Development of an appropriate procedure for estimation of RUSLE EI30 index and preparation of erosivity maps for Pulau Penang in Peninsular Malaysia

Pluviographic data at 15 min interval from 6 stations in Pulau Penang of Peninsular Malaysia were used to compute rainfall erosivity factor (R) for the revised universal soil loss equation (RUSLE). Three different modelling procedures were applied for the estimation of monthly rainfall erosivity (EI₃₀) values. While storm rainfall (P) and duration (D) data were used in the first approach, the second approach used monthly rainfall for days with rainfall ≥ 10 mm (rain₁₀) and monthly number of days with rainfall ≥ 10 (days₁₀). The third approach however used the Fournier index as the independent variable. Based on the root mean squared error (RMSE) and the percentage error (PE) criteria, models developed using the Fournier index approach was adjudged the best with an average PE value of 0.92 and an average RMSE value of 164.6. Further, this approach was extended to the development of a regional model. Using data from additional sixteen stations and the Fournier index based regional model, EI₃₀ values were computed for each month. ArcView GIS was used to generate monthly maps of EI₃₀ values and also annual rainfall erosivity (R). The rainfall erosivity factor (R) in the region was estimated to vary from 9000 to 14,000 MJ mm ha^− 1 h^− 1 year^− 1.     

Food habits of striped hyena(Hyaena hyaena) in a semi-arid conservation area of India

Striped hyena(Hyaena hyaena) is a near-threatened large carnivore known to occur in arid and semi-arid landscapes in many parts of the world. Its population is declining globally and ecological information is required urgently to meet their conservation needs. We studied the diet pattern of the striped hyena in the semi-arid Gir National Park and Sanctuary(GNPS), western India. Prey items eaten by the striped hyena were identified from scats. Around 44.4% scats represented single to three mammalian preys while 55.6% of them represented four preys to seven preys. A variety of food items were identified including mammals, birds, insects and vegetable matters. Scats analysis showed that 63.91% diet of striped hyena was contributed by wild prey items, 20.94% by domestic prey and 3.31% by birds, whereas vegetable and insects contributed 9.92% and 1.93%, respectively. Diet diversity of the striped hyena computed by the Shannon-Weiner Index(H) was found to be 2.64. The presence of domestic mammals in the scat remains implied that the striped hyena might frequently visit human habitation in search for food and hence, a potential conflict between human and wildlife might arise. Reducing the dependence of hyena on domestic livestock is a challenge to ensure the survival of striped hyena outside the protected area.     

Variant biochemical responses: intrinsic and adaptive system for ecologically different rice varieties

Journal of Crop Science and Biotechnology - India has a diverse range of agro-ecological conditions which support the cultivation of different rice varieties differing in the adaptation which is so...     

A comparative study to evaluate efficiency of EDTA and calcium in alleviating arsenic toxicity to germinating and young <Emphasis Type="Italic">Vicia faba</Emphasis> L. seedlings

Purpose

This study delineated the effect of calcium (Ca) and ethylenediaminetetraacetic acid (EDTA) addition on arsenic (As) accumulation and physiological attributes of Vicia faba L.

Materials and methods

Two separate experiments were performed. In the first experiment, V. faba seedlings, grown under hydroponic conditions, were exposed to three levels of As (25, 125 and 250 μM) in the presence and absence of three levels of EDTA (25, 125, 250 μM) and calcium (CaCl₂: 1, 5 and 10 mM). The effect of EDTA and Ca on As accumulation and physiological attributes of V. faba was assessed by determining As contents in roots and shoot, chlorophyll contents, H₂O₂ contents, and lipid peroxidation in young and old leaves. In the second experiment, V. faba seeds were grown in As-contaminated sand culture using the same treatment plan.

Results and discussion

The accumulation and toxicity of As to V. faba plants increased with increasing As levels in nutrient solution. Arsenic exposure enhanced the production of reactive oxygen species (ROS) in both roots and leaves, which resulted in lipid peroxidation and decreased chlorophyll contents. The presence of both EDTA and Ca, in general, significantly decreased As accumulation by V. faba seedlings, Ca being more effective than EDTA. Both the amendments decreased As-induced reactive oxygen species (ROS) production and lipid peroxidation. In the case of chlorophyll contents, EDTA significantly decreased chlorophyll contents, while Ca significantly increased chlorophyll contents compared to As. The effect of all the treatments was more pronounced in roots than leaves and in young leaves compared to old leaves.

Conclusions

It is proposed that EDTA and Ca greatly affect As accumulation and toxicity to V. faba, and the effect varies greatly with their applied levels as well as type and age of plant organs. The germinating seedlings of V. faba may be preferred for risk assessment studies, while transplanting 1-week-old V. faba seedlings to As-contaminated soils can decrease its toxicity.

     

The development of integrated pest management for the control of mushroom sciarid flies,Lycoriella ingenua (Dufour) and Bradysia ocellaris (Comstock), in cultivated mushrooms

Mushrooms are susceptible to a range of diseases and pests that can cause serious crop loss. Effective pest and pathogen control is a very important factor for the maintenance of efficient production of cultivated mushrooms. Integrated pest management in mushrooms is reliant upon four main principals/elements: sanitation, exclusion, monitoring and pest control. Bradysia ocellaris (Comstock) and Lycoriella ingenua (Dufour) (Diptera: Sciaridae) are major pests of cultivated mushrooms, Agaricus bisporus (Lange) Imbach. These pests cause losses in yield through larval damage of the compost, mycelium and sporophores, and affect the structural features of the compost itself. Adult flies of these species also act as vectors for the introduction of mites and fungal diseases in cultivated mushrooms. Copyright © 2010 Society of Chemical Industry     

Assessing the immobilization efficiency of organic and inorganic amendments for cadmium phytoavailability to wheat

Purpose

Rapid industrialization in China accelerated environmental pollution by xenophores and trace metals particularly cadmium. Numerous studies have been conducted to address soil contamination using organic and inorganic amendments under pot or incubation conditions, but few were performed under field conditions, particularly in the wheat-growing areas. This study aims to investigate the effectiveness of pre-applied soil amendments for Cd immobilization, changes in soil pH, and metal uptake by wheat.

