Growth Rate and % N of Field Grown Crops: Theory and Experiments

Greenwood, D. J.; Gastal, François; Lemaire, G.; Draycott, A.; Millard, P.; Neeteson, J.J.

doi:10.1093/oxfordjournals.aob.a088118

Cited by 192 publications

(95 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Belanger and Richards (1997) proposed using the ratio of plant N to an independently derived optimum N concentration to differentiate deficient (ratio < 1) from sufficient to luxuriant plants (ratio > 1). Although this approach appears promising, many factors such as luxury N uptake (Greenwood et al 1991), light (Dewar 1996) and root to shoot ratio (Hilbert 1990) are known to influence plant N concentration. Further, the timing of plant N analyses may not be early enough in the harvesting interval of the crop to allow enough time to be practical for making recommendations and applying the fertilizer.…”

Section: Discussionmentioning

confidence: 99%

“…Most studies have focused on plant N requirements for maximum yield (Greenwood et al 1991) and not on the quality for animal feed. The current study showed that crop crude-protein-and nitrate-N response to N application varies considerably with cut over the growing season.…”

Section: Discussionmentioning

confidence: 99%

“…Nitrogen used for both metabolic processes (including photosynthesis) and structural tissues (Greenwood et al 1991) is in the reduced form. It is assumed that nitrate and various non-protein reduced N compounds accumulate when N content exceeds requirement for growth (Belanger and Richards 1997).…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Within-season grass herbage crude-protein- and nitrate-N concentrations as affected by rates and seasonal distribution of fertilizer nitrogen in a high yearly rainfall climate

Bittman¹,

Kowalenko²

2000

Can. J. Plant Sci.

View full text Add to dashboard Cite

.25 proportions prior to four cut intervals examined crude-protein-N and nitrate-N concentrations in grass herbage at each cut in three trials. Crude-protein-N concentration frequently increased to a greater degree and in a different pattern (based on cut) than yield as the rate of N application increased. This showed that crude-protein-N by itself cannot be used as a method for determining the N sufficiency status of grass. Both rate and distribution of fertilizer N strongly influenced plant nitrate-N concentration; the degree of change varied considerably among cuts and trials. Plant nitrate-N concentration in the control did not correspond to yield responsiveness to N application, making it a poor indicator of the plant's need for fertilizer applications. Residual effects of N applications on plant nitrate-N were noted into the last cut of the season from a single spring application. The effect of N rate and distribution, then, was a function of immediate and residual effects of the applications. There was some evidence that N present in the soil in nitrate-N form enhanced the potential for high nitrate-N in the plant. Plant nitrate-N concentrations accounted for up to 29% of the total N in the plant with concentrations greater than 4000 mg N kg -1 at the highest N application rates. Plant nitrate-N did not exceed 1000 mg N kg -1 , a concentration considered safe for ruminants, when 75 kg N ha -1 or less ammonium nitrate was applied as a single application prior to a growth interval for all cuts. Since grass protein-and nitrate-N concentrations respond differently than yield to N applications, a specific combination of rate and distribution of fertilizer will not necessarily produce maximum herbage quantity and quality simultaneously. L'expérience était réalisée à trois emplacements. La concentration de PB augmentait souvent davantage que le rendement, suivant un mode de répartition différent selon les coupes, à mesure qu'on accroissait la dose d'é-pandage de N. Ce qui montre que la teneur en N total ne peut à elle seule servir pour déterminer le niveau de suffisance de N nitrique dans le fourrage. La concentration de N nitrique dans les plantes était fortement dépendante de la dose totale et du fractionnement du N de fumure, l'amplitude de sa réaction variant considérablement d'une récolte et d'un champ et à l'autre. La teneur en N nitrique du fourrage dans le traitement témoin ne correspondait pas à l'effet de la fumure N sur le rendement herbager et n'é-tait donc pas un indicateur de la dose de N de fumure requise par la culture. Les arrière-effets d'un apport de N unique au printemps sur le contenu en N nitrique des plantes persistaient observés jusqu'à la dernière récolte de la saison. L'effet de la dose et du fractionnement de la fumure était donc fonction des effets immédiats et des arrière-effets des épandages. Il appert que l'azote présent dans le sol sous forme nitrique accroîtrait les risques de concentrations en nitrate élevées dans l'herbage. En effet, le N nitrique représentait jusqu'à 29 % du N...

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Within-season grass herbage crude-protein- and nitrate-N concentrations as affected by rates and seasonal distribution of fertilizer nitrogen in a high yearly rainfall climate

Bittman¹,

Kowalenko²

2000

Can. J. Plant Sci.

