scholarly journals Analysis of the spatial variability of crop yield and soil properties in small agricultural plots

Bragantia ◽  
2003 ◽  
Vol 62 (1) ◽  
pp. 127-138 ◽  
Author(s):  
Sidney Rosa Vieira ◽  
Antonio Paz Gonzalez
Keyword(s):  
Spatial Variability ◽  
Soil Properties ◽  
Crop Yield ◽  
Kriging Interpolation ◽  
Climate Conditions ◽  
Factors Affecting ◽  
Semivariogram Analysis ◽  
Map Generation ◽  
Crop Cycle ◽  
One Year

The objective of this study was to assess spatial variability of soil properties and crop yield under no tillage as a function of time, in two soil/climate conditions in São Paulo State, Brazil. The two sites measured approximately one hectare each and were cultivated with crop sequences which included corn, soybean, cotton, oats, black oats, wheat, rye, rice and green manure. Soil fertility, soil physical properties and crop yield were measured in a 10-m grid. The soils were a Dusky Red Latossol (Oxisol) and a Red Yellow Latossol (Ultisol). Soil sampling was performed in each field every two years after harvesting of the summer crop. Crop yield was measured at the end of each crop cycle, in 2 x 2.5 m sub plots. Data were analysed using semivariogram analysis and kriging interpolation for contour map generation. Yield maps were constructed in order to visually compare the variability of yields, the variability of the yield components and related soil properties. The results show that the factors affecting the variability of crop yield varies from one crop to another. The changes in yield from one year to another suggest that the causes of variability may change with time. The changes with time for the cross semivariogram between phosphorus in leaves and soybean yield is another evidence of this result.

scholarly journals Spatial variability of soil fertility and its relation with cocoa yield

2017 ◽  
Vol 21 (2) ◽  
pp. 88-93 ◽  
Author(s):  
Railton O. dos Santos ◽  
◽  
Laís B. Franco ◽  
Samuel A. Silva ◽  
George A. Sodré ◽  
...  
Keyword(s):  
Decision Making ◽  
Fuzzy Logic ◽  
Spatial Variability ◽  
Soil Fertility ◽  
Soil Properties ◽  
Crop Yield ◽  
Chemical Properties ◽  
Western Region ◽  
Chemical Attributes ◽  
Cocoa Yield

ABSTRACT The knowledge on the spatial variability of soil properties and crops is important for decision-making on agricultural management. The objective of this study was to evaluate the spatial variability of soil fertility and its relation with cocoa yield. The study was conducted over 14 months in an area cultivated with cocoa. A sampling grid was created to study soil chemical properties and cocoa yield (stratified in season, off-season and annual). The data were analyzed using descriptive and exploratory statistics, and geostatistics. The chemical attributes were classified using fuzzy logic to generate a soil fertility map, which was correlated with maps of crop yield. The soil of the area, except for the western region, showed possibilities ranging from medium to high for cocoa cultivation. Soil fertility showed positive spatial correlation with cocoa yield, and its effect was predominant only for the off-season and annual cocoa.

scholarly journals Quantifying individual and collective influences of soil properties on crop yield

Soil Research ◽  
2018 ◽  
Vol 56 (1) ◽  
pp. 19 ◽  
Author(s):  
Rebecca Whetton ◽  
Yifan Zhao ◽  
Abdul M. Mouazen
Keyword(s):  
Soil Properties ◽  
Crop Yield ◽  
Near Infrared ◽  
Wheat Yield ◽  
Exchange Capacity ◽  
Large Area ◽  
High Resolution Data ◽  
Factors Affecting ◽  
Single Output ◽  
Non Linear

Quantification of the agronomic influences of soil properties, collected at high sampling resolution, on crop yield is essential for site specific soil management. The objective of this study was to implement a novel Volterra Non-linear Regressive with eXogenous inputs (VNRX) model accounting for the linear and non-linear variability (VNRX-LN) to quantify causal factors affecting wheat yield in a 22-ha field with a waterlogging problem in Bedfordshire, UK. The VNRX-LN model was applied using high-resolution data of eight key soil properties (total nitrogen (TN), organic carbon, pH, available phosphorous, magnesium (Mg), calcium, moisture content and cation exchange capacity (CEC)). The data were collected with an on-line (tractor mounted) visible and near infrared spectroscopy sensor and used as multiple-input to the VNRX-LN model, whereas crop yield represented the single-output in the system. Results showed that the largest contributors to wheat yield were CEC, Mg and TN, with error reduction ratio contribution values of 14.6%, 4.69% and 1% respectively. The overall contribution of the soil properties considered in this study equalled 23.21%. This was attributed to a large area of the studied field having been waterlogged, which masked the actual effect of soil properties on crop yield. It is recommended that VNRX-LN is validated on a larger number of fields, where other crop yield affecting parameters e.g., crop disease, pests, drainage, topography and microclimate conditions should be taken into account.

