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土壤酸碱度和石灰

土壤酸碱度在土壤肥力中起着关键作用。保持土壤的酸碱度在最佳水平会增加土壤的微生物活性,从而使土壤养分得到更好的循环和释放。Soil pH is also critical for maximising the availability of nutrients (N,P & K) applied in organic and chemical fertilizers.

石灰不断地从土壤中流失,需要作为营养管理计划的一部分予以更换。For example drainage water can remove approximately 250 – 625kg/ha,depending on the soil type,of lime equivalent each year.轻的自由排水土壤比重的土壤更容易流失石灰。因此,光地可能需要特别注意;尤其是在土壤母质或基岩中不存在石灰岩的地区。农作物和牲畜清除石灰,例如,a crop of first cut grass silage 5t/ha DM) removes approximately 75 kg/ha of lime equivalent.A finished bullock removed approximately 25kg while 1,000 litres of milk removes approximately 3kg of lime.氮肥也有酸化作用。Each 1 kg of N applied as CAN or Urea will generate acidity that will require approximately 2 kg of lime to neutralise.Urea tends to require more lime per kg N compared to CAN (27%N) and continuous application of urea will increase soil acidity.

石灰用量1970-2016

在过去的四十年里,石灰的使用量从1980年的平均170万吨下降到2000年的平均72.5万吨。This is a very large decline in lime usage and one would ask the question will lime be a limiting factor to achieving increased production targets set out in Food Wise 2025?

在过去的3年中,石灰的施用量从2014年的86.9万吨增加到了2016年的96.7万吨。天气和土壤条件等因素在每年的石灰施用中发挥着重要作用。例如,2016年8月至12月的有利天气条件导致了大量石灰的施用。curr通常,大部分土壤都需要石灰,仅对这些土壤进行石灰处理,就可以看到额外的牧草生产和更有效地利用有机肥料或袋式肥料的施用营养素的主要好处。

Target soil pH for a range of crops

一系列作物的目标土壤酸碱度如表1所示。Aim to maintain soil pH close to the target level and apply lime as recommended on the soil test report.

表1。Optimum soil pH for a range of crops

Crop Optimum pH
Beet,豆,Peas and Oilseeds 7.0
Cereals and Maize 六点五
草原 六点三
Grassland (High Molybdenum) < 6.2
Potatoes

测定石灰要求(lr)

石灰需求量在实验室根据测量土壤缓冲能力的试验进行计算。Buffering capacity is a measure of how much lime it takes to change the soil pH.因此,具有相同土壤ph值的土壤可能显示出不同的石灰要求。This is because the soils have different buffering capacities require more lime to achieve the same increase in pH.Soils that are heavier textured(clay soils) or higher organic matter levels tend to have higher buffering capacities and higher lime requirements as a result.然而,尽管土壤试验后这些土壤可能需要更多的石灰,缓冲能力越高,施用石灰后土壤的持力越好。

Timing of lime application

Lime can be applied at any convenient time of the year.For lime sensitive crops such as beet,cereals,maize,apply lime 2 years before sowing.如果没有施用石灰,则应在春耕后进行摊铺,以便在春耕期间与土壤发生反应,并与土壤充分混合。

For grassland,最好用在草地覆盖很少的地方。and to avoid grazing or cutting until sufficient rainfall has occurred to wash the lime off the herbage.对于青贮饲料,应在3月中旬前或在第二次割除土地后一周内施用石灰。Applying lime to heavy covers of grass intended for silage can reduce the silage quality if the lime is not washed off the grass by rain.

过灰

When a soil is over limed,有些作物可能会因缺乏植物性食物,如硼,iron and manganese.Crown Rot,a disease of beet,还有褐色的心,a disease of turnips are caused by boron deficiency.These diseases generally occur on alkaline or over limed soils.谷物中的灰斑是由锰缺乏引起的,这是由于石灰过多引起的。In practice,与每公顷施用量过多相比,过度施用石灰更可能是由不均匀的施用造成的。

Freshly applied lime may increase the amount of Common Scab on potatoes and this is a serious blemish in potatoes.It is a good practice to lime the soil after harvesting the potatoes.Where a good rotation is followed,at least five years will have elapsed before the next potato crop.

测试设备信息

Soil pH Meter 151

This piece of equipment will give an indication of the soils pH and can be very useful to diagnose lime shortage or crop suitability.

记住保持土壤酸度计是很重要的,through regular callibration with pH 4 and 7 buffer solutions for good results.土壤酸度计的设置和维护请参考以下指南。

石灰建议应仅基于实验室pH值读数,因为它考虑了土壤缓冲能力。The pH meter is only to give an indication of pH and is not to be used for lime advice.

有关更多信息,请参阅下面的详细信息。

Tom McHugh Engineering,
Stephensdown Lawn,
Two Mile House,
Naas
Republic of Ireland
Tel/Fax 00 353 458 76733

土壤pH测试仪151:Waterproof,重型测试仪,手动校准,range 0-14pH,精度+/-0.1ph

User Guidelines for pH Meter tests

Eco TestpH2 User Guide Test Equipment Assistance(Word文档)as above.

Articles and Publications

The following are some articles and publications

  • Liming FAQ,answers many frequently asked questions about lime and queries about liming.