scholarly journals Evaluating Calibration and Spectral Variable Selection Methods for Predicting Three Soil Nutrients Using Vis-NIR Spectroscopy

2021 ◽  
Vol 13 (19) ◽  
pp. 4000
Author(s):  
Peng Guo ◽  
Ting Li ◽  
Han Gao ◽  
Xiuwan Chen ◽  
Yifeng Cui ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Variable Selection ◽  
Soil Nutrients ◽  
Soil Nutrient ◽  
Nutrient Content ◽  
Support Vector ◽  
Selection Methods ◽  
Calibration Methods ◽  
Soil Nutrient Content

Soil nutrients, including soil available potassium (SAK), soil available phosphorous (SAP), and soil organic matter (SOM), play an important role in farmland soil productivity, food security, and agricultural management. Spectroscopic analysis has proven to be a rapid, nondestructive, and effective technique for predicting soil properties in general and potassium, phosphorous, and organic matter in particular. However, the successful estimation of soil nutrient content by visible and near-infrared (Vis-NIR) reflectance spectroscopy depends on proper calibration methods (including preprocessing transformation methods and multivariate methods for regression analysis) and the selection of appropriate variable selection techniques. In this study, raw spectrum and 13 preprocessing transformations combined with 2 variable selection methods (competitive adaptive reweighted sampling (CARS) and the successive projections algorithm (SPA)) and 2 regression algorithms (support vector machine (SVM) and partial least squares regression (PLSR)), for a total of 56 calibration methods, were investigated for modeling and predicting the above three soil nutrients using hyperspectral Vis-NIR data (400–2450 nm). The results show that first-order derivatives based on logarithmic and inverse transformations (FD-LGRs) can provide better predictions of soil available potassium and phosphorous, and the best form of soil organic matter transformation is SG+MSC. CARS was superior to the SPA in selecting effective variables, and the PLSR model outperformed the SVM models. The best estimation accuracies (R2, RMSE) for soil available potassium, phosphorous, and organic matter were 0.7532, 32.3090 mg/kg; 0.7440, 6.6910 mg/kg; and 0.9009, 3.2103 g/kg, respectively, and their corresponding calibration methods were (FD-LGR)/SPA/PLSR, (FD-LGR)/SPA/PLSR, and SG+MSC/CARS/SVM, respectively. Overall, for the prediction of the soil nutrient content, organic matter was superior to available phosphorous, followed by available potassium. It was concluded that the application of hyperspectral images (Vis-NIR data) was an efficient method for mapping and monitoring soil nutrients at the regional scale, thus contributing to the development of precision agriculture.

scholarly journals Estimation of Soil Nutrient Content Using Hyperspectral Data

Agriculture ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1129
Author(s):  
Yiping Peng ◽  
Lu Wang ◽  
Li Zhao ◽  
Zhenhua Liu ◽  
Chenjie Lin ◽  
...  
Keyword(s):  
Least Squares ◽  
Soil Nutrients ◽  
Cross Validation ◽  
Regional Scale ◽  
Soil Nutrient ◽  
Nutrient Content ◽  
New Method ◽  
Accurate Estimation ◽  
Support Vector ◽  
Soil Nutrient Content

