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A heterogeneous potassium supply enhances the leaf potassium concentration of ridge‐cultivated tobacco grown in calcareous soil

Author:
Lu, Dianjun, Huan, Weiwei, Yan, Taotao, Wang, Yiliu, Jiang, Chaoqiang, Zhang, Xiang, Chen, Xiaoqin, Wang, Huoyan, Zu, Chaolong, Zhou, Jianmin
Source:
Zeitschrift für Pflanzenernährung und Bodenkunde 2017 v.180 no.6 pp. 659-666
ISSN:
1436-8730
Subject:
Nicotiana tabacum, biomass, calcareous soils, cost effectiveness, farmers, field experimentation, leaves, potassium, potassium fertilizers, rhizosphere, soil separates, sorption, tobacco
Abstract:
The high potassium (K)‐fixing capacity of calcareous soils with homogeneous K supply limits crop K concentration. The objective of this study was to determine the increase in the leaf K concentration of tobacco (Nicotiana tabaccum L.) with a heterogeneous K supply. Two field experiments were conducted from 2013 to 2015 with five K rates applied in homogeneous environments and one K rate applied in varying fractions of soil volume (from 0% to 100%) in heterogeneous environments. Under ridge culture, leaf biomass was not significantly affected by homogeneous (K rate) or heterogeneous (patch size) K management. Under homogeneous conditions, increasing the K supply to three times the standard rate used by farmers (249 kg K ha⁻¹) increased leaf K concentration significantly, but the effect was limited and not cost‐effective. Heterogeneous supply of K fertilizer at the standard K rate in patches of 0–40% of soil volume outperformed homogeneous K supply in terms of leaf K concentrations. Furthermore, K fertilizer mixed in intermediate soil volume fractions of 1–20% resulted in higher leaf K concentrations than the smallest (0%) and larger (30–40%) soil fractions. However, such K‐rich patch application should be managed precisely with specific placement due to the sharp reduction in available K with increasing distance from the fertilizer. To maximize the sorption of immobile K, the match between the uptake volume of the rhizosphere and the area available for K diffusion is important.
Agid:
5867995