scholarly journals Compensatory Roles of Nitrogen Uptake and Photosynthetic N-use Efficiency in Determining Plant Growth Response to Elevated CO2: Evaluation Using a Functional Balance Model

2000 ◽  
Vol 86 (4) ◽  
pp. 723-730 ◽  
Author(s):  
A Zerihun
Keyword(s):  
Plant Growth ◽  
Elevated Co2 ◽  
Nitrogen Uptake ◽  
Growth Response ◽  
N Use Efficiency ◽  
Balance Model ◽  
Functional Balance ◽  
Plant Growth Response ◽  
Use Efficiency ◽  
N Use

Nitrogen uptake and N-use efficiency of Mediterranean cotton under varied deficit irrigation and N fertilization

2016 ◽  
Vol 73 ◽  
pp. 144-151 ◽  
Author(s):  
S. Stamatiadis ◽  
C. Tsadilas ◽  
V. Samaras ◽  
J.S. Schepers ◽  
K. Eskridge
Keyword(s):  
Nitrogen Uptake ◽  
Deficit Irrigation ◽  
N Fertilization ◽  
N Use Efficiency ◽  
Use Efficiency ◽  
N Use

scholarly journals Effect and Empirical Models of Nitrogen Uptake Under Different Nitrogen Sources in Dieffenbachia amoena

HortScience ◽  
2008 ◽  
Vol 43 (2) ◽  
pp. 575-579 ◽  
Author(s):  
Silvia Jiménez Becker ◽  
Maria Teresa Lao ◽  
Mari Luz Segura
Keyword(s):  
Nitrogen Uptake ◽  
N Uptake ◽  
Empirical Models ◽  
N Use Efficiency ◽  
Ammonium Concentration ◽  
Nitrogen Form ◽  
Area Index ◽  
Use Efficiency ◽  
N Form ◽  
N Use

Adjusting fertility programs according to peak demand periods will help prevent periodic nutrient disorders during crop growth, allowing enhanced use efficiency of water and fertilization. The objectives of this article were to investigate 1) the evolution of the changes in the concentration of nitrate and ammonium in the recycled solution with different N-NO3 –/N-NH4 + ratios; 2) the influence of the N form supply (N-NO3 – or N-NH4 +) on the nitrogen uptake, the nitrogen:water uptake ratio, and nitrogen use and uptake efficiency; and 3) the development of empirical models that would allow the prediction of nitrogen nutritional needs of Dieffenbachia amoena to increase the N use efficiency in a recycled system. To achieve these aims, N uptake has been correlated to climate parameters such as temperature, vapor pressure deficit and global radiation, and growth parameters such as leaf area index. The trial was carried out with Dieffenbachia amoena plants growing in a recycled system with expanded clay as substrate. The crop was placed in an INSOLE (Buried Solar Greenhouse), the plants being supplied with equal amounts of N, differing in the percentage of the N form applied (NO3 –:NH4 +): TA (100:0), TB (50:50), and TC (0:100). The nitrogen form generated important changes in the pH and nitrate and ammonium concentration in nutritive solution during the recirculating solution. In N-NO3 – treatment, pH increased and nitrate concentration showed a tendency to drop slightly. N-NH4 + treatment showed an abrupt N-NH4 + concentration decrease, and N-NO3 – concentration increased along with a pH drop. Also, the nitrogen form applied to the Dieffenbachia amoena crop affects nitrogen uptake. Nitrogen uptake rates and nitrogen uptake concentration were higher in the plants supplied with N-NH4 + or NO3 –+NH4 + than in the plants provided with N-NO3 – alone. The supply of a combination of 50:50 NO3 –+NH4 + improved the N use efficiency. The study also indicated the possibility of predicting the N uptake rate and N uptake concentration using the proposed models.

scholarly journals Growth Responses of Agropyron Mongolicum Keng to Nitrogen Addition Is Linked to Root Morphological Traits and Nitrogen-Use Efficiency.

