Iron and zinc nutrition of young apple trees, as affected by increasing available phosphorous in a calcareous soil
2004
Samar, S. Mahmood | Shahabian, Mehrdad | Divanbeygi, Soodabeh
Research results, indicated the sensitivity of some crop cultivars to high p concentration in root medium. Some cultivars are not sensitive and produce more dry matter in high P concentration. High P concentration causes Zinc and Iron nutrition problems in sensitive crops. Iron nutrition problem is a common one for apple trees grown in calcareous soils. In such conditions, iron chelate is usually applied. In many conditions like this, available P concentrations in soils are high and symptoms of zinc deficiency as well as iron deficiency is seen. It is observed that applying iron chelates, alleviate both zinc and iron deficiency symptoms. This experiment was conducted for more study of simple and interaction effects of increasing available P and Fe of a calcareous soil on Zn and Fe nutrition of Red Delicious apple seedlings. Ammonium phosphate was added in three levels of 0,3.3 and 6.7 gram per kg. of soil, and iron chelate was added in two levels of 0 and 0.158 gram per kg. of soil. Data showed that increasing soil available P caused available Zn increase, but not for Fe. Increasing soil available P to 54 microgram per gram of soil in the third level of P- fertilizer application, caused no decrease of leaf chlorophyll index or leaf size or weight, that are well known symptoms of Fe or Zn deficiencies. By available soil P increase, new leaf P and Zn concentration increased, but not for Fe. Increasing available soil P, resulted in increasing root P concentration, but not for Fe and Zn. Adding iron chelate to the soil, increased chlorophyll index of new leaves and Fe concentration of new and old leaves, but Zn concentration did not change. In low available soil P, iron chelate addition caused decrease in root Zn concentration, but there was no decrease in high available soil P. It is concluded that adding P- fertilizer to the soil, even in huge amounts, caused no problem in Fe and Zn absorption and translocation in Red Delicious apple seedling
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