Potato Review

14 POTATO REVIEW MAY/JUNE 2020 IRRIGATION Sometimes visual clues can be misleading, for example, some soils will ‘cap’ so that they look wet but inside the ridge they remain dry, so Andy always recommends taking a spade, digging a hole and having a look. Sandy loams soils can be demanding soils for water, and Andy recommends water to be applied little and often, going slowly and carefully to wet them thoroughly. Knowing the history of a eld can help ensure strategies are correctly targeted, for example if the eld was harvested late owing to the wet conditions prevailing last autumn, there are likely to be some compacted pans where any water applied is likely to run-o . Irrigate according to varietal need Knowing exactly where the roots are in the soil, and ensuring the water reaches them, is Top tips for developing an irrigation schedule · Know your soils and variety · Consider in ltration rate of the soil and application method · Take root development and depth into consideration · Allow for applications aimed at crop quality ( for example, common scab control) crucial. e challenge is that not all varieties have the same root architecture and soil penetration depth, so irrigation schedules need to be variety-speci c, Andy stressed. “For example, Markies is known to be deep rooting and therefore it has more scope for scavenging for water than a shallow rooting variety such as Innovator, which can dry out very quickly.” Also worth bearing in mind this year is that rooting depth may be inhibited as over-wet soils have resulted in compacted pans, which may then cause di culties if soil conditions change dramatically by suddenly drying out. is, of course, will depend very much on the weather and the availability of irrigation. Weather conditions can be variable, so he advises growers to pay close attention to local forecasts or eld weather stations before deciding whether to irrigate. Soil moisture sensors can also play a useful role as part of the toolbox, but, he notes, they have limitations as they are only capable of measuring the soil where they are placed. “You still need to use your spade, have a look at conditions, and use your understanding of soil type, crop variety and its growth stage and make your decisions accordingly.” At the time of writing, soils were very wet, with many of the heavier ones likely to be compacted. “You still need to use your spade, have a look at conditions, and use your understanding of soil type, crop variety and its growth stage and make your decisions accordingly.” Booms work well in large, regular-shaped fields, but moving them can be labour intensive. Photo: Gary Naylor