Evaluation of Leaf Litter Mulching and Incorporation on Skid Trails for the Recovery of Soil Physico-Chemical and Biological Properties of Mixed Broadleaved Forests

Meghdad Jourgholami,Rodolfo Picchio,Azadeh Khoramizadeh,Francesco Latterini,Angela Lo Monaco,Rachele Venanzi,Farzam Tavankar

doi:10.3390/land10060625

Meghdad Jourgholami, Rodolfo Picchio + Show 5 more

Open Access

https://doi.org/10.3390/land10060625

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Abstract

Engineering applications can be used to mitigate the adverse effects of soil compaction and amend compacted soils. Previous literature has highlighted the beneficial effects of interventions such as litter mulching and incorporation on skid trails. However, little is known about the effectiveness of these alternatives in restoring forest soil quality after forest logging. The objective of this study was to properly elucidate the effects of the above mentioned soil protection methods, litter incorporation before skidding (LI) and litter mulching after skidding (LM), on the recovery of compacted soil’s physico-chemical and biological properties on skid trails over a 2-year period in the Hyrcanian forests of Iran to identify the best option for restoration intervention. The litter used in both methods consisted of dried leaves of the hornbeam and maple tree in three intensities of 3, 6, and 9 Mg ha−1. The results showed that the application of both methods (LI and LM) significantly improved the soil properties when compared to the untreated skid trail. Results showed that the recovery values of soil properties in the LI treatments were significantly higher than those of the LM. The recovery values of soil properties by 6 and 9 Mg ha−1 were significantly higher than those of 3 Mg ha−1, while the differences were not significant between 6 and 9 Mg ha−1. Our findings showed that soil properties were partially recovered (70–80%) over a 2-year period from treatment, compared to untreated, but the full recovery of soil properties required more time to return to the pre-harvest value. Overall, the results of this study demonstrated that the application of soil protection methods accelerates the process of recovering soil properties much faster than natural soil recovery, which can take more than 20 years in these forests.

Highlights

The increase in mechanized forest harvesting and the expansion of wood production areas raises questions about the environmental impact of machine traffic on forest soil and their subsequent impact on stand productivity [1,2,3]
The highest soil bulk density, penetration resistance, and amount of sand was found in the untreated skid trail (UNT), followed by LM3, LM6, and LM9, whereas the lowest soil bulk density, penetration resistance, and amount of sand was detected in the undisturbed (control) treatments (UND)
The results of the current study revealed that the higher level recovery of soil bulk density, total porosity, and macroporosity were detected in the litter incorporation treatments (i.e., LI3, LI6, and LI9), which was more than the litter mulching treatments (i.e., LM3, LM6, and LM9), as compared to the UNT

Summary

Introduction

The increase in mechanized forest harvesting and the expansion of wood production areas raises questions about the environmental impact of machine traffic on forest soil and their subsequent impact on stand productivity [1,2,3]. Soil compaction caused by heavy machinery in skidding operations dramatically reduces the balance and regulation of forest fertility by destroying the soil structure and disrupting the physical properties of the soil [8,9]. As a result, these phenomena led to a decrease in porosity [10], a reduction in the connection of pore spaces [11], and an increase in density and soil strength [12]. It can take several years to several decades to recover soil properties after compaction and restore it to the same pre-machine traffic conditions [2,9,10,19]

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