Improving cotton yield
COTTON, REFERRED to as `White Gold' has been cultivated extensively for more than three decades in Andhra Pradesh and even today it commands larger extent of areas as one of the important commercial crops. Farmers are on cutting edge right from sowing to harvest of the crop due to lack of assurance from nature. Besides there are several production constraints that affect yield. The important among them are Non-application of organic fertilizers, non-adoption of recommended spacing irrespective of soil type and varieties and hybrids, excessive usage of complex fertilizers as top dressing leading to more accumulation of `P' and resulting in micronutrient deficiencies,lesser usage of phosphatic and potassic fertilizers, lack of knowledge about micronutrient deficiencies and their ill-effects on yield, about integrated pest management practices to control pests and to cut short the investment on plant protection.Also extending crop duration beyond 6 months, leads to pests such as pink boll worm. Indiscriminate dosage of pesticide concentration in the spray fluid poor spraying techniques are the other causes.
To overcome the above production constraints the following improved package (including IPM) may be followed.Deep summer ploughing destroys insects. Well decomposed farm yard manure, 100-150 kg of single super phosphate during preparatory cultivation to facilitate decomposition of debris can be resorted to.
Sowing can be done after 1 or 2 initial rains as it helps in eliminating the population of ground beetle. Speed treatment can be done with imidachloprid. This protect the crop up to 45 days after sowing from sucking pests (or) Stem application of 1:10 monocrotophos water mixture beginning at 15 days after sowing, for three times at 10 day intervals arrests attack of sucking pest complex. Sow the seed at recommended spacing.
Judicious use of fertilizers, preferably straight fertilizers for hybrids @ 90 kg/ha (in three equal splits at monthly intervals), 65 kg P2O5/ha and 45 kg K2O/ha and for varieties 60 kg/ha, 45 kg/ha P2O5 and 30 kg/ha K2O entirely as basalSpraying magnesium sulphate 1per cent (10 gm/1) concentration at 45 & 75 days after sowing: boric acid 0.1-0.15 per cent (1-1.5 gm/1) at 60 and 90 days after sowing (or) at 4-5 days interval for 2-3 times when the symptoms are noticed during the first 45 days of crop growth corrects micronutrient deficiencies. Topping the plant at 90-100 days after sowing eliminate the eggs of Helicoverpa. The following integrated pest management practices can be followed.
Deep summer ploughing, seed treatment with imidachloprid at 5 gm/kg of seed. Trap crops such as castor, sorgham around the cotton field and marigold to contain the egg and initial instar larval population of bollworms can be raised.
- Stem application with monocrotophos (1:10) at 15, 30 and 45 days after sowing check suckling pest. Topping at 90-100 days after sowing, use of biological control measures by releasing trichogramma, spraying of NPV etc is essential. Using pheromone traps for Helicoverpa, Spodoptera separately monitor them well.
Pulling and destroying cotton stalks break the cycle of pink boll worm and other boll worms. Rotation should be followed.
There must be balanced use of organic and chemical fertilizers. Cotton can be intercropped with pulse crop. Digging up trenches around the field and dusting with folidal or lindane avoids boll worm larvae.
`T' shaped branches as bird perches can be installedin the field. Picking and discarding of rosette flowers helps to manage efficient pink boll worm. Hand picking and use of Indoxacarb controls boll worm larvae of III instar & onwards
Gingelly oil as can be used as synergistic @ 1:2 for endosulfan and @ 1:4 for chloropyriphos. Use of synthetic pyrethroids once or twice as the last control measure for boll worms and its excess use should be avoided as it may lead to resurgence of white fly.
K. Anand Singh,
K. Prabhakar
& K. Malla Reddy
Krishi Vigyan Kendra, A.P
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