Soil nutrients play a vital role in plant growth and thus the rapid acquisition of soil nutrient content is of great significance for agricultural sustainable development. Hyperspectral remote-sensing techniques allow for the quick monitoring of soil nutrients. However, at present, obtaining accurate estimates proves to be difficult due to the weak spectral features of soil nutrients and the low accuracy of soil nutrient estimation models. This study proposed a new method to improve soil nutrient estimation. Firstly, for obtaining characteristic variables, we employed partial least squares regression (PLSR) fit degree to select an optimal screening algorithm from three algorithms (Pearson correlation coefficient, PCC; least absolute shrinkage and selection operator, LASSO; and gradient boosting decision tree, GBDT). Secondly, linear (multi-linear regression, MLR; ridge regression, RR) and nonlinear (support vector machine, SVM; and back propagation neural network with genetic algorithm optimization, GABP) algorithms with 10-fold cross-validation were implemented to determine the most accurate model for estimating soil total nitrogen (TN), total phosphorus (TP), and total potassium (TK) contents. Finally, the new method was used to map the soil TK content at a regional scale using the soil component spectral variables retrieved by the fully constrained least squares (FCLS) method based on an image from the HuanJing-1A Hyperspectral Imager (HJ-1A HSI) of the Conghua District of Guangzhou, China. The results identified the GBDT-GABP was observed as the most accurate estimation method of soil TN ( of 0.69, the root mean square error of cross-validation (RMSECV) of 0.35 g kg−1 and ratio of performance to interquartile range (RPIQ) of 2.03) and TP ( of 0.73, RMSECV of 0.30 g kg−1 and RPIQ = 2.10), and the LASSO-GABP proved to be optimal for soil TK estimations ( of 0.82, RMSECV of 3.39 g kg−1 and RPIQ = 3.57). Additionally, the highly accurate LASSO-GABP-estimated soil TK (R2 = 0.79) reveals the feasibility of the LASSO-GABP method to retrieve soil TK content at the regional scale.

Analysis of Soil Nutrient Content Characteristic for Inductive Transformed Low-Quality Forest in Greater Higgnan Mountains

2011 ◽  
Vol 361-363 ◽  
pp. 1765-1771
Author(s):  
Hao Ji ◽  
Xi Bin Dong
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Matter Content ◽  
Soil Nutrient ◽  
Nutrient Content ◽  
Potassium Content ◽  
Korean Pine ◽  
Forest Gap ◽  
Clear Cutting ◽  
Soil Nutrient Content

In This paper, the miscellaneous tree low-quality forest and Oak low-quality forest in the Greater Hinggan Mountains region were transformed inductively by planting Siberian Korean pine, Mongolica, and Larch, respectively. With the method of using different bandwidth and gap area, the soil nutrient characteristics were changed. The results indicated that the pH of soil increased slightly by different ways of induced transformation, but the variance was not significant (P﹤0.05). After reforming the induced soil organic matter content was balanced, while the basic content of hydrolysable nitrogen increased, and the availiable phosphorus decreased. Soil rapidly-available potassium content in Oak coppice was reduced but raised in the region of secondary performed miscellaneous wood. The variation coefficient of Siberia Korean pine was the largest with different soil pH value of various bandwidth and soil nutrient content (except for availiable phosphorus). Content of soil organic matter and hydrolysis nitrogen, phosphorus and potassium content are significantly positive correlated. At the same time, clear-cutting bandwidth and soil organic matter and hydrolysis nitrogen content are significantly negative correlated. During the transformation of forest gap in the sunny and shady slope, smaller area of forest gap owed the larger soil nutrient content. Generally, soil nutrient content in sunny slope is higher than the shady one.

scholarly journals Assessment of Potato Farmland Soil Nutrient Based on MDS-SQI Model in the Loess Plateau

2021 ◽  
Vol 13 (7) ◽  
pp. 3957
Author(s):  
Yingying Xing ◽  
Ning Wang ◽  
Xiaoli Niu ◽  
Wenting Jiang ◽  
Xiukang Wang
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Fertility ◽  
Soil Quality ◽  
Soil Nutrients ◽  
Organic Matter Content ◽  
Soil Nutrient ◽  
Matter Content ◽  
Soil Organic Matter Content ◽  
Farmland Soil

