[Model construction and application for nitrogen nutrition monitoring and diagnosis in double-cropping rice of Jiangxi Province, China].

The spectrometer-based nitrogen (N) nutrition monitoring and diagnosis models for double-cropping rice in Jiangxi is important for recommending precise N topdressing rate, achieving high yield, improving grain quality and increasing economic efficiency. Field experiments were conducted in Jiangxi in 2016 and 2017, involving different early rice and late rice cultivars and N application rates. Plant N accumulation (PNA) and canopy spectral vegetation indices (VIs) were measured at tillering and jointing stages with two spectrometers, i.

Hyperspectral Estimation of Canopy Leaf Biomass Phenotype per Ground Area Using a Continuous Wavelet Analysis in Wheat.

To extend agricultural productivity by knowledge-based breeding and tailoring varieties to adapt to specific environmental conditions, it is imperative to improve our ability to acquire the dynamic changes of the crop's phenotype under field conditions. Canopy leaf biomass (CLB) per ground area is one of the key crop phenotypic parameters in plant breeding. The most promising technique for effectively monitoring CLB is the hyperspectral vegetation index (VI).

A New Curve of Critical Nitrogen Concentration Based on Spike Dry Matter for Winter Wheat in Eastern China.

Diagnosing the status of crop nitrogen (N) helps to optimize crop yield, improve N use efficiency, and reduce the risk of environmental pollution. The objectives of the present study were to develop a critical N (Nc) dilution curve for winter wheat (based on spike dry matter [SDM] during the reproductive growth period), to compare this curve with the existing Nc dilution curve (based on plant dry matter [DM] of winter wheat), and to explore its ability to reliably estimate the N status of winter wheat. Four field experiments, using varied N fertilizer rates (0-375 kg ha-1) and six cultivars (Yangmai16, Ningmai13, Ningmai9, Aikang58, Yangmai12, Huaimai 17), were conducted in the Jiangsu province of eastern China.

[Estimation of sugar to nitrogen ratio in wheat leaves with near infrared spectrometry].

The soluble sugar to nitrogen ratio reflects the coordination degree of carbon (C) and nitrogen (N) metabolism. Precise and real-time monitoring of soluble sugar to nitrogen ratio is of significant importance for nitrogen diagnosis and management regulation in wheat production. In this study, time-course near infrared spectroscopy and soluble sugar to nitrogen ratio of fresh and dry leaves were obtained under different field experiments with varied years and cultivar and N rates.

[Quantitative relationships between satellite channels-based spectral parameters and wheat canopy leaf nitrogen status].

Using space-borne remote sensing information to monitor the crop canopy nitrogen status and crop productivity in a large-scale is of great significance and application prospect i1 modern agriculture. With the hyper-spectral reflectance data from the wheat canopy under different nitrogen fertilization levels, this paper constructed the spectral indices (including the single wavelength, ratio spectral index, and normalized difference spectral index) simulated by satellite channels, and established the nitrogen estimation equations by quantifying the relationships between the simulated channels spectral indices and the leaf nitrogen index. The results indicated that the spectral indices based on NDVI (MSS7, MSS5), NDVI (RBV3, RBV2), TM4, CH2, MODIS1, and MODIS2 could be reliably used for estimating the leaf nitrogen content (LNC), with R2 over 0.

[Accumulative nitrogen deficit models of wheat aboveground part based on critical nitrogen concentration].

Based on three-year field experiments, three models of critical nitrogen concentration dilution curve, nitrogen nutrition index, and accumulative nitrogen deficit were constructed for the aboveground dry matter in medium protein wheat variety Yangmai 16 and low protein wheat variety Ningmai 13, respectively. The critical nitrogen concentration dilution curve model had specific biological meaning, i. e.

[Estimation of winter wheat leaf nitrogen accumulation based on coupling ground- and space-remotely sensed information].

