水保所知识产出(1956---)知识库

Management of nitrogen (N) fertilizer is critical to avoid the environmental consequences of both over-
fertilization and excess reactive N in the system, and chronic under-fertilization and soil mining. Split N
application seeks to improve nitrogen use efficiency in both small-holdings and large-scale mechanized farms,
but lack of conclusive evidence on its benefits restricts the adoption of this practice. Here we report a global
meta-analysis of split N application in wheat using 129 studies with 2661 comparisons. Split N in 3–4 appli-
cations improved yield by 7.0 % and grain protein by 5.2 % in relation to single application. The effect of split N
on yield was larger for winter wheat than for spring wheat, while split N improved grain protein in both winter
and spring wheat. Its effects on both yield and grain protein were larger under conventional tillage, in humid
climate especially for winter wheat, in coarse textured soils, on less fertile soils, and at high N rate. Splitting N in
3–4 applications would increase annual production of winter wheat by 12.9 M t grain and 1.3 M t protein
globally. By identifying the conditions where split N application is more likely to deliver agronomic benefits, our
study would contribute to the targeted adoption of this practice.