Climate warming may significantly reduce grain yield and nitrogen, phosphorus and potassium uptake of spring wheat in irrigation area of Yellow River

Objectives The uptake and accumulation of nitrogen (N), phosphorus (P) and potassium (K) nutrient of spring wheat affected by climate warming were studied at different growth stages, so as to predict the impaction degree of climate warming on spring wheat production in the arid and semi-arid regions.

Methods A field experiment was conducted in Ningxia University Experimental Station in Yellow River Irrigation Area in 2018, using Triticumaestivum L. cv. Ningchun50 as test material. Infrared radiators, with a set of automatic temperature controlling equipment, were installed on each plot to increase required canopy temperature, and the warming period was day and night continuously. Taking the local wheat canopy temperature as control (CK), 4 warning gradients of 0.5℃, 1℃, 1.5℃ and 2.0℃ were setup. At seedling, jointing, heading, filling 10 days after filling and maturing stages, the plant samples were recollected, the biomass and N, P, K contents were measured, and the yield and yield components were investigated at harvest.

Results When the canopy temperature was increased by 0.5℃, the dry weight of spring wheat in the seedling stage, the contents and accumulation of N, P, K in leaves, stems and ears in jointing stage were significantly higher than those in CK. When canopy temperature was increased by 1.0℃, the N, K contents and accumulative N uptake in seedlings stage and the leaf N, P, K contents in jointing stage were significantly higher than those of CK, with increment of 3.2%–23.7%. When the temperature was increased by 1.5℃, only plant K content at seedling stage was significantly increased by 22.2%. When the temperature was increased by 2.0℃, all the N, P, K contents and accumulations were significantly decreased in all the growing stages. At the maturity stage, the spikelet number per spike, grain number per spike, 1000-grain weight and grain yield all decreased with the increase of temperature. In treatment of warming 2.0℃, they were decreased by 53.7%, 24.1%, 13.4% and 21.7%, respectively.

Conclusions The 0.5℃–1.0℃ increase of temperature will benefit the uptake of N, P and K nutrients before jointing stage of wheat. After jointing stage, all the tested warming degrees negatively affect the uptake and accumulation of N, P and K nutrients, lead to significantly decreased dry matter accumulation, 1000-grain weight and kernel numbers at harvest, and declined yield of spring wheat eventually.