By coupling the SPOT-5 multi-spectral RS images, ground-spectrum, and field measured data of different winter wheat ecological zones, a pure pixel spectrum extraction method was developed based on spectral response function and pixel unmixed, and the quantitative relationships between leaf nitrogen accumulation (LNA) and simulated, measured, and pure pixel spectra were analyzed. The estimation accuracy for LNA was in the sequence of simulated pixel spectra > pure pixel spectra > measured pixel spectra. However, the LNA monitoring model based on simulated pixel spectra couldn't be extrapolated directly to spatial level.

[Effects of Xue-Bi-Jing combined with forsythia suspension on the liver gene expression levels of rats with sepsis model].

Objective: To study the effects of "XUE BI JING plus LIANQIAO" injection on gene expression levels of rats with sepsis model.

Methods: One hundred and twenty rats were randomly divided into sham operation group, sepsis model group, Te-neng group and "XUE BI JING plus forsythia suspension" group. The sepsis model of rats was prepared by "CLP" method.

[Defining of wheat growth management zones based on remote sensing and geostatistics].

Taking the winter wheat planting areas in Rugao City and Haian County of Jiangsu Province as test objects, the clustering defining of wheat growth management zones was made, based on the spatial variability analysis and principal component extraction of the normalized difference vegetation index (NDVI) data calculated from the HJ-1A/B CCD images (30 m resolution) at different growth stages of winter wheat, and of the soil nutrient indices (total nitrogen, organic matter, available phosphorus, and available potassium). The results showed that the integration of the NDVI at heading stage with above-mentioned soil nutrient indices produced the best results of wheat growth management zone defining, with the variation coefficients of NDVI and soil nutrient indices in each defined zone ranged in 4.5% -6.

[Estimation of optimum normalized difference spectral index for nitrogen accumulation in wheat leaf based on reduced precise sampling method].

Four independent field experiments with 6 wheat varieties and 5 nitrogen application levels were conducted, and time-course measurements were taken on the canopy hyperspectral reflectance and leaf N accumulation per unit soil area (LNA, g N x m(-2)). By adopting reduced precise sampling method, all possible normalized difference spectral indices [NDSI(i,j)] within the spectral range of 350-2500 nm were constructed, and the relationships of LNA to the NDSI(i,j) were quantified, aimed to explore the new sensitive spectral bands and key index from precise analysis of ground-based hyperspectral information, and to develop prediction models for wheat LNA. The results showed that the sensitive spectral bands for LNA were located in visible light and near infrared regions, especially at 860 nm and 720 nm for wheat LNA.

[A near-infrared spectral index for estimating soil organic matter content].

Taking the air-dried samples of five soil types from middle and eastern China as test materials, the correlations of their organic matter content with the spectral reflectance of near-infrared (1000-2500 nm), and with the ratio index (RI), difference index (DI), and normalized difference index (ND) of the first derivative values of the reflectance between two bands were studied. Based on this, the key spectral indices and the quantitative models for estimating soil organic matter (SOM) content were developed. After corrected with Multiplicative Scatter Correction (MSC) and Savitzky-Golay (SG) smoothing methods, the spectral reflectance of near-infrared had an obviously high correlation with SOM, compared with the original spectral reflectance, while the corrected spectral indices of the first derivative values of the reflectance between two bands took the intermediate position.

[Quantitative relationships between hyper-spectral vegetation indices and leaf area index of rice].

Based on field experiments with different rice varieties under different nitrogen application levels, the quantitative relationships of rice leaf area index (LAI) with canopy hyper-spectral parameters at different growth stages were analyzed. Rice LAI had good relationships with several hyper-spectral vegetation indices, the correlation coefficient being the highest with DI (difference index), followed by with RI (ratio index), and NI (normalized index), based on the spectral reflectance or the first derivative spectra. The two best spectral indices for estimating LAI were the difference index DI (854, 760) (based on two spectral bands of 850 nm and 760 nm) and the difference index DI (D676, D778) (based on two first derivative bands of 676 nm and 778 nm).

[Exploring novel hyperspectral band and key index for leaf nitrogen accumulation in wheat].

The objectives of the present study were to explore new sensitive spectral bands and ratio spectral indices based on precise analysis of ground-based hyperspectral information, and then develop regression model for estimating leaf N accumulation per unit soil area (LNA) in winter wheat (Triticum aestivum L.). Three field experiments were conducted with different N rates and cultivar types in three consecutive growing seasons, and time-course measurements were taken on canopy hyperspectral reflectance and LNA tinder the various treatments.

