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The Journal of Research ANGRAU

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 />

12

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