scholarly journals Management Zone Delineation for Site-Specific Fertilization in Rice Crop Using Multi-Temporal RapidEye Imagery

2020 ◽  
Vol 12 (16) ◽  
pp. 2604
Author(s):  
Christos Karydas ◽  
Miltiadis Iatrou ◽  
George Iatrou ◽  
Spiros Mourelatos
Keyword(s):  
Soil Heterogeneity ◽  
Rice Crop ◽  
Growth Stages ◽  
Spectral Variation ◽  
Site Specific ◽  
Management Zone ◽  
Soil Variation ◽  
Multi Temporal ◽  
Basic Hypothesis ◽  
Seedbed Preparation

The objective of this research is to assess the potential of satellite imagery in detecting soil heterogeneity, with a focus on site-specific fertilization in rice. The basic hypothesis is that spectral variation would express soil fertility variations analogously. A 100-ha rice crop, located in the Plain of Thessaloniki, Greece, was selected as the study area for the 2016 cropping season. Three RapidEye images were acquired during critical growth stages of rice cultivation from the previous year (2015). Management zones were delineated with image segmentation of a 15-band multi-temporal composite of the RapidEye images (three dates × five bands), using the Fractal Net Evolution Approach (FNEA) algorithm. Then, an equal number of soil samples were collected from the centroid of each management zone before seedbed preparation. The between-zone variation of the soil properties was found to be 33.7% on average, whereas the within-zone variation 18.2%. The basic hypothesis was confirmed, and moreover, it was proved that zonal applications reduced within-zone soil variation by 18.6% compared to conventional uniform applications. Finally, between-zone soil variation was significant enough to dictate differentiated fertilization recommendations per management zone by 24.5% for the usual inputs.

scholarly journals Soil gas probes for monitoring trace gas messengers of microbial activity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joseph R. Roscioli ◽  
Laura K. Meredith ◽  
Joanne H. Shorter ◽  
Juliana Gil-Loaiza ◽  
Till H. M. Volkmann
Keyword(s):  
Microbial Activity ◽  
Soil Heterogeneity ◽  
Soil Gas ◽  
Microbial Processes ◽  
Trace Gas ◽  
Soil Microbiome ◽  
Sampling System ◽  
Site Specific ◽  
Gas Measurements ◽  
Subsurface Monitoring

AbstractSoil microbes vigorously produce and consume gases that reflect active soil biogeochemical processes. Soil gas measurements are therefore a powerful tool to monitor microbial activity. Yet, the majority of soil gases lack non-disruptive subsurface measurement methods at spatiotemporal scales relevant to microbial processes and soil structure. To address this need, we developed a soil gas sampling system that uses novel diffusive soil probes and sample transfer approaches for high-resolution sampling from discrete subsurface regions. Probe sampling requires transferring soil gas samples to above-ground gas analyzers where concentrations and isotopologues are measured. Obtaining representative soil gas samples has historically required balancing disruption to soil gas composition with measurement frequency and analyzer volume demand. These considerations have limited attempts to quantify trace gas spatial concentration gradients and heterogeneity at scales relevant to the soil microbiome. Here, we describe our new flexible diffusive probe sampling system integrated with a modified, reduced volume trace gas analyzer and demonstrate its application for subsurface monitoring of biogeochemical cycling of nitrous oxide (N2O) and its site-specific isotopologues, methane, carbon dioxide, and nitric oxide in controlled soil columns. The sampling system observed reproducible responses of soil gas concentrations to manipulations of soil nutrients and redox state, providing a new window into the microbial response to these key environmental forcings. Using site-specific N2O isotopologues as indicators of microbial processes, we constrain the dynamics of in situ microbial activity. Unlocking trace gas messengers of microbial activity will complement -omics approaches, challenge subsurface models, and improve understanding of soil heterogeneity to disentangle interactive processes in the subsurface biome.

scholarly journals Bacterial Leaf Blight Detection in Rice Crops Using Ground-Based Spectroradiometer Data and Multi-temporal Satellites Images

2020 ◽  
Vol 12 (2) ◽  
pp. 38
Author(s):  
Rani Yudarwati ◽  
Chiharu Hongo ◽  
Gunardi Sigit ◽  
Baba Barus ◽  
Budi Utoyo
Keyword(s):  
Image Analysis ◽  
Satellite Image ◽  
Vegetation Indices ◽  
Leaf Blight ◽  
Rice Crop ◽  
Bacterial Leaf Blight ◽  
First Derivative ◽  
Red Edge ◽  
Multi Temporal ◽  
Satellite Image Analysis

This study presents a method for detecting rice crop damage due to bacterial leaf blight (BLB) infestation. Rice crop samples are first analyzed using a handheld spectroradiometer. Then, multi-temporal satellite image analysis is used to determine the most suitable vegetation indices for detecting BLB. The results showed that healthy plants have the highest first derivative value of spectral reflectance of the different categories of diseased plants. Significant difference can be found at approximately 690-770 nm (red edge region) which peak or maximum of the first derivative occurs in healthy crop whereas the highest percentage of BLB showed the lowest in that region. Moreover, visible bands such as blue, green, red, and red edge 1 band show variation of correlation in the early (vegetative) to generative stage then getting high especially in early of harvesting stage than the other bands; the NIR band exhibits a low correlation from the early stage of the growing season whereas the red and red edge bands reveal the highest correlations in the later stage of harvesting. Similarly, the satellite image analysis also reveals that disease incidence gradually increases with increasing age of the plant. The vegetation indices whose formulas consist of blue, green, red, and red edge bands (NGRDI, NPCI, and PSRI) exhibit the highest correlation with BLB infestation. NPCI and PSRI indices indicate that crop stress due to BLB is detected from ripening stage of NPCI then the senescence condition is then detected 12 days later. The coefficients of determination between these indices and BLB are 0.44, 0.63, and 0.67, respectively

scholarly journals A geomorphological approach to the estimation of landslide hazards and risks in Umbria, Central Italy