[Monitoring of wheat leaf pigment concentration with hyper-spectral remote sensing].

In a two-year field experiment with wheat cultivars under different application rates of fertilizer N, the wheat leaf pigment concentrations were monitored with hyper-spectral remote sensing, and quantitative monitoring models were established. The results showed that the pigment concentrations in wheat leaves increased with increasing N application rate, and differed significantly among test cultivars. With the growth of wheat, the relative concentration of chlorophyll a + b varied more obviously than those of chlorophyll b and carotenoid (Car), and the sensitive bands of the pigments occurred mostly within visible light range, especially in red-edge district.

[Quantitative relationships between leaf total nitrogen concentration and canopy reflectance spectra of rice].

By the method of statistics, this paper approached the quantitative relationships between leaf total nitrogen concentration (LNC) and canopy reflectance spectra of rice, based on the data from 5-year field experiments involving different varieties and nitrogen fertilization rates. The results showed that the LNC had higher correlations with the key spectral parameters of two bands than of single band. The relative, differential, and normalized difference vegetation indices (RVI, DVI, NDVI) of the bands in near infrared (760-1,220 nm) and visible light 510 nm, 560 nm, 680 nm and 710 nm all showed significantly positive correlations to LNC, and NDVI showed the best.

[Estimation of dry matter accumulation in above-ground part of cotton by means of canopy reflectance spectra].

Through analyzing the relationships of the dry matter accumulation in above-ground part of cotton with the canopy reflectance of single waveband and all two-band combinations in ratio vegetation index (RVI, R(lamda1)/R(lamda2)), normalized difference vegetation index (NDVI, (R(lamda1)-R(lamda2))/(R(lamda1) + R(lamda2 and differential vegetation index (DVI, R(lamda1)-R(lamda2)), the characteristic spectral wavebands for indicating the dry matter accumulation in above-ground part of cotton were determined, and the corresponding prediction model was established. The results showed that the vegetation indices comprised of visible light (560 and 710 nm) and near infrared light (810, 870, 950, 1100 and 1220 nm) were highly related to the dry matter accumulation in the above-ground part of cotton, and the RVI (1100, 560) was the best spectral index for the estimation. The corresponding prediction model established by stepwise regression method was Y (g x m(-2)) = 66.

[Estimation of nitrogen concentration in cotton leaf based on canopy reflectance spectra].

Through analyzing the relationships of nitrogen concentration in cotton leaf under different nitrogen supply levels with canopy multi-spectral reflectance and its derived ratio vegetation index (RVI, rholambda1/rholambda2), normalized difference vegetation index (NDVI, (rho(lambda1) - rho(lambda2))/(rho(lambda1)) + rho(lambda2)) and differential vegetation index (DVI, rho(lambda1) - rho(lambda2)), the sensitive wave bands and prediction functions of cotton leaf nitrogen concentration were worked out. The vegetation index composed of visible region (610, 660, 680 and 710 nm) and near infrared region (760, 810, 870, 950, 1 100 and 1 220 nm) had a higher correlation with the nitrogen concentration in cotton leaf, and the RVI composed of 950 nm and 710 nm could best predict the leaf nitrogen concentration. The validation with independent field experimental data indicated that RVI (950 nm and 710 nm) -based model was suitable for estimation of leaf nitrogen concentration of different cotton cultivars at their different growth stages.

[A dynamic knowledge model for designing suitable scheme of rapeseed sowing and transplanting].

Based on the sum-up and abstraction of the relationships of rapeseed growth characters with ecological environment, cultivar type, production condition and yield target, a dynamic knowledge model was developed by using knowledge engineering and system modeling method, which could be used for designing a suitable sowing and transplanting scheme of different rapeseed varieties under different spatial and temporal environments. Case studies on the knowledge model with the data sets of three different sites, nine different variety types, and two different sowing styles indicated a good performance of the model system in decision-making, explanation, and wide applicability.