Teagasc: soil-fertility trends for 2021

Sadly, these downward tendencies coupled with lowered fertiliser (P and Ok) use in 2022 will probably result in additional operating down of soil nutrient reserves, which is able to negatively affect nitrogen-use effectivity and crop yields within the coming years.

Farmers ought to take heed of this early warning with a purpose to put plans in place to guard the productiveness and long-term sustainability of their farming enterprise.

Throughout the interval 2015 to 2019, good progress was made throughout all farming enterprises in relation to soil-fertility enhancements. Within the final two years, each dairy and drystock farms are displaying a mixed five-per-cent drop in soil fertility. On tillage farms, an identical development is rising from 2021, with a six-per-cent lower in soil fertility.

Nationwide highlights

· All farm enterprises took extra soil samples in 2021

· General decline in soils with optimum soil fertility to 16 per cent (-3 per cent)

· Soil pH declined to 54 per cent of soils with a >pH 6.2 (-8 p.c)

· Soil P ranges at Index 1 & 2 elevated (54 per cent) whereas soils at Index 3 & 4 decreased (46 per cent)

· Soil Ok ranges stay simialr with a slight lower in soils at Ok index 4

Enterprise highlights

Dairy

· 16 per cent of soils have optimum pH, P & Ok (three-per-cent lower)

· 53 per cent of soils with a soil pH >6.2 (10-per-cent lower)

· 55 per cent of soils at P index 1 and a pair of (four-per-cent improve)

· 48 per cent of soils at Ok Index 1 and a pair of (no change)

Drystock

· 13 per cent of soils have optimum pH, P & Ok (two-per-cent lower)

· 47 per cent of soils with a soil pH >6.2 (10-per-cent lower)

· 61 per cent of soils at P index 1 and a pair of (11-per-cent improve)

· 50 per cent of soils at Ok Index 1 and a pair of (three-per-cent improve)

Tillage

· 18 per cent of soils have optimum pH, P & Ok (six-per-cent lower)

· 61 per cent of soils with a soil pH >6.5 (13-per-cent lower)

· 57 per cent of soils at P index 1 and a pair of (seven-per-cent improve)

· 32 per cent of soils at Ok Index 1 and a pair of (two-per-cent lower)

Key messages from the outcomes

1. Massive requirement to use lime leads to 2021 now present that 47 per cent of dairy farms had soil pH under the optimum of pH 6.3.

Within the different enterprises, soil pH was under optimum in 53 per cent and 39 per cent of soil samples taken on drystock and tillage farms, respectively. This reveals that there’s nonetheless a big requirement for lime on Irish farms regardless of report ranges of lime utilized in 2021.

2. Shut consideration is now required to handle soil fertility

Over the past two years, the variety of soil samples from grassland with optimum P (better than Index 3) have proven a lower, whereas soil Ok ranges have remained secure over the identical interval. On tillage farms, an identical development is rising in 2021, with a drop in soil P ranges and an enchancment in soil Ok ranges. Motion is required now to stop a reverse of fertility enhancements achieved in earlier years.

3. An up-to-date nutrient administration plan is essential.

With synthetic fertiliser costing nearly thrice as a lot as two years in the past, making ready and implementing a nutrient-management plan has by no means been extra essential.

Plans needs to be primarily based on up-to-date soil samples; ought to focus firstly on correcting pH, secondly on getting probably the most from slurry and manures by figuring out the place it’s wanted most, and thirdly choose an appropriate P and Ok fertiliser mix to take care of farm soil fertility.