soil fungi are key players in nutrient cycles as decomposers, mutualists and pathogens, but the impact of tropical rain forest transformation into rubber or oil palm plantations on fungal community structures and their ecological functions are unknown. We hypothesized that increasing land use intensity and habitat loss due to the replacement of the hyperdiverse forest flora by nonendemic cash crops drives a drastic loss of diversity of soil fungal taxa and impairs the ecological soil functions. Unexpectedly, rain forest conversion was not associated with strong diversity loss but with massive shifts in soil fungal community composition. Fungal communities clustered according to land use system and loss of plant species. Network analysis revealed characteristic fungal genera significantly associated with different land use systems. Shifts in soil fungal community structure were particularly distinct among different trophic groups, with substantial decreases in symbiotrophic fungi and increases in saprotrophic and pathotrophic fungi in oil palm and rubber plantations in comparison with rain forests. In conclusion, conversion of rain forests and current land use systems restructure soil fungal communities towards enhanced pathogen pressure and, thus, threaten ecosystem health functions.Tropical rain forests are the planet's most species-rich biomes 1 . In the past two decades, tropical rain forests in many parts of the world have been rapidly converted to monospecific plantations 2 . As a result, deforestation and human land use have irretrievably destroyed large areas of unique rain forests and enforced biodiversity loss 3,4 . High plant diversities are associated with active, abundant and diverse fungal communities 5-7 . Plant diversity was, therefore, predicted to be a strong driver of fungal species richness in soils of tropical rain forests 7-9 . However, the consequences of rain forest transformation into agricultural land for soil fungal diversity and the ecological functions of these fungi are not well understood.Soil fungi are integral components of ecosystems, driving nutrient cycling as decomposers 10-13 , regulating species composition as pathogens 14 and providing mutualistic benefits as symbiotrophs, thereby playing a key role in biogeochemical processes 15,16 and in soil health 17,18 . Because of their important functions, the impact of deforestation and land use intensification on soil fungal communities in the tropics is receiving increasing attention. To date, only a few studies have used next-generation sequencing methods to characterize soil fungal communities after the conversion of rain forests into agricultural land [19][20][21][22] . Those studies focused mainly on distinct fungal groups such as mycorrhizae and the turnover of their community structure in response to distinct land use systems such as the conversion of rain forest into pasture or cash crop plantations with oil palms or rubber trees [19][20][21][22] . However, approaches linking land use systems or aboveground vegetation divers...

Conversion of tropical forests into intensely managed plantations is a threat to ecosystem functions. On Sumatra, Indonesia, oil palm (Elaeis guineensis) plantations are rapidly expanding, displacing rain forests and extensively used rubber (Hevea brasiliensis) agro-forests. Here, we tested the influence of land use systems on root traits including chemical traits (carbon, nitrogen, mineral nutrients, potentially toxic elements [aluminium, iron] and performance traits (root mass, vitality, mycorrhizal colonization). Traits were measured as root community-weighed traits (RCWTs) in lowland rain forests, in rubber agro-forests mixed with rain forest trees, in rubber and oil palm plantations in two landscapes (Bukit Duabelas and Harapan, Sumatra). We hypothesized that RCWTs vary with land use system indicating increasing transformation intensity and loss of ecosystem functions. The main factors found to be related to increasing transformation intensity were declining root vitality and root sulfur, nitrogen, carbon, manganese concentrations and increasing root aluminium and iron concentrations as well as increasing spore densities of arbuscular mycorrhizas. Mycorrhizal abundance was high for arbuscular and low for ectomycorrhizas and unrelated to changes in RCWTs. The decline in RCWTs showed significant correlations with soil nitrogen, soil pH and litter carbon. Thus, our study uncovered a relationship between deteriorating root community traits and loss of ecosystem functionality and showed that increasing transformation intensity resulted in decreasing root nutrition and health. Based on these results we suggest that land management that improves root vitality may enhance the ecological functions of intense tropical production systems.

