Study on Soil Nitrogen and Electrical Conductivity Relationship for Site-Specific Nitrogen Application

Landholder observations indicate that the growth of Distichlis spicata in saline discharge sites improves the soil condition. An extensive soil sampling survey was conducted at the Wickepin field site in Western Australia, where D. spicata had been growing for 8 years, to test the hypothesis that this halophytic grass will make improvements in chemical and physical properties of the soil. Soil measurements included saturated hydraulic conductivity, water-stable aggregates, root length and dry weight, electrical conductivity, pH, and soil nitrogen and carbon. Results confirm that marked differences in soil properties occurred under D. spicata. For example, a 12-fold increase in saturated hydraulic conductivity occurred where D. spicata had been growing for 8 years, compared to adjacent control soil where no grass had been growing. There were also improvements in aggregate stability, with the most notable improvements in the top 0.10 m of soil, again with the greatest improvements occurring where 8 years of growth had occurred. Soil nitrogen and carbon increased under the sward, with the biggest increases occurring in the top 0.10 m of soil. Electrical conductivity measurements were more variable, mostly due to the large spatial and temporal variation encountered. However, the findings generally support the proposition that the growth of D. spicata does not lead to an accumulation of salt within the rooting zone.

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Site-Specific Management Zones Based on Soil Electrical Conductivity in a Semiarid Cropping System

Agronomy Journal ◽

10.2134/agronj2003.0303 ◽

2003 ◽

Vol 95 (2) ◽

pp. 303 ◽

Cited By ~ 81

Author(s):

Cinthia K. Johnson ◽

David A. Mortensen ◽

Brian J. Wienhold ◽

John F. Shanahan ◽

John W. Doran

Keyword(s):

Electrical Conductivity ◽

Cropping System ◽

Soil Electrical Conductivity ◽

Site Specific ◽

Management Zones ◽

Specific Management

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HIGHLY REPRODUCIBLE SINGLE POLYANILINE NANOWIRE USING ELECTROPHORESIS METHOD

NANO ◽

10.1142/s1793292008000861 ◽

2008 ◽

Vol 03 (02) ◽

pp. 75-82 ◽

Cited By ~ 18

Author(s):

INNAM LEE ◽

HO IL PARK ◽

SEONGYONG PARK ◽

MOON J. KIM ◽

MINHEE YUN

Keyword(s):

Electrical Conductivity ◽

Growth Process ◽

Site Specific ◽

Post Process ◽

Polyaniline Nanowires ◽

Electrophoresis Method ◽

Polymer Nanowires

Site-specific single polyaniline nanowires were fabricated through electrophoresis growth with acetone wetting. After growing the nanowires, the post-process of acetone wetting of the nanowires improved morphology, topology, and electrical conductivity with coagulation and substitution in polyaniline. They showed resistance changes of 39.57 ± 11.57% and presented 2.38 × 10-4 ± 3 × 10-5 Ω · cm, 133.77 ± 13.82 nm thickness, and 133.17 ± 13.01 nm width in 1 μm to 5.5 μm length. The new combined growth process of electrophoresis and acetone wetting significantly improved reproducibility, reliability, and controllability in the fabrication of single polymer nanowires.

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Nitrogen Application in Winter Wheat Grown in Mediterranean Conditions: Effects on Nitrogen Uptake, Utilization Efficiency, and Soil Nitrogen Deficit

Journal of Plant Nutrition ◽

10.1080/01904160701615541 ◽

2007 ◽

Vol 30 (10) ◽

pp. 1681-1703 ◽

Cited By ~ 21

Author(s):

Francesco Montemurro ◽

Grazia Convertini ◽

Donato Ferri

Keyword(s):

Winter Wheat ◽

Soil Nitrogen ◽

Nitrogen Uptake ◽

Utilization Efficiency ◽

Nitrogen Application ◽

Mediterranean Conditions

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Delineation of management zones with measurements of soil apparent electrical conductivity in the southeastern pampas

Canadian Journal of Soil Science ◽

10.4141/cjss2012-022 ◽

2013 ◽

Vol 93 (2) ◽

pp. 205-218 ◽

Cited By ~ 27

Author(s):

Nahuel Raúl Peralta ◽

José Luis Costa ◽

Mónica Balzarini ◽

Hernán Angelini

Keyword(s):

