Search

Bulb rot, a highly damaging disease of tulip plants, has hindered their profitable cultivation worldwide. This rot occurs in both field and storage conditions posing significant challenges. While this disease has been attributed to a range of pathogens, previous investigations have solely examined it within the framework of a single-pathogen disease model. Our study took a different approach and identified four pathogens associated with the disease: Fusarium solani, Penicillium chrysogenum, Botrytis tulipae, and Aspergillus niger. The primary objective of our research was to examine the impact of co-infections on the overall virulence dynamics of these pathogens. Through co-inoculation experiments on potato dextrose agar, we delineated three primary interaction patterns: antibiosis, deadlock, and merging. In vitro trials involving individual pathogen inoculations on tulip bulbs revealed that B. tulipae,was the most virulent and induced complete bulb decay. Nonetheless, when these pathogens were simultaneously introduced in various combinations, outcomes ranged from partial bulb decay to elongated rotting periods. This indicated a notable degree of antagonistic behaviour among the pathogens. While synergistic interactions were evident in a few combinations, antagonism overwhelmingly prevailed. The complex interplay of these pathogens during co-infection led to a noticeable change in the overall severity of the disease. This underscores the significance of pathogen-pathogen interactions in the realm of plant pathology, opening new insights for understanding and managing tulip bulb rot. [ABSTRACT FROM AUTHOR]

Large-scale land degradation occurs in the foothill Himalayas mainly because of soil erosion, accelerated by tillage and poor management practices in agricultural lands and encroachment of land under forest cover. Land use exerts both direct (through C additions) and indirect (through its impact on soil erosion) influence on soil carbon. Partitioning of Total Carbon (TC) in organic and inorganic forms in degraded soils was studied, and compared these with soils under agriculture, horticulture and forest systems. Highest Total Organic Carbon (TOC) was recorded in forest soils followed by horticultural systems, whereas the least was observed in degraded and agricultural systems while Inorganic Carbon (IC) decreased in the sequence of: degraded lands > forest > agriculture ≥ horticulture. TOC stocks in the upper half-a-meter layer were 163.9 Mg ha−1 in forest soils followed by horticulture (144.7 Mg ha−1) while in case of TC, the degraded lands closely followed forest soils. The contribution of IC to TC was about 39% in degraded lands, which was about twice that of its contribution in forest soils. TOC decreased with soil depth whereas IC increased with depth. The increase in IC with depth was minor for agricultural and horticultural soils, whereas it was about 84% for degraded and about 61% for forest soils. Our study highlights the impact of erosion on dynamics of soil carbon and its partitioning and suggests the need to promote better carbon sequestering land use systems towards conservation of top carbon rich soil and promoting sustainability in hill ecosystems particularly in Himalayas. • Total carbon was partitioned into organic and inorganic forms. • Highest TOC was recorded in forest soils, whereas maximum IC was in degraded. • IC was 39% of the TC in degraded lands, which was twice that of in forest soils. • Degraded soils were at par with agricultural soils with respect to TOC. • Increase in IC carbon with depth was 84% for degraded lands. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effectiveness of conventional tillage, minimum tillage and no-tillage, with and without soil cover, on C losses in Foothill Himalayas (Shivaliks) was studied. • Zero till could not control C losses in runoff water. • Zero till significantly reduced C losses through sediments. • Soil cover could reduce carbon losses by half in conventional systems and minimum tillage. • Carbon enrichment ratio was high and was unaffected by tillage and soil cover. Agriculture intensification and land use changes in the foothills of the Himalayas have concerning inferences on the carbon pool and storage of the soils. The foothill Himalayas (Shivaliks) are prone to large-scale soil erosion by water. There have been rising concerns regarding accelerated soil carbon loss and an increase in carbon emissions to the atmosphere. There exist limited studies in the Himalayan region to quantify the loss of soil carbon under different conservation strategies, therefore, the present study was carried out to assess the impact of conservation practices. The treatments include conventional tillage (CT), minimum tillage (MT), and zero tillage (ZT) combined with mulching (m), residue retention (r) and intercropping (i) on carbon losses through soil erosion in the foothill Himalayas. The results from one year of observations revealed that the carbon concentration in runoff water is comparable to or even greater in conservation tillage practices than under conventional tillage practices. While comparing mulch and intercropping combinations, the minimum amount of C losses were in Zero tillage + intercrop. The application of residue or mulches or intercropping with pulses effectively reduced the C losses mainly because of the reduction of runoff generated during different rainfall events. The concentration of carbon losses in sediments ranged from 1.5 to 2%. C loss in sediments during the growing season ranged from 11.87 kg ha−1 to 53.40 kg ha−1. The maximum values for sediment-associated carbon loss occurred under CT (53.40 kg ha−1) while the least was in ZTm (11.87 kg ha−1). A very high carbon enrichment ratio of 3.3 to 4.4% was observed. We observed that no till reduced soil carbon losses in sediments while covering the soil helped in controlling runoff losses as well. [ABSTRACT FROM AUTHOR]

A study was conducted to assess the impact of different land use systems on labile C pools and soil organic carbon stocks in the foothill Himalayas. Soil samples were collected from four different land use systems viz. agriculture, forest, horticulture and degraded lands from each of the seven locations up to a depth of 0.5m. Potassium permanganate oxidizable (KOC) and microbial biomass carbon (MBC) followed the trend: forest>horticulture>agriculture>degraded lands in each of the depths. In case of soil organic carbon (SOC), agriculture and degraded lands had similar levels. Soil organic carbon stocks in the top half a meter soil were highest in forest soils [47.5 Mg ha-1 (±2.49)] followed by horticultural systems [42.4 Mg ha-1 (±2.92)], degraded [36.3 Mg ha-1 (±4.40)] and agricultural lands [35.1 Mg ha-1 (±3.51)]. Agricultural and degraded lands had up to 25% lower SOC stocks than forest soils, indicating that deforestation or conversion of forest land to agricultural uses is contributing to losses of up to 12.4Mgha-1 SOC over time from the top half a meter layer of soil. The typical decrease of carbon content with depth was the sharpest for agricultural soils, where the values in the lowest depth (30-50cm) were nearly 50% (MBC and SOC) or over 50% (KOC) of that in surface. Among the different carbon pools KOC seemed to be strongly related with soil textural properties including CEC, but overall it seems that land use played a major role in determining C levels in soils. [ABSTRACT FROM AUTHOR]