scholarly journals Long-term fertilizer field trials: comparison of three mathematical response models

1997 ◽  
Vol 6 (2) ◽  
pp. 151-160 ◽  
Author(s):  
Stefan T. Bäckman ◽  
S. Vermeulen ◽  
V.-M. Taavitsainen
Keyword(s):  
Production Function ◽  
Field Trial ◽  
Crop Production ◽  
Mineral Fertilizer ◽  
Field Trials ◽  
The European Union ◽  
Response Models ◽  
Economic Use ◽  
Term Field

Accession to the European Union caused a drop of nearly 60 per cent from 1994 to 1995 in prices of wheat, barley and oats in Finland. The economic use of fertilizer therefore decreased accordingly. To calculate the effect of the price changes on the economic optima, the physical production function must be known. Three physical production functions, the quadratic, the linear response and plateau (LRP) and the exponential function were estimated for this purpose. The models differed little in respect of the R2adj value (0.82-0.90) but the calculated optimum varied, depending on the production function. Data on a long-term field trial (21 years) were analysed. The field trial was established in 1973 to demonstrate the effect of mineral fertilizer in crop production. The crops grown in the trial were barley, wheat and oats. Different varieties were included in the models.

scholarly journals Microbial processing of humic acids extracted from soils of a long-term field trial

2004 ◽  
Vol 52 (4) ◽  
pp. 137-146
Author(s):  
Zdeněk Filip ◽  
Jaromír Kubát
Keyword(s):  
Humic Acids ◽  
Field Trial ◽  
Field Trials ◽  
Structural Transformations ◽  
Microbial Activities ◽  
Aerobic Conditions ◽  
Ft Ir ◽  
The Individual ◽  
Term Field

Humic acids (HA) extracted with alkali from non-fertilized and fertilized (NPK + organic manure) soils of field trials established 45 years ago were exposed to activities of a mixed population of indigenous soil microorganisms in the laboratory. The individual cultures were kept on a rotary shaker for 21 days (aerobic conditions) or left standing for 12 months (semi-aerobic conditions) in order to determine the utilization of HA as nutrients, and possible HA structural transformations. In a full-strength nutrient broth HA positively affected the yields of microbial biomass, that, however, was strongly diminished if HA served as the only sources of carbon and nitrogen. In contrary, the utilization of HA was up to 47.3% under semi-aerobic conditions in cultures deficient in easy utilizable sources of carbon (glucose). No substantial differences were observed in the microbial processing of HA from non-fertilized or fertilized soils. Usually, microbial activities resulted in elemental and structural transformations of HA. Aliphatic structural units were preferably utilized as determined by FT-IR spectroscopy, while aromatic structures became rather dominating. Conclusively, independent of the type of microbial processing, HA from soils of a long-term field trial showed rather low resistance to microbial activities, and perhaps they should not account for a resistant fraction of the soil organic matter.

scholarly journals Discrimination of conventional and organic white cabbage from a long-term field trial study using untargeted LC-MS-based metabolomics

2014 ◽  
Vol 406 (12) ◽  
pp. 2885-2897 ◽  
Author(s):  
Axel Mie ◽  
Kristian Holst Laursen ◽  
K. Magnus Åberg ◽  
Jenny Forshed ◽  
Anna Lindahl ◽  
...  
Keyword(s):  
Field Trial ◽  
White Cabbage ◽  
Term Field

Changes in soil biological and biochemical characteristics in a long-term field trial on a sub-tropical inceptisol

2006 ◽  
Vol 38 (7) ◽  
pp. 1577-1582 ◽  
Author(s):  
R. Ebhin Masto ◽  
P.K. Chhonkar ◽  
Dhyan Singh ◽  
A.K. Patra
Keyword(s):  
Field Trial ◽  
Biochemical Characteristics ◽  
Term Field

Correlation Between Soil P and Wheat Shoot P Contents in a Network of Hungarian Long‐Term Field Trials

2005 ◽  
Vol 36 (1-3) ◽  
pp. 275-293 ◽  
Author(s):  
Péter Csathó ◽  
Marianna Magyar ◽  
Katalin Debreczeni ◽  
Katalin Sárdi
Keyword(s):  
Field Trials ◽  
Soil P ◽  
Wheat Shoot ◽  
Term Field

Long-Term Field Trial to Control the Invasive Argentine Ant (Hymenoptera: Formicidae) With Synthetic Trail Pheromone

2010 ◽  
Vol 103 (5) ◽  
pp. 1784-1789 ◽  
Author(s):  
K. Nishisue ◽  
E. Sunamura ◽  
Y. Tanaka ◽  
H. Sakamoto ◽  
S. Suzuki ◽  
...  
Keyword(s):  
Field Trial ◽  
Trail Pheromone ◽  
Argentine Ant ◽  
Term Field
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