Postponed and reduced basal nitrogen application improves nitrogen use efficiency and plant growth of winter wheat

Abstract

Excessive nitrogen (N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency (NUE) and has led to environmental problems in the Yangtze River Basin, China. However, wheat requires less N fertilizer at seedling growth stage, and its basal N fertilizer utilization efficiency is relatively low; therefore, reducing the N application rate at the seedling stage and postponing the N fertilization period may be effective for reducing N application and increasing wheat yield and NUE. A 4-year field experiment was conducted with two cultivars under four N rates (240 kg N ha-1 (N240), 180 kg N ha-1 (N180), 150 kg N ha-1 (N150), and 0 kg N ha-1 (N0)) and three basal N application stages (seeding (L0), fourleaf stage (L4), and six-leaf stage (L6)) to investigate the effects of reducing the basal N application rate and postponing the basal N fertilization period on grain yield, NUE, and N balance in a soil-wheat system. There was no significant difference in grain yield between the N180L4 and N240L0 (control) treatments, and the maximum N recovery efficiency and N agronomy efficiency were observed in the N180L4 treatment. Grain yield and NUE were the highest in the L4 treatment. The leaf area index, flag leaf photosynthesis rate, flag leaf nitrate reductase and glutamine synthase activities, dry matter accumulation, and N uptake post-jointing under N180L4 did not differ significantly from those under N240L0. Reduced N application decreased the inorganic N content in the 0-60-cm soil layer, and the inorganic N content of the L6 treatment was higher than those of the L0 and L4 treatments at the same N level. Surplus N was low under the reduced N rates and delayed basal N application treatments. Therefore, postponing and reducing basal N fertilization could maintain a high yield and improve NUE by improving the photosynthetic production capacity, promoting N uptake and assimilation, and reducing surplus N in soil-wheat systems.

Comprehensive evaluation of physiological traits under nitrogen stress and participation of linolenic acid in nitrogen-deficiency response in wheat seedlings

“…These indices are recommended to quickly screening N-deficiency tolerant genotypes. Considering about different response to N deficiency during the different growth stages, although the most critical growth stages of wheat for N deficiency is the jointing to booting growth period [ 37 , 38 ], the responses of wheat seedlings to N deficiency could also have a serious impact on the later stage of plant development [ 39 , 40 ]. In the present study, the shoot biomass and chlorophyll content of seedlings were significantly changed in response to N deficiency in 24 wheat cultivars, and different cultivars showed different degrees of changes, suggesting that those two physiological indicators could also be the useful indicator in evaluation of wheat N deficiency response (Table 1 ; Table 2 ; Fig.…”

Efficiency of Mineral Nitrogen Fertilization in Winter Wheat under Pannonian Climate Conditions

“…The agronomic N efficiency (ANE) is defined as the increase of GY per unit nitrogen applied and was calculated using Equation (13) according to Yang et al [3] and Tian et al [12]:…”

“…Besides genotype, the N fertilization management also determines the N efficiency in plant production [3,12,13]. The N management variables are amount of fertilized N, the source of N fertilizer (organic N, inorganic N: nitrate N, ammonium N, carbamide N), splitting (one, two or three doses) and timing of application.…”

Optimized split nitrogen fertilizer increase photosynthesis, grain yield, nitrogen use efficiency and water use efficiency under water-saving irrigation

“…Under application of nitrogen fertilizer in wheat production can prolong the grain-filling stage and improve photosynthesis capacity, thereby enhancing grain yield 9 . However, over nitrogen application has been found to result in an increase in nitrogen loss and decreases in nitrogen use efficiency and grain yield 10 , 11 . Previous studies have shown that total application of nitrogen as a basal fertilizer results not only in high nitrogen loss via volatilization but also low nitrogen utilization efficiency, and that top-dressing applications can enhance grain yield and nitrogen use efficiency compared with exclusive basal applications 12 .…”