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Patra D.K.,Zonal Adaptive Research Station | Patra D.K.,Rice Research Station | Biswas A.,Pulses and Oilseeds Research Station | Biswas A.,Rice Research Station
Pestology | Year: 2011

Field experiment was conducted during kharif (wet) season, 2007 to evaluate the relative efficacy of new fungicides against banded leaf and sheath blight disease of maize caused by Rhizoctonia solani f. sp. sasakii. Two sprays of ready-mix compound Flusilazole 12.5% + Carbendazim 25% SE (0.1 %) followed by Trifloxystrobin 25%+Tebuconazole 50% WG (0.04%) were highly effective in reducing banded leaf and sheath blight intensity and improving grain yield over other fungicides. Source


Patra D.K.,Zonal Adaptive Research Station | Patra D.K.,Rice Research Station | Biswas A.,Pulses and Oilseeds Research Station | Biswas A.,Rice Research Station
Pestology | Year: 2010

Alternaria leaf blight of rapeseed-mustard caused by the fungus Alternaria brassicae (Berk). Sacc. is an economically important disease and occurs regularly during the rabi (dry) crop season in West Bengal with an average loss in yield of about 47%. Field experiments were done to evaluate the relative efficacy of five botanicals (bio-fungicides) viz. Biotos, Wanis, Neemrain, Ecomonas and Garlic clove extract, at different concentrations and one standard check fungicide mancozeb 75% WP. All the bio-fungicides were significantly effective in reducing the disease severity and increased yield. Ecomonas followed by Biotos were the best bio-fungicides in controlling Alternaria blight disease of rapeseed-mustard. Source


Barrow N.J.,University of Western Australia | Debnath A.,Bidhan Chandra Krishi Viswavidyalaya | Chatterjee S.,Zonal Adaptive Research Station
European Journal of Soil Science | Year: 2016

We investigated whether long-term application of phosphate fertilizers, often as phosphate rock, had led to the accumulation of soluble fluoride in soil from tea estates in northern India. We also compared fluoride sorption and desorption with that of sulphate and of phosphate. We found no evidence of build-up of soluble fluoride and ascribed this to the very heavy rainfall of about 3 m, nearly all of which occurs during a 4-month monsoon period. Fluoride sorption was more sensitive than phosphate or sulphate sorption to the build-up of a negative charge caused by long-term application of phosphate fertilizers. We think that this occurred because the fluoride ion is smaller and the mean centre of charge is, therefore, located closer to the surface. When the negative charge is increased, it, therefore, experiences a greater decrease in potential than ions for which the mean centre of charge is further from the surface. When the phosphate status of the soil was low, fluoride showed sorption-desorption hysteresis. That is the desorption curve differed from the sorption curve. When the phosphate status of the soil was higher, this was not the case. Similar effects have been observed previously for both phosphate and sulphate. We had speculated that the fluoride ion, being smaller, might have been able to penetrate pores 'blocked' by a previous reaction with phosphate, but this did not happen. We conclude that characterizing the charge on sorbed ions, its location and especially the accumulation of a negative charge following a long-term reaction with phosphate is important for understanding specific sorption on ions. Highlights: We investigated the effects of long-term application of phosphate rock on tea estates. We ascribed the lack of build-up of soluble fluoride to monsoon rainfall of about 3 m. Fluoride sorption was more sensitive than phosphate or sulphate sorption to the build-up of a negative charge caused by long-term application of phosphate fertilizers. Characterizing the charge on sorbed ions, its location and the accumulation of a negative charge is important. © 2016 British Society of Soil Science. Source


Chatterjee S.,Bidhan Chandra Krishi Viswavidyalaya | Chatterjee S.,Zonal Adaptive Research Station | Santra P.,Indian Central Arid Zone Research Institute | Majumdar K.,International Plant Nutrition Institute | And 3 more authors.
Environmental Monitoring and Assessment | Year: 2015

A large part of precision agriculture research in the developing countries is devoted towards precision nutrient management aspects. This has led to better economics and efficiency of nutrient use with off-farm advantages of environmental security. The keystone of precision nutrient management is analysis and interpretation of spatial variability of soils by establishing management zones. In this study, spatial variability of major soil nutrient contents was evaluated in the Ghoragacha village of North 24 Parganas district of West Bengal, India. Surface soil samples from 100 locations, covering different cropping systems of the village, was collected from 0 to 15 cm depth using 100 × 100 m grid system and analyzed in the laboratory to determine organic carbon (OC), available nitrogen (N), phosphorus (P), and potassium (K) contents of the soil as well as its water-soluble K (KWS), exchangeable K (KEX),and non-exchangeable forms of K (KNEX). Geostatistical analyses were performed to determine the spatial variation structure of each nutrient content within the village, followed by the generation of surface maps through kriging. Four commonly used semivariogram models, i.e., spherical, exponential, Gaussian, and linear models were fitted to each soil property, and the best one was used to prepare surface maps through krigging. Spherical model was found the best for available N and P contents, while linear and exponential model was the best for OC and available K, and for KWS and KNEK, Gausian model was the best. Surface maps of nutrient contents showed that N content (129–195 kg ha−1) was the most limiting factor throughout the village, while P status was generally very high (10–678 kg ha−1) in the soils of the present village. Among the different soil K fractions, KWS registered the maximum variability (CV 75 %), while the remaining soil K fractions showed moderate to high variation. Interestingly, KNEX content also showed high variability, which essentially indicates reserve native K exploitation under intensive cultivation. These maps highlight the necessity of estimating the other soil K fractions as well for better understanding of soil K supplying capacity and K fertilization strategy rather than the current recommendations, based on the plant-available K alone. In conclusion, the present study revealed that the variability of nutrient distribution was a consequence of complex interactions between the cropping system, nutrient application rates, and the native soil characteristics, and such interactions could be utilized to develop the nutrient management strategies for intensive small-holder system. © 2015, Springer International Publishing Switzerland. Source

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