Search

Roots of crop species produce exudates with biologically active chemicals which are known to affect the growth of crops and weed species. An experiment was conducted at the Uganda National Crop Resources Research Institute, Namulonge during 2016 to identify compounds released in root exudates of potted Cymbopogon nardus, Desmodium uncinatum, upland rice (NERICA 1), Mucuna pruriens and Zea mays (LONGE 6H) at forty-five days after planting. This marked near the average stationary phase for test crop growth when secondary metabolite levels were high. Organic compounds in soils were extracted using solid-phase micro-extraction (SPME) and by solvent extraction. Samples were subjected to analysis using a 7890A Gas Chromatography system. Data files were transferred into a distinct folder and data was uploaded onto the XCMS online platform for pairwise comparison and other related statistical analyses in the National Institute of Science and Technology Library. The blank soil produced 15 terpenoids, two alcohols and one each of trihalomethanes, ethers, phenols, ketones, furans, alkanes and aldehydes. Cymbopogon exuded five terpenoids, one phenol and an alkane. Desmodium plant roots released three terpenoids, one alkane and a phenol. The rice crop produced eight terpenoids, two alkanes and a furan. Five terpenoids, one phenol and an alkane were released by the mucuna crop, while six terpenoids were found in maize soil. The profiled compounds from cymbopogon, desmodium, rice, mucuna and maize could be responsible for allelopathic properties expressed by the study crops in natural and agricultural ecosystems and could be used in synthesis and development of herbicides.

Microorganisms are involved in the formation of soil fertility, both potential and effective. They facilitate the processes of humification and dehumification and play a key role in the cycling of nutrients - macro and microelements. Rhizosphere is the soil in direct contact with plant roots and influenced by plant exudates. Root exudates of maize significantly affect the composition and abundance of microorganisms in the rhizosphere. Bio-fertilizers are microbial fertilizers composed of highly effective strains of bacteria, algae and fungi isolated from soil. Their application activates microbial processes that secure a better and steadier supply of plants with nitrogen, phosphorus, potassium and some micronutrients. The application of PGPR-containing biofertilizers reduces the need for expensive nitrogen fertilizers, facilitates phosphorus uptake by plants and affects the direction and dynamics of microbial processes.

Copyright of Field & Vegetable Crops Research / Ratarstvo i povrtarstvo is the property of Institute of Field & Vegetable Crops and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)