Development of Agricultural Field DEM Using Repeated GPS Measurements from Field Operations: Effects of Sampling Intensity and Pattern

2007 ◽  
Author(s):  
Samsuzana Abd Aziz ◽  
Brian L Steward
Keyword(s):  
Agricultural Field ◽  
Gps Measurements ◽  
Sampling Intensity

GPS measurements on the island of Hawaii in 1992

1994 ◽  
Author(s):  
Asta Miklius ◽  
E.Y. Iwatsubo ◽  
R.P. Denlinger ◽  
A.T. Okamura ◽  
M.K. Sako ◽  
...  
Keyword(s):  
Gps Measurements

Dissolved Phosphorus Losses in Tile Drainage under Subirrigation

2006 ◽  
Vol 41 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Nicolas Stämpfli ◽  
Chandra A. Madramootoo
Keyword(s):  
Water Table ◽  
Residual Effect ◽  
Surface Water Quality ◽  
Soil Surface ◽  
Quality Standard ◽  
Tile Drainage ◽  
Agricultural Field ◽  
Shallow Water Table ◽  
Dissolved Phosphorus ◽  
Water Table Control

Abstract Recent studies have shown subirrigation (SI) to be effective in reducing nitrate losses from agricultural tile drainage systems. A field study was conducted from 2001 to 2002 in southwestern Québec to evaluate the effect of SI on total dissolved phosphorus (TDP) losses in tile drainage. In an agricultural field with drains installed at a 1-m depth, a SI system with a design water table depth (WTD) of 0.6 m below the soil surface was compared with conventional free drainage (FD). Subirrigation increased drainage outflow volumes in the autumn, when drains were opened and water table control was interrupted for the winter in the SI plots. Outflows were otherwise similar for both treatments. Throughout the study, the TDP concentrations in tile drainage were significantly higher with SI than with FD for seven out of 17 of the sampling dates for which data could be analyzed statistically, and they were never found to be lower for plots under SI than for plots under FD. Of the seven dates for which the increase was significant, six fell in the period during which water table control was not implemented (27 September 2001 to 24 June 2002). Hence, it appears that SI tended to increase TDP concentrations compared with FD, and that it also had a residual effect between growing seasons. Almost one-third of all samples from the plots under SI exceeded Québec's surface water quality standard (0.03 mg TDP L-1), whereas concentrations in plots under FD were all below the standard. Possible causes of the increase in TDP concentrations in tile drainage with SI are high TDP concentrations found in the well water used for SI and a higher P solubility caused by the shallow water table.

ESTIMATING THE NITROGEN LOAD TO GROUNDWATER BENEATH AN AGRICULTURAL FIELD

2018 ◽  
Author(s):  
Madeline B. Gotkowitz ◽  
◽  
Jacob J. Krause ◽  
Michael Cardiff ◽  
Laura Schachter
Keyword(s):  
Agricultural Field

scholarly journals Kinematics of faults in Bengal Basin: Constraints from GPS measurements

2020 ◽  
Vol 11 (4) ◽  
pp. 242-251
Author(s):  
Mallika Mullick ◽  
Dhruba Mukhopadhyay
Keyword(s):  
Bengal Basin ◽  
Gps Measurements

scholarly journals An analysis of the spatial association between deforestation and agricultural field sizes in the tropics and subtropics

PLoS ONE ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. e0209918 ◽  
Author(s):  
Doan K. D. Dang ◽  
Amy C. Patterson ◽  
Luis R. Carrasco
Keyword(s):  
Spatial Association ◽  
Agricultural Field ◽  
The Tropics

scholarly journals Identification of a juvenile-hormone signaling inhibitor via high-throughput screening of a chemical library

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Takumi Kayukawa ◽  
Kenjiro Furuta ◽  
Keisuke Nagamine ◽  
Tetsuro Shinoda ◽  
Kiyoaki Yonesu ◽  
...  
Keyword(s):  
Juvenile Hormone ◽  
Cell Line ◽  
Signaling Pathway ◽  
High Throughput ◽  
High Throughput Screening ◽  
Large Scale ◽  
Ex Vivo ◽  
Agricultural Field ◽  
Chemical Library ◽  
Field Development

Abstract Insecticide resistance has recently become a serious problem in the agricultural field. Development of insecticides with new mechanisms of action is essential to overcome this limitation. Juvenile hormone (JH) is an insect-specific hormone that plays key roles in maintaining the larval stage of insects. Hence, JH signaling pathway is considered a suitable target in the development of novel insecticides; however, only a few JH signaling inhibitors (JHSIs) have been reported, and no practical JHSIs have been developed. Here, we established a high-throughput screening (HTS) system for exploration of novel JHSIs using a Bombyx mori cell line (BmN_JF&AR cells) and carried out a large-scale screening in this cell line using a chemical library. The four-step HTS yielded 69 compounds as candidate JHSIs. Topical application of JHSI48 to B. mori larvae caused precocious metamorphosis. In ex vivo culture of the epidermis, JHSI48 suppressed the expression of the Krüppel homolog 1 gene, which is directly activated by JH-liganded receptor. Moreover, JHSI48 caused a parallel rightward shift in the JH response curve, suggesting that JHSI48 possesses a competitive antagonist-like activity. Thus, large-scale HTS using chemical libraries may have applications in development of future insecticides targeting the JH signaling pathway.

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