中国农业科学 ›› 2016, Vol. 49 ›› Issue (20): 3896-3903.doi: 10.3864/j.issn.0578-1752.2016.20.004

• 耕作栽培·生理生化·农业信息技术 • 上一篇    下一篇

石灰用量对酸性土壤酸度及大麦幼苗生长的影响

胡 敏1,向永生2,鲁剑巍1

 
  

  1. 1华中农业大学资源与环境学院/农业部长江中下游耕地保育重点实验室,武汉 430070
    2湖北省恩施州土壤肥料工作站,湖北恩施 445000
  • 收稿日期:2016-04-08 出版日期:2016-10-16 发布日期:2016-10-16
  • 通讯作者: 鲁剑巍,E-mail:lunm@mail.hzau.edu.cn
  • 作者简介:胡敏,E-mail:huxiaomin@webmail.hzau.edu.cn
  • 基金资助:
    国家“十二五”科技支撑计划(2014BAD11B03)、国家测土配方施肥补贴资金(财农[2009]211号)、恩施州科技计划(XYJ2014000039)

Effects of Lime Application Rates on Soil Acidity and Barley Seeding Growth in Acidic Soils

HU Min1, XIANG Yong-sheng2, LU Jian-wei1   

  1. 1College of Resources and Environment, Huazhong Agricultural University/Key Laboratory of Arable Land Conservation  (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, Wuhan 430070
    2 Soil and Fertilizer Station of Enshi Prefecture, Enshi 445000, Hubei
  • Received:2016-04-08 Online:2016-10-16 Published:2016-10-16

摘要: 【目的】研究生石灰用量对酸性土壤(pH3.9)降酸效果和大麦幼苗生长的影响,以期明确适宜的生石灰用量,为酸性土壤改良及生石灰的合理施用提供科学依据。【方法】试验于华中农业大学盆栽场进行,采用土壤培养和盆栽试验方法,依据Ca(OH)2滴定法计算出石灰需要量,设置不施生石灰和生石灰用量0.3、0.9、1.8、2.4和4.8 g·kg-16个处理,分别于培养后10、20、30、40、50、60、70和90 d取样8次,监测土壤pH、土壤交换性酸总量、土壤交换性H+含量和土壤交换性铝含量动态变化;于培养后第90天播种大麦,2周后进行观测,研究不同生石灰用量改良后的土壤对大麦幼苗生物量、根系形态指标及根系活力的影响。【结果】土壤培养试验结果表明,生石灰施入初期(前30 d)可明显提高土壤pH,降低土壤交换性酸总量和土壤交换性铝含量。石灰用量越高,潜在酸的含量越低,以至于石灰用量4.8 g·kg-1处理的土壤交换性酸总量、土壤交换性H+和交换性铝含量均降为零。但受土壤缓冲性能的影响,其降酸效果随着培养时间的延长而降低,到培养第90天,低石灰用量(< 1.8 g·kg-1)对于提高土壤pH已没有明显效果,而对降低土壤潜在酸效果显著。盆栽试验结果表明,施用生石灰可以显著提高大麦株高和生物量,促进大麦根系生长发育。在生石灰用量1.8 g kg-1的范围内,大麦幼苗株高、生物量、根系总根长、总表面积和根系活力均随生石灰用量的增加而提高,大麦幼苗根系平均直径随生石灰用量的增加而降低;用量超过1.8 g·kg-1后,生石灰对大麦幼苗生长的促进作用明显减弱。尤其是当生石灰用量为4.8 g·kg-1时,大麦根系活力显著低于石灰用量0.9 g·kg-1处理,过量生石灰的施用,抑制了根系的生长。这表明生石灰用量1.8 g·kg-1的改良效果最佳,与采用Ca(OH)2滴定法计算出的石灰需要量1.76 g·kg-1相吻合。【结论】在酸性土壤上施用生石灰能明显中和土壤酸性,显著促进大麦幼苗生长。在本试验条件下,酸性土壤(pH3.9)最佳生石灰施用量为1.8 g·kg-1(相当于4 t·hm-2生石灰用量),与采用Ca(OH)2滴定法计算出的石灰需要量一致,证实该方法确定的石灰用量是适宜的。

关键词: 生石灰用量, 土壤酸度, 大麦幼苗, 根系形态指标

Abstract: 【Objective】The aim of this study was to assess the effects of lime on soil acidity and barley seedling growth in an acidic soil (pH 3.9), and to determine the suitable dosage of lime and thus providing scientific proof for acidic soil improvement and reasonable application rate. 【Method】 The trial was conducted at the experimental base of Huazhong Agricultural University. Soil incubation and pot experiments were used. The Ca(OH)2 titration method was employed to estimate the lime requirement, and six treatments were designed: no lime, 0.3 g·kg-1, 0.9 g·kg-1, 1.8 g·kg-1, 2.4 g·kg-1 and 4.8 g·kg-1 lime application rates. Samples were collected on 10, 20, 30, 40, 50, 60, 70 and 90 days after incubation to monitor the dynamic changes of soil pH, soil exchangeable acidity, exchangeable H+ and exchangeable Al3+. Barley was sowed on the 90th day and harvested after 2 weeks to assess the effects of liming rates on barley biomass, morphological parameters, and root activity. 【Result】 Soil incubation results demonstrated that lime application significantly improved soil pH, however the content of exchangeable acidity and exchangeable Al3+ were decreased significantly during the first 30 days. The content of potential acid decreased gradually with the increasing dosage of lime, therefore the content of soil exchangeable acid, exchangeable H+ and exchangeable Al3+ were zero in the treatment of 4.8 g·kg-1. From then on, due to the influences of soil buffer, low lime dosages (< 1.8 g·kg-1) showed no obvious effects on improving soil pH but significantly reduced soil potential acidity. The results of pot experiment showed that application of lime significantly enhanced barley growth through improving plant height, biomass and root development. Barely seedlings plant height, dry mass, total root length and surface area, and root activity improved with the lime application rate from 0 to 1.8 g·kg-1. Whereas, lime input decreased root average diameter. Barley growth was inhibited significantly when lime application rate was above 1.8 g·kg-1. The root activity in the treatment of 4.8 g·kg-1 was lower than that of 0.9 g·kg-1, the excess of lime application retarded the root growth. Thus, the optimum liming rate was 1.8 g·kg-1, which agreed with the lime requirement calculated using the Ca(OH)2 titration method. 【Conclusion】 Lime application is capable of neutralizing soil acidity and promoting barley seedling growth. Under the conditions of this study (soil pH 3.9), the appropriate liming rate was 1.8 g·kg-1 (4 t·hm-2). This rate was consistent with that from the Ca (OH)2 titration method, confirming that the approach adopted in this study is appropriate for determining the lime application rate.

Key words: lime application rate, soil acidity, barley seedling, root morphological index parameters