scholarly journals Optimization of the sampling scheme for maps of physical and chemical properties estimated by kriging

2013 ◽  
Vol 37 (5) ◽  
pp. 1128-1135 ◽  
Author(s):  
Gener Tadeu Pereira ◽  
Zigomar Menezes de Souza ◽  
Daniel De Bortoli Teixeira ◽  
Rafael Montanari ◽  
José Marques Júnior

The sampling scheme is essential in the investigation of the spatial variability of soil properties in Soil Science studies. The high costs of sampling schemes optimized with additional sampling points for each physical and chemical soil property, prevent their use in precision agriculture. The purpose of this study was to obtain an optimal sampling scheme for physical and chemical property sets and investigate its effect on the quality of soil sampling. Soil was sampled on a 42-ha area, with 206 geo-referenced points arranged in a regular grid spaced 50 m from each other, in a depth range of 0.00-0.20 m. In order to obtain an optimal sampling scheme for every physical and chemical property, a sample grid, a medium-scale variogram and the extended Spatial Simulated Annealing (SSA) method were used to minimize kriging variance. The optimization procedure was validated by constructing maps of relative improvement comparing the sample configuration before and after the process. A greater concentration of recommended points in specific areas (NW-SE direction) was observed, which also reflects a greater estimate variance at these locations. The addition of optimal samples, for specific regions, increased the accuracy up to 2 % for chemical and 1 % for physical properties. The use of a sample grid and medium-scale variogram, as previous information for the conception of additional sampling schemes, was very promising to determine the locations of these additional points for all physical and chemical soil properties, enhancing the accuracy of kriging estimates of the physical-chemical properties.

Author(s):  
Marcos Renan Besen ◽  
Michel Esper Neto ◽  
Bruno Maia Abdo Rahmen Cassim ◽  
Evandro Antonio Minato ◽  
Tadeu Takeyoshi Inoue ◽  
...  

2021 ◽  
Vol 13 (7) ◽  
pp. 3617
Author(s):  
Agnieszka Medyńska-Juraszek ◽  
Agnieszka Latawiec ◽  
Jolanta Królczyk ◽  
Adam Bogacz ◽  
Dorota Kawałko ◽  
...  

Biochar application is reported as a method for improving physical and chemical soil properties, with a still questionable impact on the crop yields and quality. Plant productivity can be affected by biochar properties and soil conditions. High efficiency of biochar application was reported many times for plant cultivation in tropical and arid climates; however, the knowledge of how the biochar affects soils in temperate climate zones exhibiting different properties is still limited. Therefore, a three-year-long field experiment was conducted on a loamy Haplic Luvisol, a common arable soil in Central Europe, to extend the laboratory-scale experiments on biochar effectiveness. A low-temperature pinewood biochar was applied at the rate of 50 t h−1, and maize was selected as a tested crop. Biochar application did not significantly impact the chemical soil properties and fertility of tested soil. However, biochar improved soil physical properties and water retention, reducing plant water stress during hot dry summers, and thus resulting in better maize growth and higher yields. Limited influence of the low-temperature biochar on soil properties suggests the crucial importance of biochar-production technology and biochar properties on the effectiveness and validity of its application in agriculture.


Author(s):  
Vítězslav Vlček ◽  
Miroslav Pohanka

Soil samples (n = 11) were collected in the chernozem areas of the Czech Republic (the Central Europe) from the topsoil and used as representative samples. All sampling areas have been used for agricultural purposes (arable soil) and they were selected as typical representatives of agricultural soil. These samples represented the soil with same genesis (to reduction differencies between soil types) but with different soil properties (physical and chemical). Complete chemical and physical analyses were made for confirmation of copper adsorption on solid phase: we analysed the particle size distribution, content of oxidizable carbon (Cox), the cation exchange capacity (CEC), supply of exchange calcium, magnesium, sodium, phosphorus and potassium, soil reaction and the total supply of Fe, Al, Mn, Ca, Mg, K, P and N. The strongest simple correlation between analysed soil properties and copper concentration had content of available magnesium (r = 0.44) and available phosphorus (r = −0.51). In the case of multiple correlations (i. e. collective influence of multiple soil properties) had the strongest influence combination of clay, soil reaction, total content of phosphorus, available magnesium and available phosphorus. The main influence of phosphorus and magnesium is evident. We suppose that copper and phosphorus enter into specific complex. Influence of these five soil properties can explain 92.7 % (r = 0.927) changes in the content of copper changes in the experiment.


