Nutrient Management

 

Organic manuring and biofertilizers

Apply organic manure in the form of farmyard manure or compost or green leaf @ of 5 t/ha and incorporate into the soil while ploughing. The entire quantity of phosphatic fertilizers may be applied along with the organic manures.

Cowpea may be raised as an intercrop in dry seeded low land (semi-dry) rice by sowing 12.5 kg seed/ha along with rice to serve as a source of green manure. When the rice field gets submerged with the onset of southwest monsoon, cowpea at the age of about six weeks and at active vegetative stage decays and gets self-incorporated in the soil adding substantial quantity of green manure. Such a system of concurrent growing of cowpea also reduces weed pressure in semi-dry rice.

Liming
  • In general, addition of lime is absolutely necessary when the pH is lower than 5.5 and it is advisable when pH varies between 5.5 and 6.5.

  • For direct seeded crops during the first season, apply lime @ 600 kg/ha in two split doses, the first dose of 350 kg/ha as basal dressing at the time of first ploughing and the second dose of 250 kg/ha as top dressing about one month after sowing.

  • For transplanted crop, apply lime @ 600 kg/ha in two split doses, 350 kg/ha as basal dressing and 250 kg/ha as top dressing about one month after transplanting.

  • A time lag of one week should be given between application of lime and fertilizers. For top dressing, lime may be applied one week prior to the application of fertilizers.

Fertilizer recommendation for rice

Fertilizer recommendation for rice, kg/ha 

Kind of land / region Variety N P2O5 K2O
Uplands (modan) PTB 28, 29, 30 40 20 30
-do- High yielding short duration varieties 60 30 30
Wet lands (All regions) -do- 70 35 35
-do- High yielding medium duration varieties 90 45 45
-do- Local varieties 40 20 20
-do- H4 70 45 45
-do- Mahsuri 50 25 25
Kole lands *Short duration varieties 90 35 45
  *Medium duration high yielding varieties 110 45 45
Kattukampal and Ponnani kole lands *Medium duration high yielding varieties 110 45 55

*Location specific recommendations. Strict surveillance of pests and diseases is a must under such situations

  • For modan cultivation (upland crop) and direct seeded crop in wet lands, apply nitrogen in three equal split doses, first as basal dressing, second at tillering stage (three weeks after seeding) and the third at panicle initiation stage (about thirty days before flowering).

  • Apply the full dose of P2O5 at the time of land preparation as basal dressing. Apply K2O either in a single dose as basal or in two split doses half as basal and half at the panicle initiation stage.

  • The general principle to be followed is that in light soils as well as in soils with high leaching, N may be applied in three or four split doses according to the duration of the variety.

  • During the first crop season, when basal application of N is not possible due to incessant rains, basal dose can be shifted to 15 days after transplanting.

  • For dry sown Mahsuri, the fertilizer dose of 50:25:25 kg/ha N:P2O5:K2O is sufficient. Nitrogen dose may be given in three equal splits at basal and 45 and 85 days after sowing.

Methods of fertilizer application
  • For pre-planting application, apply the fertilizers at the final ploughing. In areas where availability of water is assured, temporarily draining the field one day prior to application and re-flooding after twelve hours is recommended for top dressing of fertilizer.

  • For increasing the efficiency of urea for top dressing, mix urea with six times its weight of slightly moist soil and apply to the field 24-28 hours after mixing. Oil seed cakes such as punna and neem cakes can also be mixed with urea (1 part of oil cake + 5 parts of urea by weight) for increasing fertilizer efficiency. This method is particularly useful for basal application of N. Under special conditions of drought and waterlogging, apply N as foliar spray. Urea may be applied as a low volume spray at 15% concentration using power sprayer or at 5% concentration using a high volume sprayer, the quantity applied in one application being limited to 15 kg/ha.

  • Whenever carbofuran application is needed at around 20 days after planting, it would be advantageous to mix 10 kg N in the form of urea. Carbofuran should be used @ 0.75 kg ai/ha.

  • When zinc deficiency is noticed, apply zinc sulphate @ 20 kg/ha. Early stages of zinc deficiency are evidenced by interveinal chlorosis, bleaching of midribs and light yellow colouration of the leaf. Older leaves develop brown rusty spots and are extremely brittle. Zinc sulphate and potash should not be applied on the same day.

  • Split application of water-soluble phosphatic fertilizers in two equal splits as basal and at maximum tillering stage is effective in giving higher grain and straw yield than the full dose as basal dressing under certain situations.

  • When the soil has less than 10 ppm of calcium chloride extractable sulphur or 15 ppm of phosphate extractable sulphur, substitute urea with ammonium phosphate sulphate to correct sulphur deficiency. For medium duration rice grown in brown hydromorphic soils ammonium phosphate sulphate may be used to supply 25 kg sulphur per hectare to protect the crop from sulphur deficiency (ad hoc recommendations).

Stages of fertilizer application in rice

Kind of land / region

Variety

Stages of application

Remarks

N P K
    BA ** AT API BA AT API BA ** AT API ** For direct seeded crop, one week after sowing
Uplands PTB 28, 29, 30 1/3 1/3 1/3 Full     1/2 *   1/2 * Full dose as basal is also recommended
HY short duration 1/3 1/3 1/3 Full     1/2 *   1/2 * Full dose as basal is also recommended
Wet land, direct seeded General 1/3 * 1/3 1/3 Full     1/2 *   1/2 * For wet seeded, the first dose to be given 1 week after sowing. For dry seeded, first application to be given after establishment of the seedlings
Mahsuri 1/3 1/3 * 1/3 ** Full     1/2   1/2 ** * 45 DAS, ** 85 DAS
Wet land, transplanted HY, short duration 2/3   1/3 * Full     1/2   1/2 * 5-7 days before PI
HY, medium duration 1/2   1/2 * Full     1/2   1/2 * * 5-7 days before PI
Mahsuri 1/2 1/4 * 1/4 ** Full     1/2   1/2 ** * 40 DAP, ** 60 DAP
Onattu­kara General 1/2 1/4 1/4 Full     1/2   1/2 In very coarse soils, N & K may be given in five equal splits
Wyanad & hilly region Long duration transplanted   1/2 1/2   Full *     1/2 1/2 * Along with first application of N & K
Direct seeded   1/2 * 1/2   Full **     1/2* 1/2 * 45 days after seeding, ** With first application of N & K
Pokkali General Full*     Full*           * Apply entire quantity at the time of dismantling of mounds
Kootu­munda­kan First crop 1/2   1/2 Full     1/2   1/2  
Second crop Full*     Full*     Full*     *Entire quantity as single dose immediately after the harvest of first crop

BA = Basal application; AT = At tillering; API = At panicle initiation; HY = High yielding;
DAP = Days after planting; DAS = Days after seeding

References Kerala Agricultural University.  2011.  Package of Practices Recommendations: Crops.14th edition. Kerala Agricultural University, Thrissur- 360 p.