Soil Phosphorus Availability and Pearl Millet Water-Use Efficiency

Payne, W A and Drew, M C and Hossner, L R and Lascano, R J and Onken, A B and Wendt, C W (1992) Soil Phosphorus Availability and Pearl Millet Water-Use Efficiency. Crop Science, 32 (4). pp. 1010-1015.

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The effects of P and water stress on transpirational water-use efficiency (WUET) of pearl millet (Pennisetum glaucum) cv. ICTP 8203 were studied in outdoor pot and growth chamber experiments. Plants were grown outdoors under semiarid conditions in covered pots containing 85 kg of acid, P-deficient Betis sand (sandy, siliceous, thermic Psammentic Paleustalf). Pots were given 0-7.77 g P/m² (equivalent to 0-70 kg P/ha), water stressed or not stressed, and plants harvested at 14-d intervals. Significant main and interactive effects on WUET due to P level, water treatment, and harvesting date occurred. The slope of the curve relating DM to cumulative transpiration increased with P level and water stress when data from all harvests were pooled. In the growth chamber, WUET of non-water-stressed plants ranged with increasing P level from 3.22 to 9.12 g/kg at 29 d after sowing (DAS) in pots containing 6 kg soil, and from 0.84 to 9.24 g/kg at 49 DAS in pots containing 18 kg soil. The ratio of leaf net photosynthetic rate to transpiration (WUEgas) at 500 µmol/m² per s photosynthetic photon flux density (PPFD) ranged from 1.88 µg/mg for plants receiving no P to 10.25 µg/mg for those receiving 0.31 g P/6 kg soil. Between PPFD levels of 500 and 2000 µmol/m² per s plants receiving no P increased WUEgas to only 3.60 µg/mg, whereas those receiving higher levels of P increased WUEgas to as much as 18.2 µg/mg. It was concluded that water supply in semiarid environments cannot be effectively managed for improved crop production without addressing soil fertility constraints.

Item Type: Article
Subjects: Mandate crops > Millets
Depositing User: Library ICRISAT
Date Deposited: 15 Sep 2011 03:26
Last Modified: 14 Sep 2013 12:27
Official URL:
Acknowledgement: UNSPECIFIED
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