S.S. Dhaliwal

Vermicomposting of tannery sludge mixed with cattle dung into valuable manure using earthworm Eisenia fetida (Savigny)

The present study revealed the role of earthworm in converting tannery sludge into a valuable product. Tannery sludge was toxic to earthworm, therefore it was mixed with cattle dung in different proportions viz. 0:100 (T(0)), 10:90 (T(10)), 25:75 (T(25)), 50:50 (T(50)) and 75:25 (T(75)) on dry weight basis. The minimum mortality and highest population buildup of worms was in T(0) mixture. Nitrogen, sodium, phosphorus and pH increased from initial in the range of 7.3-66.6%, 16.90-70.58%, 8.57-44.8% and 2.8-13.65%, respectively. On the other hand potassium, organic carbon and electrical conductivity decreased in the range of 4.34-28.5%, 7.54-22.35% and 32.35-53.12%, respectively. C:N ratio decreased from 20.53% to 47.36% in the final products. Transition metals increased significantly from the initial value and within the permissible limit. The result indicated that vermicomposting with Eisenia fetida is better for changing this sludge into nutrient rich manure in a short period of time.

Cocomposting with and without Eisenia fetida for conversion of toxic paper mill sludge to a soil conditioner.

Present study was envisaged for fast bioremediation of toxic paper mill sludge into a soil ameliorating agent. Although a rich source of organic carbon this sludge cannot be directly applied in fields and is recycled very slowly in landfills as it is deficient in other nutrients. Therefore it was mixed with cattle dung in various proportions and subjected to aerobic cocomposting (without worms) and vermicocomposting (with Eisenia fetida). It was observed that mixing cattle dung with the sludge improved physico-chemical characteristics (with transition metals in the permissible range for manures) of the products of both the processes and enhanced its acceptability for worms. Higher decline in organic carbon and higher content of nitrogen and phosphorous along with lower electrical conductivity and higher pH of the products of vermicomposting indicated that E. fetida helped in fast conversion of toxic paper mill sludge into a soil conditioner in 100days.

Distribution of different forms of Mn and their association with soil properties in arid zone soils of Punjab, India

Six pedons from arid zones soils of Punjab, north western India, were investigated for different forms of manganese (Mn): total Mn, diethylenetriamine penta-acetic acid (DTPA)-extractable Mn, soil solution plus exchangeable Mn, adsorbed Mn onto inorganic sites, and oxide surfaces, and Mn bound by organic sites. Total Mn content ranged from 241–517 mg kg−1, DTPA-extractable Mn content ranged from 1.40–4.52 mg kg−1, soil solution plus exchangeable Mn content ranged from 0.04–0.30 mg kg−1, Mn adsorbed onto inorganic sites ranged from 34–109 mg kg−1, and that onto oxide surfaces ranged from 28–173 mg kg−1. The Mn bound by organic sites ranged from 14–56 mg kg−1. The forms of Mn did not exhibit any consistent pattern of distribution. Irrespective of the different fractions of Mn their content was higher in the fine textured soils as compared to the coarse textured soils. The soil solution plus exchangeable Mn held onto organic site and oxide surface (amorphous) increased with increase in organic carbon, silt and clay contents. The Mn adsorbed onto inorganic site (crystalline) increased with only silt and clay content. The DTPA-Mn increased with increase in organic carbon content, whereas Mn adsorbed onto oxide surfaces increased with an increase in organic carbon, silt and clay. However, both these fractions decreased with an increase in calcium carbonate and pH. Total Mn was strongly correlated with organic carbon, silt and clay content of soil. Among the forms, Mn held on the organic site, water soluble + exchangeable and Mn adsorbed onto oxide surface were positively correlated with DTPA-extractable Mn. DTPA-extractable Mn and soil solution plus exchangeable Mn seem to be good indices of Mn availability in soils and are helpful for correction of Mn deficiency in the soils of the region.

Novel Alleles of Phosphorus-Starvation Tolerance 1 Gene (PSTOL1) from Oryza rufipogon Confers High Phosphorus Uptake Efficiency

Limited phosphorus availability in the soil is one of the major constraints to the growth and productivity of rice across Asian, African and South American countries, where 50% of the rice is grown under rain-fed systems on poor and problematic soils. With an aim to determine novel alleles for enhanced phosphorus uptake efficiency in wild species germplasm of rice Oryza rufipogon, we investigated phosphorus uptake1 (Pup1) locus with 11 previously reported SSR markers and sequence characterized the phosphorus-starvation tolerance 1 (PSTOL1) gene. In the present study, we screened 182 accessions of O. rufipogon along with Vandana as a positive control with SSR markers. From the analysis, it was inferred that all of the O. rufipogon accessions undertaken in this study had an insertion of 90 kb region, including Pup1-K46, a diagnostic marker for PSTOL1, however, it was absent among O. sativa cv. PR114, PR121, and PR122. The complete PSTOL1 gene was also sequenced in 67 representative accessions of O. rufipogon and Vandana as a positive control. From comparative sequence analysis, 53 mutations (52 SNPs and 1 nonsense mutation) were found in the PSTOL1 coding region, of which 28 were missense mutations and 10 corresponded to changes in the amino acid polarity. These 53 mutations correspond to 17 haplotypes, of these 6 were shared and 11 were scored only once. A major shared haplotype was observed among 44 accessions of O. rufipogon along with Vandana and Kasalath. Out of 17 haplotypes, accessions representing 8 haplotypes were grown under the phosphorus-deficient conditions in hydroponics for 60 days. Significant differences were observed in the root length and weight among all the genotypes when grown under phosphorus deficiency conditions as compared to the phosphorus sufficient conditions. The O. rufipogon accession IRGC 106506 from Laos performed significantly better, with 2.5 times higher root weight and phosphorus content as compared to the positive control Vandana. In terms of phosphorus uptake efficiency, the O. rufipogon accessions IRGC 104639, 104712, and 105569 also showed nearly two times higher phosphorus content than Vandana. Thus, these O. rufipogon accessions could be used as the potential donor for improving phosphorus uptake efficiency of elite rice cultivars.

Effect of N, ZN and FE Application on N, P, K Content and Their Total Uptake in Parmal Rice (Oryza Sativa L.)

An experiment was conducted in split-split plot design to study the effect of N, Zn and Fe application on N, P and K content in grain and straw and their total uptake in parmal rice crop. The results of the study showed that N and K content were significantly higher at 125% of RDN as compared to 75% of RDN both in grain and straw. Zn also had significant effect on N and K content; Zn4 and Zn2 were statistically at par with each other and were significantly higher than Zn3 and Zn1 which were also statistically at par with each other. P content was not affected by N, Zn and Fe application. Total N, P and K uptake by rice crop was significantly affected by N levels and Zn application methods but the effect of Fe on uptake of N, P and K was found to be non-significant.