More and more crops of potatoes in Ireland are being irrigated.This is mainly to control common scab on our washing variety Rooster.In addition,灌溉以增加产量也越来越受欢迎。
Irrigation should commence at tuber initiation.This is when the tip of the first stolon is twice the diameter of the stolon itself.
(a) Reduces Common Scab.
(c) Reduces risk of cracked tubers.
(a) High capital cost
(b) High labour cost in moving equipment from place to place.
(e) Can cause machinery mobility problems during harvesting on heavy land or land with poor soakage.
Crop Responses (Per Mm Of Water Applied
|Peas - vining||0.04|
|Peas - dried||0.04|
Few potato soils are over bedrock which confine rooting,但剖面中的压实可以改变所有土壤的有效土壤深度，light and heavy.In seasons where there is moderate,均匀分布的降雨，crops grown without compaction can yield close to similar crops grown with irrigation.压实后，尤其是在浅水区，potato crops yield poorly.The target for minimizing the need for irrigation is clear;要创建尽可能深的根系统，关键是种植作物的土壤条件的质量。
Too Much Water:
到期时，potato plants lose much mater through transpiration.
- August the plant requires a regular supply of moisture for optimum yield and growth.
- During the months of July and August the crop requires 3½ mm of water per acre every 24 hours (almost 25mm per week).无论是由降雨还是灌溉提供，这对作物都没有什么影响。
- Do not apply in excess of 30 mm of water at any one time as this may result in restrictions to growth caused by temporary waterlogging,对土壤和树冠的物理破坏，并导致质量缺陷，如喷发的皮孔。
- Watch the frequency of repeat applications in relation to crop growth rate/canopy size.(Large canopies remove water rapidly through the transpiration system.小雨棚-水分通过蒸发从土壤表面流失。
If powdery scab is present in either seed or in the soil,在块茎发生后的时期，土壤水分的大幅度波动会加剧这种疾病。Cold soil temperatures and low oxygen concentration as a result of waterlogging delays suberization of lenticles,从而增加两种形式的结痂感染的易感性。
This disease causes serious loss of skin quality in potatoes,particularly in susceptible varieties.研究表明，当新组织形成时，如果土壤干燥，块茎就会受到攻击。Young skin over new tissue contains small pores called stomata: as the skin matures these develop into larger pores called lenticles.The organism responsible for common scab can infect tubers through stomata and newly forming lenticles,但不是成熟的透镜体。
Each successive layer of new tissue on a tuber is susceptible to attack for a period of ten to fifteen days only,and it then becomes immune for the rest of the season.As the tuber grows fresh areas of new tissue at the rose end are vulnerable,但生长模式是这样的，大多数从气孔到透镜体的转变是在块茎开始后的前六周完成的。The major concern,therefore,is to control common scab during the initial six weeks.冲洗可防止常见结痂组织感染。So growers using irrigation to control common scab must be prepared for a 6 weeks irrigation programme.
Common scab can be reduced by paying careful attention to irrigation for six weeks immediately after the first visual signs of tuber initiation.
When irrigating to control common scab note the following:
- Identify the crops where skin finish is a priority.
- 及时开始灌溉，即at tuber initiation - this stage must be identified by lifting plants and examining stolens (physical ageing will reduce the period from planting to tuber initiation.
- Apply small amounts of water - 12 15 mm.
- 取决于土壤湿度，applications may have to be made every 7 days
Applying the Water:
With maincrops,early irrigation is to control common scab and late irrigation (mainly July) is to increase yield.Irrigation may have to commence before tuber initiation if soils are dry and continue for the full period of initiation.我们最新的信息给了我们4个品种从50%出苗到50%块茎开始的天数；
- 卡拉- 27天
- Lady Rosetta - 18 days
The greatest need for irrigation occurs in dry and sunny periods that are associated with blight spread.然而，there is often a need to apply some irrigation to crops even in dull damp weather,as rain falls during such periods is often inadequate.
If a crop is irrigated,it should be considered as being in a "high-risk" situation for potato blight.
应根据建议使用杀菌剂，but after irrigation whenever possible in order to prevent their being washed off.On heavier soils,灌溉后可能无法行走。在这种情况下，spraying a few days earlier would be a better option