View full text Add to dashboard Cite

show abstract

“…Plant N concentration (PNC) and uptake (PNU) have been commonly used as crop N status indicators. To improve crop N status diagnosis, the concept of critical N concentration (Nc) has been proposed as the minimum PNC necessary to achieve maximum aboveground biomass production [8,9]. Nc decreases with increasing biomass.…”

Section: Introductionmentioning

confidence: 99%

Satellite Remote Sensing-Based In-Season Diagnosis of Rice Nitrogen Status in Northeast China

et al. 2015

View full text Add to dashboard Cite

Rice farming in Northeast China is crucially important for China's food security and sustainable development. A key challenge is how to optimize nitrogen (N) management to ensure high yield production while improving N use efficiency and protecting the environment. Handheld chlorophyll meter (CM) and active crop canopy sensors have been used to improve rice N management in this region. However, these technologies are still time consuming for large-scale applications. Satellite remote sensing provides a promising technology for large-scale crop growth monitoring and precision management. The objective of this study was to evaluate the potential of using FORMOSAT-2 satellite images to diagnose rice N status for guiding topdressing N OPEN ACCESS Remote Sens. 2015, 7 10647 application at the stem elongation stage in Northeast China. Five farmers' fields (three in 2011 and two in 2012) were selected from the Qixing Farm in Heilongjiang Province of Northeast China. FORMOSAT-2 satellite images were collected in late June. Simultaneously, 92 field samples were collected and six agronomic variables, including aboveground biomass, leaf area index (LAI), plant N concentration (PNC), plant N uptake (PNU), CM readings and N nutrition index (NNI) defined as the ratio of actual PNC and critical PNC, were determined. Based on the FORMOSAT-2 imagery, a total of 50 vegetation indices (VIs) were computed and correlated with the field-based agronomic variables. Results indicated that 45% of NNI variability could be explained using Ratio Vegetation Index 3 (RVI3) directly across years. A more practical and promising approach was proposed by using satellite remote sensing to estimate aboveground biomass and PNU at the panicle initiation stage and then using these two variables to estimate NNI indirectly (R 2 = 0.52 across years). Further, the difference between the estimated PNU and the critical PNU can be used to guide the topdressing N application rate adjustments.

show abstract

“…A ausência da adubação nitrogenada é considerada um dos fatores que mais tem limitado a produção de biomassa nas regiões tropicais (GREENWOOD et al, 1991). O nitrogênio tem funções metabólicas essenciais.…”

Section: Introductionunclassified

Efeito do nitrogênio em características agronômicas da mandioca

et al. 2005

View full text Add to dashboard Cite

Para avaliar o efeito do nitrogênio em características agronômicas de mandioca (Manihot esculenta Crantz) foi desenvolvido um experimento na Universidade Estadual do Sudoeste da Bahia, em Vitória da Conquista (BA), no período de abril de 2002 a março de 2003. Estudou-se a aplicação de seis doses de nitrogênio (0, 50, 100, 200, 300 e 400 kg ha-1 de N) em duas variedades de mandioca, Sergipe e Lisona, adotando-se o delineamento experimental em blocos casualizados, com os tratamentos arranjados segundo um esquema fatorial (2x6). Foi verificado efeito do nitrogênio na altura das plantas, na produção da parte aérea, produtividade de raízes tuberosas, porcentagem de matéria seca e de amido em raízes tuberosas e rendimento de farinha. O número de brotações por planta, o índice de colheita e o índice de área foliar não foram influenciados pelo nitrogênio. Na variedade Sergipe observaram-se resultados superiores aos da variedade Lisona para as características produtividade de parte aérea, produtividade de raízes tuberosas, produção de matéria seca e amido da raiz e rendimento de farinha.

show abstract

Growth Rate and % N of Field Grown Crops: Theory and Experiments

Cited by 192 publications

References 16 publications

Within-season grass herbage crude-protein- and nitrate-N concentrations as affected by rates and seasonal distribution of fertilizer nitrogen in a high yearly rainfall climate

Within-season grass herbage crude-protein- and nitrate-N concentrations as affected by rates and seasonal distribution of fertilizer nitrogen in a high yearly rainfall climate

Satellite Remote Sensing-Based In-Season Diagnosis of Rice Nitrogen Status in Northeast China

Efeito do nitrogênio em características agronômicas da mandioca

Contact Info

Product

Resources

About