Sakae Shibusawa

Textural analysis of soil images to quantify and characterize the spatial variation of soil properties using a real-time soil sensor

The primary aim of this work was to predict soil moisture content and soil organic matter using soil image texture statistics. Co-occurrence method texture statistics were used to characterize Andisol soils to extend the possibility of using RGB color space in representing composite soil color. Four co-occurrence method textural features; angular second moment (ASM), contrast (CON), correlation (COR) and inverse difference moment (IDM) calculated from generalized matrix for image texture representation were used to describe soil moisture content variation under laboratory conditions. It was found that CON and COR had negative responses to moisture content (MC) and ASM had positive response to MC. The same were also observed in direct captured field soil images in terms of textural indices against MC and soil organic matter (SOM). The correlations were significant for ASM and COR in fertilizer and combined (fertilizer-manure) plots and insignificant in manure plots. To relate sub-surface image textural indices and soil properties for individual years, stepwise multiple linear regression (SMLR) and supervised feed-forward neural networks (NN) were investigated in an attempt to provide minimal prediction errors. The improvements achieved by NN with minimal prediction errors were better than SMLR in different years. It was assumed that several years of data sets with a much larger number of observations could be used to differentiate fundamental soil properties.

Tumor suppression effects of bilberry extracts and enzymatically modified isoquercitrin in early preneoplastic liver cell lesions induced by piperonyl butoxide promotion in a two-stage rat hepatocarcinogenesis model

To investigate the protective effect of bilberry extracts (BBE) and enzymatically modified isoquercitrin (EMIQ) on the hepatocarcinogenic process involving oxidative stress responses, we used a two-stage hepatocarcinogenesis model in N-diethylnitrosamine-initiated and piperonyl butoxide (PBO)-promoted rats. We examined the modifying effect of co-administration with BBE or EMIQ on the liver tissue environment including oxidative stress responses, cell proliferation and apoptosis, and phosphatase and tensin homolog (PTEN)/Akt and transforming growth factor (TGF)-β/Smad signalings on the induction mechanism of preneoplastic lesions during early stages of hepatocellular tumor promotion. PBO increased the numbers and area of glutathione S-transferase placental form (GST-P)(+) liver cell foci and the numbers of Ki-67(+) proliferating cells within GST-P(+) foci. Co-administration of BBE or EMIQ suppressed these effects with the reductions of GST-P(+) foci (area) to 48.9-49.4% and Ki-67(+) cells to 55.5-61.4% of the PBO-promoted cases. Neither BBE nor EMIQ decreased microsomal reactive oxygen species induced by PBO. However, only EMIQ suppressed the level of thiobarbituric acid-reactive substances to 78.4% of the PBO-promoted cases. PBO increased the incidences of phospho-PTEN(-) foci, phospho-Akt substrate(+) foci, phospho-Smad3(-) foci and Smad4(-) foci in GST-P(+) foci. Both BBE and EMIQ decreased the incidences of phospho-PTEN(-) foci in GST-P(+) foci to 59.8-72.2% and Smad4(-) foci to 62.4-71.5% of the PBO-promoted cases, and BBE also suppressed the incidence of phospho-Akt substrate(+) foci in GST-P(+) foci to 75.2-75.7% of the PBO-promoted cases. These results suggest that PBO-induced tumor promotion involves facilitation of PTEN/Akt and disruptive TGF-β/Smad signalings without relation to oxidative stress responses, but this promotion was suppressed by co-treatment with BBE or EMIQ through suppression of cell proliferation activity of preneoplastic liver cells.

Capillary flow responses in a soil–plant system for modified subsurface precision irrigation

Water movement in a soil–plant system was evaluated based on capillary flow in a modified subsurface irrigation system that incorporates a plant-water measuring device. Water from a reservoir tank located underneath the plant pot was supplied to the root zone through a fibrous medium. Evapotranspiration was measured from the water uptake and evaluations were performed based on soil moisture distribution and mass balance. Potential evapotranspiration was used as a reference for the plant–water uptake. Data were obtained from a test plant provided with the modified subsurface irrigation system. The plant was grown in a phytotron under controlled air temperature and humidity, and a comparison was made for different levels of soil moisture condition. The experimental results confirmed the operational efficiency of the modified subsurface irrigation system for precision irrigation.