Protists, abundant but enigmatic single-celled eukaryotes, are important soil microbiota providing numerous ecosystem functions. We employed high-throughput sequencing of environmental DNA, targeting the V4 region of the 18S rRNA gene, to characterize changes in their abundance, species richness, and community structure with conversion of lowland rainforest into rubber agroforest (jungle rubber), and rubber and oil palm plantations; typical agricultural systems in Sumatra, Indonesia. We identified 5,204 operational taxonomic units (OTUs) at 97% identity threshold of protists from 32 sites. Protists species richness was similar in rainforest, jungle rubber and oil palm plantations but significantly lower in rubber plantations. After standardization, 4,219 OTUs were assigned to five trophic groups, and inspected for effects of land-use change, and potential biotic and abiotic driving factors. The most abundant trophic group was phagotrophs (52%), followed by animal parasites (29%), photoautotrophs (12%), plant parasites (1%), and symbionts (<1%). However, the relative abundance and OTU richness of phagotrophs and photoautotrophs increased significantly with increasing land-use intensity. This was similar, but less pronounced, for the relative abundance of symbionts. Animal and plant parasites decreased significantly in abundance and species richness with increasing land-use intensity. Community compositions and factors affecting the structure of individual trophic groups differed between land-use systems. Parasites were presumably mainly driven by the abundance and species richness of their hosts, while phagotrophs by changes in soil pH and increase in Gram-positive bacteria, and photoautotrophs by light availability. Overall, the results show that relative species richness, relative abundance, and community composition of individual trophic groups of protists in tropical lowland rainforest significantly differ from that in converted ecosystems. This is likely associated with changes in ecosystem functioning. The study provides novel insight into protist communities and their changes with land-use intensity in tropical lowland ecosystems. We show, that trophic groups of protists are powerful indicators reflecting changes in the functioning of ecosystems with conversion of rainforest into monoculture plantations.

The use of NPK fertilizer and bokashi composting, which is a fermented organic matter combined with microbial stock, have been reported as potential agricultural practices to enhance the farming land and crop production. The aim of this research is to understand the type of bokashi fertilizer and the correct dosage of NPK inorganic fertilizer in improving entisol soil quality and shallot yield in the dry land. The research used the split-plot design, which was divided into two factors. The first factor of the main plot was the bokashi type consisting of two levels: 3 t ha-1 of bokashi compost of Gliricidia sp. tree leaves (B1); and bokashi cow manure 3 t ha-1 (B2). The second factor as the subplot was the NPK inorganic fertilizer dose which were consisted of four levels: without fertilizers (K0), NPK 100 kg ha-1 (K1), NPK 200 kg ha-1 (K2), and NPK 300 kg ha-1 (K3). By combination of these two factors 8 combined treatments with 3 replications totally 24 units were obtained. The result of the research showed that application of 3 t ha-1 bokashi cow manure (B2) coupled with NPK inorganic fertilizer at 200 kg ha-1 (K2) caused a decrease in evaporation of its land and soil temperature, while increase shallot bulb yield compared with other treatments. The analysis of soil and soil microbes showed an increase in soil fertility by elevated levels of C-organic from 0.66 % to 3.28 %, N-fixing bacteria from 27 x 10 5 CFU ml-1 to 47 x10 6 CFU ml-1 and phosphate solubilizing bacteria from 20 x10 3 CFU ml-1 to 90 x10 3 CFU ml-1. The shallot bulb yield increased from 4.79 t ha-1 to 11.74 t ha-1 .

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Conversion of lowland tropical rainforests to intensely fertilized agricultural land-use systems such as oil palm (Elaeis guineensis) plantations leads to changes in nitrogen (N) cycling. Although soil microbial-driven N dynamics has been largely studied, the role of the plant as a major component in N uptake has rarely been considered. We address this gap by comparing the root N contents and uptake in lowland rainforests with that in oil palm plantations on Sumatra, Indonesia. To this aim, we applied 15 N-labeled ammonium to intact soil, measured the 15 N recovery in soil and roots, and calculated the root relative N uptake efficiency for 10 days after label application. We found that root N contents were by one third higher in the rainforest than oil palm plantations. However, 15 N uptake efficiency was similar in the two systems. This finding suggests that lower N contents in oil palm roots were likely caused by plant internal utilization of the absorbed N (e.g., N export to fruit bunches) than by lower ability to take up N from the soil. 15 N recovery in roots was primarily driven by the amount of root biomass, which was higher in oil palm plantation than rainforest. The oil palms unveiled a high capacity to acquire N, offering the possibility of enhancing sustainable plantation management by reducing N fertilizer application.

At the oil palm landscape, conserving biodiversity and ecosystem processes can range from continuous adjacent forest remnant to tree patches (agroforestry) maintained within the oil palm landscape on steep slopes and riparian margins. The objective of the research was to analyze patched of tree planting inside monoculture oil palm plantation (agroforestry) as one variant of landscape multifunctionality for enhancing biodiversity-based ecosystem functions including soil macrofauna, soil water recharge/retention, and pollinators. The observation was carried out in 2019 in agroforestry islands established in 2013 by EFForTS research project inside monoculture oil palm plantation. At the agroforestry age of 5 years in 2019, the abundance of individual soil fauna in agroforestry plots and oil palm plantation was not significantly different. The infiltration and soil big pores in agroforestry tended to be higher than in oil palm active rows. Pollinator species richness was not significantly different in all plant diversity levels and plots. Similar to its richness, pollinator abundance is neither affected in different plant diversity levels nor plots. The lack of pollinator presence may be caused by the haze from forest and land fires that happened during the research.

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