Nitrogen Index Research Articles

Differences in nitrogen and phosphorus sinks between the harvest and non-harvest of Miscanthus lutarioriparius in the Dongting Lake wetlands.

Plant non-harvest changes element circulation and has a marked effect on element sinks in the ecosystem. In this study, a field investigation was conducted on the fixation of nitrogen and phosphorus in Miscanthus lutarioriparius, the most dominant plant species in the Dongting Lake wetlands. Further, to quantitatively compare the difference in nitrogen and phosphorus sinks between harvest and non-harvest, an in situ experiment on the release of the two elements from two types of litters (leaves and stems) was studied. The nitrogen concentrations in the plant had no significant relationship with the environmental parameters. The phosphorus concentrations were positively related to the plot elevation, soil organic matter, and soil total potassium and were negatively related to the soil moisture. The leaves demonstrated a higher decomposition coefficient than that of the stems in the in situ experiment. The half decomposition time was 0.61 years for leaves and 1.12 years for stems, and the complete decomposition time was 2.83 years for leaves and 4.95 years for stems. Except for the nitrogen concentration in the leaves, all the concentrations increased during the flood period. All concentrations unsteadily changed in the backwater period. Similarly, except for the relative release index of nitrogen in the leaves, all the relative release indices decreased in the flood period. At the end of the in situ decomposition experiment, the relative release indices of both the nitrogen and phosphors were greater than zero, indicating that there was a net release of nitrogen and phosphorus. Under the harvest scenario, the aboveground parts of the plant were harvested and moved from the wetlands, thus increasing the nitrogen and phosphorus sinks linearly over time. The fixed nitrogen and phosphorus in the aboveground parts were released under the non-harvest scenario, gradually accumulating the nitrogen and phosphorus sinks from the first year to the fifth year after non-harvest, reaching a maximum value after the fifth year. This study showed that the nitrogen and phosphorus sinks greatly decreased after the non-harvest of M. lutarioriparius compared to that after harvest. It is recommended to continue harvesting the plant for enhancing the capacity of element sinks.

Satellite retrieval of oceanic particulate organic nitrogen concentration

Over the past several decades, satellite ocean color remote sensing has greatly improved our understanding of the biogeochemical properties of the global ocean. Particulate organic nitrogen (PON) refers to the nitrogen contained in biological or other debris particles, and it plays important roles in the ecosystem functions and biogeochemical processes of the marine biology. However, few studies have focused on the satellite retrieval of oceanic PON concentrations. With an attempt to fill the gap, this study aimed to explore the feasibility of retrieving oceanic PON concentrations from remote sensing data, determine the bio-optical proxies for satellite PON retrievals, and develop satellite oceanic PON retrieval models for the global ocean. In situ PON data collected over the global ocean and Moderate-resolution Imaging Spectroradiometer (MODIS) Level-3 products were used. Three different types of models were tested: (1) apparent optical property (AOP)-based models, 2) inherent optical property (IOP)-based models, and 3) biological property-based models. Results showed that ocean color remote sensing could be used for oceanic PON concentration retrieval in the global ocean, and AOP-based models calibrated produced better fitting performance than the other two types; models based on blue-to-green band ratio (BG) and normalized difference nitrogen index (NDNI) produced comparable and better fitting and validation performance; and IOP-based and biological property-based models produced lower but also acceptable performance. With the PON models developed, the monthly variations of PON concentrations in the global ocean were also explored. In further studies, PON models will be used to explore oceanic PON spatiotemporal variations and the underlying driving forces.

Impacts of Drought Stress and Mycorrhizal Inoculation on the Performance of Two Spring Wheat Cultivars.

