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Spatial variability of uncultivated soils in derived savanna

100%

Obalum S. E., Oppong J., Igwe C. A., Watanabe Y., Obi M. E.

International Agrophysics

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2013

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tom 27

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nr 1

The spatial variability of some physicochemical properties of topsoils/subsoils under secondary forest, grassland fallow, and bare-soil fallow of three locations was evaluated. The data were analyzed and described using classical statistical parameters. Based on the coefficient of variation, bulk density, total porosity, 60-cm-tension moisture content, and soil pH were of low variability. Coarse and fine sand were of moderate variability. Highly variable soil properties included silt, clay, macroporosity, saturated hydraulic conductivity, organic matter concentration, and cation exchange capacity. Overall, soil pH and silt varied the least and the most, respectively. Relative weighting showed that location dominantly influenced the soil variability, except for soil porosity and organic matter concentration influenced mostly by land use. Most of the soil data were normally distributed; others were positively skewed and/or kurtotic. The minimum number of samples (at 25 samples ha-1) required to estimate mean values of soil properties was highly soil property-specific, ranging from 1 (topsoil pH-H2O) to 246 (topsoil silt). Cation exchange capacity of subsoils related fairly strongly with cation exchange capacity of topsoils (R2 = 0.63). Spatial variability data can be used to extrapolate dynamic soil properties across a derived-savanna landscape.

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Puddling intensity for late-season sawah systems based on soil hydrophysical conditions and rice performance

100%

Obalum S. E., Watanabe Y., Igwe C. A., Obi M. E., Wakatsuki T.

International Agrophysics

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2014

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tom 28

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nr 3

Lowland sawah farmers often puddle to improve soil hydrophysical conditions for rice, but the puddling intensity beyond which no extra yield increases occur is unknown. Agro- nomic effects of six mechanical puddling intensities were assessed in three Nigerian inland-valley bottoms. All puddled plots, irrespec- tive of intensity, produced similar effects at all three locations. At 10 days after transplanting, soil bulk density of all puddled plots re- presented mean decreases relative to control plots of about 22.4, 15.8, and 31.7% at Akaeze, Adani, and Ejeti, respectively. Soil bulk density and moisture content upon saturation were similar during 40-120 days after transplanting. All puddled plots consistently showed taller plants and greater tillering than control plots only at Ejeti. Grain yields were similar among treatments in Akaeze and Adani (mean, 3.71 and 6.42 Mg ha -1 , respectively), but one-pass puddling yielded numerically highest in both locations. At Ejeti, grain yields followed the trend for plant growth, with mean values of 4.36 and 1.81 Mg ha -1 for puddled and control plots, respecti- vely. One-pass puddling may be sufficient for sawah rice grown late particularly in less humid environments.

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Effect of intravenous administration of glucagon-like peptide. I on growth hormone secretion in sheep

86%

Kurose Y., Kuwahara A., Oshiba Y., Takahashi H., Watanabe Y., Terashima Y.

Journal of Animal and Feed Sciences. Supplement

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2004

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tom 13

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nr 1

4

Photosynthetic characteristics and nitrogen allocation in the black locust (Robinia pseudoacacia L.) grown in a FACE system

86%

Choi D., Watanabe Y., Guy R. D., Sugai T., Toda H., Koike T.

Acta Physiologiae Plantarum

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2017

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tom 39

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nr 03

Ograniczanie wyników

2 International Agrophysics

1 Acta Physiologiae Plantarum

1 Journal of Animal and Feed Sciences. Supplement

4 Watanabe Y.

2 Igwe C. A.

2 Obalum S. E.

2 Obi M. E.

1 Choi D.

1 Guy R. D.

1 Koike T.

1 Kurose Y.

1 Kuwahara A.

1 Oppong J.

1 Oshiba Y.

1 Sugai T.

1 Takahashi H.

1 Terashima Y.

1 Toda H.

1 Wakatsuki T.

1 2017

1 2014

1 2013

1 2004

Spatial variability of uncultivated soils in derived savanna

Puddling intensity for late-season sawah systems based on soil hydrophysical conditions and rice performance

Effect of intravenous administration of glucagon-like peptide. I on growth hormone secretion in sheep

Photosynthetic characteristics and nitrogen allocation in the black locust (Robinia pseudoacacia L.) grown in a FACE system