Electrical Conductivity ◽

Soil Properties ◽

Stepwise Regression ◽

Clay Soil ◽

Crop Yields ◽

Management Strategies ◽

Site Specific ◽

Management Zones ◽

Apparent Electrical Conductivity ◽

Specific Management

Peralta, N. R., Costa, J. L., Balzarini, M. and Angelini, H. 2013. Delineation of management zones with measurements of soil apparent electrical conductivity in the southeastern pampas. Can. J. Soil Sci. 93: 205–218. Site-specific management demands the identification of subfield regions with homogeneous characteristics (management zones). However, determination of subfield areas is difficult because of complex correlations and spatial variability of soil properties responsible for variations in crop yields within the field. We evaluated whether apparent electrical conductivity (ECa) is a potential estimator of soil properties, and a tool for the delimitation of homogeneous zones. ECamapping of a total of 647 ha was performed in four sites of Argentinean pampas, with two fields per site composed of several soil series. Soil properties and ECawere analyzed using principal components (PC)–stepwise regression and ANOVA. The PC–stepwise regression showed that clay, soil organic matter (SOM), cation exchange capacity (CEC) and soil gravimetric water content (θg) are key loading factors, for explaining the ECa(R2≥0.50). In contrast, silt, sand, extract electrical conductivity (ECext), pH values and [Formula: see text]-N content were not able to explain the ECa. The ANOVA showed that ECameasurements successfully delimited three homogeneous soil zones associated with spatial distribution of clay, soil moisture, CEC, SOM content and pH. These results suggest that field-scale ECamaps have the potential to design sampling zones to implement site-specific management strategies.

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240 RELATIONSHIP OF GROWING LOCATIONS, HARVEST MATURITY, SUMMER PRUNING, SOIL NITROGEN APPLICATION, AND STORAGE ON FRUIT POSTHARVEST PERFORMANCE IN `HAYWARD' KIWIFRUIT

HortScience ◽

10.21273/hortsci.29.5.464a ◽

1994 ◽

Vol 29 (5) ◽

pp. 464a-464

Author(s):

Sanliang Gu ◽

Carlos H. Crisosto ◽

R. Scott Johnson ◽

Robert C. Cochran ◽

David Garner

Keyword(s):

Soil Nitrogen ◽

Soluble Solids ◽

Soluble Solids Content ◽

Nitrogen Application ◽

Central California ◽

Flesh Firmness ◽

Solids Content ◽

Free Environment ◽

Harvest Maturity ◽

Relationship Of

Fruit from 8 `Hayward' kiwifruit vineyards in central California were harvested at 2 week intervals after soluble solids content (SSC) reached 6% and subjected to 4 and 6 months of storage at 0°C in an ethylene free environment. Fruit characteristics at harvest and postharvest performance varied considerably among locations. Fruit stored for 6 months had the same fresh weight, less flesh firmness and higher SSC, than the 4 months storage. Later harvested fruit had greater fruit flesh firmness and higher SSC after storage. SSC after storage was predictable based on ripe soluble solids content (RSSC) at harvest. Summer pruning reduced while soil nitrogen application increased fruit SSC.

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Low-Input Estimation of Site-Specific Lime Demand Based on Apparent Soil Electrical Conductivity and In Situ Determined Topsoil pH

Sensors ◽

10.3390/s19235280 ◽

2019 ◽

Vol 19 (23) ◽

pp. 5280

Author(s):

Moritz von Cossel ◽

Harm Druecker ◽

Eberhard Hartung

Keyword(s):

Electrical Conductivity ◽

Field Measurements ◽

Ex Situ ◽

Soil Electrical Conductivity ◽

Standard Equipment ◽

Site Specific ◽

Input Estimation ◽

Low Input ◽

North Germany

Site-specific liming helps increase efficiency in agricultural production. For adequate determination of the lime demand, a combination of apparent soil electrical conductivity (ECa) and topsoil pH can be used. Here, it was hypothesized that this can also be done at low-input level. Field measurements using the EM38 MK I (Geonics, Canada) were conducted on three experimental sites in north Germany in 2011. The topsoil pH was measured based on two approaches: on the field using a handheld pH meter (Spectrum-Technologies Ltd., Bridgend, UK) with a flat electrode (in situ), and in the lab using standard equipment (ex situ). Both soil ECa (0.4–35.9 mS m−1) and pH (5.13–7.41) were heterogeneously distributed across the sites. The same was true of the lime demand (−1.35–4.18 Mg ha−1). There was a significant correlation between in situ and ex situ determined topsoil pH (r = 0.89; p < 0.0001). This correlation was further improved through non-linear regression (r = 0.92; p < 0.0001). Thus, in situ topsoil pH was found suitable for map-overlay with ECa to determine the site-specific lime demand. Consequently, the hypothesis could be confirmed: The combined use of data from EM38 and handheld pH meters is a promising low-input approach that may help implement site-specific liming in developing countries.

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