Cereal production is becoming challenging, given ongoing climate change. Arbuscular mycorrhizal fungi (AMF) are discussed to mitigate effects of drought for plants and enhance nutrient uptake. Thus, we investigated the impacts of drought and mycorrhiza on the growth and allocation patterns of two cultivars of spring wheat (Triticum aestivum). Plants were grown under three irrigation regimes (well-watered, continuous or pulsed drought) and in three substrates (absence or presence of one or three AMF species). Applied water use efficiency (WUEapplied), harvest index (HI) and contents of carbon (C), nitrogen (N) and phosphorous (P) were determined when grains were watery ripe. When grains were hard, again, WUEapplied, HI and the thousand-kernel weight were measured. The WUEapplied and HI were lowest in plants under pulsed drought stress at the second harvest, while the thousand-kernel weight was lower in mycorrhized compared to non-mycorrhized plants. The C/N ratio dropped with increasing drought stress but was enhanced by mycorrhiza, while the P content was surprisingly unaffected by mycorrhiza. The total root length colonization was higher in substrates with the AMF mix, but overall, fungal presence could not alleviate the effects of drought. Our results highlight the complexity of responses to challenging environments in this highly domesticated species.

Ohmic heating treatment in high-protein vanilla flavored milk: Quality, processing factors, and biological activity

The processing of high-protein vanilla-flavored milk was performed under different electric field strengths of ohmic heating (5.22 V/cm, OH6; 6.96 V/cm, OH8; 8.70 V/cm, OH10; 10.43 V/cm, OH12) to evaluate the energy consumption, processing parameters, and microbiological, rheological, and biological aspects, compared with the sample submitted to conventional pasteurization (PAST, 72 °C/15 s). All samples showed higher than 12 g/100 mL of protein, consisting of high-protein content products. In addition, Ohmic Heating (OH) generated lower energy expenditure and more significant microbial inactivation of lactic acid bacteria, molds and yeasts, total mesophiles, and psychotropics. Furthermore, OH at lower electric field strengths, mainly OH8, improved anti-diabetic, anti-oxidant, and anti-hypertensive activities and rheological properties, and resulted in lower hydroxymethylfurfural contents, and higher whey protein nitrogen index. The results suggest that OH is a technology that can be used in flavored milk with high-protein content, being recommended an electric field strength of 6.96 V/cm. However, more studies are necessary to evaluate the effect of OH on high-protein dairy products, mainly by studying other OH processing parameters.

Impacts of Land Use on Pools and Indices of Soil Organic Carbon and Nitrogen in the Ghaggar Flood Plains of Arid India

Changes in land use have several impacts on soil organic carbon (C) and nitrogen (N) cycling, both of which are important for soil stability and fertility. Initially, the study area was barren uncultivated desert land. During the late 1960s, the introduction of a canal in the arid region converted the barren deserts into cultivated land. The objectives of the present study were to evaluate the effects of various land use systems on temporal changes in soil organic C and N pools, and to evaluate the usefulness of different C and N management indices for suitable and sustainable land use systems under arid conditions. We quantified soil organic C and N pools in five different land uses of the Ghaggar flood plains, in hot, arid Rajasthan, India. The study focused on five land use systems: uncultivated, agroforestry, citrus orchard, rice–wheat, and forage crop. These land use systems are ≥20 years old. Our results showed that total organic carbon (TOC) was highest (7.20 g kg−1) in the forage crop and lowest in uncultivated land (3.10 g kg−1), and it decreased with depth. Across different land uses, the very labile carbon (VLC) fraction varied from 36.11 to 42.74% of TOC. In comparison to the uncultivated system, forage cropping, rice–wheat, citrus orchard, and agroforestry systems increased active carbon by 103%, 68.3%, 42.5%, and 30.6%, respectively. Changes in management and land use are more likely to affect the VLC. In soil under the forage crop, there was a considerable improvement in total N, labile N, and mineral N. Lability index of C (LIC), carbon management index (CMI), and TOC/clay indices were more sensitive to distinguishing land uses. The highest value of CMI was observed in the forage crop system followed by rice–wheat and agroforestry. In the long term, adoption of the forage crop increased soil quality in the hot, arid desert environment by enhancing CMI and VLC, which are the useful parameters for assessing the capacity of land use systems to promote soil quality.

