ESTIMATION OF SOIL NITROGEN STATUS WITH CANOPY REFLECTANCE SPECTRA IN RICE

Non-destructive monitoring of leaf nitrogen (N) status can assist in growth diagnosis, N management and productivity forecast in field crops. The objectives of this study were to determine the relationships of leaf nitrogen concentration on a leaf dry weight basis (LNC) and leaf nitrogen accumulation per unit soil area (LNA) to ground-based canopy reflectance spectra, and to derive regression equations for monitoring N nutrition status in wheat (Triticum aestivum L.). Four field experiments were conducted with different N application rates and wheat cultivars across four growing seasons, and time-course measurements were taken on canopy spectral reflectance, LNC and leaf dry weights under the various treatments. In these studies, LNC and LNA in wheat increased with increasing N fertilization rates. The canopy reflectance differed significantly under varied N rates, and the pattern of response was consistent across the different cultivars and years. Overall, an integrated regression equation of LNC to normalized difference index (NDI) of 1220 and 710 nm of canopy reflectance spectra described the dynamic pattern of change in LNC in wheat. The ratios of several near infrared (NIR) bands to visible light were linearly related to LNA, with the ratio index (RI) of the average reflectance over 760, 810, 870, 950 and 1100 nm to 660 nm having the best index for quantitative estimation of LNA in wheat. When independent data were fit to the derived equations, the average root mean square error (RMSE) values for the predicted LNC and LNA relative to the observed values were no more than 15.1 and 15.2%, respectively, indicating a good fit. Our relationships of leaf N status to spectral indices of canopy reflectance can be potentially used for non-destructive and real-time monitoring of leaf N status in wheat. Key words: Wheat, leaf nitrogen concentration, leaf nitrogen accumulation, canopy reflectance, spectral index, nitrogen monitoring

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Estimation of litchi ( Litchi chinensis Sonn.) leaf nitrogen content at different growth stages using canopy reflectance spectra

European Journal of Agronomy ◽

10.1016/j.eja.2016.08.001 ◽

2016 ◽

Vol 80 ◽

pp. 182-194 ◽

Cited By ~ 11

Author(s):

Dan Li ◽

Congyang Wang ◽

Wei Liu ◽

Zhiping Peng ◽

Siyu Huang ◽

...

Keyword(s):

Nitrogen Content ◽

Leaf Nitrogen ◽

Reflectance Spectra ◽

Growth Stages ◽

Canopy Reflectance ◽

Leaf Nitrogen Content ◽

Litchi Chinensis ◽

Different Growth Stages

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Modelling the effects of nitrogen addition on soil nitrogen status and nitrogen uptake in a Norway spruce stand in Denmark

Nitrogen, the Confer-N-s ◽

10.1016/b978-0-08-043201-4.50059-9 ◽

1998 ◽

pp. 409-414

Author(s):

Claus Beier ◽

Henrik Eckersten

Keyword(s):

Norway Spruce ◽

Soil Nitrogen ◽

Nitrogen Uptake ◽

Nitrogen Addition ◽

Nitrogen Status

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Impacts of Bioinoculants Pseudomonas jesenii MP1 and Rhodococcus qingshengii S10107 on Chickpea (Cicer arietinum L.) Yield and Soil Nitrogen Status

Pedosphere ◽

10.1016/s1002-0160(19)60807-6 ◽

2019 ◽

Vol 29 (3) ◽

pp. 388-399 ◽

Cited By ~ 4

Author(s):

Divya JOSHI ◽

Ramesh CHANDRA ◽

Deep Chandra SUYAL ◽

Saurabh KUMAR ◽

Reeta GOEL

Keyword(s):

Cicer Arietinum ◽

Soil Nitrogen ◽

Nitrogen Status ◽

Cicer Arietinum L

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Effects of soil nitrogen status and rate of inoculation on the establishment of populations of Bradyrhizobium japonicum and on the nodulation of soybeans

Australian Journal of Agricultural Research ◽

10.1071/ar9890753 ◽

1989 ◽

Vol 40 (4) ◽

pp. 753

Author(s):

J Brockwell ◽

RR Gault ◽

LJ Morthorpe ◽

MB Peoples ◽

GL Turner ◽

...

Keyword(s):

Glycine Max ◽

Soil Nitrogen ◽

Bradyrhizobium Japonicum ◽

Clay Soil ◽

Mineral Nitrogen ◽

Soil Mineral ◽

Soil Mineral Nitrogen ◽

Nitrogen Status ◽

Mineral N ◽

Glycine Max L

Soybeans (Glycine max [L.] Merrill cv. Forrest) were grown under irrigation on a well-structured grey clay soil, previously free of Bradyrhizobium japonicum and containing relatively high levels of mineral N, at Trangie, N.S.W. There were two soil pretreatments, pre-cropped (which had the effect of reducing the level of mineral nitrogen in the soil) and pre-fallowed, and four rates of inoculation (B. japonicum CB 1809 - nil, 0.01 X, 1.OX [=normal] and 100X).Mineral nitrogen (0-10 cm) initially was higher in pre-fallowed soil than in pre-cropped soil (37.6 v. 18.5 mg N per kg). Depletion of mineral nitrogen occurred more rapidly in pre-fallowed treatments, so that, 7 days after harvest, mineral-N in pre-cropped soil was significantly higher than in pre-fallowed soil (14.4 v. 10.6 mg per kg).With high levels of soil mineral nitrogen, colonization of seedling rhizospheres by rhizobia and plant nodulation were diminished. These effects were ameliorated but not eliminated by increased rates of inoculation. The development of the symbiosis was also impeded by lower rates of inoculation (0.01 X, 1.OX).

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Fertility studies of pasture soils in the wet tropical coast of Queensland. 3. Basaltic soils

Australian Journal of Experimental Agriculture ◽

10.1071/ea9720049 ◽

1972 ◽

Vol 12 (54) ◽

pp. 49 ◽

Cited By ~ 3

Author(s):

JK Teitzel ◽

RC Bruce

Keyword(s):

Plant Growth ◽

Soil Nitrogen ◽

Phosphorus Deficiency ◽

Growth Responses ◽

Nitrogen Status ◽

Fertility Status ◽

High Soil ◽

Basaltic Soils ◽

Tropical Coast

Results of thirteen investigations into the fertility status of fifteen basaltic soils in the wet tropical coast of Queensland are presented. Although farming experience has shown these soils to be among the most fertile in the area, a widespread phosphorus deficiency is recorded. Plant growth responses to molybdenum, sulphur and calcium also occurred. The molybdenum deficiency appears to be particularly important in older , pastures where the initailly high soil nitrogen status has been depleted.

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