Aluminium dynamics from soil to tea plant (Camellia sinensis L.): is it enhanced by municipal solid waste compost application?

Application of municipal solid waste compost (MSWC) in tea (Camellia sinensis L.) cultivation can increase the fertility status of soils and thus enhance the plant growth. The present study attempts at application of MSWC in tea (TV1 and TV23 clones) cultivation to assess the effect of different doses of MSWC on growth and translocation potential of Al on this plant as well as fate of Al in soil, through the calculation of a risk assessment code (RAC). The sequential extraction of Al in MSWC amended soils showed that the fractionation of Al in soil changed after compost application, with an overall increase of the fractions associated to with Fe-Mn oxides, organic and of the residual fraction. The accumulation of Al in different parts ofC. sinensisL., grown on MSWC amended soil effected an overall increased growth of the plant with increasing doses of MSWC. According to RAC, Al falls in medium to high risk, though no adverse effect on plant health was observed. Tea plants were found to adapt well to MSWC amended soils. However, long term field trials are necessary to completely assess the risk of Al accumulation in soils upon MSWC application. Hierarchical cluster analysis was applied aiming to check for the presence of homogenous groups among different treatments. It was found that in both TV1 and TV23, treatments formed two different groups.

Composting of cow dung and crop residues using termite mounds as bulking agent.

The present study reports the suitability of termite mounds as a bulking agent for composting with crop residues and cow dung in pit method. Use of 50 kg termite mound with the crop residues (stover of ground nut: 361.65 kg; soybean: 354.59 kg; potato: 357.67 kg and mustard: 373.19 kg) and cow dung (84.90 kg) formed a good quality compost within 70 days of composting having nitrogen, phosphorus and potassium as 20.19, 3.78 and 32.77 g kg(-1) respectively with a bulk density of 0.85 g cm(-3). Other physico-chemical and germination parameters of the compost were within Indian standard, which had been confirmed by the application of multivariate analysis of variance and multivariate contrast analysis. Principal component analysis was applied in order to gain insight into the characteristic variables. Four composting treatments formed two different groups when hierarchical cluster analysis was applied.

Chromium in soil and tea (Camellia sinensis L.) infusion: Does soil amendment with municipal solid waste compost make sense?

In this study, two clones (TV1 and TV23) of tea (Camellia sinensis L.) plants were allowed to grow in earthen pots in a greenhouse, treated with municipal solid waste compost (MSWC) to study the effect of MSWC to the fractionation of chromium (Cr) ion, plant biomass production, plant uptake of Cr, fate of Cr in soils through risk assessment code (RAC) and Cr in tea infusion. Increasing rate of MSWC applications increased both total Cr and DTPA-extractable Cr in soil. Fractionation studies have revealed that Cr in soils was mainly associated with the organic and Fe-Mn oxide and the contribution of residual fractions is nearly 87.7-96.1%. The biomass yields of the tea plants were increased with the increase in MSWC, indicating that nutrient uptake of the plants from MSWC was dependent on the root-MSWC interface. High accumulation of Cr in the root of tea plants and its subsequent lower movement towards aerial parts corroborated the hypothesis that the root of the tea plants acts as a buffer. In this experiment the transfer factor was <1, indicating that the tea plants did not have a significant phytoextraction potential. In the application of 10tha-1 MSWC, Cr was found to be in medium risk for both clones whereas the application of 8tha-1 MSWC showed medium risk with respect to the Cr for TV23 clone applying RAC. Therefore, MSWC amendment rate above 8tha-1 increased the total biomass of the tea plants but posed a threat on environmental prospect with respect to Cr. It was also found that only 2.5µgL-1 to 4.8µgL-1 Cr was present in tea infusion when infusion was prepared from tea leaves receiving different doses of MSWC. Furthermore, stepwise regression technique was applied to choose the most significant regression variables to express the variability in leaves, stem, main root and feeder root biomass. The one-way analysis of variance along with the Dunnett's multiple comparison method was used to determine the significant differences between the means of different treatments. On the application of hierarchical cluster analysis, treatments were grouped in two distinct homogeneous groups.