Soil nutrients are essential nutrients provided by soil for plant growth. Most researchers focus on the coupling effect of nutrients with potato yield and quality. There are few studies on the evaluation of soil nutrients in potato fields. The purpose of this study is to investigate the soil nutrients of potato farmland and the soil vertical nutrient distributions, and then to provide a theoretical and experimental basis for the fertilizer management practices for potatoes in Loess Plateau. Eight physical and chemical soil indexes were selected in the study area, and 810 farmland soil samples from the potato agriculture product areas were analyzed in Northern Shaanxi. The paper established the minimum data set (MDS) for the quality diagnosis of the cultivated layer for farmland by principal component analysis (PCA), respectively, and furthermore, analyzed the soil nutrient characteristics of the cultivated layer adopted soil quality index (SQI). The results showed that the MDS on soil quality diagnosis of the cultivated layer for farmland soil included such indicators as the soil organic matter content, soil available potassium content, and soil available phosphorus content. The comprehensive index value of the soil quality was between 0.064 and 0.302. The SPSS average clustering process used to classify SQI was divided into three grades: class I (36.2%) was defined as suitable soil fertility (SQI < 0.122), class II (55.6%) was defined as moderate soil fertility (0.122 < SQI < 0.18), and class III (8.2%) was defined as poor soil fertility (SQI > 0.186). The comprehensive quality of the potato farmland soils was generally low. The proportion of soil nutrients in the SQI composition ranged from large to small as the soil available potassium content = soil available phosphorus content > soil organic matter content, which became the limiting factor of the soil organic matter content in this area. This study revolves around the 0 to 60 cm soil layer; the soil fertility decreased gradually with the soil depth, and had significant differences between the respective soil layers. In order to improve the soil nutrient accumulation and potato yield in potato farmland in northern Shaanxi, it is suggested to increase the fertilization depth (20 to 40 cm) and further study the ratio of nitrogen, phosphorus, and potassium fertilizer.

scholarly journals Effects of Two Trichoderma Strains on Plant Growth, Rhizosphere Soil Nutrients, and Fungal Community of Pinus sylvestris var. mongolica Annual Seedlings

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 758 ◽  
Author(s):  
Saiyaremu Halifu ◽  
Xun Deng ◽  
Xiaoshuang Song ◽  
Ruiqing Song
Keyword(s):  
Enzyme Activity ◽  
Community Structure ◽  
Plant Growth ◽  
Soil Nutrients ◽  
Fungal Community ◽  
Rhizosphere Soil ◽  
Soil Nutrient ◽  
Nutrient Content ◽  
Root Structure ◽  
Soil Nutrient Content

Trichoderma spp. are proposed as major plant growth-promoting fungi that widely exist in the natural environment. These strains have the abilities of rapid growth and reproduction and efficient transformation of soil nutrients. Moreover, they can change the plant rhizosphere soil environment and promote plant growth. Pinus sylvestris var. mongolica has the characteristics of strong drought resistance and fast growth and plays an important role in ecological construction and environmental restoration. The effects on the growth of annual seedlings, root structure, rhizosphere soil nutrients, enzyme activity, and fungal community structure of P. sylvestris var. mongolica were studied after inoculation with Trichoderma harzianum E15 and Trichoderma virens ZT05, separately. The results showed that after inoculation with T. harzianum E15 and T. virens ZT05, seedling biomass, root structure index, soil nutrients, and soil enzyme activity were significantly increased compared with the control (p < 0.05). There were significant differences in the effects of T. harzianum E15 and T. virens ZT05 inoculation on the growth and rhizosphere soil nutrient of P. sylvestris var. mongolica (p < 0.05). For the E15 treatment, the seedling height, ground diameter, and total biomass of seedlings were higher than that those of the ZT05 treatment, and the rhizosphere soil nutrient content and enzyme activity of the ZT05 treatment were higher than that of the E15 treatment. The results of alpha and beta diversity analyses showed that the fungi community structure of rhizosphere soil was significantly different (p < 0.05) among the three treatments (inoculated with T. harzianum E15, T. virens ZT05, and not inoculated with Trichoderma). Overall, Trichoderma inoculation was correlated with the change of rhizosphere soil nutrient content.