2020 ◽  
Vol 12 (11) ◽  
pp. 4384
Author(s):  
Prapasiri Tongsiri ◽  
Wen-Yu Tseng ◽  
Yuan Shen ◽  
Hung-Yu Lai

The soil properties, climate, type of management, and fermentation process critically affect the productivity and quality of tea. In this study, tender tea leaves were collected from central Taiwan, and organic components in their infusions as well as physical and chemical soil properties differentiated using aerial photographs where good (G) and bad (B) growth exhibitions were determined. Eleven physical and chemical soil properties as well as five compounds in tea infusions were analyzed to determine the main factor that affects the growth of these tea trees. The Fleiss’ kappa statistic results revealed that the wet aggregate stability, pH, and exchangeable potassium content exhibit the most significant effect, with scores of 0.86, 0.64, and 0.62, respectively. Soil quality calculated using the mean weight diameter based on 11 soil properties revealed that ~67% of the total score of G is greater than that of B. Generally, contents of total polyphenols (51.67%) and catechins (51.76%) in the infusions of B were greater than those of G. In addition, significant positive correlations between the free amino acids content and soil properties, including pH and copper content, were observed. However, a negative correlation between the free amino acids and flavone contents and most of the soil properties was observed. The survey data set obtained from this study can provide useful information for the improved management of tea plantations.


2006 ◽  
Vol 1 (1) ◽  
pp. 23 ◽  
Author(s):  
Paolo Bazzoffi ◽  
Sergio Pellegrini ◽  
Andrea Rocchini

1966 ◽  
Vol 46 (2) ◽  
pp. 155-160 ◽  
Author(s):  
G. R. Saini ◽  
A. A. MacLean ◽  
J. J. Doyle

The relationship of the mean weight diameter of water-stable aggregates to certain soil properties (clay, organic matter, free iron, free aluminum, and polysaccharide contents) and the relationship of the increase in aggregation caused by VAMA to the same properties of 24 New Brunswick soils were evaluated by correlation and regression analyses.Simple correlation coefficients relating aggregation to soil properties indicated that organic matter (r = 0.627), polysaccharides (r = 0.602), and aluminum (r = 0.679) were the most important factors. However, when the influence of each factor was separated by partial correlation, the coefficients were not significant. On the other hand, the combined effects of all factors as indicated by the multiple correlation coefficient (r = 0.743) was significant at the 1% level. The effect of the same soil properties on response to VAMA, as shown by increase in mean weight diameter, indicated that clay exerted the greatest influence. The relationship with other factors was nonsignificant.


2010 ◽  
Vol 87 (3) ◽  
pp. 457-461 ◽  
Author(s):  
Thomas Oszinda ◽  
Matthias Schaller ◽  
Daniel Fischer ◽  
Christine Walsh ◽  
Stefan E. Schulz

2004 ◽  
Vol 44 (12) ◽  
pp. 1241 ◽  
Author(s):  
W. E. Cotching ◽  
L. A. Sparrow ◽  
K. Hawkins ◽  
B. E. McCorkell ◽  
W. Rowley

Selected soil properties and paddock management characteristics were measured for 121 potato and poppy crops in north and northwest Tasmania to see if variation in these characteristics explain variation in crop yield. The soil properties we selected were those that previous work found had changed the most as a result of cropping and, therefore, may be affecting yield on the particular soil type. The soil properties and management characteristics that were significantly correlated with crop yield varied with crop and soil type. None of the soil characters had correlation coefficients greater than 0.63, probably reflecting the capacity of individual farmers to overcome particular soil limitations through their management of tillage, nutrition, irrigation, weeds and pathogens. On ferrosols, a visual score of soil structure was significantly correlated with potato yield (r = 0.57) and exchangeable aluminium was significantly correlated with poppy yield (r = 0.63). Exchangeable calcium (r = 0.54) and penetration resistance (r = 0.38) correlated positively and topdressed nitrogen (r = –0.49) correlated negatively with poppy alkaloid assay, an important determinant of overall poppy yield. On dermosols, depth to 2000 kPa penetration resistance (r = 0.60) and fertiliser P (r = –0.67) were correlated with potato yield, structure score correlated with poppy yield (r = 0.59), and penetration resistance with poppy assay (r = 0.52). On sodosols, fertiliser K (r = –0.41 and r = 0.55) and N (r = –0.45 and 0.42) correlated negatively with poppy yield and positively with poppy assay. On clay loam soils such as dermosols and ferrosols, increased topsoil cloddiness appears to be having a deleterious effect on crop yield. Cloddiness is readily assessed on these soils using the structure scorecard, which could therefore become a practical diagnostic test for farmers and advisers.


1969 ◽  
Vol 52 (4) ◽  
pp. 269-280 ◽  
Author(s):  
L. C. Liu ◽  
H. Cibes Viadé

Thirteen soils representing a wide range of physical and chemical properties were used in this study. Four herbicides including Atrazine, Ametryne, Prometryne, and Diuron were applied at a concentration series from 0.5 to 32 p.p.m. to each soil, with the exception of Caño Tiburones soil. Kanota oat (Avena sativa L.) was chosen as an indicator plant. ED50  values were obtained for the various soil types. The result indicated that ED50  values varied greatly with different soil types. Simple, partial, and multiple correlations were made among ED50  values and different soil properties. It was found that the organic matter was the major soil property which contributed chiefly to the phytotoxicity of herbicides. A theoretical relationship between percent soil organic matter and p.p.m.w. of herbicides required for 50-percent fresh-weight reduction of oat was obtained for herbicide dosage-prediction purpose.


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