Microbiota of the rhizosphere zone of Calamagrostis epigeios from a coal mine waste dump

The microbiota plays an important role in the processes of plant overgrowth of coal mine waste dumps, enabling the transformation of numerous compounds into forms available to plants. The overgrowth of coal mine dumps is influenced by many factors. Pioneers are plant species that have a wide ecological and phytocenotic amplitude. Calamagrostis epigeios (L.) Roth. occupies a special place among them. The composition of the microbiota of the rhizosphere zone of C. epigeios was studied in relation to the age of the plants and the stage of the succession of the “Vizeyska” mine dump (Ukraine). It was established and confirmed as a result of two-factor variance analysis that the growth phase of C. epigeios and the stage of the succession of coal mine waste dumps have different effects on the number of microorganisms from the rhizosphere zone of plants. The number of pedotrophic microorganisms, microorganisms that metabolize nitrogen of organic compounds, cellulose-degrading microorganisms, and microscopic fungi depended more on the age of C. epigeios, and not on the stage of the succession of the studied area. The number of chemolithotrophic bacteria, particularly thiobacteria, decreased with the change of the growth phase of C. epigeios. The number of acidophobic thiobacteria depended more on the stage of succession, and the number of acidophilic thiobacteria depended more on the age of the C. epigeios. The number of microorganisms that metabolize nitrogen of organic compounds, oligonitrophilic microorganisms and microorganisms that metabolize nitrogen of inorganic compounds in the samples of tailings from the area with grasses and perennials and from the area with grasses, shrubs, and sun-loving trees was higher, compared to the number of these groups of microorganisms in the control and changed with the change in the growth phase of C. epigeios. The number of microorganisms that metabolize nitrogen of organic compounds, oligonitrophilic microrganisms and microorganisms that metabolize nitrogen of inorganic compounds was the highest in the samples from the area with grasses, shrubs, and sun-loving trees during the adult growth phase of C. epigeios. In the area where C. epigeios dominated within the vegetation, the highest number of microorganisms that metabolize nitrogen of organic compounds was also during the adult phase of C. epigeios, and the number of bacteria that assimilate mineral forms of nitrogen and oligonitrophilic microorganisms was the highest during the sub-adult stage. The index of pedotrophicity is higher in the samples taken in the area where C. epigeios prevails among other herbaceous plants, and where in the tree layer there are Betula pendula, Populus tremula with an admixture of Pinus sylvestris. Pedotrophicity indices which were calculated for these samples do not depend on the growth stage of C. epigeios and are higher than for the control area. Immobilization-mobilization of nitrogen indices in samples of tailings from the area with grasses and perennials and from the area with grasses, shrubs, and sun-loving trees ranged from 1.94 to 3.52 and were higher compared to the control site.

MODEL FOR DESCRIBING THE VARIATION OF SOME AGROCHEMICAL INDICES OF THE SOIL

The study evaluated the interdependence relationship between certain agrochemical indices of soil fertility. Soil reaction (pH), organic matter (H), nitrogen index (NI), base saturation degree (V), phosphorus (P) and potassium content (K) were analyzed. The variation of NI in relation to H was described by a polynomial equation of degree 2, inconditions of R2 = 0.876, p = 0.0151. Mobile phosphorus soil content (P) in relation to soil pH was described by a polynomial equation of degree 2, and from the derivation of the equation was obtained the value of pH = 6.77 at which P had high mobility in soil, and high accessibility for plants. The P variation was analyzed by regression analysis in relation to pH and V, under conditions of R<sup<2</sup< = 0.817. The distribution in 3D form and in the form of isoquants of the P values in relation to soil pH and V was obtained. The variation of K was analyzed by regression analysis in relation to pH and P (R<sup<2</sup< = 0.776), and in relation to pH and NI (R<sup<2</sup< = 0.949) respectively. The graphical distribution in 3D and isoquants form of the K values in relation to pH and P, respectively in relation to pH and NI was obtained.

Suitability of Turkey Oak, European Beech, and Hornbeam to Gypsy Moth Feeding

Pest resistance of trees should be taken into account in future forest strategy planning and predicting risks of defoliation. The gypsy moth (GM) (Lymantria dispar L.) is a serious forest pest with outbreaking population dynamics. To estimate defoliation risk of the most widely distributed tree species in Balkan Peninsula and Europe (Turkey oak Quercus cerris L., European beech Fagus sylvatica L. and hornbeam Carpinus betulus L.), we carried out laboratory feeding trials and investigated their acceptability and suitability for GM development. We determined morphological and chemical attributes of these hosts as well as larval host preference, growth and nutritional indices. Preference, growth, and efficiency of food conversion into biomass were ranked in the order: Turkey oak ˃ European beech ˃ hornbeam. Hornbeam was the most avoided and showed the lowest conversion efficiency although, comparing to optimal oak host, its leaves were less tough, contained more water and exhibited similar values of nitrogen (index of protein content) and C/N ratio (index of investment into carbon based plant defense). We suggest that hornbeam and beech leaf chemical profiles should be further studied to reveal specific compounds that impose high metabolic cost to GM larvae. Moreover, additional research are needed to understand how intermediate hosts in natural populations affect GM outbreaks.

