Soil nitrogen content forecasting based on real-time NIR spectroscopy

2016 ◽  
Vol 124 ◽  
pp. 29-36 ◽  
Author(s):  
Yao Zhang ◽  
MinZan Li ◽  
LiHua Zheng ◽  
Yi Zhao ◽  
Xiaoshuai Pei
2014 ◽  
Vol 31 (4) ◽  
pp. 925-933 ◽  
Author(s):  
M. M. E. Colmán ◽  
D. L. Chicoma ◽  
R. Giudici ◽  
P. H. H. Araújo ◽  
C. Sayer

2019 ◽  
Vol 11 (23) ◽  
pp. 2819 ◽  
Author(s):  
Muhammad Abdul Munnaf ◽  
Said Nawar ◽  
Abdul Mounem Mouazen

Visible and near infrared (vis–NIR) diffuse reflectance spectroscopy has made invaluable contributions to the accurate estimation of soil properties having direct and indirect spectral responses in NIR spectroscopy with measurements made in laboratory, in situ or using on-line (while the sensor is moving) platforms. Measurement accuracies vary with measurement type, for example, accuracy is higher for laboratory than on-line modes. On-line measurement accuracy deteriorates further for secondary (having indirect spectral response) soil properties. Therefore, the aim of this study is to improve on-line measurement accuracy of secondary properties by fusion of laboratory and on-line scanned spectra. Six arable fields were scanned using an on-line sensing platform coupled with a vis–NIR spectrophotometer (CompactSpec by Tec5 Technology for spectroscopy, Germany), with a spectral range of 305–1700 nm. A total of 138 soil samples were collected and used to develop five calibration models: (i) standard, using 100 laboratory scanned samples; (ii) hybrid-1, using 75 laboratory and 25 on-line samples; (iii) hybrid-2, using 50 laboratory and 50 on-line samples; (iv) hybrid-3, using 25 laboratory and 75 on-line samples, and (v) real-time using 100 on-line samples. Partial least squares regression (PLSR) models were developed for soil pH, available potassium (K), magnesium (Mg), calcium (Ca), and sodium (Na) and quality of models were validated using an independent prediction dataset (38 samples). Validation results showed that the standard models with laboratory scanned spectra provided poor to moderate accuracy for on-line prediction, and the hybrid-3 and real-time models provided the best prediction results, although hybrid-2 model with 50% on-line spectra provided equally good results for all properties except for pH and Na. These results suggest that either the real-time model with exclusively on-line spectra or the hybrid model with fusion up to 50% (except for pH and Na) and 75% on-line scanned spectra allows significant improvement of on-line prediction accuracy for secondary soil properties using vis–NIR spectroscopy.


Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2486 ◽  
Author(s):  
Shupei Xiao ◽  
Yong He

Soil nitrogen is the key parameter supporting plant growth and development; it is also the material basis of plant growth. An accurate grasp of soil nitrogen information is the premise of scientific fertilization in precision agriculture, where near-infrared (NIR) spectroscopy is widely used for rapid detection of soil nutrients. In this study, the variation law of soil NIR reflectivity spectra with soil particle sizes was studied. Moreover, in order to precisely study the effect of particle size on soil nitrogen detection by NIR, four different spectra preprocessing methods and five different chemometric modeling methods were used to analyze the soil NIR spectra. The results showed that the smaller the soil particle sizes, the stronger the soil NIR reflectivity spectra. Besides, when the soil particle sizes ranged 0.18–0.28 mm, the soil nitrogen prediction accuracy was the best based on the partial least squares (PLS) model with the highest Rp2 of 0.983, the residual predictive deviation (RPD) of 6.706. The detection accuracy was not ideal when the soil particle sizes were too big (1–2 mm) or too small (0–0.18 mm). In addition, the relationship between the mixing spectra of six different soil particle sizes and the soil nitrogen detection accuracy was studied. It was indicated that the larger the gap between soil particle sizes, the worse the accuracy of soil nitrogen detection. In conclusion, soil nitrogen detection precision was affected by soil particle sizes to a large extent. It is of great significance to optimize the pre-treatments of soil samples to realize rapid and accurate detection by NIR spectroscopy.


