Article taken from CPM Magazine
Most, if not all nitrogen is applied at the establishment/early stages of the crop and there's often insufficient nitrogen remaining during the latter stages of crop development, so it's often a limiting factor when it comes to reaching yield potential, believes Peter Waite of Dow AgroSciences.
""When nitrogen fertiliser is applied to the soil, a nitrification process takes place where the ammonium-nitrogen is converted to nitrite (NO2) by Nitrosomonas bacteria, and then to nitrate (NO3) by the bacteria Nitrobacter," he explains. ""When nitrogen is in the nitrite and nitrate forms, the nitrogen can be lost through the soil profile by leaching, and in wet conditions can denitrify and be lost to the atmosphere as greenhouse gases. Keeping nitrogen in the ammonium form means it's attracted to the soil particles so that the nitrogen remains in the rooting zone."" N-Lock works by inhibiting Nitrosomonas bacteria, preventing them from converting the ammonium to nitrite and any subsequent conversion to nitrate.
""It's this inhibition of the bacteria that helps stabilise the nitrogen, meaning less nitrate can be leached away from the crop's root zone. So it's available for longer into the growing season, helping optimise the yield and quality potential," explains Peter Waite. Agrovista conducted a variety trial to show the performance of 56 maize varieties and the benefits of N-Lock application at their trial site in Norfolk on a sandy clay loam. FYM was applied at at/ha and ploughed in with the cover crop of rye. Nitrogen was applied to the seed bed at 40kg/ha, followed by 20kg/ha of Nitrogen and Sulphur, applied with a post-emergence herbicide. A Sumo cultivator was run through the soil just prior to drilling to loosen the soil up and create a seedbed. Pendimethalin was applied pre-emergence at 2.5 I/ha in tank mix with Agrovista's adjuvant Remix. On the same day N-Lock was applied at the full rate of 2.5 I/ha, followed by 14mm of rain shortly after drilling which was ideal because N-Lock needs to be incorporated into the soil within 10 days of application, either by light cultivation, or with 12mm of rain, explains Agrovista agronomist, Craig Green.
A robust post-emergence herbicide treatment of Elumis (mesotrione+ nicosulfuron) was applied to give a broad spectrum of weed control. This was made at the four true-leaf stage of the crop at the rate of 1.51/na. ""I was pleased with the performance of N-Lock in this maize variety trial. I'd always treated it as a bit of 'muck and mystery', but Dow AgroSciences have got it right," says Craig Green. ""When used on nitrogen-limiting soils, it works well. It certainly seems to prolong what little N there might be in the soil and it seems to have benefits in the maize. Average cob weight in the N-Lock treated varieties was consistently higher than in those that were untreated, and showed a marked increase, particularly in the varieties Ramirez, Kougar, Dualto, Hobbit and Absalon.""