Characterization of Soil-Plant Leaf Nutrient Elements and Key Factors Affecting Mangoes in Karst Areas of Southwest China

Baise city is one of the largest producers of mangoes, with this agricultural industry located in the karst region of Southwest China. However, calcium-rich and alkaline soils, severe soil fragmentation, and poor water and fertilizer retention capacity contribute to low mango yields and are key issues that limit the development of the mango industry in karst areas. Our study objectives were to identify the soil factors that limit mango growth and yield in the karst region of Southwest China, and to determine how these growth- and production-limiting conditions vary between landscape positions. This study analyzed the differences in soil nutrient and element contents in mango leaves, and used a Random Forest algorithm to calculate the eigenvalues of the mango leaf and soil elemental indices in the different geomorphic parts (slopes, transition zone, passes, high-yielding depressions, and low-yielding depressions) of the karst peak-cluster depressions. The key factors affecting the mango leaves and soil were screened based on the diagnostic results and the eigenvalues. The results showed that for the elemental contents of Fe, Mg, Ca, and Mn in the mango leaves in the different geomorphic parts of the karst, the peak-cluster depressions were generally deficient and varied significantly. The contents of available B (AB), soil organic matter (SOM), pH, total nitrogen, available Fe, available Mn, alkaline hydrolysis nitrogen, exchangeable Ca (Caex), exchangeable Mg, and other indices in the soils differed significantly, and AB, available Zn, and available K (AK) showed low or very low content levels. In addition, the key soil factors limiting mango yield in the karst areas were AB, fulvic acid, SOM, Fe, Mn, Caex, soil water, and AK; and the key mango leaf factors were Ca, Mn, Fe, Zn, and Mg. Consequently, the characteristics of soil water content, pH, and soil organic matter may be the main drivers affecting the differences in the mango yield and the elemental characteristics. These findings suggest that the addition of organic fertilizer could improve the quality and yield of mangoes in karst areas.

Foliar Brassinolide Sprays Ameliorate Post-Silking Heat Stress on the Accumulation and Remobilization of Biomass and Nitrogen in Fresh Waxy Maize

Heat stress (HS) during grain filling is an extreme environmental factor and affects plant growth and development. Foliar application of exogenous brassinolide (BR) is an effective practice to relieve HS injuries, but the influence on the accumulation and remobilization of biomass and nitrogen is still unclear. In the present study, the effect of foliar BR application at the silking stage on the accumulation and remobilization of biomass and nitrogen in fresh waxy maize under ambient (28/20 °C) and high (35/27 °C) temperatures during grain filling were studied in a phytotron using heat-sensitive Yunuo7 (YN7) and heat-tolerant Jingkenuo2000 (JKN2000) as materials. HS reduced the fresh ear yield by 21.8% and 19.8% in YN7 and JKN2000, respectively, but fresh grain yield was only reduced in the heat-sensitive hybrid (6.9%) and unaffected in the heat-tolerant hybrid. BR application improved the yields of fresh ears (11.3% and 10.9% in YN7 and JKN2000, respectively) and grains (19.9% and 13.2% in YN7 and JKN2000, respectively) under HS, and the increases were higher in YN7. HS decreased the post-silking biomass accumulation by 67.3% and 51.8%, and nitrogen deposition by 61.9% and 50.5%, in YN7 and JKN2000, respectively. The remobilization of pre- and post-silking biomass and nitrogen were increased and decreased by HS in YN7, respectively, but both were unaffected in JKN2000. Under HS, BR application increased the remobilization of post-silking biomass and nitrogen in both hybrids. The grain nitrogen concentration was increased by HS but decreased by BR application in both hybrids. The harvest index of biomass and nitrogen was increased by HS, and it was improved in YN7 and unaffected in JKN2000 by BR application under HS. In conclusion, BR application at the silking stage can relieve HS injuries on fresh waxy maize yields by improving the remobilization of biomass and nitrogen to grain and increasing the harvest index, especially in the heat-sensitive hybrid. Therefore, foliar BR application is a simple, feasible, efficient practice in fresh waxy maize production and is worth popularizing, especially under warmer climates.

