Dang, Y. P. and Pringle, M. J. and Schmidt, M. and Dalal, R. C. and Apan, A. (2011) Identifying the spatial variability of soil constraints using multi-year remote sensing. Field Crops Research, 123 (3). pp. 248-258. ISSN 0378-4290
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Identification Number or DOI: doi: 10.1016/j.fcr.2011.05.021
In north-eastern Australia, soil attributes such as salinity, sodicity, acidity, and phytotoxic concentrations of chloride constrain the growth of crops. It is difficult to delineate constrained areas using conventional sampling methods. Alternatively, where crops fail, over multiple years, to pass a certain yield threshold, we might infer the presence of a soil constraint. For a wheat-growing farm over 10-year period we used remote sensing to obtain a large volume of surrogate yield data, by calibrating an archive of Normalised Difference Vegetation Index (NDVI) to an archive of (limited) ground-based observations. The model used was a generalised additive model that related wheat yield as a non-linear function of NDVI and a linear function of post-anthesis rainfall. Field locations where predicted yield consistently failed to reach the 75th percentile in a given year, over a number of years, we regarded as limited by at least one unknown soil constraint. Soil samples averaged for the constrained locations showed, compared with the unconstrained locations, relatively high concentrations of subsoil chloride, and, in the topsoil, relatively high exchangeable sodium percentage, and unused nitrate nitrogen. On-farm experiments suggested that, for constrained areas, preclusion of monoammonium phosphate (MAP) fertiliser application, coupled to gypsum amelioration, could potentially benefit the farm by A$32/ha/year (MAP) and A$207/ha/3 years (gypsum).
|Item Type:||Article (Commonwealth Reporting Category C)|
|Additional Information:||Permanent restricted access to published verison due to publisher copyright policy.|
|Uncontrolled Keywords:||soil constraints; crop yield; precision agriculture; NDVI; whole-farm economics|
|Fields of Research (FOR2008):||07 Agricultural and Veterinary Sciences > 0703 Crop and Pasture Production > 070306 Crop and Pasture Nutrition|
09 Engineering > 0909 Geomatic Engineering > 090905 Photogrammetry and Remote Sensing
05 Environmental Sciences > 0503 Soil Sciences > 050302 Land Capability and Soil Degradation
|Socio-Economic Objective (SEO2008):||B Ecomonic Development > 82 Plant Production and Plant Primary Products > 8205 Winter Grains and Oilseeds > 820507 Wheat|
|Deposited On:||02 Mar 2012 14:41|
|Last Modified:||04 Jul 2012 13:10|
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