In recent years, oil palm has grown on a major scale as it is a prominent commodity crop that contributes the most to almost every producing country’s gross domestic product (GDP). Nonetheless, existing threats such as the Ganoderma basal stem rot (BSR) disease have been deteriorating the oil palm plantations and suitable actions to overcome the issue are still being investigated. The BSR disease progression in oil palm is being studied using the disease progression through the plant disease triangle idea. This concept looks at all potential elements that could affect the transmission and development of the disease. The elements include pathogenic, with their mode of infection in each studied factor.

This study was performed to i) compare root distribution of legume/non-legume intercrops determined by qPCR and amplicon sequencing (Meta-barcoding) to root growth of the individual species determined visually, and ii) compare the qPCR and amplicon sequencing techniques as a method for quantifying root growth of individual species grown in mixtures. Red beet (Beta vulgaris L. cv Detroit) and lucerne (Medicago sativa L. cv Creno) were grown in one-meter-high transparent tubes. Root competition was studied by direct observation on the tube surface determining root intensity (RI), root wash and extraction followed by determination of root length density (RLD), and DNA based methods. Intercropping decreased lucerne RI strongly, whereas the RI of red beet was not affected. The determination of RLD did not allow us to distinguish species in mixed samples. However, both DNA methods showed apparently a tendency to overestimate the fraction of lucerne roots compared to the direct root observations. The discrepancy between methods was explained by the fact that visual methods provide estimates of root length while the DNA methods provide estimates of root mass. In conclusion, DNA based estimates of species fractions in mixed root samples give valuable information on root interactions in mixed crops.

Tropical forests play an important role in carbon storage, accumulating large amounts of carbon in their aboveground and belowground components. However, anthropogenic land-use activities have increasingly threatened tropical forests, resulting in accelerated global greenhouse gas emissions. This research aimed to estimate the carbon stocks in soil, organic layer, and litterfall in tropical montane forests under three different land uses (intact forest, logged-over forest, and plantation forest) at Long Mio, Sabah, Malaysia. Field data were collected in a total of 25 plots from which soil was randomly sampled at three depths. Litterfalls were collected monthly from November 2018 to October 2019. The results showed that the soil in the study area is Gleyic Acrisol, having pH values ranging between 4.21 and 5.71, and high soil organic matter contents. The results also showed that the total soil carbon stock, organic layer, and litterfall is higher in the intact forest (101.62 Mg C ha⁻¹), followed by the logged-over forest (95.61 Mg C ha⁻¹) and the plantation forest (93.30 Mg C ha⁻¹). This study highlights the importance of conserving intact forests as a strategy to sequester carbon and climate change mitigation.

Macropropagation using cutting for larger multiplying seedlings is cheaper and efficient instead of clonal seeds for uniform plant material seedling production. However, information on root growth of Eucalyptus pellita at early development from seed and stem cutting of E. pellita seedlings is still lacking. With such information, it is useful for forest plantation company management in enhancing the understanding of strategies to optimize yield production with the appropriate agronomic or silvicultural approach in the field of planting. Therefore, the objectives of this study were to compare the root development of two different types of propagation seedlings of E. pellita and to study the effect of various nitrogen concentration levels on two different types of propagation of E. pellita seedlings. The study was conducted using E. pellita seedlings from two different types of propagation, namely, seed and stem cuttings, along with three different nitrogen concentrations (0, 50, and 200 kg N ha−1). Shoot biomass, root intensity (RI), total root intensity (TRI), root biomass, root length density (RLD), and specific root length (SRL) were recorded. Dried shoot biomass, RLD, and SRL of E. pellita seedlings using stem cutting were significantly higher ( P < 0.05 ) compared to seed, whereas there were no significant differences ( P > 0.05 ) for root biomass, TRI, and RI between the propagation types of E. pellita seedlings. In conclusion, E. pellita seedlings from stem cutting were greater in terms of root distribution compared to propagation by seeds at the nursery stage, and 50 kg N ha−1 was the optimal nitrogen concentration level from the considered levels to be applied to the E. pellita seedlings.

Naturally coloured roots as a tool for studying root interactions in mixed cropping | Affendy Hassan, Dorte Bodin Dresbøll, Kristian Thorup-Kristensen | Agricultural Journals

Falcataria moluccana (Miq.) Barnaby & Grimes is an important species for forest plantation programmes in Malaysia and is widely used in the wood industry. However, its root interactions have not been widely investigated due to the limited methodologies and information about the root distribution of trees and crops in forest plantation and agroforestry systems. This study was conducted to determine the rhizotron-scale root interactions of F. moluccana at different tillage and nitrogen concentrations under four different treatments: control, tillage, fertiliser, and tillage with fertiliser. The rhizotron-scale experiment was conducted at a greenhouse where F. moluccan a (Batai) seedlings were transplanted in transparent rhizotron tubes (onemetre-high transparent polycarbonate solid sheet) using topsoil and river sand to simulate natural growing conditions. Root Intensity (RI), Root Length Density (RLD), Specific Root Length (SRL), dried shoot bio-mass and root biomass were recorded. Root biomass and SRL were notably higher (25–50 cm depth) at 6 WAT (Weeks After Transplanting), and the shoot biomass (tillage + fertiliser) was significantly higher at 14 WAT. However, plants treated with different tillage and nitrogen concentrations showed no significant impact on the RI and RLD. Fertiliser treatment only, and tillage with fertiliser treatment, showed greater root distribution at the rhizotron scale. These findings contribute to forest plantation and natural forest rehabilitation efforts by helping optimise the soil resources within ecosystems for sustainable forest management.