Effect of density of Tephrosia candida stands on soil characteristics

2016 ◽  
Author(s):  
Zhiyang Lie ◽  
Zhuomin Wang ◽  
Li Xue
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Ph Value ◽  
Soil Nutrient ◽  
Stand Density ◽  
Nutrient Content ◽  
Total N ◽  
One Year ◽  
Tephrosia Candida ◽  
Total P

With one-year-old Tephrosia candida trees as experimental material, influence of stand density on soil nutrient content and enzyme activity was studied. The results showed that density had little influenced on pH value in 2, 4 and 8 trees m2 stands. The contents of soil organic matter, effective nitrogen and effective phosphorus significantly increased in 2 trees m2 stands. The contents of soil organic matter and effective nitrogen significantly increased, whereas total N, total P, total K, effective N, effective P and effective K significantly decreased in 4 trees/m2 stand. Soil organic matter and nutrients except for total P significantly decreased in 8 trees m2 stand. Among the three density stands, the activities of urease, catalase and phosphatase were the lowest in 8 trees m2 stand.

scholarly journals A Smart Agriculture System Based On Intel Galileo For Detection Of Cultivable Crops And Implemented On Soil Nutrients

2019 ◽  
Vol 8 (9) ◽  
pp. 98-102
Keyword(s):  
Soil Nutrients ◽  
Soil Nutrient ◽  
Nutrient Content ◽  
Ph Sensors ◽  
Food Grains ◽  
The World ◽  
Current Scenario ◽  
Soil Nutrient Content ◽  
Smart Agriculture ◽  
Intel Galileo

The world is in need of food, water, Shelter and without any of these there is no possibility to live. Agriculture is backbone of our nation which indeed supplies food for the entire people but the producers of food are facing many problems like moisture content, fertility of soil which affects the farming. Because of this reason cultivation and production of food grains are decreased. Current scenario is that the farmers need to go research center to test the fertility content of soil and to predict kind of plants can be cultivable in that land. In this paper perfect cultivable plants can be detected properly without approaching soil research centers which consumes more money as well time. By the application of pH sensors the fertility of soil can be measured. By measuring the pH soil nutrient content can be measured and so the suitable cultivable crop for different soil varieties can be predicted. In this view to give a healthful support to farmers, soil nutrients are analyzed and report the requirement using advanced sensors.

scholarly journals Germplasm Screening of Green Manure Rapeseed through the Effects of Short-Term Decomposition on Soil Nutrients and Microorganisms

Agriculture ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1219
Author(s):  
Xiaodan Wang ◽  
Hua Ma ◽  
Chunyun Guan ◽  
Mei Guan
Keyword(s):  
Soil Nutrients ◽  
Green Manure ◽  
Soil Microorganisms ◽  
Soil Nutrient ◽  
Principal Component ◽  
Nutrient Content ◽  
Germplasm Screening ◽  
Significant Difference ◽  
Soil Nutrient Content ◽  
Phosphorus And Potassium

The rapidly emerging fertilizer rapeseed used as green manure has wide applications for use. However, there have been few studies on its decomposition and effects on soil nutrients and microorganisms after its decay. In this study, 12 rapeseed lines to be screened were decomposed through a randomized block field design with two green-manure-specific varieties as the controls. The contents of nitrogen, phosphorus, and potassium from the plants, soil nutrients, and microbial changes after degradation were measured. There were substantial differences in the rates of decomposition and cumulative release of nutrients among the different lines after 30 days of rolling. The contents of phosphorus and potassium in the soil were 1.23–2.03 and 3.93–6.32 times those before decomposition, respectively. In addition, there was a significant difference in the relative content of soil microorganisms at the phylum level after the decomposition of different species of rapeseeds. Most of the top 20 bacterial groups significantly correlated with the characteristics of plant decomposition and soil nutrient content, including Proteobacteria, Actinomycetes, Armatimonadetes, Rokubacteria, and Planctomycetes. A principal component analysis showed that the soil microorganisms and nutrients are the leading factors that enable the evaluation of the decomposing characteristics of green manure rapeseed. Numbers 5 (purple leaf mustard) and 8 (Xiafang self-seeding) were more effective than two controls, which can be used as excellent types of germplasm to promote the breeding of green manure rapeseed.

