Increase in growth, productivity and nutritional status of wheat (Triticum aestivum L. cv. WH-711) and enrichment in soil fertility applied with organic matrix entrapped urea.

Field experiments were conducted during two consequent years in semi-arid, subtropical climate of Rohtak district situated in North-West Indian state Haryana to evaluate the effects of eco-friendly organic matrix entrapped urea (OMEU) on wheat (Triticum aestivum L. cv. WH-711). The OMEU prepared in granular form contained cow dung, rice bran (grain cover of Oryza sativa), neem (Azadirachta indica) leaves and clay soil (diameter of particles <0.002mm) in 1:1:1:1 ratios and saresh (plant gum of Acacia sp.) as binder entrapping half of the recommended dose of urea. A basal application of organic matrix entrapped urea showed increase in plant growth in terms of fresh and dry weights, root length, root number, leaf number, tillers, plant height, earlet number, earlet length and productivity in terms of grain yield and straw yield over free form of urea (FU) and no fertilizer (NF) application. The OMEU increased total soluble proteins, organic N and free ammonium content in the leaves at 45 and 60 days. The nutritional status of wheat grains in OMEU applied plants was almost similar to that observed for FU applied plants. An increase in organic carbon and available phosphorus (P) was observed in OMEU applied plots on harvest, whereas pH was slightly decreased over FU applied plots. The microbial population and activity in terms of fungal and bacterial colony count and activities soil dehydrogenase and alkaline phosphatase were significantly higher in OMEU applied plots as compared to the FU applied plots. Our data indicate that OMEU which are low cost, biodegradable and non-toxic can be used to replace the expensive chemical fertilizers for wheat cultivation in semi-arid, subtropical climate.

Accumulation of metals in selected macrophytes grown in mixture of drain water and tannery effluent and their phytoremediation potential.

Phytoremediation is an emerging, ecofriendly and economically feasible technique for the restoration of heavy metals contaminated environment. In the present investigation, five native macrophytes growing naturally in a drain receiving tannery effluent viz Bacopa monnieri, Eichhornia crassipes, Hydrilla verticillata, Ipomoea aquatica and Marsilea minuta were evaluated for their heavy metal (Cr, Cu, Ni and Pb) accumulation potential in field conditions at Unnao, U.P., India. The results showed that metal accumulation by these macrophytes differed among species and tissue parts. The concentration of Cr, Cu, Ni and Pb in the root tissues were estimated in the range 3.38 -45.59, 1.01 -16.85, 1.81-4.43 and 1.02 -4.24 µg g-1 d.wt., whereas the corresponding shoot values were 8.79 -48.81, 1.01-8.67, 0.84 -2.89 and 1.02 -2.84 for Cr, Cu, Ni and Pb respectively. Among the studied plants the translocation factor (TF) ranged between 1.07-2.60, 0.75-3.83, 1.44-2.57 and 0.49-3.76 for Cr, Cu, Ni and Pb, respectively. The highest metal TF was found in M. minuta (2.60, 3.83 and 2.57) for Cr, Cu and Ni respectively, whereas Pb was best translocated (3.76) by B. monnieri. Roots and shoots of the studied macrophytes showed a value of greater than 1 for metal enrichment coefficient. Findings suggest that E. crassipes can be used for phytoremediation of Cu and Ni whereas M. minuta and H. verticillata can be applied for the removal of Cr and Pb respectively from the contaminated water bodies.

Differential toxicity of cadmium to mustard (Brassica juncia L.) genotypes under higher metal levels.

Cadmium application inhibited various growth and biochemical parameters in seedlings of five cultivars of Brassica juncia L. with different magnitude at lower Cd supply, however, at higher metal applications the variation in Cd toxicity ranged with minor differences. The seedling vigour index (SVI) was inhibited more severely in Gangotri (62.25% over control) and least in Pusa Jai Kisan (8.95%) at 1.0 mM CdCl2. The SVI of all five mustard cultivars, however, severely inhibited (84.29-91.80%) at 5.0 mM Cd. The root and shoot elongation in 7 days old seedlings were inhibited by 32.39-40.38 and 11.83-56.40% respectively at 1.0 mM CdCl2, whereas the varietal differences in root and shoot elongation were 76.71-82.47 and 71.57-78.91 respectively at 5.0 mM CdCl2. The genotypic differences at lower Cd level were more pronounced in shoot elongation than that in the root elongation. The dry weight and moisture content of the seedlings, however, does not show much varietal differences even at lower Cd level, though the Cd toxicity increased at higher level of Cd application. The metal tolerance index (MTI) and % phytotoxicity of 3 days old seedlings ranged between 43.30-98.37 and 1.63-56.70% respectively at 1.0 mM CdCl2 for different mustard genotypes, whereas at 5.0 mM CdCl2 these factors ranged between 12.26- 20.92 and 80.08-87.74% respectively. The varietal differences of MTI and % phytotoxicity was, however, less pronounced at all the metal levels when the seedling attained an age of 7 days. A similar trend of genotypic variation was noticed in Cd accumulation in the seedlings at lower and higher levels of Cd supply to the seedlings. Amongst some biochemical parameters e.g. photosynthetic pigments, carbohydrates and proteins in the leaves, the photosynthetic pigments i.e. chlorophylls and carotenoids were decreased more drastically. The carbohydrate content of leaves, however, was the least affected component. Our data indicate that the differential toxicity of cadmium to Indian mustard genotypes was dependent on the level of contamination and growth phases.