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61.
Supriyo Chowdhury Arpita Basu Tathagata Ray Chaudhuri Surekha Kundu 《European journal of plant pathology / European Foundation for Plant Pathology》2014,138(2):361-375
There are major gaps in our knowledge of the stages of infection in soil borne pathogens. Soil borne diseases, such as charcoal root rot caused by Macrophomina phaseolina on sesame, have been studied, yet due to the difficulty in observing fungal behaviour in the soil, there has been no detailed study of the infection events. Moreover no study has attempted to compare the infection events in roots of resistant versus susceptible hosts. We present the first ultra-structural report to characterize the behaviour of the fungus in the proximity of the root, the appearance of fungal hyphae on the surface of roots, microsclerotia formation on hyphal strands, early penetration events and subsequent infection processes of M. phaseolina in sesame. We observed distinct differences in fungal behaviour in the rhizosphere and during infection of susceptible and resistant varieties. This study also describes a framework for comparative experiments. The possible reasons for the difference in behaviour of M. phaseolina in the vicinity of and during infection of roots of resistant vs. susceptible varieties of sesame and its implications for disease resistance are discussed. 相似文献
62.
Recovery and recycling of plant nutrients from municipal sewage effluent (SE) can reduce consumption of costly chemical fertilizers, besides reducing eutrophication of water bodies. Field experiment was conducted on Vertisol of central India for six years with the objective of quantifying recovery of major plant nutrients by aboveground biomass of wheat-soybean cropping system from untreated SE. Wheat crop was grown with irrigation (groundwater and sewage effluent) and fertilizer treatments; while soybean was grown without any treatments. Recoveries of nitrogen (N), phosphorus P) and potassium (K) by the aboveground biomass were considerably more from SE than from fertilizers and manures. Recovery of nutrients from SE was the highest by wheat grain for N and by soybean straw for P and K. Straw biomass of both the crops recovered about 31% N, 22% P and 69% K from SE, which can be recycled back into agricultural land of groundwater (GW) irrigated as well as rainfed area. 相似文献
63.
S. S. Kundu R. Podder K. E. Bett J. J. Schoenau 《Communications in Soil Science and Plant Analysis》2017,48(13):1584-1594
Zinc and iron deficiencies affect billions of people globally and have direct impact on human health. Zinc and iron concentrations in plant materials are commonly analyzed by flame atomic absorption spectrometry (F-AAS). This research describes the optimal analysis method for precise zinc (Zn) and iron (Fe) analysis of seeds from the seven species of genus Lens. Estimation of Zn and Fe concentration in whole lentil seeds by F-AAS is destructive, using nitric acid digestion of seeds prior to instrument analysis. The procedure proposed for the determination of Zn and Fe concentration uses the minimum amount of lentil seed of all lentil species with suitable standard reference materials. The relative standard deviations of the method were about 5% for both Zn and Fe. The minimum sample amount 0.3 g of wild and 0.5 g of cultivated lentil seed samples was identified for accurate and precise estimation of Zn and Fe concentration. 相似文献
64.
65.
S.P. Mazumdar D.K. Kundu A.R. Saha B. Majumdar R. Saha A.K. Singh 《Archives of Agronomy and Soil Science》2018,64(11):1595-1607
Impacts of 43-year nutrient management on carbon (C) and nutrient dynamics were studied in a rice-wheat-jute system in tropical India. Carbon dynamics was investigated on the basis of its distribution of labile (microbial biomass C, permanganate oxidizable C and water soluble C) and slow pools (Walkley Black oxidizable organic C), its indices (C pool index, lability index) and C management index (CMI) at different soil depths. Nutrient dynamics was judged by major nutrients availability, and related soil enzymatic activities. We studied seven treatments including unfertilized control, 100% NPK (N:P2O5:K2O 60:30:60), 50% NPK, 150% NPK, 100% NP, 100% N, 100% NPK + farm yard manure (10 tonnes FYM ha?1). Nutrients availability and soil enzymatic activities were significantly increased under balanced fertilization (100% NPK + FYM) over other treatments. Labile, slow and total C was also found highest in 100% NPK + FYM. Enhanced C indices under 100% NPK + FYM over 100% NPK and other treatments signified the importance of long term balanced fertilization on soil C stabilization. Lability indexes were lower at sub-soil (30-45cm). In terms of favourable nutrient dynamics and CMI, balanced application of NPK plus organics were recommend for long term sustainability of rice-wheat-jute system in tropics. 相似文献
66.
