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NUTRIENT REQUIREMENT AND EFFECT OF Bt COTTON ON SOIL PROPERTIES IN GUNTUR DISTRIC

KrishiKosh

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Title NUTRIENT REQUIREMENT AND EFFECT OF Bt COTTON ON SOIL PROPERTIES IN GUNTUR DISTRIC
 
Creator DEEKSHITHA, DKD
 
Contributor RAVINDRA BABU, P
 
Subject cotton, sulphur, fertilizers, planting, yields, nutrients, nitrogen, land resources, potassium, tillage equipment
 
Description An experiment entitled “Nutrient requirement and effect of Bt cotton on soil properties in Guntur district” was performed to study the effect of Bt cotton on soil properties and to determine the nutrient requirement of Bt cotton. An initial survey was conducted in cotton growing belt of Guntur district. Thirty representative surface soil samples were collected under three categories viz., six samples from non Bt cotton areas and twelve each from areas under Bt cotton for 2-5 years and 8-10 years. They were analyzed for physical, physico-chemical, chemical and biological properties.
Soils under Bt cotton were low in bulk density. All the soils were slightly alkaline and non saline. When compared to non Bt cotton areas, soils under continuous cultivation of Bt cotton for 2-5 years were lower in available nitrogen. 8-10 years continuous cultivation of Bt cotton further decreased the available N content in soil. Similar trend was followed by other nutrients like potassium, sulphur and micronutrients (Zn, Fe, Mn and Cu) but available P content was more in soils under Bt cotton than non Bt cotton soils.
The soil samples were medium to high in phosphorus, very high in potassium, sufficient in sulphur and micronutrients like manganese, copper and deficient in iron. Soils under Bt cotton were deficient in zinc content but sufficient available zinc content was noticed in soils under non Bt cotton. The biological properties of soil like microbial biomass carbon, dehydrogenase activity, bacterial population including plate count agar, phosphate solubilising bacteria, Rhizobium and Azotobacter were less in Bt cotton cultivated soils compared to non Bt cotton.
A field experiment was conducted during kharif, 2013. The experimental soil was clay loam in texture, non saline, slightly alkaline in soil reaction with low organic matter. The soil was low in available nitrogen, medium in phosphorus, very high in potassium and sufficient in micronutrients with values above critical limits. The treatments imposed were control (no fertilizers) (T1), Farmers practice (T2), 100% RDF (150-60-60 kg N, P2O5, K2O) (T3), 100% RDF + S @ 30 kg ha-1 (T4), Soil test based recommendation (T5), 125% RDF (T6), 125% RDF + S @ 30 kg ha-1 (T7), 150% RDF (T8), 150% RDF + S @ 30 kg ha-1(T9). Totally nine treatments were tested with three replications laid out in randomised block design (RBD). Entire phosphorus and sulphur were applied as basal dose in the form of SSP and elemental sulphur granules as per the treatments. Recommended dose of nitrogen and potassium were applied in four splits in the form of urea and MOP.
Highest yield, dry matter accumulation, number of sympodial branches per plant, boll weight and boll number were recorded in the treatment which received 125% RDF + S @ 30 kg ha-1. Sulphur application alomg with 100, 125 and 150% RDF increased the kapas yield by 9, 16 and 9% respectively over the 100, 125 and 150 per cent RDF application alone. Increase in fertilizer levels increased the nutrient uptake upto 125% RDF level only. Highest uptake of nutrients was recorded in 125% RDF + S @ 30 kg ha-1 treatment.
The treatments had no significant impact on soil physical and physicochemical properties. When compared to non sulphur treatments, sulphur applied treatments were superior in available macro and micro nutrient contents in soil. Among the sulphur applied treatments although 150% RDF + S @ 30 kg ha-1 recorded highest available macro and micronutrient status in soil, it was on par with 125% RDF + S @ 30 kg ha-1 and 100% RDF + S @ 30 kg ha-1. Application of higher doses of fertilizers and combination of sulphur significantly influenced the microbial properties viz., microbial biomass carbon, plate count agar and bacterial populations. Treatments which received 125 and 150% RDF + S @ 30 kg ha-1 were on par and higher in microbial activity over the 100% RDF treatment of all the treatments 125% RDF + S @ 30 kg ha-1 gave the most favourable cost benefit ratio followed by soil test based recommendation.
 
Date 2016-12-22T10:24:49Z
2016-12-22T10:24:49Z
2014
 
Type Thesis
 
Identifier 157P.
http://krishikosh.egranth.ac.in/handle/1/92042
 
Language en_US
 
Relation D5072;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY