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Item Effect of liming, phosphorus and ammonium sulphate on ammonification and nitrification in peat(Pak. J. Sci. Ind. Res., 1989-09) Mandal, R.; Parsons, J. W.Mincralizalion of native N in an cxticmcly acid [x^l following liming and addition of P and (NH^)jSO^ was ijivesligalaJ. All Uic UcaUncnLs increased NM^-N uplo 20 days inculiation followed by a rapid d c c T e a s e lo a tniniinum at 35 days.'I hc trend, Uiereafler, mainly followed a slow increase at 45 days. Released of NHj-N increased significanlJy witJi ])H and added (NH^)jSO^ specially where lime and N were applied together.Item Influence of aluminum on pH and recovery of exchangeable aluminum from peat(Pak. J. Sci. Ind. Res., 1989-03) Mandal, R.; Parsons, J. W.Incubation experiment was conducted to obtain infomiation on tlie extent of acidity developed due to added AlCI, (0, 25, 50 and 100 tig g ') at different pH levels and changes in exchangeable A1 in peat. Results showed that A1 at high pH is hydrolysed causing an increased acidity by releasing H* from hydroxy aluminium compounds. Concentration of exchangeable A! is tremendously reduced with increasing pH possibly due to formation of mono-aluminium compounds or polynuclcar complexes of hydroxy aluminium. Extractable Al in IM KCI was very low Ix-cause of the presence of organic binding sites in peat. Thus, the recovery of exchangeable Al from Fisoii peat (I) containing more humified material was extremely low (1.0-2.1%) in comparison to Re^i Mo,‘?s peat (47.6-52.8%).Item Amounts and mineralization of organic phosphorus compounds and derivatives in some surface soils of Bangladesh(Elsevier Scientific Publishing Company, 1977) Islam, A.; Mandal, R.Concentrations of a few organic phosphorus compounds and their hydrolysis products have been determined in a number of Bangladesh soils. The amounts of DNA and its derivatives, inositol penta- and hexaphosphates, ranged from 0.16 to 1.30, and 18.5 to 130.0 ppm, respectively. The hydrolysis products of phospholipids such as choline, ethanolamine and glycerophosphate ranged from 0.36 to 3.29, 0.28 to 2.52 and 0.20 to 1.05 ppm, respectively. Multiple correlation suggested that pH, organic matter, organic phosphorus and total phosphorus were collectively related to the amounts of different organic phosphorus fractions in soil samples. Individually, DNA and its derivatives were found to be significantly related to total phosphorus and inositol penta- and hexaphosphates to organic phosphorus. Choline was significantly related to organic matter, organic phosphorus and total phosphorus; ethanolamine to organic matter and total phosphorus; and glycerophosphate to organic phosphorus. Moisture and lime promoted progressive mineralization of organic phosphorus with time. Potassium dihydrogen phosphate, glucose and ammonium sulphate showed rapid initial and final mineralization. In contrast, the application of compost caused an initial luxury immobilization followed by a marked increase in mineralization with time. Maximum mineralization was observed when ammonium sulphate was added to samples in submerged conditions. The least mineralization occurred when lime was added to samples at 50% of field moisture capacity.Item Effect of chlorides of cobalt, nickel and copper on nitrification in peat(Pak. J. Sci. Ind. Res., 1989-09) Mandal, R.; Parsons, J. W.Mineralization of N in ihe presence ofO to 2000 mg kg ' each of Co. Ni and Cu as chlorides in peat was studied. Tliese s;dts of metals did not produce any significant change in tlie proccss of niLrificalion and ammonificalion up to 40 and 50 days respectively. However, lliereafter tlie general trend was forNH^-N to decrease up to 110 days as (NOj+NOj)- N accumulated. Nitrificaiion was increasingly sujipressed as tlie Co, Ni and Cu were increa.Item Release of sulphate sulphur from gypsum and elemental sulphur in soil under submerged condition(Dhaka University Studies, 1986-01) Mandal, R.; Hossain, M. S. A.; Islam, R.Item Conversion of urea placed at different depths and its subsequent impact on growth and yield of rice(Indian J. of Agric. Sci., 1980-11) Islam, A.; Mandal, R.; Ahmed, Z.; Rashid, M. H.In a study on the effect of urea with depths in rice {Oryza sativa Linn.), conversion of urea into NHj-N was maximum at 15 days in most of the treatments and into NOj-N was at 7 days. But with surface placement of urea it continued up to 15 days of placement and thereafter the concentrations of both declined with time in all the treatments. Fertilizers @ 80 kg N + 60 kg P + 40 kg K/ha placed 8-cm depth produced the highest dry matter and grain yield. At this treatment, the rice plants also accumulated highest amount of N in the shoot and grain.Item Mineralization of inositol penta and hexaphosphates in some soils of Bangladesh(Bangladesh J. Sci. Res., 1977) Mandal, R.; Islam, A.The nature of iP;, and changes iP^ in Bangladesh soil* has been examined. Mineralization of iP^ and ipj was found at all moisture levels cither alone or with lime. A rapid mineralization occurred in the first 30 days followed by a moderate disappearance in the next 30 days in all treatments. Maximum mineralization of iPj and iPj occurred in submerged condition with lime. The hydrolysis was greater in soils containing more organic matter and iPu and ipj. Mineralization also increased with pH for inducing conditions to proliferate of the phytase for the breakdown of ipj and iP.Item Influence of aluminum chloride on nitrification in teat(Pak. J. Sci. Ind. Res., 1990-03) Mandal, R.; Parsons, J. W.The of feel of iilumiiiiiimon atnniDnificalion and nilriHcalion was slucliod in a series of incubalionsof peal with ;uk1 williout added (Nll,)jSO,. Addition of AlCI, (0, 200, 4(X), 600 jig A! « ') caused a iionsigniricaiii incrciise in NH, N up to 25 days of incubation in ilic absence of (NI i,)jSO,;md tlie release followed by iminobilizaiion of N in tiie piesence of applied (NH^)jSO^. Similarly a significani cbangc in nitrification occurrcd after 25 days of incubation ;uid was found to be a function of NI I^-N concentration. Aluminium u|)to 2TO ug g ' i)eat apjieared to stimulate nitrate production but tJie successive increments resulted in partial suppression (5 14%) of nitiilication. Greatest inhibition (14%) was caused by the highest level of aluminium. Results showed that addal AlCl^ had no significant toxic effect on ammonification, Change in pM at 60 days of incubation was controlled but did not chatige significantly.Item Effect of aluminum, iron and manganese on nitrification in peat(Srilankan Journal of Agricultural Sciences, 1989) Mandal, R.; Parsons, J. W.Nitrification in the presence of 0 to 3000 pg of each of Al, Fe and Mn as chlorides in peat (g ) has been studied. About up to 40 days the added elements could not produce any appreciable change in the processes of N mineralization and transformation. However, thereafter the salts suppressed nitrification and encouraged ammonification. The interalia transformation of N increased with concentration having the threshold value of 2000 \xg peat. The divergence of two trend (ammonification and nitrification) in the presence of metals attained the maximum at about 80 days. Addition of elements in freshly prepared peat was found to be more responsive than the aged one.Item Characterization and categorization of Azotobacter and related microorganisms of Bangladesh soils(Bangladesh J. Sci. Res., 1989-12) Mandal, R.; Parsons, J. W.Free.living nitrogen fixing bacterial isolates were purified from eleven soil samples representing eight typical zones of Bangladesh. The isolates were categorized on the basis of their colonial, morphological and physic-biochemical characteristics. Only one isolate could not be fitted into any recognized group. The rest were the members of Azotobacter and Azomona.i genera.