2002 ◽  
Vol 2 (1/2) ◽  
pp. 57-72 ◽  
Author(s):  
M. Cardinali ◽  
P. Reichenbach ◽  
F. Guzzetti ◽  
F. Ardizzone ◽  
G. Antonini ◽  
...  
Keyword(s):  
Central Italy ◽  
Landslide Hazard ◽  
Aerial Photographs ◽  
Site Specific ◽  
Landslide Hazards ◽  
Umbria Region ◽  
Multi Temporal ◽  
Landslide Inventory Map ◽  
Hazard And Risk ◽  
Inventory Map

Abstract. We present a geomorphological method to evaluate landslide hazard and risk. The method is based on the recognition of existing and past landslides, on the scrutiny of the local geological and morphological setting, and on the study of site-specific and historical information on past landslide events. For each study area a multi-temporal landslide inventory map has been prepared through the interpretation of various sets of stereoscopic aerial photographs taken over the period 1941–1999, field mapping carried out in the years 2000 and 2001, and the critical review of site-specific investigations completed to solve local instability problems. The multi-temporal landslide map portrays the distribution of the existing and past landslides and their observed changes over a period of about 60 years. Changes in the distribution and pattern of landslides allow one to infer the possible evolution of slopes, the most probable type of failures, and their expected frequency of occurrence and intensity. This information is used to evaluate landslide hazard, and to estimate the associated risk. The methodology is not straightforward and requires experienced geomorphologists, trained in the recognition and analysis of slope processes. Levels of landslide hazard and risk are expressed using an index that conveys, in a simple and compact format, information on the landslide frequency, the landslide intensity, and the likely damage caused by the expected failure. The methodology was tested in 79 towns, villages, and individual dwellings in the Umbria Region of central Italy.

Multi temporal ERS-1 SAR data for identification of rice crop

1995 ◽  
Vol 23 (2) ◽  
pp. 33-39 ◽  
Author(s):  
N K Patel ◽  
T T Medhavy ◽  
C Patnaik ◽  
A Hussain
Keyword(s):  
Rice Crop ◽  
Multi Temporal ◽  
Sar Data

Mineral nitrogen in soils undergoing irrigated rice-upland crop rotations

1980 ◽  
Vol 20 (107) ◽  
pp. 731 ◽  
Author(s):  
IR Willett ◽  
ML Higgins
Keyword(s):  
Ammonium Nitrogen ◽  
Early Growth ◽  
Mineral Nitrogen ◽  
Lowland Rice ◽  
Rice Crop ◽  
Growth Stages ◽  
Poor Growth ◽  
Nitrogen Levels ◽  
Crop Uptake ◽  
Upland Crop

Surface soil (0-150 mm) mineral nitrogen levels were monitored in field plots undergoing rice-wheat-wheat and rice-fallow rotations to study the effects of rice growing on the mineral nitrogen content of soils for subsequent crops. Ammonium nitrogen accumulated in the soils during the first 3 weeks of flooding of the rice crop, reaching 54 mg N kg-1 in a grey clay, and 23 mg N kg-1 in a transitional red-brown earth. Thereafter, ammonium nitrogen decreased so that at the time of drainage the soils contained between 2 and 6 mg N kg-1. Nitrate levels during the flooding period fluctuated between 1 and 7 mg N kg-1. In each subsequent fallowing period, nitrate levels increased so that there was approximately 20 mg N kg-1 as nitrate present during the early growth stages of the post-rice crops. However, at the harvests of each post-rice crop, nitrate nitrogen levels had decreased to between 1 and 7 mg N kg-'. Fluctuations in nitrate levels were interpreted in terms of gains from mineralization and nitrification and losses by crop uptake, although leaching and denitrification during periods of heavy rainfall or irrigations could not be assessed. Ammonium levels in the post-rice period increased in the months of October and November when fallowed, but other fluctuations showed no consistent trends. Nitrite levels were low (< 0.6 mg N kg-1) throughout the experiments. Total mineral nitrogen levels during the early growth stages of the crops grown after the rice corresponded to between 31 and 95 kg N ha-1 in the surface 0-150 mm of soil. It was concluded that in the rotations studied, lowland rice cropping did not lead to depletion of mineral nitrogen to such an extent that it could be implicated as a factor in the poor growth of upland crops grown in rotation with lowland rice.

Rice crop parameter retrieval using multi-temporal, multi-incidence angle Radarsat SAR data

2005 ◽  
Vol 59 (5) ◽  
pp. 310-322 ◽  
Author(s):  
M. Chakraborty ◽  
K.R. Manjunath ◽  
S. Panigrahy ◽  
N. Kundu ◽  
J.S. Parihar
Keyword(s):  
Incidence Angle ◽  
Rice Crop ◽  
Multi Temporal ◽  
Sar Data ◽  
Parameter Retrieval
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