Method of cost-effectiveness-based total maximum allocated load index and measures of nitrogen and phosphorus pollutants on jurisdictions in Jiangsu coast, China

Cost-effective total maximum allocated load (TMAL) management of land-based pollutants is required to promote sustainable and healthy development of coastal areas. For the high concentrations of nitrogen and phosphorus pollutants and the deterioration in water quality in the coastal waters of Jiangsu Province, China, the TMALs of total nitrogen (TN) and total phosphorus (TP) pollutants within jurisdictions were calculated using a cost-efficiency optimization calculation method with a 3D hydrodynamic water quality model. This method is suitable for collaborative pollution prevention and land–sea integration management in coastal areas. Our calculation results showed that the emission TMALs of TN and TP in 43 jurisdictions near the coast of Jiangsu Province were approximately 8.6 × 104 and 0.8 × 104 ton/a, respectively, and the source TMALs were 55.8 × 104 and 14.9 × 104 ton/a, respectively. The high concentrations of nitrogen and phosphorus in these waters were caused mainly by Yancheng, Suqian and Lianyungang City. The average responsibility sharing rates (the responsibility sharing of land-based over-pressured administrative areas to marine pollution areas) of these three cities were 48.3%, 23.4%, and 12.2%, respectively. Regarding over-pressured administrative areas (the administrative regions where the discharge exceeds the allocation capacity), we suggest pollution prevention and technical control measures based on the cost-effectiveness optimization method. First, source control should be strengthened, including the control of industrial point source and agricultural nonpoint source pollution, which account for approximately 77.3% of total reduction. Second, it is necessary to strengthen the construction of the municipal wastewater collection and treatment system, which accounts for approximately 16.3% of total reduction. Further, it is necessary to perform wetland ecological restoration and implement capacity-increasing measures, which account for approximately 6.4% of total reduction. The cost-effectiveness optimization calculation method for the technical indicators of collaborative prevention and control of coastal pollution provides a scientific quantitative basis suitable for global coastal pollution control.

Physicochemical Properties of Fatty and Low-Fat White Cheese Produced with Cultures Forming Exopolysaccharide

In this study, the possibilities of the usage of Exopolysaccharide (EPS)-producing cultures in White cheese production have been researched. For this purpose, physical, chemical, were investigated at days 1, 15, 30, 60 and 90 of cheese that produced two replicas with fat and non-fat cow milk via different cultures. It has been detected that the EPS has different effects on full fat and non- fat cheeses. The yields value was he cheese produced with EPS-producing cultures.). In all cheeses, the dry matter ratio was increased during ripening period (p>0.0.5), fat was stable (p>0.0.5), faded proportion was decreased (p>0.0.5), total nitrogen ratio was decreased; water-soluble and 12% TCA-soluble nitrogen ratio and index of ripening and treatable acidity were increased (p>0.0.5 were increased. Also, EPS producing culture was exhibited positive effect on texture and aroma in full-fat cheeses.

Effects of harvest residue management on soil organic nitrogen fractions in young Cunninghamia lanceolata plantation

