scholarly journals Precision nitrogen management using chlorophyll meter for Improving Growth, Productivity and N Use Efficiency of Rice in Subtropical Climate

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Mainak Ghosh ◽  
Dillip Kumar Swain ◽  
Madan Kumar Jha ◽  
Virendra Kumar Tewari
Keyword(s):  
Nitrogen Management ◽  
N Use Efficiency ◽  
Subtropical Climate ◽  
Chlorophyll Meter ◽  
Use Efficiency ◽  
N Use

scholarly journals The nitrogen sufficiency index underlying estimates of nitrogen fertilization requirements of common bean

2012 ◽  
Vol 36 (1) ◽  
pp. 183-192 ◽  
Author(s):  
Suelen Cristina Mendonça Maia ◽  
Rogério Peres Soratto ◽  
Beatriz Nastaro ◽  
Lucas Barbosa de Freitas
Keyword(s):  
Common Bean ◽  
Block Design ◽  
Relative Yield ◽  
N Use Efficiency ◽  
N Application ◽  
Chlorophyll Meter ◽  
Use Efficiency ◽  
The Moment ◽  
N Use ◽  
Leaf N

Chlorophyll determination with a portable chlorophyll meter can indicate the period of highest N demand of plants and whether sidedressing is required or not. In this sense, defining the optimal timing of N application to common bean is fundamental to increase N use efficiency, increase yields and reduce the cost of fertilization. The objectives of this study were to evaluate the efficiency of N sufficiency index (NSI) calculated based on the relative chlorophyll index (RCI) in leaves, measured with a portable chlorophyll meter, as an indicator of time of N sidedressing fertilization and to verify which NSI (90 and 95 %) value is the most appropriate to indicate the moment of N fertilization of common bean cultivar Perola. The experiment was carried out in the rainy and dry growing seasons of the agricultural year 2009/10 on a dystroferric Red Nitosol, in Botucatu, São Paulo State, Brazil. The experiment was arranged in a randomized complete block design with five treatments, consisting of N managements (M1: 200 kg ha-1 N (40 kg at sowing + 80 kg 15 days after emergence (DAE) + 80 kg 30 DAE); M2: 100 kg ha-1 N (20 kg at sowing + 40 kg 15 DAE + 40 kg 30 DAE); M3: 20 kg ha-1 N at sowing + 30 kg ha-1 when chlorophyll meter readings indicated NSI < 95 %; M4: 20 kg ha-1 N at sowing + 30 kg ha-1 N when chlorophyll meter readings indicated NSI < 90 % and, M5: control (without N application)) and four replications. The variables RCI, aboveground dry matter, total leaf N concentration, production components, grain yield, relative yield, and N use efficiency were evaluated. The RCI correlated with leaf N concentrations. By monitoring the RCI with the chlorophyll meter, the period of N sidedressing of common bean could be defined, improving N use efficiency and avoiding unnecessary N supply to common bean. The NSI 90 % of the reference area was more efficient to define the moment of N sidedressing of common bean, to increase N use efficiency.

Increased N-use efficiency using a chlorophyll meter on high-yielding irrigated rice

1996 ◽  
Vol 47 (2-3) ◽  
pp. 243-252 ◽  
Author(s):  
S. Peng ◽  
F.V. Garcia ◽  
R.C. Laza ◽  
A.L. Sanico ◽  
R.M. Visperas ◽  
...  
Keyword(s):  
N Use Efficiency ◽  
Irrigated Rice ◽  
Chlorophyll Meter ◽  
Use Efficiency ◽  
N Use

Characterizing physiological N-use efficiency as influenced by nitrogen management in three rice cultivars

2004 ◽  
Vol 88 (2-3) ◽  
pp. 239-250 ◽  
Author(s):  
Ligeng Jiang ◽  
Tingbo Dai ◽  
Dong Jiang ◽  
Weixing Cao ◽  
Xiuqin Gan ◽  
...  
Keyword(s):  
Nitrogen Management ◽  
N Use Efficiency ◽  
Rice Cultivars ◽  
Use Efficiency ◽  
N Use

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.

scholarly journals Single and split nitrogen dose in wheat yield indicators

2018 ◽  
Vol 22 (1) ◽  
pp. 16-21 ◽  
Author(s):  
Juliane S. P. Costa ◽  
Rubia D. Mantai ◽  
José A. G. da Silva ◽  
Osmar B. Scremin ◽  
Emilio G. Arenhardt ◽  
...  
Keyword(s):  
Block Design ◽  
Wheat Yield ◽  
N Use Efficiency ◽  
Phenological Stages ◽  
Split Dose ◽  
N Supply ◽  
N Release ◽  
Residual N ◽  
Use Efficiency ◽  
N Use

ABSTRACT Single or split nitrogen (N) supply can maximize the expression of wheat yield indicators. The objective of the study was to evaluate the greater N use efficiency on wheat yield indicators by the single and split N supply under favorable and unfavorable year conditions to the crop in succession system of high and reduced residual N release. The study was conducted in 2014 and 2015, in a randomized complete block design with four replicates in a 4 x 3 factorial, for N-fertilizer doses (0, 30, 60, 120 kg ha-1) and supply forms [full dose (100%) in the phenological stage V3 (third expanded leaf); split dose (70 and 30%) in the phenological stages V3/V6 (third and sixth expanded leaves, respectively) and; split dose (70 and 30%) in the phenological stages V3/R1 (third expanded leaf and early grain filling)], respectively, in soybean/wheat and maize/wheat cultivation systems. The highest N use efficiency for wheat yield was obtained with the single dose supply in favorable year of temperature and rainfall and with the split dose in the V3/V6 stages in unfavorable year, regardless of the succession system of high and reduced residual N release.

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