The present study assessed the effect of   Arbuscular mycorrhizal fungi on nutrient uptake and soil enzyme activity of tobacco rhizosphere under parasitic weed stress condition. The experiment was carried out in Orobanche infested soils of Belagavi district during 2018-19. During the investigation different inoculation methods of Arbuscular mycorrhizal fungi were screened for their ability to improve the nutrient uptake and soil enzyme activity i.e. (pre inoculation of nursery seedlings; direct soil application and the combination of both). The present experimental results revealed that soil enzyme activities like dehydrogenase, phosphates and urease activity was highest in treatments received planting of pre colonized tobacco seedling with STD AMF along with soil application at the time of planting and second highest was recorded in the treatment received pre colonized UASDAMFT plus soil application. Furthermore nutrient uptake like N, P, K and micronutrients were found to be the highest in the plots received mycorrhization compare to the rhizosphere of non mycorrhized plants. In mycorrhizosphere the activity of mycorrhizal fungi and other beneficial microorganisms could be a source for different soil enzyme needed for biochemical reaction in the plant rhizosphere.

Landslides cause major loss of natural forest ecosystem and it is negatively impact on forest land by depleting soil biological, physical and chemical properties to reduce crop productivity. The present study was conducted to assess the impact of landslides on soil quality of central Western Ghats regions of Karnataka. Soil samples were collected from Adlur, Kavalalli, Dongri, Artibail and Mastikatta to study the variation of soil biological physical and chemical properties in eroded and pristine soils. The results of the present investigation has revealed that the soil physicochemical properties such as water stable aggregates (60%), organic carbon (1.23%), organic matter (2.12%) and available N, P and K (323.41, 18.23 and 328.71 kg/ha respectively) were found to be higher in pristine ecosystem compared to eroded soils. Furthermore, soil biological properties like microbial biomass carbon, glomalin content and mycorrhizal spores and soil enzyme activity were found to be greater extent in the pristine ecosystem compared to eroded soils. The study highlights the impact of landslides on soil physicochemical and biological properties such that suitable remedies can be undertaken in order to prevent soil loss such that soil biological properties can be maintained which is pre-requisite for plant growth and development.

An investigation was carried out to evaluate the methods of application of AMF cultures in the management of Orobanche viz., planting of pre colonized tobacco seedling; soil application and the combination of both. The experiment was carried out in Orobanche infested soils of tobacco growing areas of Belagavi district. The results of the present investigations have revealed that the treatment received STD AMF had reduced the emergence of Orobanche (1.33 plot-1) compared to UASDAMFT (1.67 plot-1) and UASDAMFS (2.89 plot-1). The results with respect to different methods of applications of AMF on Orobanche numbers revealed that planting of pre colonized tobacco seedling plus soil application at the time of planting suppressed the Orobanche emergence (0.00 plot-1) compared to planting of pre colonized seedlings (1.67 plot-1) and direct soil application of AMF cultures at the time of planting (4.22 plot-1).The results pertaining to the interactive effect between mycorrhizal cultures in conjunction with the methods of application of AMF cultures significantly reduced the population of Orobanche with the treatment received planting of pre colonized seedling along with soil application of UASDAMFT, UASDAMFS and STD AMF recorded zero emergences of Orobanche at 60 DAP. However, the highest numbers of weeds were recorded in uninoculated control (68.67plot-1). Furthermore, mycorrhizal parameters like spore count and percent of root colonization were found to be the highest in the plots received mycorrhization in the form of pre-colonization and soil application with STD AMF at the time of transplanting in the main field compared to uninoculated control.