scholarly journals Soil nutrient evolution under different vegetation types in semiarid loess area

2021 ◽  
pp. 969-976
Author(s):  
Lirong He ◽  
Yuhu Luo
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Nutrients ◽  
Total Nitrogen ◽  
Organic Fertilizer ◽  
Nutrient Balance ◽  
Soil Nutrient ◽  
Available Phosphorus ◽  
Vegetation Types ◽  
Nitrogen And Phosphorus

The soil nutrient characteristics under three vegetation types of arbor ( I ), shrub ( II ) and herb ( III ) were studied by mathematical statistics method combined with field investigation and indoor detection analysis. The change characteristics of soil nutrients under different land use patterns were discussed. The results showed that the average contents of soil organic matter, total nitrogen, available phosphorus and available potassium were 21.30 and 0.65 g/kg, 3.67 and 67.61 mg/kg, respectively. Compared with grassland, woodland has better effect on fertilizer conservation in the Loess Plateau. In the process of soil nutrient improvement, the nutrient indexes such as organic matter, total nitrogen, available phosphorus and available potassium increased synchronously, and the soil alkaline environment that was not conducive to plant growth was also gradually improved. In the correlation between soil nutrients, available phosphorus and available potassium have good relative independence. In the future, organic fertilizer should be applied in this area, and nitrogen and phosphorus fertilizers should be supplemented to improve soil organic matter, nitrogen and phosphorus content, and to ensure soil nutrient balance by optimizing fertilization methods. In addition, in the case of uneven distribution of soil nutrients in the soil profile, it is recommended to take appropriate soil ploughing and reasonable human management measures to improve soil nutrient status, achieve high-quality sustainable development of soil, and promote the positive succession of vegetation communities. Bangladesh J. Bot. 50(3): 969-976, 2021 (September) Special

scholarly journals EVALUATION OF SOIL NUTRIENT STATUS IN APPLE ORCHARDS LOCATED IN DIFFERENT ALTITUDES IN KALIKOT DISTRICT, NEPAL

2021 ◽  
Vol 5 (2) ◽  
pp. 99-103
Author(s):  
Dhruba Baral ◽  
Anup Paudel ◽  
Himal Acharya ◽  
Madhav Prasad Neupane
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Nutrients ◽  
Soil Depth ◽  
Block Design ◽  
Soil Nutrient ◽  
Soil Samples ◽  
Apple Orchards ◽  
Nitrogen And Phosphorus ◽  
Poor Soil

This study was conducted to assess the fertility status of different altitude of apple orchard and their effect upon soil nutrients and to study the relationship between different altitude and their availability. Seven different orchards located in 2800, 2700 2600, 2500, 2400, 2300 and 2200 at Apple Zone, Raskot, Kalikot were selected as treatments. They were replicated three times in Randomized Complete Block Design. Composite soil samples were collected in each study site from 0-3 ft soil depth in ‘W’ pattern from each plot. Analyses of soil samples were done in regional soil testing laboratory, Surkhet for chemical properties. There was a significant effect (p<0.05) of altitude on soil macronutrients except available potassium level. Maximum amounts of soil organic matter, acidic and soil rich in nitrogen and phosphorus were found in 2800 masl whereas more basic soil , poor soil organic matter and soil poor in nitrogen and phosphorus were found in 2200 masl. Result showed that in altitude of 2200 masl has poor soil nutrients compared to apple orchards in higher altitude. Kalikot is the top producer of apple in Nepal. This assessment will helps apple growers for adopting better nutrient management plan in their orchards according to the altitude in the district. Further, it is recommended to conduct soil nutrient assessments for all other apple growing regions in the country.

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