2013 ◽  
Vol 664 ◽  
pp. 142-145
Author(s):  
Shan Shan Zhang ◽  
Li Yuan Yang ◽  
Hui Wang ◽  
Qing Lin Chen ◽  
Qian Li

In order to explore the variations and impact factors of soil nitrogen contents, 0-20 cm mineral soil under herb, shrub, Platycladus orientalis plantation of limestone mountains after restoration for 5 years and 10 years were collected and examined in Jinan, Shandong province. The results showed that there was different soil mineral nitrogen content under different vegetation during the natural succession and artificial restoration succession. Shrub community (14.35 mg/Kg) > herb community (12.73 mg/Kg); Platycladus orientalis plantation restored for 10 years (27.82 mg/Kg) > Platycladus orientalis plantation restored for 5 years (20.76 mg/Kg). NO3--N has highly significant positive correlations with soil organic carbon and total nitrogen content (r = 0.626, 0.564, p 4+-N has not significantly correlated with total nitrogen and organic carbon content (r = 0.218, 0.155). However, it has highly significant positive correlation with the NO3--N (r = 0.531, p 3--N and NH4+-N have highly significant negative correlations with soil pH (r = -0.657, -0.605, p < 0.01), respectively. But the correlation with the soil moisture was not significant (r = -0.181, 0.114). The research provided base information for the evaluation of restoration effects and restoration practice on the limestone mountains.


2003 ◽  
Vol 57 (2) ◽  
pp. 132-138 ◽  
Author(s):  
E. Tamburini ◽  
G. Vaccari ◽  
S. Tosi ◽  
A. Trilli

Near-infrared (NIR) spectroscopy has been developed as a noninvasive tool for the direct, real-time monitoring of glucose, lactic acid, acetic acid, and biomass in liquid cultures of microrganisms of the genera Lactobacillus and Staphylococcus. This was achieved employing a steam-sterilizable optical-fiber probe immersed in the culture (In-line Interactance System®). Second-derivative spectra obtained were subjected to partial least-squares (PLS) regression and the results were used to build predictive models for each analyte of interest. Multivariate regression was carried out on two different sets of spectra, namely whole broth minus the spectral subtraction of water, and raw spectra. A comparison of the two models showed that the first cannot be properly applied to real-time monitoring, so this work suggests calibration based on non-difference spectra, demonstrating it to be sufficiently reliable to allow the selective determination of the analytes with satisfactory levels of prediction (standard error of prediction (SEP) < 10%). Direct interfacing of the NIR system to the bioreactor control system allowed the implementation of completely automated monitoring of different cultivation strategies (continuous, repeated batch). The validity of the in-line analyses carried out was found to depend crucially on maintaining constant hydrodynamic conditions of the stirred cultures because both gas flow and stirring speed variations were found to markedly influence the spectral signal.


1952 ◽  
Vol 24 (3) ◽  
pp. 127-134
Author(s):  
Armi Kaila ◽  
Pertti Kivinen

In the experiments reported above the effect of organic material upon the aggregation of soil particles and the simultaneous immobilization of mineral nitrogen by microorganisms were studied. The relative amount of water-stable aggregates larger than 0.5 mm in diameter was considered to indicate the aggregation state of the soil samples. Probably, somewhat different results were obtained if the crumb formation had been determined by some other method, but it is not sure that these would have been more reliable. Since the incubation of soil samples were performed under aerobic conditions, and all the samples were mineral soils, it seemed justifiable to take the nitrate-nitrogen content of the soil samples to characterize the amount of mineral nitrogen in them. On the basis of the results the general conclusion may be drawn that the more favourable the conditions are for the development of an active and large microflora in the soil, the more intensively the crumb formation and the immobilization of nitrogen takes place, but also the destruction of aggregates begins the more rapidlv. This appeared to be true with regard to the indigenous fertility of soil as well as to the fertilization. Liming, however, did not improve the conditions in these experiment, probably due to the rather slight acidity of the soil samples used. Under otherwise similar conditions the larger amount of straw produced larger amount of aggregates, but the differences in the nitrate-nitrogen content of soil in the presence of various amounts of straw were neglibigle. Generally, the degree of immobilization of soil nitrogen seemed largely to depend on the properties of soil and on other environmental conditions, and nitrogen applications, theoretically enough for the needs of microorganisms that decomposed the straw, could not always prevent an intensive absorption of soil nitrogen. The crumb formation appeared to need mere energy-yielding material than the immobilization of nitrogen, or the destruction of crumbs occurred more rapidly than the nitrification of microbiologically bound nitrogen.


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