Magnesium deficiency of kiwifruit (Actinidia deliciosa)

Abstract

Magnesium deficiency was associated with large yield reductions in a five-year-old commercial kiwifruit (Actinidia deliciosa) orchard. The effect on yield resulted primarily from a reduction in fruit numbers, there being no difference in mean fruit weight between fruit harvested from affected and unaffected vines. Magnesium deficiency had no deleterious effect on postharvest storage characteristics of fruit stored at 0.5 1 ~ for 18 weeks; fruit from deficient vines were firmer but had slightly lower soluble solids than fruit from control vines.Although deficiency symptoms were first observed on the basal leaves of the non-fruiting shoots mid season, indications of the impending deficiency could be established very early in the season using foliar analysis. Magnesium concentrations in youngest fully expanded leaves (YFEL) on the affected vines were less than 2.0 g kg ~ DM four weeks after budbreak and remained below this value for the rest of the season; concentrations in YFEL on unaffected vines did not decrease below this value and gradually increased after fruitset to 4.5gkg ~DM at harvest. To avert potential production losses, it is suggested that soluble magnesium fertilizers (containing at least 200 kg ha 1 Mg) should be broadcast early in the season if foliar magnesium concentrations less than 2.0 g kg-~ DM are measured four-six weeks after budbreak.

Soil and Leaf Chemical Properties and Fruit Quality in Kiwifruit Orchard

“…근권 분포는 지표면 약 60 cm(clay loam)이내에 대부분 분포하고 있다 [10]. 이 같은 생장을 위한 연간 질소, 칼리 그 리고 칼슘 흡수량은 1,000 m 2 기준 약 12.5-14.0 kg 내외이 고, 인산과 마그네슘 그리고 황 함량은 2.5 kg 수준이라고 알 려져 있다 [11,12]. 또한 키위 양분 함량은 수확기 전후에 최 대량을 나타낸다고 한다 [13].…”

“…토양 환원 이온의 증 가는 세포의 Fenton-Haber Weiss 반응을 이끌어 hydroxyl radicals(•OH)과 reactive oxygen species 생산을 통해 세 포막 구조 장해 등 생리적 장해를 유발한다 [17,18,19]. 토양 유기물은 토양 생물성과 물리적 환경 및 근권 생장 등 토양의 질에 미치는 영향이 크며 [20,21], 유효인산 등 음이온과 양 이온의 양적 부적절성은 결핍과 과잉에 따른 생육 불량을 유 도한다 [22][23][24][25][26][27].…”