Fertilizer use efficiency in citrus, grape, banana, mango and guava as influenced by time of application and placement method.
Murthy S. V. K., Kotur S. C.
Author Affiliation: Indian Institute of Horticultural Research, Hessaraghatta Lake P.O., Bangalore - 560 089, India.
Karnataka Journal of Agricultural Sciences 11 : 1023-1029
Abstract : Studies were conducted at Bangalore, Karnataka, India, during 1985-97 in fruit crops raised on a red sandy loam soil (Typic Haplustalf), weakly acidic in reaction and having low cation exchange capacity, under semi-arid tropic conditions, using 32P-labelled single superphosphate and 15N-labelled ammonium sulfate. The fertilizers were placed in circular bands around the plants during different seasons, in split doses coinciding with growth flushes, and N and P derived from the fertilizers were determined over a period of time to monitor differences in absorption due to time and placement method. The P fertilizer use efficiency ranged from 0.51 to 2.36% in sweet orange, 1.08 to 4.51% in Coorg mandarin, 2.35 to 3.21% in Thompson Seedless grape, 1.32 to 4.65% in Alphonso mango, 0.58 to 16.35% in Arka Mridula guava, and 2.90 to 17.70% in Robusta banana. N fertilizer use efficiency in Robusta banana ranged from 6.8 to 60.0%. Application of fertilizer during the rainy season and placement within the drip circle always resulted in higher fertilizer absorption. Split application was always more efficient than single application.