Responses of wheat to manganese fertilization on some calcareous soils of Fars Province in Iran

摘要

Wheat (Triticum aestivum L.) is the most important field crop in Iran. Since most soils of Iran are calcareous, the plant availability of micronutrients such as manganese is low. Despite this knowledge, there is little information about the manganesenutrition of wheat on the highly calcareous soils of Iran. In order to study the effects of Mn fertilization on wheat production, a greenhouse experiment was conducted on 25 selected highly calcareous soils of Fars province in south of Iran. The soils contained high levels of calcium carbonate (31%-49%) with DTPA - extractable Mn of 2.3 to 10.8 mg kg~(-1). In a randomized complete design with three replications, 0 and 10 mg kg~(-1) Mn as manganese sulphate was applied to 5 kg of soil in each pot. The results showed that the application of manganese sulphate significantly increased dry matter, total and grain yield from 11.2, 18.3 and 7.1, to 12.2, 20.2 and 8.0 g pot~(-1) respectively. Mn fertilization also significantly increased the Mn content, Mn uptake by leaves and grains, protein content, weight of 1000 grains and number of grains in each spikelet. The Mn content in the leaves and grain increased from 52 and 38.6, to 70 and 42.7 ugg~(-1) and Mn uptake by these organs increased from 579 to 850 andfrom 275 to 340 ug pot~(-1) respectively. Correlation coefficients between Mn extracted by DTPA and responses were relatively low, but increased when certain soil characteristics, especially calcium carbonate equivalent, were taken into account hi the regression equations. Based on information from the pot experiments, the critical level of Mn in the highly calcareous soils studied was 3.8 mgkg~(-1).