Aboveground Biomass, Carbon Sequestration, and Yield of Pyrus pyrifolia under the Management of Organic Residues in the Subtropical Ecosystem of Southern Brazil

Abstract

Organic residues management (ORM) alter plant traits and soil properties by changing nutrient and carbon cycling. It is unclear how ORM (mulching, compost, and their combination) applied for 18 months creates a mechanism to promote changes in a P. pyrifolia field. Our aim was to evaluate the influence of ORM on P. pyrifolia nutritional status, plant traits, yield, and carbon sequestration in a 16-year subtropical P. pyrifolia field. For this purpose, we performed an experiment in a randomized block design, using a factorial scheme 2 × 2, with the use of Compost and Mulching (e.g., presence and absence). The highest values of leaves N content, plant height, stem biomass, root biomass, total biomass, yield, and above- and belowground carbon (C) density were found on plots that received compost as the ORM. For soil organic C stock, the highest values were found on plots where mulching was applied. Finally, the highest values of total C density were found on plots that received the combination of Mulching and Compost. Our findings suggest that: (i) the use of Compost is the best alternative to promote leaves N content, plant height, stem dry biomass, root dry biomass, and total dry biomass, plant yield, and above- and belowground C density into a 16-year P. pyrifolia field into subtropical conditions; and (ii) the soil organic C stocks were improved using just the mulching treatment. The results highlight the importance of considering just one organic residue practice based on a sustainable way to improve both plant production and carbon sequestration, no differences were found between the use of compost and the combination of compost and mulching.

Forest–Fruticulture Conversion Alters Soil Traits and Soil Organic Matter Compartments

“…On the other hand, by considering the soil layers, the highest values of p-SOC were found in the topsoil due to the high deposition rate of litter and their decomposition. Thus, the maintenance of p-SOC content depends on the litter input in a way that benefits the soil organic matter mineralization [ 22 ], and this SOM fraction is more influenced by land uses than SOC [ 23 ]. Thus, the p-SOC can be used as a good indicator of soil quality for short-term land uses [ 24 ].…”

“…The total organic carbon was determined by the rapid dichromate oxidation method following the protocol described in Okalebo et al [ 44 ]. Soil organic carbon stock (SOC stock) was determined as described by da Silva et al [ 23 ]. The physical fractioning of the soil organic matter was carried out following the methodology described by Cambardella and Elliot [ 45 ].…”

“…We used Bonferroni’s test (“stats” package) to compare the variables at plots with the different crop systems and soil depths. We performed a principal component analysis (PCA) using the “vegan” package to outline the dissimilarities among the soil’s physicochemical traits, the soil organic matter fractions, and the studied crop systems [ 23 ].…”