石灰性土壤中几种蔬菜幼苗吸钾特点的研究

STUDIES ON POTASSIUM UPTAKE CHARACTERISTICS OF SELECTED VEGETABLE CROPS IN CALCAREOUS SOILS

本文选用8种蔬菜作物在两种石灰性土壤上进行幼苗耗钾试验,以探讨不同蔬菜作物在苗期的吸钾特点。试验结果表明,各种蔬菜作物吸钾和耐钾饥饿的能力有明显的差异。在耗钾试验中,作物吸收的钾绝大部分来自土壤非交换性钾,其中 1M热HNO_3一次不能提取的非交换性钾部分最高可达55％,其数量随种植次数及作物吸钾总量的增长而提高。

In order to study potassium uptake characteristics of vegetable crops, greenhouse seedling exhaustive experiments with 8 species ( radish, rape, three-colored amaranth, cucumber, tomato, cauliflower, chilli and celery)were conducted in two calcareous soils of different fertility. Results showed that, under experimental conditions, the potassium uptake characteristics of various vegetables were significantly different. Of the 8 species, radish and rape had higher potassium uptake ability and potassium starvation enduring ability; cucumber and three-colored amaranth had mediate potassium uptake ability but lower potassium starvation enduring ability; chilli, tomato, cauliflower and celery had lower potassium uptake ability but relatively high potassium starvation endurance.More than 80% of potassium uptaken by crops were from soil non-exchangeable potassium in the continuously croping process. Fur-thermore, part of the absorbed non-exchangeable potassium (up to 55%) was not 1 M HNO3 soluble, the percentage taken from this part in the total potassium uptake increased along with the total increasing. Mean-while, the percentage of this part in potassium uptake of each harvest increased with the croping going on.