Reuse of Pruning Waste from Subtropical Fruit Trees and Urban Gardens as a Source of Nutrients: Changes in the Physical, Chemical, and Biological Properties of the Soil

Abstract

A field experiment was conducted on the Andalusian coast (Granada, Southern Spain) to study the time course of nutrient release into the soil after the addition of bagged pruning waste from subtropical orchard trees (avocado, cherimoya, and mango) and urban garden waste over three two-year periods. N, P, and K concentrations were greater in the garden waste, whilst avocado and cherimoya pruning waste registered the highest values for Mg. In general, micronutrient contents were low in all waste, especially Cu. Macronutrient release followed a three-phase dynamic: fast initial release, intermediate stabilization, and final increase. Garden waste showed a similar time course in all three trees and released greater concentrations of K and P. The annual decomposition rate factor k was negative for N and Ca in the avocado tree, indicating strong biological activity in this plot. Avocado, cherimoya, and garden waste showed a good microbial degradation, improving soil quality by increasing carbon and nitrogen contents as well as soil microbial activity. As for the mango tree, its special microclimatic conditions appeared to favor waste photodegradation, thus eliminating nutrients that were not incorporated into the soil. Soil enzymatic activities increased in the avocado and cherimoya trees with the addition of all waste. In the mango tree, only an increase in urease was detected after the addition of garden waste. Our results suggest that the time course of organic waste in different subtropical trees grown on similar soils is significantly conditioned by the microclimatic characteristics.

Design of a pyrolysis system and the characterisation data of biochar produced from coconut shells, carambola pruning, and mango pruning using a low-temperature slow pyrolysis process

“…The data for these analyses can be accessed from the data files entitled “CHNS Analyses.xlsx”, “Physicochemical and calorific value.xlsx”, and “Porosity BET.xslx” in the Mendeley repository. The data indicated that the elemental composition of the raw materials was comparable with that of other materials [1 , 2] . Meanwhile, the carbon content of the biochar was higher than that of the raw materials and surpassed 50% elemental composition, indicating that the product materials (biochar) conserved high percentages of carbon.…”

Determination of polycyclic aromatic hydrocarbons in bud-derived supplements by magnetic molecular imprinted microparticles and GC-MS: D-optimal design for a fast method optimization

“…A potential alternative source could be represented by city pruning. Every year, tons of plant material is cut from urban trees and considered as waste, ignoring its potential value 9 , 10 . Instead, the 3-R principle of circular economy (reduce, reuse and recycle) conveys a much more rational exploitation of environmental resources 11 .…”

“…Instead, the 3-R principle of circular economy (reduce, reuse and recycle) conveys a much more rational exploitation of environmental resources 11 . This objective involves the recovery of molecules of interest from by-products or waste, to generate benefits for several productive sectors 9 , 12 .…”