8.
Calcium uptake by bell pepper
(Capsicum annuum L. cv. ‘California Wonder') varied by stage of plant development and N form supplied (NO
3 ‐NH
4 + ratios: 1:0, 3:1, 1:1, 1:3, and 0:1) in a hydroponic study. Uptake of Ca
++ was highest at bloom and during fruit expansion, making the fruit development stage the highest demand period. Calcium uptake declined with each increasing increment of NH
4 + relative to NO
3 ‐ supplied, although fruit yield was not significantly reduced until the ratio of NH
4 + to NO
3 ‐ exceeded 50%. Tissue Ca
++ levels in the blossom‐end of the fruit were reduced whenever NH
4 + was included with N supplied. Vegetative yield of plants followed the same trend as that observed for total fruit dry weights. Our results indicate that pepper yields are higher when NO
3 ‐ is the predominant form of N. Also, these results strongly suggest that Ca
++ fertilizer applications should precede the bloom period and continue during fruit development to ensure adequate Ca
++ availability for fruit development.
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