Farm Table says:
What is the problem?
The aim of this trial was to examine Nitrogen Fertilizer Use Efficiency, through the effect on yield of different rates of nitrogen (N) fertilizer. Replicated trials were also carried out across other cotton growing regions by the Regional Development Officers.
What did the research involve?
The trials are located at Farm 169 on the western side of Emerald. The soil type used in the trials is brown medium clay Vertisol with rainfall average 359mm between September 2014 to February 2015.
What were the key findings?
The crop received two Fipronil sprays at 0.03L/Ha on 5 and 16 Nov, a Shield spray at 0.15 L/Ha on 11 Dec and a Pegasus at 0.8 L/Ha on 13 Jan. An application of Pix on 18 Jan at 1 L/Ha and defoliation began on 11 Feb with 0.08 L/Ha and another on 17 Feb at 0.12 L/Ha along with 1.5 L/Ha of Prep. Buffer 2 3 1 3 2 1 1 2 3 Buffer The growing season in Emerald was quite challenging with hot dry conditions and low early season retention due mainly to Heliothis which meant the crop tended to grow vegetatively after the first flower where pix was considered but not applied. Root growth was poor and no explanation for this was established and this may have contributed to the crop approaching cutout prematurely which required careful management.
The last five crops in this field have been cotton-cotton-corn-cotton-cotton but yields obtained this season were the best ever. Petiole levels at the start of the season appear to be satisfactory according to NutriLogic however they did decline to levels below 45ppm which would seem quite low. This soil does have sodicity at a depth which would limit yield and it would also appear that increasing Nitrogen does increase yield at economic returns.