Effect of split and foliar application of nitrogen on leaf nitrogen concentration, SPAD index and photosynthesis in Bt. Cotton (Gossypium hirsutum L.)

Ad Tumbare,Mb Dhonde,Md Giri

doi:10.3329/sja.v14i2.31239

Ad Tumbare, Mb Dhonde + Show 1 more

Open Access

https://doi.org/10.3329/sja.v14i2.31239

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Abstract

A field experiment was carried out at Rahuri (Maharashtra) India in consecutive years of 2011 to 2012 to study the response of split and foliar application of nitrogen on leaf nitrogen concentration, SPAD index and photosynthesis in Bt cotton (Gossypium hirsutum L). Ten treatments comprising nitrogenmanagement practices (application of recommended dose of nitrogen in 3, 4, 5, 6 splits; foliar application of 20 g KNO3 litre-1 water, 20 g urea litre-1 water, combination of split application of nitrogen and foliar spray of 20 g KNO3 litre-1 water, 20 g urea litre-1 water and control) were tested on inceptisol. Results indicated that application of nitrogen in six splits (20% at sowing as basal and remaining in 5 equal splits at 30, 45, 60, 75 and 90 DAS) registered significantly higher leaf nitrogen content, SPAD index and rate of photosynthesis except 60 DAS where 4 nitrogen split showed higher leaf nitrogen content and SPAD index. Similarly the same treatment registered significantly higher plant height, dry matter accumulation, number of bolls plant-1 and lint yield.SAARC J. Agri., 14(2): 1-11 (2016)

Highlights

Cotton is the world’s leading fibre crop and grown in more than 80 countries
Insufficient nitrogen supply often affects the growth of cotton and developmental processes, resulting in a reduced leaf area index (LAI), low leaf chlorophyll concentration, photosynthetic rate, and biomass production (Zhao and Oosterhuis, 2000), as well as reduced lint yield and poor fibre quality (Reddy et al, 2004)
N application in 4 equal splits at sowing, 30, 45 and 60 Days after sowing (DAS) recorded significantly higher leaf N concentration and SPAD index at 60 DAS and it was at par with rest of the treatments except no nitrogen

Summary

INTRODUCTION

Cotton is the world’s leading fibre crop and grown in more than 80 countries. India accounts for about 32% of the global cotton area and contributes to 21% of the global cotton, currently ranking second after China (Anonymous, 2012). Yield can be drop sharply if apply inadequate nitrogen whereas apply nitrogen at improper time resulted slow growth of fruit, more attack of insects pests and delay in maturity. Insufficient nitrogen supply often affects the growth of cotton and developmental processes, resulting in a reduced leaf area index (LAI), low leaf chlorophyll concentration, photosynthetic rate, and biomass production (Zhao and Oosterhuis, 2000), as well as reduced lint yield and poor fibre quality (Reddy et al, 2004). Nutrient requirement during critical stages can be better met with split application pattern. As such present investigation was planned to find out the response of split and foliar application of nitrogen in Bt cotton

MATERIALS AND METHODS

RESULTS AND DISCUSSION

90 DAS 120 DAS