2021 ◽  
Author(s):  
Aiyun XU ◽  
Xing Wang ◽  
Xiaojia Wang ◽  
Dongmei Xu ◽  
Bing Cao
Keyword(s):  
Native Species ◽  
Morphological Traits ◽  
Growth Response ◽  
N Deposition ◽  
N Use Efficiency ◽  
N Addition ◽  
Desert Grassland ◽  
Growth Responses ◽  
Use Efficiency ◽  
N Use

Abstract Background and aimsNitrogen (N) is the primary limiting factors for plant growth and development, and increasingly N deposition alters plant composition, consequently affecting ecosystem function have been widely acknowledged. However, the effects of N fertilization on native species in desert grassland ecosystem and underlying mechanisms of these effects are still poorly understood. This study was conducted to examine the growth response of Agropyron mongolicum keng to N addition and potential mechanisms underlying this effect.MethodsA.mongolicum Keng was subjected to five N addition levels (0, 0.8,1.6, 2.4, and 4.0g N m−2 yr−1) for six months under greenhouse conditions. A combination of linear and structural equation modelling was used to examine growth response of A.mongolicum Keng to N addition and test whether its response related to root morphological traits and N-use efficiency.ResultsGrowth responses of A. mongolicum Keng to increasing N addition appeared a unimodal-shaped with a N saturation threshold at 3.2g N m-1 yr-1. Its response closely related to the root surface area, volume, length, and forks number, N uptake and utilization efficiency. Besides, N-induced changes in soil available nutrient have an indirect impaction biomass of A. mongolicum Keng via regulation of root morphological traits and N-use efficiency.ConclusionsThese findings highlight the sensibility of A. mongolicum Keng to N addition and the importance of root morphological traits and N-use efficiency in affecting biomass. Therefore, these can provide important insights into potential changes of native species survival and development in nutrient-limited desert grassland caused by N deposition.

scholarly journals Influence of Nitrogen Fertilizer Application on Grain Yield, Nitrogen Uptake Efficiency, and Nitrogen Use Efficiency of Bread Wheat (Triticum aestivum L.) Cultivars in Eastern Ethiopia

2017 ◽  
Vol 9 (7) ◽  
pp. 202
Author(s):  
Nano Alemu Daba
Keyword(s):  
Grain Yield ◽  
Bread Wheat ◽  
Nitrogen Uptake ◽  
N Uptake ◽  
N Use Efficiency ◽  
Wheat Cultivars ◽  
Eastern Ethiopia ◽  
Nitrogen Uptake Efficiency ◽  
Use Efficiency ◽  
N Use

The study was conducted in Eastern Ethiopia, namely Meta and Tullo districts, during the 2015 cropping season to determine the effect of N fertilizer levels on N uptake, N use efficiency (NUE) and grain yield on bread wheat cultivars. Factorial combinations of five N levels (0, 30, 60, 90, and 120 kg N ha-1) and four bread wheat cultivars (Danda’a, Digalu, Kakaba and local cultivar) were laid out as a randomized complete block design (RCBD) with three replications. The interactions of sites, N levels, and cultivars significantly (p ≤ 0.01) affected grain yield (GY), nitrogen uptake by grains, total nitrogen uptake, nitrogen uptake efficiency (NUpE) and nitrigen use efficiency for grain yield (NUEGY). Main effects of sites, N levels and cultivars had significant (p < 0.01) effect on grain and straw N contents, straw N uptake, N biomass production efficiency, N utilization efficiency (NUtE) and nitrogen harvest index (NHI). The cultivar Kakaba at rate of 90 kg N ha-1 produced the highest grain yield (4880 kg ha-1) in Tullo, which was statistically similar with the grain yield (4816 kg ha-1) obtained from the cultivar Digalu with 120 kg N ha-1 in Meta district. The NUEGY was higher with values of 24.2 and 24.1 kg grain kg-1 N in Tullo and Meta districts, respectively, for Digalu cultivar at 30 kg N ha-1 application rate than the remaining N levels and variety interactions at both sites. Cultivars variations in NUEGY under low N application levels were mainly due to higher variations in NUpE than in NUtE. Therefore, there is a need for exploration of the effectiveness of various combinations of N rates with time of applications for improvements of N-use efficiency traits and cost effectiveness in improved wheat cultivars production.

