Sensing soil and foliar phosphorus fluorescence in Zea mays in response to large phosphorus additions

Autor: Thanh H. Dao
Rok vydání: 2016
Předmět:
Zdroj: Precision Agriculture. 18:685-700
ISSN: 1573-1618
1385-2256
Popis: Additions of large loads of phosphorus (P) enriched animal manure to soils and the persistence of their environmental impact have been associated with continued water quality impairment in regions of high density of confined animal feeding operations. Foliar P in corn (Zea mays L.) and changes in labile P in Aquic Hapludults were determined following P application of 0–560 kg P ha−1 as KH2PO4 and an application of Fe3+ (150 mg Fe3+ kg−1) in field mini-lysimeters to develop calibrations of soil and plant nutritional responses. X-ray fluorescence (XRF) scanning of uppermost leaves of plants at the V2, V5, and V8 stages showed that foliar P proportionally increased with addition rates. Exchangeable and enzyme-labile P forms were effective indicators of foliar XRFS-P for up to 30 days after emergence. Phosphorus calibration curves developed for flag leaves showed that spatial distribution of foliar P (3.6, 4.2, and 5.3 g kg−1) corresponded to field zones treated with 0, 15, and 30 kg P ha−1 as dairy manure P for the past 18 years. Up-to-date crop uptake and availability of P in these Hapludults were best described by a square root function of soil XRFS-P and total exchangeable inorganic P (r2 = 0.4; RMSE = 419 and 422 g ha−1, respectively). Therefore, a timely knowledge of canopy P status and its linkage to actual soil P status supports in situ element-specific sensing and precision nutrient management in order to manage the declining use-efficiency in crops and reduce potential loss to the environment.
Databáze: OpenAIRE
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