Jayanta K. Saha Amar B. Singh A. N. Ganeshamurthy Samaresh Kundu Ashish K. Biswas 《植物养料与土壤学杂志》2001,164(3):317-320
Application of S through inorganic sources is recommended to the crops in the cropping system in S deficient soils of India. However, transformations of S in the soil profile following continuous gypsum application are not known. The accumulation of S into different fractions due to application of a total of 180—540 kg S ha—1 over a six‐year‐period in soybean — wheat cropping system and its effect on the yield and quality of soybean produce were investigated in a vertisol area. About 25—38% of the S added was retained in the 90 cm depth of profile. Significant changes in the total S content in soil layers were recorded wherein a total of 360 kg S ha—1 or more S was applied. Maximum increase in total S content was recorded in upper layers. Soluble S accumulated more in the 30—75 cm depth; whereas, proportion of sorbed fraction of S increased with depth. Build up of S in the surface layer of the profile was mostly related to the increase in organic fraction. The S accumulation in lower layers of the profile was mostly due to increase in soluble and sorbed fractions of S. Such an increase of the S content in the soil caused an increase in seed yield, uptake of S as well as content of oil and S containing amino acids, cystine, and methionine in seed of soybean crop. 相似文献
67.
R. Bhattacharyya S. Kundu S.C. Pandey K.P. Singh H.S. Gupta 《Agricultural Water Management》2008,95(9):993-1002
Conservation tillage systems generally improve soil organic C (SOC), plant available water capacity (PAWC), aggregation and soil water transmission. A field experiment was conducted for 4 years (2001-2002 to 2004-2005) to study tillage (conventional tillage (CT) and zero tillage (ZT)) systems. The selected irrigation treatments were at four levels (I1: pre-sowing (PS), I2: PS + active tillering (AT)/crown root initiation (CRI), I3: PS + AT/CRI + panicle initiation (PI)/flowering (FL), and I4: PS + AT/CRI + PI/FL + grain filling (GF)), applied at the critical growth stages on rice (Oryza sativa L.) and wheat (Triticum aestivum L.). Their effects on direct seeded rice productivity and soil properties (SOC and selected physical properties) after rice and wheat harvest were investigated. Soil organic C contents after rice and wheat harvest in the 0-15 cm soil depth were higher under ZT than under CT. Soil organic C increased significantly with I2 over I1 for both crops and with I4 over I2 for the wheat crop. The PAWC was significantly higher with ZT than CT. Zero tilled and frequently irrigated plots showed enhanced infiltration characteristics (infiltration rate, cumulative infiltration and sorptivity) and saturated hydraulic conductivity. Both direct seeded rice and wheat yields were not significantly different in the plots under ZT and CT. There was a significant increase in both rice and wheat yields in the plots under I2 over I1. However, water use efficiency between irrigation treatments was not significantly different. Hence, under direct seeded rice-wheat system in a sandy clay loam soil of the sub-temperate Indian Himalayas, farmers may adopt ZT with two irrigations in each crop for optimum resource conservation. 相似文献
68.