Green Window Approach for improving nitrogen management by farmers in small-scale wheat fields

2014 ◽  
Vol 153 (3) ◽  
pp. 446-454 ◽  
Author(s):  
X. L. YUE ◽  
Y. HU ◽  
H. Z. ZHANG ◽  
U. SCHMIDHALTER
Keyword(s):  
Plant Growth ◽  
Grain Yield ◽  
N Fertilizer ◽  
N Use Efficiency ◽  
Cereal Crops ◽  
Small Scale ◽  
Residual Soil ◽  
Use Efficiency ◽  
Window Approach ◽  
N Use

SUMMARYImprovement of nitrogen (N) use efficiency is urgently needed since excessive application of N fertilizer has been widespread in small-scale fields in China, causing great losses of N fertilizer and environmental pollution. In the present study, a simple technology, termed the Green Window Approach (GWA), to optimize N strategies for cereal crops is presented. The GWA represents an on-field demonstration site visualizing the effects of incremental N levels and enables farmers to conduct such a trial within their own fields. The lowest N rate that achieves no visible change in plant growth or biomass shows the optimal N requirement of crops. Therefore the objective was to develop the key procedures of GWA and to evaluate the effects of its application in cereal crops on grain yield, N use efficiency and economic benefit. A total of seven GWA trials were performed from 2009 to 2011 on farmers’ irrigated wheat fields in the North China Plain. The GWA consisted of eight small plots placed in a compact layout on a well-accessible part of the field. Plot size varied from 2·5×2·5 to 4×4 m2, depending on the size and shape of each field. All GWA plots received basal nitrogen (N), phosphorus (P) and potassium (K) rates of 30 kg N/ha (except for the nil-N plot), 80 kg P2O5/ha and 100 kg K2O/ha. Nitrogen supplies, including residual soil nitrate in 0–90 cm determined at Zadoks growth stages (GS) 21–23 in early spring and the split-topdressing N at GS 21–23 and GS 41–52, were incrementally increased from 0 to 420 kg N/ha. The remaining part of the field still received farmers’ customary fertilization (FCF). Optimal N rate could be estimated as the lowest N rate that achieved no visible change in plant growth at GS 60–73. Compared with FCF area, grain yield was increased by 13% to a maximum or near maximum value of 5·8 t/ha, optimal N rate was sharply decreased by 69% to 116 kg N/ha, apparent N recovery was greatly increased from 11 to 46%, whereas the cost of fertilizer input was decreased by 57% to 1045 Chinese Renminbi (RMB)/ha (162 US$/ha), the profit of grain yield was increased by 13% to 12 211 RMB/ha (1891 US$/ha) and the net economic benefits were increased by 60% to 7473 RMB/ha (1157 US$/ha). Most importantly, the GWA does not need laboratory facilities, complicated procedures or professional knowledge of N balances, and farmers can easily understand and use GWA by themselves.

scholarly journals Optimization of Topdressing for Winter Wheat by Accurate Growth Monitoring and Improved Production Estimation

2021 ◽  
Vol 13 (12) ◽  
pp. 2349
Author(s):  
Jingchun Ji ◽  
Jianli Liu ◽  
Jingjing Chen ◽  
Yujie Niu ◽  
Kefan Xuan ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Crop Production ◽  
Optimization Method ◽  
Growth Potential ◽  
N Use Efficiency ◽  
Growth Monitoring ◽  
Aerial Vehicle ◽  
Use Efficiency ◽  
Improved Model ◽  
N Use