Study on Water Distribution Imaging in the Sand Using Propagation Velocity of Sound with Scanning Laser Doppler Vibrometer

We propose a method for the monitoring and imaging of the water distribution in the rooting zone of plants using sound vibration. In this study, the water distribution measurement in the horizontal and vertical directions in the soil layer was examined to confirm whether a temporal change in the volume water content of the soil could be estimated from a temporal changes in propagation velocity. A scanning laser Doppler vibrometer (SLDV) is used for measurement of the vibration velocity of the soil surface, because the highly precise vibration velocity measurement of several many points can be carried out automatically. Sand with a uniform particle size distribution is used for the soil, as it has high plasticity; that is, the sand can return to a dry state easily even if it is soaked with water. A giant magnetostriction vibrator or a flat speaker is used as a sound source. Also, a soil moisture sensor, which measures the water content of the soil using the electric permittivity, is installed in the sand. From the experimental results of the vibration measurement and soil moisture sensors, we can confirm that the temporal changes of the water distribution in sand using the negative pressure irrigation system in both the horizontal and vertical directions can be estimated using the propagation velocity of sound. Therefore, in the future, we plan to develop an insertion-type sound source and receiver using the acceleration sensors, and we intend to examine whether our method can be applied even in commercial soil with growing plants.

Paradigm of value-driven and community-based precision farming

This paper describes a Japanese model of community-based precision farming and learning groups of farmers and companies. The community-based precision farming is a new regional farming system to get high profitability and reliability under regional and environmental constraints, promoted by wisdom farmers and technology platform, through creating both information-oriented fields and information-added products, with supply chain management of field to table. Two participating local learning groups are: a technology driven Precision farming network of Toyohashi-Atsumi (PFNET) in Toyohashi city and a farmers learning group Honjo precision farming society (HPFS) in Honjo city. PFNET is aimed at realising a total system of technologies in precision farming with agriculture-linked industries and wisdom and skills of farmers. HPFS (Honjo) strives to produce information-added products and information-oriented fields, and also grows them as new Honjo branded products. The first action was a market research on information-added products through in-shop experiments.

Basic Study on Estimating Water Stress of a Plant Using Vibration Measurement of Leaf

A new noninvasive method for estimating the water stress of a plant was proposed. In order to investigate this method, we first examined the characteristic frequency of an individual leaf picked from the plant, and obtained the result that its characteristic frequency decreased in proportion to the reduction in the water content of the leaf. Next, we applied this method to a leaf on a branch and confirmed the same tendency when the water stress was increased by stopping the water supply of a plant cultured in water. From these results, it was suggested that the water stress of the plant could be estimated from the vibration measurement of the leaf. Lastly, the relationship between the water potential of the leaf and its elastic constant was discussed with the soil-plant-atmosphere-continuum model (SPAC model), and Youngs modulus of a tomato leaf was roughly estimated.

Water Uptake Response of Plant in Subsurface Precision Irrigation System

Abstract The spatial and temporal variability of root-water uptake from the soil remain unclear due to the limitations of the measuring method and subsequently difficult in attempting to accurately model the soil-plant-atmosphere system. In this study, an experimental setup was designed to collect the data needed to develop a more realistic plant water uptake model using a modified subsurface irrigation system that allows the change of soil moisture content. The plant uptake response was determined from evapotranspiration, water consumption and soil moisture content at different soil depths. A plant water uptake model was reviewed and an extension of this model was proposed for the modified subsurface irrigation system. Preliminary investigation was performed using the experimental data and the results were essential.

Carbon Sequestration Potential and Farming Income

Carbon sequestration through agricultural soil is increasingly promoted as a win-win strategy for mitigating climate change and improving farmers livelihoods, especially in dry land. A better understanding of agricultural management for paddy fields that can increase both soil carbon and household income is therefore necessary. Using a DeNitrification-DeComposition (DNDC) model, this paper evaluates different farming management practices both by their capacity of carbon sequestration and contribution to household income, thereby to identify the optimal carbon-capturing farming practices for paddy fields. A real-time soil sensor and several comprehensive field surveys were employed for data collection. The farming practices of no-till, reduced tillage combing increased organic fertilizers were identified as cost-effective strategies to increase carbon sequestration in the paddy fields of Matsuyama.

Carbon Sequestration Potential and Farming Income: Identifying the Optimal Carbon Farming Practices in Japanese Paddy Fields*

Carbon sequestration through agricultural soil is increasingly promoted as a win-win strategy for mitigating climate change and improving farmers livelihoods, especially in dry land. A better understanding of agricultural management for paddy fields that can increase both soil carbon and household income is therefore necessary. Using a DeNitrification-DeComposition (DNDC) model, this paper evaluates different farming management practices both by their capacity of carbon sequestration and contribution to household income, thereby to identify the optimal carbon-capturing farming practices for paddy fields. A real-time soil sensor and several comprehensive field surveys were employed for data collection. The farming practices of no-till, reduced tillage combing increased organic fertilizers were identified as cost-effective strategies to increase carbon sequestration in the paddy fields of Matsuyama.