RESPONSE OF RICE TO SOURCES AND TIME OF PHOSPHORUS APPLICATION
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Date
2019
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ACHARYA N G RANGA AGRICULTURAL UNIVERSITY, GUNTUR
Abstract
A field experiment entitled “Response of rice to sources and time of phosphorus application.” was conducted at Agricultural College Farm, Bapatla, on sandy clay loam soils during kharif, 2018-2019.
The treatments consisted of four sources of phosphorus i.e., SSP (S1), DAP (S2), 20:20:0 (S3) and 28:28:0 (S4) and two times of application viz., 60 kg P2O5 ha-1 as basal (T1), 60 kg P2O5 ha-1 as basal + 25 kg P2O5 ha-1 at maximum tillering stage (T2). The design adopted was RBD with factorial concept and replicated thrice.
Plant height of rice recorded at all the stages of observation was found to be non significant with respect to sources as well as time of application. The interaction effect between sources and time of application was found non significant at all the stages of study.
At all the intervals of sampling, sources had no significant effect on total number of tillers as well as drymatter production. With regard to the time of application, it had a significant effect on total number of tillers m-2 at all the stages of crop growth. Similar trend was observed with drymatter production except at 30 DAT. Significantly higher total number of tillers m-2 as well as drymatter production was obtained with the application of 60 kg P2O5 ha-1 as basal + 25 kg P2O5 ha-1 at maximum tillering stage (T2). The lowest total number of tillers m-2 and drymatter production was recorded with the application of 60 kg P2O5 ha-1 as basal (T1).
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Larger yield structure, comprising of number of panicles m-2 were found non significant with the choice of sources but found significant with time of application. All other yield attributes like total number of grains panicle-1, number of filled grains panicle-1 and sterility per cent were significantly affected by sources as well as time of application except panicle length and 1000-grain weight which were not found significant with sources as well as time of application. Among the sources, DAP (S2) produced significantly superior yield attributes which was on par with 28:28:0 (S4) with regard to total number of grains panicle-1 and number of filled grains panicle-1, whereas SSP recorded the highest sterility per cent (S1). In all the parameters which were significantly affected by time of application, T2 (60 kg P2O5 ha-1 as basal + 25 kg P2O5 ha-1 at MT stage) was significantly superior to T1 (60 kg P2O5 ha-1 as basal).
Maximum grain yield was obtained with DAP (S2) compared to rest of the sources. Between times of application, 60 kg P2O5 ha-1 as basal + 25 kg P2O5 ha-1 at maximum tillering stage (T2) recorded the highest grain and stover yields. Harvest index could not be altered significantly either due to sources or time of application.
Maximum gross returns, net returns and returns per rupee investment were obtained with DAP (S2). In case of time of application, all these economic parameters were found to be highest with 60 kg P2O5 ha-1 as basal + 25 kg P2O5 ha-1 at maximum tillering stage (T2).
With regard to phosphorus uptake by rice at 30 DAT it was found non significant with sources. However, at 60, 90 DAT and at maturity stages, significantly higher P uptake by grain and straw associated with DAP (S2). Maximum uptake of phosphorus at 30, 60, 90 DAT and maturity (Grain and Straw) was noticed with 60 kg P2O5 ha-1 as basal + 25 kg P2O5 ha-1 at maximum tillering stage (T2) and the lowest being observed with 60 kg P2O5 ha-1 as basal (T1).
Post harvest soil nutrient status (N, P2O5 and K2O) did not alter significantly due to sources as well as time of application except in the case of phosphorus. Significantly higher amount of post harvest soil phosphorus status was observed with the application of 60 kg P2O5 ha-1 as basal + 25 kg P2O5 ha-1 at maximum tillering stage (T2) while, it was minimum with 60 kg P2O5 ha-1 as basal (T1).
The present investigation could be concluded that as phosphorus is necessary in the early growth stages, top dressing of phosphorus at maximum tillering stage by using complex fertilizers especially DAP helps for higher productivity and profitability in rice.
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D5900
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