Different treatments of harvest residues will change the quantity and quality of soil organic matter, with direct or indirect effects on the composition and content of soil nutrient. Nitrogen is one of the most important soil nutrients. However, the response of soil organic nitrogen fractions to different harvest residue treatments is still unclear. In this study, harvest residue treatments, including harvest residue removed, residue retained and residue burnt, were set up after clear-cutting a 50-year-old mature Cunninghamia lanceolata forest in Sanming City, Fujian, China. The H2SO4 hydrolysis method was used to determine soil organic nitrogen fractions and their driving factors in the 0-10 cm and 10-20 cm soil layers after 5 years of harvest residue treatments. The results showed that residue retained treatment significantly enhanced the contents of soil organic nitrogen and its liable fractions. In the 0-10 cm soil layer, soil organic nitrogen content under residue retained treatment (3.36 g·kg-1) was 1.5 and 1.3 times as those of residue removed and residue burnt treatments, respectively. Residue retained treatment had the highest contents of labile nitrogen Ⅰ and Ⅱ fractions. In 10-20 cm soil layer, the contents of soil organic nitrogen and labile nitrogen Ⅱ fraction were also significantly higher in residue retained treatment (2.20, 0.73 g·kg-1) than that in residue removed and residue burnt treatments. The labile nitrogen index Ⅱ in residue retained treatment (33.9%) was significantly higher than in residue burnt treatment (26.1%). The contents of total carbon, dissolved organic carbon, dissolved organic nitrogen, microbial biomass under residue retained treatment were the highest in both soil layers. Compared with residue removed treatment, residue retained treatment significantly enhanced the abundance of soil bacteria (Gram-positive bacteria and Gram-negative bacteria) in 0-10 cm soil layer. In 10-20 cm soil layer, residue retained treatment had the highest content of fungi and the lowest content of actinomycetes. Pearson analysis showed that there were significant positive correlations of labile fractions of soil organic nitrogen with total carbon, dissolved organic carbon, dissolved organic nitrogen, microbial biomass carbon, microbial biomass nitrogen, bacteria (Gram-positive bacteria, Gram-negative bacteria), and fungi, and negative correlations with actinomycetes. It was concluded that the retention of harvest residue was beneficial to increase the content of soil organic nitrogen and labile fractions, improve soil biochemical properties and had a positive effect on soil microbial community composition. Retention of harvest residue was an effective management measure to maintain soil fertility and improve forest productivity.

Synergistic use of spectral features of leaf nitrogen and physiological indices improves the estimation accuracy of nitrogen concentration in rapeseed

ABSTRACT Estimation of nitrogen content in crop leaves using hyperspectral techniques encounters the challenge of limited model stability. In this study, a method for the construction of nitrogen estimation model of oilseed rape (Brassica napus L.) was proposed, which combines the spectral features of nitrogen and nitrogen-containing physiological components. Based on the pot experiment, a total of 320 sets of canopy spectra were collected in the five growth stages using hyperspectral technology, and the concentration of leaf nitrogen (LNC), malondialdehyde (MDA), proline, soluble sugar (SS), and water were determined in indoor chemical experiments. Original spectra was preprocessed by five kinds of spectral conversions, and the random frog (RF) method was used to screen the spectral features of nitrogen and nitrogen-containing physiological components that were used to construct the partial least square regression (PLSR) and support vector machine (SVM) models. The results showed that the selection of spectral features of LNC and nitrogen-containing physiological components based on RF greatly reduced the collinearity and redundant information among bands. The accuracy of the models based on the spectral features of LNC and nitrogen-containing physiological components were higher than that of the model based on the spectral features of single LNC. Further interannual test showed that the prediction accuracy of the N + MDA + SS model was higher than that of other models, especially at the rapid growth stage, with R2 of 0.871. This study provides a new idea for improving the accuracy and stability of crop nitrogen estimation model.

Tongbixiao Pills Improve Gout by Reducing Uric Acid Levels and Inhibiting Inflammation.

Gout is a chronic disease. Gout symptoms are often experienced in the middle of the night. The onset of gout in the middle of the night is closely related to abnormal liver and gallbladder meridian. The purpose of this study was to investigate the clinical efficacy and possible mechanism of action of Tongbixiao pills in the treatment of hyperuricemia and gouty arthritis. The Tongbixiao pills we used included several traditional Chinese medicines, most of which tonify the spleen; strengthen the liver; benefit the kidney; and reduce heat, dampness, and blood stasis. In this randomized clinical study of 105 patients, we found that Tongbixiao pills can reduce uric acid levels in hyperuricemia patients. Additionally, the efficacy was similar to that of allopurinol and the level of uric acid did not increase significantly at eight weeks after withdrawal. In the absence of notable adverse reactions, Tongbixiao pills can also increase uric acid excretion, reduce serum creatinine and lipid levels, and reduce inflammation and relieve gout symptoms. In addition, we used SD rats to simulate gout and arthritis and divided them into five groups: normal group, model group, low-dose group, medium-dose group, and high-dose group. The inflammatory indices of the 40 SD rats were observed. After seven days, ankle swelling in rats in the treatment group was significantly reduced. The indices of uric acid, creatinine, and urea nitrogen in the treatment group were significantly lower than those in the model group, which proved that Tongbixiao pills could inhibit hyperuricemia in rats, thus treating gout. This study demonstrates that Tongbixiao pills can treat gout, provide more treatment options for gouty arthritis, and improve the quality of life of patients.