Materials and methods

In this study, 12 treatments, i.e., control (CK), lime, DaSan Yuan (DASY), DiKang No. 1 (DEK1), biochar, Fe-biochar, Yirang, CaMgP, and green stabilizing agents (GSA-1, GSA-2, GSA-3, and GSA-4), were evaluated for Cd immobilization in incubation and field experiments. Changes in soil pH and available metal content with amendments were monitored from 30 to 150 days of incubation. Single extraction method and DTPA-extractable and sequential extraction procedures were employed to assess the variations in available Cd contents of field soil. The impact of soil amendments on Cd uptake and bioaccumulation in food part of wheat was measured at harvesting stage in a contaminated site.

Results and discussion

Lime treatment increased soil pH by 32% and reduced available Cd to 0.213 mg kg^?1, as compared to CK (control) in the incubation experiment (0.343 mg kg^?1). Effects of the amendments on wheat growth, soil pH, and Cd phytoavailability were reported. Wheat biomass was highest in treatment GSA-2 (13,880 kg ha^?1) and GAS-4 resulted in an increase in grain yield (5350 kg ha^?1). Soil pH of the treated field at harvesting stage increased up to 6.50, 6.50, and 6.47 by application of GSA-4, GSA-2, and lime, respectively. Cadmium contents in wheat grain were declined significantly in the treatments of GSA-2, GSA-4, and lime.

Conclusions

Results of this study revealed a significant decrease in available Cd concentration with the application of amendments. Composite amendments were more effective in terms of metal uptake and bioaccumulation in wheat. In addition, our results indicate the effectiveness of composite amendments in stabilizing Cd in contaminated soil.

     

Effect of compost and casing treatments of insecticides against the sciarid Bradysia ocellaris (Diptera: Sciaridae) and on the total yield of cultivated mushrooms,Agaricus bisporus

BACKGROUND: Bradysia ocellaris (Comstock) is one of the major pests of cultivated mushrooms, Agaricus bisporus (Lange) Imbach. The feeding of sciarid fly larvae causes damage to the cultivation substrates, compost and casing. A comparative study of insecticidal treatments incorporated into compost and casing against B. ocellaris was conducted during 2003–2004. Treatments with an organophosphate, diazinon, a pyrazole, fipronil, and an insect growth regulator (IGR), triflumuron, were incorporated into casing. Another IGR, cyromazine, was incorporated into compost. Insecticidal incorporation into compost and casing has been associated with reductions in mushroom yield. Therefore, the effect of these insecticidal treatments on the overall yield was evaluated. RESULTS: A combined treatment, incorporation of cyromazine at 10 mg kg^?1 into compost and of triflumuron at 20 mg kg^?1 into casing, provided 100% control against B. ocellaris. There was no apparent reduction in yield as a result of incorporation of the tested chemicals into either compost or casing. CONCLUSION: The results obtained from this study suggest that incorporation of insecticides into both compost and casing is required to control a moderate to high pressure of insect pests. There were no significant yield reductions as a result of the incorporation of pesticides in the Australian mushroom‐growing system. Copyright © 2009 Society of Chemical Industry     

Molecular screening for identification of blast resistance genes in North East and Eastern Indian rice germplasm (Oryza sativa L.) with PCR based makers

Molecular screening and genetic diversity of major rice blast resistance (R) genes were determined in 32 accessions of rice germplasm from North East and Eastern India with ten gene based single nucleotide polymorphisms and sequence tagged sites (STS) markers, namely z56592, zt56591, k39512, k3957, candidate gene marker, Pita3, YL155/YL87, YL183/YL87, Pb28, 195R-1 which showed close-set linkage to nine major rice blast resistance (R) genes, Piz, Piz-t, Pik, Pik-p, Pik-h, Pita/Pita-2, Pib and Pi9 and one susceptible pita gene. Among the 32 accessions, 13 were positive for Piz gene and six for Piz-t gene. Six accessions were positive for Pik gene, seven for Pik-p and 16 for Pik-h gene. One accession, Atte thima, was positive for three of Pik multiple genes. Out of 32, only two germplasm, Dudhraj and Nepali dhan, were detected with both Pita3 and YL155/YL87 marker for Pita/Pita-2 gene. The Pib gene appeared to be omnipresent and was detected in 31 of 32 germplasm with marker Pb28. The gene specific STS marker, 195R-1, for Pi9 gene produced positive bands in only two germplasm, Kalchatti and Bachi thima. The Uniform Blast Nursery (UBN) analysis showed that out of 32, six germplasm was resistant, ten moderately resistant and 16 germplasm were susceptible. Presence of Piz-t, Pita/Pita-2 and Pi9 gene ensured a resistant reaction in outdoor blast nursery whereas germplasm carrying Pib was susceptible when present alone. Presence of multiple genes, however, contributed to slow blasting resistance in the field. These results are useful in identification and incorporation of resistant genes from the germplasm into elite cultivars through marker assisted selection in rice breeding programs.