Effects of DMPP [3,4-dimethylpyrozole phosphate] on the growth and chemical composition of ryegrass (Lolium perenne L.) raised on calcareous soil

Abstract

This paper reports a 406 day outdoor experiment (performed in pots) to determine the influence of the new nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP), when added to pig slurry (PS), on the growth and chemical composition of ryegrass. Pots containing a loamy, calcareous soil were treated with either no PS or 73.7, 147.3 or 221 cubic cm pot-1, with or without DMPP, prior to seeding with ryegrass. The greatest quantity of above ground dry matter was obtained with the highest dose of PS + DMPP (36.3 g pot-1) – 7.4% greater than that obtained for the same treatment without DMPP, and 46.1% greater than with the no PS treatment. The plants treated with the high and medium doses of PS + DMPP absorbed 70% of total N during the first quarter of the experimental season (104 days). Without DMPP, N uptakes were 55.7% and 63% for the high and medium treatments respectively. The inhibition of nitrification with DMPP increased agronomic efficiency and reduced N leaching by 17%.