A family of mesoporous molecular sieves (denoted MSU-G) with vesiclelike hierarchical structures and unprecedented thermal (1000 degreesC) and hydrothermal stabilities (more than 150 hours at 100 degreesC) associated with high SiO4 cross-linking was prepared through a supramolecular assembly pathway that relies on hydrogen bonding between electrically neutral gemini surfactants of the type CnH2n+1NH(CH2)2NH2 and silica precursors derived from tetraethylorthosilicate. The vesicle shells are constructed of one or more undulated silica sheets that are about 3 nanometers thick with mesopores (average diameters from 2.7 to 4.0 nanometers) running both parallel and orthogonal to the silica sheets, which makes the framework structure bicontinuous and highly accessible. Catalytic metal ion centers [for example, Ti(IV) and Al(III)] have been incorporated into the framework with the retention of hierarchical structure. 相似文献
69.
Christopher Mulanda Aura Chrisphine S. Nyamweya Monica Owili Nicholas Gichuru Rodrick Kundu James M. Njiru Micheni Japhet Ntiba 《Fisheries Management and Ecology》2020,27(4):314-324
The present study demonstrates the declining state of the major commercial fisheries of Lake Victoria, Kenya, a situation threatening sustainability of the lake's fishery. Data in the present study were derived from resource monitoring programmes that included hydro‐acoustics (2009–2018), trawl net fishing (2011–2018), frame surveys (2000–2016) and catch assessment surveys (2000–2015). The activities provided information on fish stocks and supported advice for fisheries management. The average fish stock densities for Tanzania, Uganda and Kenya of 8.92, 8.25 and 8.19 t/km2, respectively, were relatively similar. Diplomatic and sustainable efforts for harmony in fish harvesting among the fishers of the riparian countries are encouraged given the interdependence of the lake. The Kenyan and River Kagera regions had a higher proportion (≈ 4% each) of big‐sized Nile perch (≥50 cm total length) in 2018, signifying the critical breeding areas for Nile perch. To sustain the fishery, there is need to enforce a 36%–44% effort reduction for all the major fisheries, and enforcement of gear limits to avoid harvesting of immature fish and destruction of the lake ecosystem. 相似文献
70.
Irrigation management strategy invites the quantification of crop response to irrigation frequencies. Conventionally, mulches increase the yield and water use efficiency (WUE) to a great extent by augmenting the water status in the root zone profile. A field study was carried out during the winter season (November-March) of 2003-2004 and 2004-2005 at the Central Research Farm of Bidhan Chandra Krishi Viswavidyalaya (Latitude 22°58′N, Longitude 88°31′E and altitude 9.75 m amsl), Gayeshpur, India, to evaluate the effect of irrigation frequencies and mulches on evapotranspiration rate from tomato crop field as well as leaf area index (LAI), fruit yield and WUE of the crop. The experiment was laid out in a split-plot design where three irrigation treatments {rainfed (RF); CPE50 and CPE25 where irrigation was given at 50 and 25 mm of cumulative pan evaporation (CPE)} were kept in the main plots and the subplots contained four mulch managements {no mulch (NM), rice straw mulch (RSM), white polyethylene mulch (WPM) and black polyethylene mulch (BPM)}. Under CPE25, tomato crop recorded significantly higher leaf area index (LAI) over CPE50 and rainfed condition. LAI value under BPM was 9-30% more over other mulches. Maximum variation of LAI among different treatments was recorded at 60 days after transplanting (DAT). Fruit yield under CPE25 was 39.4 Mg ha−1; a reduction of 7 and 30% has been obtained under CPE50 and RF condition. The use of mulch increased 23-57% yield in comparison to NM condition. Actual evapotranspiration rate (ETR) was 1.82 mm day−1 under CPE25 and declined by 15 and 31% under CPE50 and RF condition, respectively. The variation of ETR among different mulches became more prominent under maximum water stressed (RF) condition, whereas the variation was negligible under CPE25 frequency. Irrespective of mulching WUE was highest under moderately wet (CPE50) soil environment. Among different mulches, BPM was responsible for attaining the highest WUE value (25.1 kg m−3), which declined by 22, 21 and 39% under WPM, RSM and NM, respectively. 相似文献