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Morimoto E.,Ishikawa Agricultural Research Center | Hirako S.,Shibuya Machinery Co. | Yamasaki H.,Iseki Co. | Izumi M.,Iseki Co.
Engineering in Agriculture, Environment and Food

The objective of this paper was to provide the development of on-the-go soil sensor for rice transplanter, particularly from a perspective of precision agriculture applications. Ultrasonic sensor, electrodes and platinum resistance thermometer were employed for topsoil depth (TD) and apparent electrical conductivity (ECa) measurement. Soil fertility value (SFV) defined as new soil parameter, which consisted of ECa / TD. The results of field test revealed that the developed equipments could measure the TD (R 2 = 0.999), and the SFV had a strong relationship with measured EC (R2 = 0.937). Source

Maruyama T.,Ishikawa Prefectural University | Noto F.,Ishikawa Prefectural University | Murashima K.,Ishikawa Prefectural University | Hashimoto I.,Ishikawa Prefectural University | Kitada K.,Ishikawa Agricultural Research Center
Paddy and Water Environment

A nitrogen balance study was carried out by setting up a test paddy in order to estimate the nitrogen pollution load potential (NPLP) from farmland in the Tedori River Alluvial Fan Areas and the load from the entire area under consideration was estimated using the cropping record and fertilizer application rate (FAR). The total NPLP was estimated to be 261 tons/year and the load from the paddy 79 tons/year for 5,704 ha, which would translate to an intensity of 14 kg/ha, while the load from the vegetable field was estimated to be 118 tons/year for 215 ha, which would equate to an intensity of 549 kg/ha. The pollution loads for the vegetables were significantly greater than those for the rice. The load for the barley was 57 tons/year for 261 ha (216 kg/ha) and that for the orchards was 23 tons/year for 64 ha (359 kg/ha). The estimation of soybean load was a negative 15 tons/year for 717 ha (-21 kg/ha), which meant that the nitrogen in the yield was greater than the FAR. The results also confirmed the yield absorption ratio in relation to the FAR. The load from the paddy for the entire area was also estimated using the percolation rate and the water quality load underneath the farmland was estimated to be 89 tons/year. © 2010 Springer-Verlag. Source

Fukuoka N.,Ishikawa Prefectural University | Suzuki T.,Ishikawa Prefectural University | Yamada Y.,Ishikawa Agricultural Research Center
Journal of Horticultural Science and Biotechnology

The aim of the present study was to determine the effects of infrared irradiation (IRI) on polyphenol biosynthesis and anti-oxidant activity in Gynura bicolor DC. leaves. To achieve this, infrared light lamps were placed 75 cm above the top of the canopy, and the plants were covered with a black nylon mesh to exclude the influence of natural light. Higher activities of ascorbate peroxidase (APX), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PDH), L-phenylalanine ammonia-lyase (PAL), and polyphenol oxidase (PPO) were detected in leaves when plants were subjected to IRI. Although IRI resulted in a significant decrease in anthocyanin content, HPLC analysis of the phenolic components showed a higher content of chlorogenic acid that was accompanied by a higher 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) radical-scavenging activity in IRI-treated leaves. These observations suggest that IRI causes oxidative stress and stimulates the activities of enzymes that regulate non-flavonoid polyphenol biosynthesis in G. bicolor leaves. Source

Fukuoka N.,Ishikawa Prefectural University | Suzuki T.,Ishikawa Prefectural University | Minamide K.,Ishikawa Prefectural University | Minamide K.,Ishikawa Agricultural Research Center | Hamada T.,Ishikawa Prefectural University

The effect of shading in midsummer on anthocyanin and non-flavonoid polyphenol biosynthesis of Gynura bicolor DC leaves was examined using a control (full solar radiation) and a shade treatment (50% shading of full solar radiation). Leaf temperature in the shade plot remained ∼40 °C in the daytime, ∼6 °C lower than in the control. Plants in the shade plot grew better than the control. The content of chlorogenic acid (CGA) in leaves decreased with leaf maturation for both treatments, and a larger amount of CGA was detected in leaves from the control than the shade treatment. The profiles of reactive oxygen species (ROS) scavenging activity exhibited an identical pattern to the content of CGA. Although there was an abrupt increase in the content of anthocyanin in the early stage of leaf expansion, the content decreased rapidly as the leaves matured. The increase in anthocyanin early during leaf expansion was much more limited in control leaves than shaded leaves. There were no correlation between the profiles of anthocyanin and gene expression such as GbPAL, GbC4H, Gb4CL, GbCHS, GbCHI, GbF3H, and GbUFGT. However, the profiles of expression of genes such as GbMYB2, GbF3#H, GbDFR, and GbANS were similar to the anthocyanin profiles. These results suggest that artificial shading in midsummer is an effective method to promote anthocyanin accumulation but reduces ROS scavenging capacity as a result of lowered CGA production. © 2014, HORTSCIENCE. All rights reserved. Source

Sakamoto T.,Ishikawa Prefectural University | Masuda D.,Ishikawa Agricultural Research Center | Nishimura K.,Ishikawa Agricultural Research Center | Ikeshita Y.,Ishikawa Agricultural Research Center
Journal of Horticultural Science and Biotechnology

Low sweetness in freshly-harvested tuberous roots is an undesirable characteristic of the sweet potato (Ipomoea batatas L. Lam.) cultivar, 'Kokei 14'. In the present study, we sought to characterise the biochemical and molecular aspects of sucrose accumulation in the tuberous roots of 'Kokei 14' during cold storage in comparison with another sweet potato cultivar, 'Beniazuma'.The tuberous roots of both cultivars were harvested and stored at 4°C for 30 d.The sucrose, fructose, and glucose concentrations, the activities of two sugar-metabolising enzymes, and the expression of six sucrose-cleaving acid invertase (AI) genes were monitored. Exposure to chilling temperatures (4°C) for up to 30 d increased the sucrose concentration in the tuberous roots of 'Kokei 14', but not in those of 'Beniazuma'. In line with this phenomenon, we found that the activity of AI was suppressed to approx. 0.4-times the pre-treatment value in 'Kokei 14', but increased to 2.7-times the pre-treatment value in 'Beniazuma' during cold storage for 30 d.The patterns and levels of expression of six genes encoding AIs indicated that the protein encoded by IbAINV1 was the main AI that degraded sucrose in the tuberous roots of both cultivars. IbAINV1 gene expression increased transiently and reached a maximum (2.3-times the pre-treatment value) at 20 d in 'Beniazuma', whereas it decreased to approx. 0.14- times the pre-treatment value by 10 d in 'Kokei 14' and remained low for the duration of the experiment. Sucrose concentrations did not change in the tuberous roots of 'Kokei 14' stored at 13°C for 20 d.Therefore, we conclude that the accumulation of sucrose in the tuberous roots of 'Kokei 14' was caused mainly by suppression of IbAINV1 gene expression in response to chilling. Source

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