Soil Organic Carbon in Forest and Other Land Use Types at Bengkulu City, Indonesia

Abstract

Conversion of natural forest into agricultural land uses has decreased soil organic carbon (SOC) and increased carbon emission into the atmosphere, but proper management of agricultural land can sequester carbon from the atmosphere and increase the SOC. This study was conducted to estimate the SOC content and storage in a forest, agroforestry land, oil palm plantation, and agricultural experimental field and to analyze the correlation between the SOC and other soil characteristics at Bengkulu City, Indonesia. Soil were sampled from the following depths: 0–10 cm, 10–20 cm, and 20–30 cm. The biomass of litter and ground cover was also sampled. This study found that the forest had the highest average SOC content from the three depths, and 0–30 cm depth SOC storage, while the agroforestry system had the lowest of both SOC content and storage. The 0–10 cm depth had the highest SOC content and storage, while the 20–30 cm depth had the lowest of both variables. The SOC was positively correlated with litter biomass, field capacity, exchangeable potassium, cation exchange capacity, and negatively correlated with bulk density and exchangeable calcium, but not correlated with total nitrogen and available phosphorus. High litter biomass input is the key to the maintenance of high SOC.

Soil Carbon Storage in Forest and Agriculture Land Use in the Tanralili Watershed

“…Compared to active agricultural land with annual crops, the biomass is rather low, so the carbon content is also low. [14] in a forest litter biomass will continue to be contributed by fallen leaves and branches. This litter enriches the soil with organic matter which will break down into humus, so it is not surprising that the soil carbon stock is highest in forests.…”

Assessing soil properties in various agroforestry lands in Kuningan District, West Java, Indonesia using Visual Evaluation of Soil Structure (VESS)

“…C-organic soil in the agroforestry area was 1.29-2.36%, which was less than 5%. Generally, tropical natural vegetation sites have C-organic values that exceed 5% due to the high litter produced by their constituent vegetation (Wiryono et al 2021). The low value of organic C on land is related to vegetation species that have not reached balance.…”

“…Litterfall helps the natural return of soil nutrients into the soil in addition to other inputs such as fertilization activity. The soil covered by litter, continuous input of C-organic into the soil and the absence of disturbance is the main drivers of soil aggregation and improvement of soil physical quality under natural vegetation (Auler et al 2017;Cherubin et al 2017;Guimarães et al 2017b, Wiryono et al 2021). The natural forest has a higher diversity and activity of soil biota than agricultural land (Franco et al 2016).…”

Ecosystem services provided by agroforestry home gardens in Bengkulu, Indonesia: Smallholder utilization, biodiversity conservation, and carbon storage

“…In addition to conserving biodiversity and providing several agricultural products, the agroforestry system also sequesters carbon from the atmosphere and stores it in the plant biomass and soil (Wiryono et al 2016;Wiryono et al 2021). Having trees that live long and have large stems, the agroforestry system has larger above-ground carbon stock than cultivation land with seasonal crops.…”