Monitoring of Nitrogen Indices in Wheat Leaves Based on the Integration of Spectral and Canopy Structure Information

Canopy spectral reflectance can indicate both crop nutrient and canopy structural information. Differences in canopy structure can affect spectral reflectance. However, a non-imaging spectrometer cannot distinguish such differences while monitoring crop nutrients, because the results are likely to be influenced by the canopy structure. In addition, nitrogen application rate is one of the main factors influencing the canopy structure of crops. Strong correlations exist between indices of canopy structure and leaf nitrogen, and thus, these can be used to compensate for the spectral monitoring of nitrogen content in wheat leaves. In this study, canopy structural indices (CSI) such as wheat coverage, height, and textural features were obtained based on the RGB and height images obtained by the RGB-D camera. Moreover, canopy spectral reflectance was obtained by an ASD hyperspectral spectrometer, based on which two vegetation indices—ratio vegetation index (RVI) and angular insensitivity vegetation index (AIVI)—were constructed. With the vegetation indices and CSIs as input parameters, a model was established to predict the leaf nitrogen content (LNC) and leaf nitrogen accumulation (LNA) of wheat based on partial least squares (PLS) and random forest (RF) regression algorithms. The results showed that the RF model with RVI and CSI as inputs had the highest prediction accuracy for LNA, the coefficient of determination (R2) reached 0.79, and the root mean square error (RMSE) was 1.54 g/m2. The vegetation indices and coverage were relatively important features in the model. In addition, the PLS model with AIVI and CSI as input parameters had the highest prediction accuracy for LNC, with an R2 of 0.78 and an RMSE of 0.35%, among the vegetation indices. In addition, parts of both the textural and height features were important. The results suggested that PLS and RF regression algorithms can effectively integrate spectral and canopy structural information, and canopy structural information effectively supplement spectral information by improving the prediction accuracy of vegetation indices for LNA and LNC.

Accuracy of narrow-band spectral indices estimation by wide-band remote sensing data

Narrow-band spectral indices are quite informative and important in various applications of remote sensing – to assess the condition of vegetation, soils, water bodies and other land surface formations. However, direct measurement of narrow-band spectral indices requires hyperspectral imaging. But most of modern multispectral aerospace imaging systems are wide-band. Accordingly, it is not possible to calculate the narrow-band index directly from wide-band remote sensing data. This paper discusses approaches to the narrow-band spectral indices restoration by wide-band remote sensing data using statistical models of interrelations of narrow- and wide-band indices itself, of source wide-band and narrow-band signals in close spectral bands, as well as of land surface reflectance quasi-continuous spectra translation from wide bands to narrow ones.The experimental accuracy estimation of narrow-band spectral indices restoration by wide-band multispectral satellite image is performed. Three most complicated narrow-band spectral indices, which covering a range of spectrum from visible to short-wave infrared, were considered, namely – the transformed chlorophyll absorption in reflectance index (TCARI), the optimized soil-adjusted vegetation index (OSAVI) and the normalized difference nitrogen index (NDNI). All three mentioned methods for narrow-band spectral indices restoration are analyzed. The worst result is demonstrated for regression-restored signals in spectral bands, and the best result is for the spectra translation method. Therefore, the method on the basis of spectra translation is recommended for practical implementation.