Topdressing accounts for approximately 40% of the total nitrogen (N) application of winter wheat on the Huang-Huai-Hai Plain in China. However, N use efficiency of topdressing is low due to the inadaptable topdressing method used by local farmers. To improve the N use efficiency of winter wheat, an optimization method for topdressing (THP) is proposed that uses unmanned aerial vehicle (UAV)-based remote sensing to accurately acquire the growth status and an improved model for growth potential estimation and optimization of N fertilizer amount for topdressing (NFT). The method was validated and compared with three other methods by a field experiment: the conventional local farmer’s method (TLF), a nitrogen fertilization optimization algorithm (NFOA) proposed by Raun and Lukina (TRL) and a simplification introduced by Li and Zhang (TLZ). It shows that when insufficient basal fertilizer was provided, the proposed method provided as much NFT as the TLF method, i.e., 25.05% or 11.88% more than the TRL and TLZ methods and increased the yields by 4.62% or 2.27%, respectively; and when sufficient basal fertilizer was provided, the THP method followed the TRL and TLZ methods to reduce NFT but maintained as much yield as the TLF method with a decrease of NFT by 4.20%. The results prove that THP could enhance crop production under insufficient N preceding conditions by prescribing more fertilizer and increase nitrogen use efficiency (NUE) by lowering the fertilizer amount when enough basal fertilizer is provided.

INFLUENCE OF THE SYSTEM OF RICE INTENSIFICATION ON RICE YIELD AND NITROGEN AND WATER USE EFFICIENCY WITH DIFFERENT N APPLICATION RATES

2009 ◽  
Vol 45 (3) ◽  
pp. 275-286 ◽  
Author(s):  
LIMEI ZHAO ◽  
LIANGHUAN WU ◽  
YONGSHAN LI ◽  
XINGHUA LU ◽  
DEFENG ZHU ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
N Use Efficiency ◽  
System Of Rice Intensification ◽  
N Application ◽  
Application Rates ◽  
Rice Intensification ◽  
Use Efficiency ◽  
N Rates ◽  
N Use

SUMMARYField experiments were conducted in 2005 and 2006 to investigate the impacts of alternative rice cultivation systems on grain yield, water productivity, N uptake and N use efficiency (ANUE, agronomic N use efficiency; PFP, partial factor productivity of applied N). The trials compared the practices used with the system of rice intensification (SRI) and traditional flooding (TF). The effects of different N application rates (0, 80, 160 and 240 kg ha−1) and of N rates interacting with the cultivation system were also evaluated. Resulting grain yields with SRI ranged from 5.6 to 7.3 t ha−1, and from 4.1 to 6.4 t ha−1 under TF management. On average, grain yields under SRI were 21% higher in 2005 and 22% higher in 2006 than with TF. Compared with TF, SRI plots had higher harvest index across four fertilizer N rates in both years. However, there was no significance difference in above-ground biomass between two cultivation systems in either year. ANUE was increased significantly under SRI at 80 kg N ha−1 compared with TF, while at higher N application rates, ANUE with SRI was significantly lower than TF. Compared with TF, PFP under SRI was higher across all four N rates in both years, although the difference at 240 kg N ha−1 was not significant. As N rate increased, the ANUE and PFP under both SRI and TF significantly decreased. Reduction in irrigation water use with SRI was 40% in 2005 and 47% in 2006, and water use efficiency, both total and from irrigation, were significantly increased compared to TF. With both SRI and TF, the highest N application was associated with decreases in grain yield, N use efficiency and water use efficiency. This is an important finding given current debates whether N application rates in China are above the optimum, especially considering consequences for soil and water resources. Cultivation system, N rates and their interactions all produced significant differences in this study. Results confirmed that optimizing fertilizer N application rates under SRI is important to increase yield, N use efficiency and water use efficiency.

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