Soil organic matter (SOM) is a crucial component of soil, through which physical, chemical, and biological characteristics interact in a local context. Within the forest category, the conversion of natural forests to monoculture plantations has raised concerns in Indonesia over the loss of soil functions, similar to conversion to agriculture. In natural forests, SOM can accumulate as part of a closed nutrient cycle with minimal nutrient losses; in plantation forestry, SOM decline and recovery can alternate over time, associated with larger nutrient losses. We reviewed existing studies to quantify how shifts from natural forests to short-rotation plantation forests (SRPF) affect SOM dynamics, soil nutrient contents, and soil-borne pathogens that cause disease. The review combines descriptive and quantitative methods (meta-analysis). The results show that conversion affects the soil C balance, soil structure and water balance, soil nutrient balance, and soil-borne diseases. Contributing factors include the reduced diversity of plant and rhizosphere communities, lower annual litter production, more uniform litter quality, and nutrient removal at the harvest cycle. Conversion from natural to plantation forest conditions also increases plant disease incidence by changing biological control mechanisms.

AbstrakWalaupun tersembunyi di dalam tanah komunitas rhizosfir merupakan penentu kehidupan di muka bumi dan berperan penting pada pelestarian alam. Rhizosfir merupakan daerah di sekitar perakaran tanaman yang dihuni oleh berbagai mikrobia tanah yang berperan dalam menentukan pertumbuhan dan kesehatan tanaman. Struktur dan komposisi komunitas mikrobia sangat dipengaruhi oleh macam, konsentrasi dan komposisi eksudat akar. Perubahan yang terjadi pada tanaman (umumnya sangat dipengaruhi oleh aktivitas manusia) mempengaruhi komunitas rhizosfir, sebaliknya komunitas rhizosfir akan menentukan struktur tumbuhan dan fungsi ekosistem. Review ini membahas pengaruh aktivitas manusia yang mempengaruhi kualitas lingkungan terhadap komunitas mikrobia di rhizosfir, yang merupakan hasil kajian dari berbagai sumber terbaru yang dianalisis secara induktif. Aktivitas manusia yang dikaji meliputi praktek pertanian intensif, deforestasi hutan menjadi perkebunan serta perubahan iklim. Hasil kajian menunjukkan bahwa praktek monokulturisasi telah menurunkan biodiversitas mikrobia rhizosfir, menurunkan kinerja enzim tanah dan menurunkan keragaman dan konsentrasi senyawa glukosinolat untuk melawan patogen. Pengolahan tanah, pemupukan anorganik dan penggunaan pestisida telah menurunkan biodiversitas mikrobia rhizosfir. Sebaliknya pemupukan organik tidak berpengaruh terhadap biodiversitas mikrobia tanah. Perubahan fungsi hutan menjadi kebun intensif telah merubah dominansi kelompok mikrobia serta kemampuan mikrobia sesuai fungsinya di ekosistem. Perubahan iklim berdampak pada peningkatan suhu tanah, hal ini telah mengubah komposisi mikrobia rhizosfir. Perubahan komposisi, dominansi dan kemampuan mikrobia di rhizosfir tersebut dapat merubah komposisi populasi tumbuhan di atasnya. Hal ini dapat mengubah keseimbangan dan fungsi ekosistem yang berakibat pada berubahnya kesejahteraan manusia.AbstractEven though it is hidden underground, rhizosphere communities define the life in this earth planet and has an important role on nature preservation. Rhizosphere is the zone of soil adjacent immediately to plant roots which inhabited by varies species of beneficial soil microbes for facilitating plants growth and health. Human activities are strongly influence on plant performance. Alteration on plant growth and health statues determine rhizosphere communities that will define the vegetation structures and ultimately ecosystem functions. This paper discuss the negative influences of human activities (anthropogenic factors) on the environment to the rhizosphere communities. Especially the impacts of intensive farming, deforestation and climate changes. It is sourced from current referrences in inductive analysis. One of intensive farming management is monoculture that is not only drastically depleted microbes diversity in the rhizosphere hence decresed soil enzimes activities, but also reduced glucocynolates production, a crucial compound against pathogen. Whereas, tillage, fertilizers and pesticide application significantly diminished microbe biodiversity. Organic fertilizers, on the other hand, did not give crucial impacts this biodiversity. Modify forest into estate have changed domination of groups and lessened capability of phosphate solubilizers. While climate changes, that enhance soil temperature escalation, have altered rhizosphere microbes composition and structure. Replacement of composition, domination, abundance and capability of rhizosphere communities will modify composition and structure of vegetation aboveground. Eventually, will alter the ballance and functions of the ecosystem, which determine the wealth of human population in the earth.

Pruning is a removing some parts of the tree canopy, either for improving tree shape or increasing shoot productivity.\ud It can be implemented in yield management of commodities that are harvested its shoot biomass, such as tea or\ud kilemo. This activity interferes plant growth, hence affect root secretion. Consequently, it alters soil microbe\ud populations in the rhizosphere. This paper observes the impacts of pruning on fluctuation of root exudates (soil\ud sugar) and rhizosphere communities of 2-years-old kilemo (Litsea cubeba L. Pers.). Tree samples were pruned by\ud removing shoots above the lowest branches. A month after cutting, trees fertilized using 3 types of fertilizers: leaf,\ud NPK, and organic fertilizer. As a control, there were non-fertilized treated trees. To observe the root exudation and\ud th th th th\ud microbes populations, 0−20 cm depth of soil at rhizospheres were collected from 10 , 30 , 60 , and 90 day after\ud pruning. Samples were further analyzed for observing the amount of soil-sugar and microbes population, such as Nfixer, cellulose degrader, and phosphate solubilizer. Results show that kilemo root drastically decreased their sugar\ud exudation by 22% (10th day), 28% (30th day), 44% (60th day), and 70% (90th day), respectively. Therefore, those\ud populations were significantly depleted. Rhizosphere sugar can be improved by fertilization, however, the\ud augmentation did not enhance the rhizosphere communitie

Arbuscular mycorrhizal fungi (AMF) support plant establishment and soil recovery in degraded lands, yet their long-term associations with vegetation in restored quarries remain poorly understood. This study quantified AMF spore density and genus-level occurrence in pioneer-plant rhizospheres at a cement quarry revegetated more than two decades earlier. AMF infective potential was assessed using Pueraria javanica trap cultures. Relationships among AMF attributes, vegetation strata, rhizosphere flavonoids, and soil chemical properties were evaluated using mixed-effects, correlation, and multivariate analyses. Trap-culture colonization was high across tree-, shrub-, and herb-associated inocula, with no significant difference among vegetation strata. Spore density differed significantly among strata and was highest in herbaceous rhizospheres, including Imperata cylindrica, Cymbopogon citratus, and Themeda gigantea; Eupatorium odoratum also supported high density among shrubs. Available phosphorus was the only soil property that remained significantly associated with spore density after accounting for vegetation stratum and plant species. Exchangeable potassium and soil organic carbon were positively correlated with spore density but did not remain significantly associated in the adjusted models. Total flavonoids differed strongly among vegetation strata but were not significantly associated with field AMF spore density after adjustment for vegetation stratum and plant species and were not correlated with trap-culture colonization or genus richness. Glomus sensu lato was the most frequently detected taxon. Trap-culture colonization of 70–90% and the positive association between available phosphorus and field spore density suggest that AMF propagule metrics may serve as candidate indicators of belowground condition in long-term tropical quarry restoration.