Please use this identifier to cite or link to this item: http://krishikosh.egranth.ac.in/handle/1/72618
Authors: MADHURI, T
Advisor: SREE RAMULU, A
Title: NITROGEN MINERALIZATION AND ENZYME ACTIVITIES IN SUBMERGED PADDY SOIL UNDER LONG TERM FERTILIZATION
Publisher: ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY RAJENDRANAGAR, HYDERABAD.
Language: en
Type: Thesis
Series/Report no.: D3341;
Agrotags: NITROGEN, MINERALIZATION, ENZYME, ACTIVITIES, SUBMERGED, PADDY,
Abstract: f\ field experiment was conducted during kharif, 1988 in the experimental plots of Long Term Fertilizer Experiment operating since 1971 on a sandy clay loam soil (Tropaquept) at Agricultural Research Institute, Rajendranagar with rice ( Var. Tellaham~n), to study the effect of long term use c·f fertilizers and manures on soil properties, yield, upta k~ of N, P, K, nitrogen mineralization and enzyme activitie!:O viz., dehydrogenase, .urease and phosphatase. The fertilizer and manurial treatments comprised of 50% NPK (T 1 ), 100·~~ NPK (T..,), 150~~ NPK (T~), 100% NPK coupled with hand weeding (T 4 t, 100% N PK .f' Zn (T 5 ), 100% NP (T 6 ), 100~~ N (T 7 ), 100% NPK + FYM (T 8 ), 100%' NPK-S (T 9 1 ana a control without fertilization or manuring (T 10 J. The pH, EC, available N, P, K and nitrogen mineralizahon of the soil wPre studied in the samples collE>cted at harvest of rice. The enzyme activity and organic carbon were studied in the soil samples collected before puddling, 10 days after transplanting (DAT), 50 OAT and at harvest. The plant s:~mples collected at harvest were used to study the uptake of N, P and K. Long tern) u!:.e of fertilizers and manure~ dicf net have a ny significant infl~.tence on pH, EC and a.vallable nitrogen cont<:>nt of the soil. The organic carbon content was the hlcaho:st in the treatment receiving 100% NPK in conjunction with E"YM ( T 8 ) at all stages of sampling. The available P content was also highest in this treatment. Besides thes , the grain and straw yields and uptake :·: . 1 of nutrients viz., N, P, K were highest in T8 indicating the beneficial effects of application of organic matter along with 100% NPK through chemical fertilizers. With increase in level of application from 50 to 100 and 150% NPK, increase in yield and uptake of N, P and K were noticed. Nitrogen mineralization studies. revealed that the ammoniacal, nitrate and nitrite nitro.,;ren contents were highest in the treatment rece1v1ng FYM at 7 and 14 days of incubation. There was no appreciable increase in ammoniacal nitrogen content after 7 days of incubation however, an increase in nitrate nitrogen was evident between 7 and 14 days of incubation. Total mineral N content increased with increase in period of incubation from 7 to 14 days. Significant positive correlations of organic carbon with ammoniacal, nitrate and nitrite nitrogen contents were observed. The dehydrogenase, urease and phosphatase activities were highest in the treatment receiving 100% NPK in conjunction with FYM (T ) and these activities correlated significantly with organ~c carbon at all stages of sampling. An increase in urease and phosphatase activity with increase in level of fertilizer from 50 to 100 and 150% NPK was observed. The mean dehydrogenase activity was maximum before puddling and minimum at harvest while reverse was the case with urease activity. The mean phosphatase activity was maximum be fore puddling and it was lower during crop growth periods i.e. 10 OAT and 50 DAT. The results have confirmed the profound influence of FYM application along with chemical fertilizers on the availability of nutrients and soil enzymatic activities. Conjunctive use of FYM along with optimal levels of NPK is, therefore, ad vacated as a better agronomic practice under intensive cropping for maintaining soil fertility and higher productivity of rice under submerged conditions in a light textured sandy clay loam soil.
Issue Date: 1990
Appears in Collections:Theses

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