Back to square one: While there was some drying last weekend, many parts of the country are quite wet again, with parts of the south remaining driest, but not dry. We will have this cold snap for a few days and then the forecast is for a return to rain, so there is no immediate chance of getting out on land – perhaps there is no good reason to be there either. Most tillage areas seem to have received an inch so far this month, with much more in north Leinster and the northwest.

Crop condition varies considerably, from strong to struggling. But everything is still much better than this time last year. While land remains too wet, some more backward crops will need feeding once the ground dries out and we get some growth.

Spring nitrogen: It is still on the early side for nitrogen and other nutrients for most crops, but some of our more backward crops would benefit from some feeding shortly. Most crops do not need it yet and they are very unlikely to benefit from it, even if you could get out on the land. Nitrogen is about growth – no growth, no need. But some crops could do with an injection of pace to help get them to where they need to be in the coming weeks.

When we say nitrogen, that implies all required basic nutrients and sulphur. Trace elements are more important during active growth and we are not there yet. Rape and barley are the highest priority, as well as more backward crops.

All crops need sulphur, especially on lighter and more worn land, but this requirement can be reduced or removed on land that has been in regular receipt of organic manures. Sulphur can be the easiest to apply in the first application where relatively little N is required.

Get 30-50kg of N out on backward crops when you can travel. That might apply to all backward winter cereals and low-canopy oilseed rape crops now. There is no rush on most other crops for a few weeks.

N for oilseed rape: Use green area index (GAI) to guide N rate on rape. This crop needs a specific amount of growth, but only that much, and too much nitrogen early can be negative for yield. The aim is to control the amount of canopy produced. This can mean between 60kg and 160kg N/ha in early spring, depending on the GAI measured at the end of February.

If you record a GAI of 1.5 then, to produce the target level of 3.5, you need to create two more GAI points in spring growth. Each one of these requires 50kg of N to build the foliage, so that would be 100kg. If we think we might have 20kg in the soil, that means we must get 80kg into the plant from the bag.

As applied fertiliser is only about 60% efficient, we need to apply 135kg to provide the 80kg to make the canopy. And with 90kg being the recommended split at stem extension to help drive yield and retain lower leaves, that keeps us withing our 225kg/ha legal limit for the crop.