): i) total P increased since SOM represented its main source into the soil environment (Capra et al, 2014); ii) CEC increased as a consequence of increased colloidal fractions, thus increasing exchangeable Ca and positively charged micronutrients (Fe, Mn, Cu, and Zn); iii) at increasing SOM content there was a concomitant increase in H + release in soil solution as a consequence of SOM degradation processes, thereby decreasing pH values (Prates et al, 2020). Factor F2 can thus be interpreted as the key role of SOM in soil micronutrient and pH behavior.…”