苹果 - Chlorosis
症状
Old leaves bluish-green with scorched margins (brown or grey). Margins may first appear light green and later turn necrotic. Necrosis progresses from the margins inward to the midrib.
原因
Potassium deficiency
Frost and drought can cause similar symptoms
苹果 - Necrosis
症状
Old leaves bluish-green with scorched margins (brown or grey). Margins may first appear light green and later turn necrotic. Necrosis progresses from the margins inward to the midrib.
原因
Potassium deficiency
Frost and drought can cause similar symptoms
Potassium deficiency使变得更糟
- Acidic soils (low pH)
- Sandy or light soils (leaching)
- Drought conditions
- High rainfall (leaching)
- or heavy irrigation
- Heavy clay (illite) soils
- Soils with low K reserves
- Magnesium rich soils
钾很重要
- New growth is healthy
- Cold hardiness is improved
- Flower number increases
- Fruit are longer and are generally more intensely coloured
- Fruit may mature earlier and have improved flavour
- Yields are increased
对于钾雅苒推荐的产品是
YaraVita FOLIAR POTASH
Apple: 5 l/ha at bud burst. Also, two to three applications of 2 to 3 l/ha at 10 to 14 day intervals starting at petal fall. A further application of 5 l/ha may also be applied post-harvest before leaf fall. Water rate: 500 l/ha.
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