Effects of Planting Density, Levels, and Forms of Nitrogen Application on the Yield and Nitrogen Utilization of Wheat following Rice in East China

Abstract

A major challenge is to achieve the goal of synergistically increasing grain yield and nitrogen use efficiency in wheat production. Many studies have focused on one aspect of cultivation such as fertilizer management, suitable planting density, and straw returning. However, there are few studies on the effect of integrated cultivation practices on yield and nitrogen absorption and utilization of wheat. A field experiment to investigate the characteristics was conducted across two years using Yangmai 16 and Yangmai 20 with five cultivation practices including nitrogen blank area (NB), local practices (LP), nitrogen reduction (NR), planting density reduction and nitrogen reduction (DN), and organic fertilizer (OF). As compared with LP, the DN treatment improved the yield (+4.54%), recovery efficiency of N fertilizer (+5.59%), N partial factor productivity (+15.28%), agronomic N use efficiency (+21.43%), physiological N use efficiency (+14.90%), and nitrogen harvest index (+6.45%). All previous indices were increased by 16.84%, 28.18%, 19.59%, 45.81%, 13.96%, and 3.37% under the OF treatment, as compared with LP. The DN and OF significantly improved nitrogen use efficiency, photosynthetic characteristics, dry matter accumulation, root total and active absorbing surface area, root oxidation activity, nitrogen accumulation, nitrogen harvest index, and nitrogen transportation in various organs. The results suggest that integrated cultivation practices are beneficial to achieve high yield and high nitrogen use efficiency through improving the agronomic performance and root physiological characteristics.

Effects of Nitrogen Forms on Root Morphology and Nitrogen Accumulation in Pinus tabuliformis carr. Seedlings under Exponential Fertilization

“…A well-developed root system is the basis for efficient nutrient uptake by plants; the more developed the root system, the finer the average diameter of the roots, the greater the number of root tips, the longer the total root length, and the more favorable it is to the plant's access to nitrogen [53]. Nitrogen accumulation in the root system of Pinus tabuliformis is not only related to root morphology, but also to the choice of fertilization method and nitrogen form, similar to the experimental results of Xiao et al [54].…”

Optimizing plant spatial competition can change phytohormone content and promote tillering, thereby improving wheat yield

“…If the distribution of plants is not sufficiently uniform, it will lead to competition in the utilization of soil nutrients in areas with dense plant distribution, which will further lead to excessive growth. Further optimization of the allocation of plant row spacing to optimize crop spatial competition under conditions of equal density has attracted increasing research attention ( Ballaré, 1999 ; Golubski et al., 2008 ; Liu et al., 2021c ; Xiao et al., 2022 ).…”

“…If the distribution of plants is not sufficiently uniform, it will lead to competition in the utilization of soil nutrients in areas with dense plant distribution, which will further lead to excessive growth. Further optimization of the allocation of plant row spacing to optimize crop spatial competition under conditions of equal density has attracted increasing research attention (Ballare, 1999;Golubski et al, 2008;Liu et al, 2021c;Xiao et al, 2022). Alzueta et al (2012) reported that changing row spacing affects interactions between neighboring plants; such interactions involve competition for resources and active morphogenetic responses triggered by neighbors' perceptions.…”

Partial Substitution of Chemical N with Solid Cow Manure Improved Soil Ecological Indicators and Crop Yield in a Wheat–Rice Rotation System

“…This can lead to insufficient soil nutrient supply during the early tillering and elongation of both crops, resulting in late ripening and declining the yield. Nutrients in chemical fertilizers are readily available for the plants [23].…”