Development and evaluation of nitrogen (liquid Urea) applicator for straw mulched no-till wheat

Abstract

The broadcasting of urea under high straw no-till farming often exhibit suppressed yields because of lesser nitrogen availability due to slower soil mineralization and greater N immobilization, de-nitrification and ammonia volatilization.  Prior to development of nitrogen (liquid urea) applicator, appropriate machines were not available for application of urea into the soil surface in a directly sown high straw mulched wheat crop.  To solve the problems of urea application in high straw no-till farming, self-propelled nitrogen (liquid urea) applicator was developed and evaluated under actual field conditions.  Average field capacity and efficiency of the applicator were found to be 0.33 ha/h and 80.49%, respectively.  Total plant N uptake at maturity was higher with wheat fertilized with developed nitrogen applicator (121.24 kg ha^-1) in comparison to conventional broadcasting (81.69 kg ha^-1).  Yield of wheat fertilized with the developed nitrogen (liquid urea) applicator was 20% higher than with broadcasting.  The increase in wheat yield under nitrogen applicator was primarily due to higher spike density, higher spike length, more grains per spike, more grain weight and higher nitrogen uptake.  Among point injection nitrogen application, the grain yield was at par at different straw load conditions; however, in case of broadcast N application, significantly lower grain yield was obtained under high straw load conditions compared to that of low straw load conditions.  This effect was attributed to the low accessibility of fertilizer N to the plant at high straw load in case of broadcast of urea.

Keywords: Nitrogen (liquid urea) applicator, broadcasting, straw load, field capacity, nitrogen uptake, yield