N-Uptake and Yields in Spring Wheat Affected By Waterlogging at Different Growth Stages.

Nitrogen (N) is an essential nutrient for crop growth and crop yields. Mineral nitrogen in the soil is affected by the reduction conditions in soil which is affected by abiotic stress factors like waterlogging (WL). Crop N uptake has been reported to decrease, resulting in lower yields and potentially inferior grain quality. With climate change resulting in increased precipitation and more extreme rain events WL is more likely to occur, and thus represents a global challenge for agricultural production. The effect of short-term WL on yield and N uptake in wheat was investigated in a pot experiment, set up in climate chambers. A randomized pot-trial (four replicates, seven treatments) with spring wheat (Ningchun50) was completed for the growth period from tillering to maturity under weather conditions like Xinjiang, China. Treatment included complete WL for either 5 or 10 days at growth stages: tillering, booting and flowering.
Grain yield in the treatments with WL during flowering for 5 or 10 days was reduced by 12% and 40% respectively. No yield reductions were observed in the tillering or booting WL treatments. At harvest, the total N-uptake in the treatment, which was waterlogged for 10 days during flowering, was reduced by 31%. However, the lower total N-uptake was not due to lower N-concentrations in the plants as there were no significant differences among the N-concentration for any of the treatments but only the reduction in DM yields.Thus the lower total N-uptake due to WL during flowering was a result of reduced N-uptake during the grain filling period. These results show that flowering is the most sensitive development stage to WL in relation to yield losses, and that longer duration decrease N uptake and DM yields of WL.