The Journal of Research ANGRAU
Contents of 41(1) 2013 - acharya ng ranga agricultural university
Contents of 41(1) 2013 - acharya ng ranga agricultural university
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PRASAD and PRASADINI<br />
seasons during the two years over the crop grown<br />
entirely with chemical fertilizers. But, the substitution<br />
<strong>of</strong> 50 % N fertilizer with glyricidia was more beneficial.<br />
It increased the uptake <strong>of</strong> Fe by rice in significantly<br />
larger quantities upto panicle initiation both in kharif<br />
and rabi season during the two years. Such a<br />
beneficial effect <strong>of</strong> integrated nutrient management<br />
by substituting 25 % N fertilizer with glyricidia was<br />
on the other hand persistent only at tillering stage.<br />
d. Manganese<br />
Rice grown with different levels <strong>of</strong> fertilizers<br />
and integrated with organic source <strong>of</strong> nutrients<br />
removed larger quantities <strong>of</strong> this micronutrient than<br />
from the unfertilized soil. <strong>The</strong> crop removed 187.4 g<br />
ha -1 Mn at tillering, 384.9 g at panicle initiation and<br />
137.9 g ha -1 at harvesting stage during kharif 2005-<br />
06 (Table 8). <strong>The</strong> crop grown in the subsequent<br />
season removed 269.8, 328.5 and 324.69 g ha -1 Mn.<br />
During the second year rice removed 154.9, 351.9<br />
and 474.9 kg Mn ha -1 in kharif. In the rabi season it<br />
removed 192.1, 313.6 and 215.7 g Mn ha -1 at tillering,<br />
panicle initiation and harvesting stage. <strong>The</strong><br />
continuous application <strong>of</strong> 50 % recommended dose<br />
<strong>of</strong> fertilizers increased the uptake <strong>of</strong> this micronutrient<br />
during the corresponding crop growth stages in kharif<br />
and rabi in both the years. <strong>The</strong> crop fertilized with<br />
this treatment dose removed 276.0, 629.9 and 574.9<br />
g Mn ha -1 at tillering, panicle initiation and harvesting<br />
stage in the kharif season, while it removed 287.4,<br />
525.1 and 676.8 g ha -1 in rabi 2005-06. <strong>The</strong> uptake<br />
was 183.1, 374.7 and 784.5 g Mn ha -1 in kharif, while<br />
it was 232.3, 483.3 and 643.7 g ha -1 in the rabi season<br />
during the three crop growth stages in the second<br />
year crop cycle. <strong>The</strong> contribution <strong>of</strong> FYM or glyricidia<br />
to substitute 50 % N fertilizer was superior to<br />
chemical fertilizers alone in enhancing the uptake <strong>of</strong><br />
this micronutrient only at tillering stage during 2005-<br />
06.<br />
<strong>The</strong> available Zn and Cu in the fertilized soil<br />
was on par with the unfertilized soil at different stages<br />
<strong>of</strong> crop growth during the two year rice-rice cropping<br />
sequence. <strong>The</strong> co-application <strong>of</strong> 50 per cent<br />
recommended dose <strong>of</strong> NPK through fertilizers and<br />
FYM or glyricidia equivalent 50 per cent N fertilizer<br />
in the kharif season followed by the recommended<br />
dose <strong>of</strong> fertilizers in the rabi season significantly<br />
enhanced the availability <strong>of</strong> Fe both in the surface 0-<br />
15 and lower soil depth <strong>of</strong> 15-30 cm. <strong>The</strong> substitution<br />
<strong>of</strong> 25 per cent N fertilizer with these organic materials<br />
in the kharif season and application <strong>of</strong> 75 per cent<br />
recommended dose <strong>of</strong> fertilizers in rabi season also<br />
enriched the soil with more quantity <strong>of</strong> available Zn.<br />
But, this improvement was relatively less consistent<br />
at different stages <strong>of</strong> crop growth than their<br />
substitution for 50 % N fertilizer. This trend was also<br />
similar for the soil available Cu content. Additionally,<br />
its improvement was also recorded by substituting<br />
50 or 25 % N fertilizer with paddy straw only in the<br />
first year. <strong>The</strong> benefit <strong>of</strong> increased availability <strong>of</strong> Fe<br />
in the soil was recorded at the tillering stage during<br />
2005-06 by the substitution <strong>of</strong> 50 per cent N fertilizer<br />
with FYM in kharif season and application <strong>of</strong><br />
recommended dose <strong>of</strong> fertilizers in the rabi season<br />
only in the surface layer. On the other hand, the<br />
availability <strong>of</strong> Mn was not influenced by the<br />
application <strong>of</strong> fertilizers or the conjunctive use <strong>of</strong><br />
nutrients through organic and inorganic sources.<br />
Rajeev Kumar et al., (1993), Singh et al., (1999)<br />
reported that the incorporation <strong>of</strong> organic sources in<br />
the soil along with the fertilizers increased the<br />
available micronutrients. <strong>The</strong> magnificent responses<br />
<strong>of</strong> integrated nutrient management treatments in<br />
leaving behind larger quantities <strong>of</strong> copper sustained<br />
the crop requirement in sufficient quantity. <strong>The</strong><br />
availability <strong>of</strong> Zn increased by the co application <strong>of</strong><br />
FYM by substituting 25 or 50% N fertilizer.<br />
Nonetheless, the site <strong>of</strong> present experiment<br />
continuously cropped with rice-rice cropping<br />
sequence for the past 17 years contained much higher<br />
quantities <strong>of</strong> Zn, Cu, Fe, Mn than the critical limit <strong>of</strong><br />
0.6 mg kg -1 Zn, 0.2 mg kg -1 Cu, 4 mg kg -1 Fe, and 3<br />
mg kg -1 Mn even in the unfertilized control. Not<br />
complacent with the data so achieved, it would be a<br />
wise step to substitute 50 per cent N fertilizer with<br />
FYM or glyricidia to averse the likely depletion <strong>of</strong><br />
these micro but essential elements for crop growth<br />
in the years to come<br />
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