Effect of potassium application on yield and nutrient uptake by Bt cotton
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Date
2015
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
CCSHAU
Abstract
A field experiment was carried out at the farm of Krishi Vigyan Kendra, Sirsa during kharif 2014
to study the effect of K application on yield and nutrient uptake by Bt. Cotton. The soils at two
experimental sites were sandy loam in texture, slightly alkaline in reactions, low in organic carbon and
nitrogen, medium in phosphorus with medium to high potash levels. There were seven treatments
based on different K levels viz. T
1 - N175
P
60
, T2 - N175
P
60
+ Water Spray, T
3 - N175
P
60
+ 1% foliar spray
of KNO
3
, T4 - N175
P
60+ K
30
, T5 - N175
P
60+ K
30+1% foliar spray of KNO
3
, T6 - N175
P
60+K
60
and T
7 -N175
P
60+K
60+ 1% foliar spray of KNO3. Potash was applied through soil application and foliar spary
which were done at the time of peak flowering and boll development stages. The number of boll/plant
and boll weight increased with application of K in all the treatments in both soils where as the ginning
over turn and harvest index remained unaffected. The mean seed cotton yield was higher in High K
fertility soil as compare to Medium K fertility soil. The seed cotton yield increased significantly in the
high K fertility soil up to the treatment T4 (N175
P
60 + K
30). Which indicated that in the high K fertility
soils, application of potassium at the rate of 30 kg/ha is sufficient of optimizing the seed cotton yield.
However, in the medium K fertility soil, the highest seed cotton yield was obtained in the treatment
where the recommended doses of N, P and K was applied along with two foliar spray of 1% KNO3.
The nitrogen and potassium concentration in different plant parts significantly affected by the
potassium application and available potassium in the soil, whereas the phosphorus concentration was
not affected. The mean highest N,P and K uptake was obtained in the treatment where two foliar spray
of KNO
3
was applied along with recommended doses of nitrogen phosphorus and potassium. The NPK
uptake followed the order Seed>stem>Khokri>leaves. The dry matter yield of different plant parts was
significantly affected by potassium application and available potassium status in the soil. The post
harvest available N status in the soil decreased as compared to its initial level. However, a slight
increase in available P and K was observed in plots where soil application of K was done.
Description
Keywords
Seed cotton yield, Potassium, Uptake, Soil fertility