scholarly journals Spatial Variability and Geostatistical Analysis of Soil Properties in the Diversified Cropping Regions of Bangladesh Using Geographic Information System Techniques

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Md. Zulfikar Khan ◽  
Md. Rafikul Islam ◽  
Ahmed Bin Abdus Salam ◽  
Tama Ray
Keyword(s):  
Spatial Variability ◽  
Soil Properties ◽  
Nutrient Management ◽  
Sampling Site ◽  
Geostatistical Analysis ◽  
Kriging Interpolation ◽  
Total N ◽  
Study Region ◽  
Site Specific ◽  
Classical Statistics

Mapping of soil properties is an important operation as it plays an important role in the knowledge about soil properties and how it can be used sustainably. The study was carried out in a local government area in Bangladesh in order to map out some soil properties and assess their variability within the area. From the study area, a total of 92 soil samples (0–20 cm) were collected from different cropping patterns at an interval of 2.2 × 2.2 km2 on a regular grid design. A portable global positioning system (GPS) was used to collect coordinates of each sampling site. Then, soil properties, that is, pH, electrical conductivity (EC), soil organic carbon (SOC), total nitrogen (Total N), and soil available nutrients (P, K, and S) were measured in the laboratory. After the normalization of data, classical statistics were used to describe the soil properties, and geostatistical analysis was used to illustrate the spatial variability of the soil properties by using kriging interpolation techniques in a GIS environment. Results show that the spatial distribution and spatial dependency level of soil properties can be different even within the small or large scale. According to cross-validation results, for most soil properties, the kriging interpolation method provided the least interpolation error. The generated maps of soil properties that indicate soil nutrient status over the study region could be helpful for farmers and decision-makers to enhance site-specific nutrient management. Also, these prototype maps would be helpful for future nutrient and fertilizer applications management, including a site-specific condition to not only reduce the cost of input management but also prevent any environmental hazard. It also demonstrates that the effectiveness of geostatistics and GIS techniques provided a powerful tool for this study in terms of regionalized nutrient management.

scholarly journals Seasonal variation in the phenol content of Eugenia uniflora L. leaves

2011 ◽  
Vol 13 (1) ◽  
pp. 85-89
Author(s):  
R.M Santos ◽  
M.S Oliveira ◽  
P.H Ferri ◽  
S.C Santos
Keyword(s):  
Principal Component ◽  
Climatic Changes ◽  
Total Phenols ◽  
Chemometric Methods ◽  
Phenol Content ◽  
Climate Conditions ◽  
Factors Affecting ◽  
Eugenia Uniflora ◽  
Hydrolysable Tannins ◽  
One Year

Hydrolysable tannins, total phenols and flavonoids in Eugenia uniflora leaves were monthly analysed for one year. The results were correlated with climate conditions (rainfall, humidity, cloudiness and mean temperature) through chemometric methods. Principal component analysis revealed high levels of hydrolysable tannins in the rainy season, whereas flavonoids were mainly produced in the dry season. These facts suggest that climatic changes may be one of the factors affecting phenol levels in Eugenia uniflora.

Spatial variability of some chemical properties of a Cambisol soil with cocoa (Theobroma cacao L.) cultivation

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Sergio Salgado García ◽  
Joana Acopa Colorado ◽  
Sergio Salgado-Velázquez ◽  
Samuel Córdova Sánchez ◽  
David Palma López ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Soil Properties ◽  
Spatial Dependence ◽  
Chemical Properties ◽  
Kriging Interpolation ◽  
Management Zones ◽  
Agronomic Management ◽  
Management Area ◽  
Theobroma Cacao L ◽  
Exchangeable P

Objective: To evaluate the spatial variability of some chemical properties of a Cambisolsoil, in order to establish specific agronomic management zones for cocoa cultivation.Methodology: A sampling of 42 georeferenced points equidistant at 40 m was carriedout. Geostatistical variability maps were made with the results of the chemical analysisof the soil properties, using the ordinary Kriging interpolation technique.Results: It was found that the percentage of saturation of acidity (PSA), acidity and H+showed high variability; P-Olsen and interchangeable K, Ca and Mg displayed mediumvariability, and pH, MO, CIC and Al presented low variability. Soil properties pH, PSA;Exchangeable P-Olsen, Ca and Mg showed high spatial dependence (<25%) and OM,exchangeable K and CIC moderate spatial dependence (25-75%).Study limitations / Implications: The generated maps allowed the identification ofpartial areas with different variability, as well as the direction of greatest variability of theproperty as a function of distance.Conclusions: With the maps, it was possible to make recommendations for agronomicmanagement depending on each specific management area.

