Effect of pellets made of waste materials from the paper industry enhanced with seaweed (Ulva lactuca L.) on N mineralization and lettuce production

Abstract

The need to reduce the use of traditional fertilizers and prevent soil degradation demands the search for new ways of fertilization. The combined application of waste materials (generated by the paper industry) and seaweed may be an alternative source of fertilization. The objective of this study was to evaluate the effect of pellets made of waste materials ash and sludge, produced by the paper industry with the addition of seaweed (Ulva lactuca L.) on the production of lettuce (Lactuca sativa L.) as an indicator plant and N mineralization in the soil. Two trials were conducted on an Entisol soil. The first trial evaluated the productive response of lettuce to the combined application of pellet+seaweed. Lettuce plants were grown in pots under greenhouse conditions for 3-mo. Three types of pellets, with and without seaweed added, were applied in doses of 10, 20, and 30 t ha . N mineralization was measured by 12 wk incubation, evaluating the three types of pellets with and without the addition of seaweed. The results showed that all the combined pellet+seaweed treatments had higher aerial biomass production (p ≤ 0.05) and increased chlorophyll content. The aerial biomass production reached 4.16 g pot -1 and was 7-fold higher than pellet treatments without seaweed, while chlorophyll content was 17% higher (p ≤ 0.05). In terms of N mineralization, the maximum release was recorded in the Pellet 3+seaweed treatment, reaching 55 mg kg -1 . All the treatments with seaweed (p ≤ 0.05) better higher N mineralization values compared to the treatments without seaweed. Similarly, increased values for potentially mineralizable N and mineralization rate constant were observed in the treatments that included pellets+seaweed and seaweed alone compared to those consisting of pellets alone. The pellets+seaweed amendments resulted in an increase in soil N mineralization and production parameters of lettuce.

Pelletized paper mill waste promotes nutrient input and N mineralization in a degraded Alfisol

“…The control treatment had relatively stable net N mineralization rates between 30 and 60 d incubation (between 4.32 and 6.65 mg kg -1 , Table 5) and the lowest was at 15 d. Net mineralized N displayed contrasting behaviors in the incubation of Alfisol amended with pellets, depending on pellet type and dose, because of the low contribution of C from sludge and ash for soil microorganism development (Table 2). This contrasted with findings by San Martin et al (2016), who supplemented pellets with seaweed. Organic N sources applied to soils with less C, as an energy source for microorganisms, reduced N losses because of a lower mineralization rate and prevented N 2 O generation.…”

“…These residues would otherwise be discarded in sanitary landfills, thus giving them a further use as degraded soil fertility enhancers for their input of nutrients, such as K, Ca, P, to improve acidic soils (Park et al, 2012) and activate N mineralization attributable to organic C from sludge (San Martin et al, 2016). Pelletizing is also important because it allows handling two different waste mixtures under controlled proportions, facilitates transport, and is applied to the soil with conventional agricultural machinery, which provides an adequate dose and uniform application.…”

“…Pelletizing technology allows the sustainable use of waste that can be reused and recycled (Brannvall et al, 2015;San Martin et al, 2016). Therefore, future research is necessary to continue evaluating binders that are more suitable than gypsum, testing sludge/ash proportions, or incorporating another type of waste from the pulp and paper industry.…”

Nitrogen mineralization in an Alfisol amended with thermoelectrical industry by-products

“…Treatments Control, M 4 and M 5 presented a decrease in N MN concentration in the last week of incubation generating differences between them (p < 0.05). The behavior of N MN concentration observed in Figure 1 is similar to that reported by Laos et al (2000), Mohanty et al (2013) andSan Martín et al (2016), who observed a steady increase in N MN concentration with mild lows between weeks. These results also were similar in all treatments to the results of Masunga et al (2016) using different amendments used in agriculture from animal and green origin.…”

Effect of a Newly Developed Pelleted Papermill Biosolids on Crop and Soil

“…They also reported that anion exchange extractable soil NO 3 -N was decreased by application of a deinking PB with C:N ratio of 65 (N-immobilization) and increased with application of a combined (primary and secondary treated) PB with C:N ratio of 14 [8]. Net N mineralization in an Entisol amended with 10 Mg•ha −1 of a PB (C:N = 15.5) was not significantly more than that of the non-amended soil San Martin et al (2016) [9]. In general application of PB with wide C:N ratio had increased N immobilization but application of PB with low C:N ratio had increased soil inorganic N Nunes et al (2008) [10], Cabral et al (1993) [11].…”