Crop performance, water use, economics and energy indices in rabi groundnut (Arachis hypogaea L.) under micro irrigation methods

Aim: A field investigation was conducted during 2016-17 and 2017-18 to assess the relative performance of micro irrigation methods with regard to yield, water use, economics, nitrogen indices and energy use pattern in rabi groundnut on irrigated Alfisols. Methodology: One conventional and three micro-irrigation methods viz., drip, sprinkler and rain gun were evaluated in rabi groundnut. Besides growth, reproductive traits and pod yield, the information on nodule count, water use efficiency, economic benefits, nitrogen and energy indices was generated. High yielding, high water, power and energy use efficient irrigation scheduling method for rabi groundnut cultivation was identified. Results: Drip irrigation @ 0.8 Epan + fertigation at recommended dose of fertilizers not only recorded better growth and reproductive attributes but also resulted in 8-10% higher dry pod yield over sprinkler irrigation, raingun irrigation and conventional method. Besides, drip method also recorded higher water use efficiency (6.31 kg ha-1 mm-1) and higher economic yield per kg N applied (95.9 kg). This method also proved to be energy efficient and remunerative with higher net income (` 70,280 ha-1). Interpretation: Scheduling of irrigation and fertigation through drip method helped in achieving higher pod yield, water and nitrogen use efficiency utilizing less power and energy in groundnut cultivation.

Application of PGPB Combined with Variable N Doses Affects Growth, Yield-Related Traits, N-Fertilizer Efficiency and Nutritional Status of Lettuce Grown under Controlled Condition

Nitrogen (N) fertilization is a crucial agricultural practice for boosting production traits in vegetables. However, N synthetic fertilizers—commonly adopted by farmers—have several counterproductive effects on the environment and on humans. The research was performed to assess the combined influence of plant growth promoting bacteria (PGPB) (Azospirillum brasilense DSM 1690, A. brasilense DSM 2298 and Pseudomonas sp. DSM 25356) and various N fertilization doses (0, 30, 60 or 120 kg ha−1) on growth, yield, quality and nitrogen indices of lettuce in protected cultivation. Plant height, root collar diameter, number of leaves and fresh weight were enhanced by A. brasilense DSM 2298 inoculation and N at 30 or 60 kg ha−1. Overall, soluble solids content (SSC), ascorbic acid, total phenolics, carotenoids, total chlorophyll and total sugars were augmented by the combined effect of A. brasilense strains and 30, 60 or 120 kg N ha−1. Furthermore, PGBP inoculation improved potassium (K) and magnesium (Mg) concentrations in leaf tissues. PGPB inoculation increased N leaf concentration; however, it hastened N indices. These results suggest that the PGPB tested can be considered an eco-friendly tool to improve lettuce yield, particularly when combined with N at 30 or 60 kg ha−1.

Melatonin in the prevention of cisplatin-induced acute nephrotoxicity: a randomized, controlled clinical trial.

Background and purpose:Cisplatin-induced nephrotoxicity (CisIN) remains the most dose-limiting adverse effect of its clinical use. The protective effects of melatonin on CisIN have been addressed in several non- clinical and animal studies. This study aimed at investigating the potential effects of melatonin on the prevention of CisIN in human.Experimental approach:Our study was a randomized controlled clinical trial, performed on 66 eligible patients in two groups of melatonin or control (no intervention). Melatonin was administrated daily at a dose of 20 mg for 5 days to the patients receiving cisplatin-containing regimens along with the standard protocol of CisIN prevention. Patient demographic information, blood and urinary indices of nitrogen, creatinine, and electrolytes such as sodium, potassium, magnesium as well as neutrophil gelatinase-associated lipocalin were measured in both groups at the baseline, 24 h and five days after melatonin administration.Findings/Results:Cisplatin administration resulted in significant magnesium and potassium loss in patients with cancer. In comparison with the control group, the prevalence of acute renal injury and the rate of urinary magnesium and potassium loss improved with melatonin administration; however, the results were not statistically significant. Tolerable side effects such as daytime drowsiness, nausea, and vomiting were reported in the melatonin group.Conclusion and implications:Although pretreatment with melatonin led to amelioration in urinary electrolyte loss due to CisIN, it failed to show a positive result on acute renal injury prevention. Future well-designed studies with a longer duration of follow-up, larger sample sizes, and higher doses of melatonin are warranted.