Effect of Slope Mesorelief on the Spatial Variability of Soil Properties and Vegetation Index Based on Remote Sensing Data

2019 ◽  
Vol 55 (9) ◽  
pp. 1329-1337
Author(s):  
N. V. Gopp ◽  
T. V. Nechaeva ◽  
O. A. Savenkov ◽  
N. V. Smirnova ◽  
V. V. Smirnov
Keyword(s):  
Remote Sensing ◽  
Spatial Variability ◽  
Soil Properties ◽  
Vegetation Index ◽  
Remote Sensing Data ◽  
Sensing Data

Spatial Variability of Rainfed Wheat Production Under the Influence of Topography and Soil Properties in Loess-Derived Soils, Northern Iran

2020 ◽  
Vol 14 (4) ◽  
pp. 597-608
Author(s):  
Mohammad Ajami ◽  
Ahmad Heidari ◽  
Farhad Khormali ◽  
Mojtaba Zeraatpisheh ◽  
Manouchehr Gorji ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Soil Properties ◽  
Northern Iran ◽  
Wheat Production ◽  
Rainfed Wheat

Coronary endarterectomy in coronary artery disease: Factors affecting graft patency and survival

2021 ◽  
pp. 021849232110068
Author(s):  
Simon CY Chow ◽  
Jacky YK Ho ◽  
Micky WT Kwok ◽  
Takuya Fujikawa ◽  
Kevin Lim ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Graft Patency ◽  
Complete Revascularization ◽  
Coronary Endarterectomy ◽  
Factors Affecting ◽  
Early Results ◽  
Cerebrovascular Events ◽  
Obtuse Marginal ◽  
One Year

Background Coronary endarterectomy aims to improve completeness of revascularization in patients with occluded coronary vessels. The benefits of coronary endarterectomy remain uncertain. The aim of this study was to evaluate short-term surgical outcomes and factors affecting graft patency post-coronary endarterectomy. Methods Between 2009 and 2019, 81 consecutive patients who had coronary endarterectomy done were evaluated for their perioperative and early results. A total of 36 patients with follow-up coronary studies were included in patency analysis. Mortality rates, major adverse cardiac and cerebrovascular events, and graft patency were outcomes of interest. Survival and risk factor analysis were performed with Kaplan–Meier and logistic regression analysis. Results The average age of the cohort was 61.9 ± 9.29 years. Complete revascularization rate was 95.4% post-coronary endarterectomy. The 30-day and 1-year mortality was 2.5 and 6.2%, respectively. One-year major adverse cardiac and cerebrovascular events rate was 11.1%. Periprocedural myocardial infarction rate was 7.4%. Three patients required repeat revascularization within a mean follow-up duration of 49.6 ± 36.5 months. Overall graft patency was 89.2% at 20.2 months and graft patency post-coronary endarterectomy was 85.4%. Arterial grafts showed 100% patency. Vein grafts to endarterectomized obtuse marginal branch had patency rates of 33.3%. Multiple endarterectomies were associated with worse one-year major adverse cardiac and cerebrovascular events (OR: 28.6 ± 1.16; P = 0.003). Conclusions Coronary endarterectomy facilitates completeness of revascularization and does not increase early mortality. Graft patency post-coronary endarterectomy on obtuse marginal artery was suboptimal. Judicious use of coronary endarterectomy should be practiced to balance the need of completeness of revascularization against the risk of myocardial infarction.

Analysis of Single-Vehicle Crash Injury Severities in Urban River-Crossing Road Tunnels

2015 ◽  
Vol 743 ◽  
pp. 526-532 ◽  
Author(s):  
C.M. Jiang ◽  
J.J. Lu ◽  
L.J. Lu
Keyword(s):  
Heavy Vehicles ◽  
Probit Regression ◽  
Factors Affecting ◽  
Explanatory Variables ◽  
Urban Road ◽  
Road Tunnels ◽  
Negative Effect ◽  
Single Vehicle ◽  
Injury Severities ◽  
One Year

Based on the originally unprocessed data from the Official Platform of“110”Alarming Receiving Center (OP110ARC) of Shanghai Public Security Bureau (SPSB), 529 single-vehicle crashes reported during one year and a half which happened at the thirteen urban road tunnels going across the Huangpu River are used in this study. To investigate the factors affecting the crash influence severity levels, ordered probit regression is established. Several categories of factors are considered as explanatory variables in the models. The study finds that the entrance of the tunnels is the site where severe injury crashes trend to occur. Rainy and snowy days impose vehicles and motorists driving via the tunnel sections in danger. Tunnels with a low speed limit (40 km/h in this study) may be not as safe as we thought before. Two-wheel vehicles without sufficient physical protection for its drivers and heavy vehicles also show a negative effect on the operation safety of single-vehicle at these studied tunnels. Alcohol involved drivers are more likely to suffer from a severe crashes and gets badly hurt.

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