Direct and residual effect of nitrophosphates of varying water solubility on crop yield and olsen-P in a typic haplustept
2003
Khurana, H.S. | Saroa, G.S. | Vig, A.C., Punjab Agricultural University, Ludhiana (India). Dept. of Soils)
In a long-term experiment (in progress at PAD research farm since 1994) on a Typic Haplustept involving potato-sunflower-pearlmillet sequence; three differentially water-soluble P carriers [DAP (18:46:0),ANP (20:20:0) and Suphala (15:15:15)] were applied at five rates (0, 30, 60, 90 120 kg PPs ha-') to potato crop and the succeeding crops (sunflower pearl millet) were raised on residual P. Surface (0-15 cm) and the sub-surface (15-30, 30-45,45-60, 60-90 90 90-120 cm) soil samples were collected after the harvest of each crop from 60 and 120 kg P205 ha- treatment plots, to study Olsen-P distribution and accumulation in soil profile. Potato tuber yield increased significantly up to 60 kg P205 ha-'. Olsen-P content generally decreased with depth but the decrease was non significant beyond 45 cm depth. The highest values of Olsen-P in the profile were observed with Suphala followed by ANP and the least with DAP. The three fertilizers used, however, did not differ significantly as far as yield, P uptake and P accumulation were concerned. Less than one-third (33 percent) of added P to potato crop was accumulated as Olsen-P in the surface (0-15 cm) layer and the accumulation decreased with depth. Nearly 61 percent of the total Olsen-P in the profile accumulated in the upper 30 cm layer with 60 kg PzOs ha-' application rate while for 120 kg P20s ha-I rate, 58 percent was accumulated in the upper 45 cm. This indicates that translocation of Olsen-P increased with increase in rate of P application.
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Эту запись предоставил Indian Council of Agricultural Research