Soil Fertility Management on the Teagasc Tillage BETTER Farms Williamsons in Wexford

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1 Soil Fertility Management on the Teagasc Tillage BETTER Farms By Mark lunkett and David Wall, Teagasc, Crops Environment and Land Use Centre, Johnstown Castle Cereal crop yields in Ireland are amongst the highest in the world and in 2011, winter and spring barley, and spring oats recorded their highest yields compared to Central Statistic Office records (since 1985). In the same year winter and spring wheat recorded their 2 nd highest yields since 1985 (2004 being the highest).the high yield potential in Ireland is brought about by a combination of favourable weather conditions and soil factors and if a number of critical crop and soil management factors are achieved high cereal crop yields can be realised. Soil fertility management is a key component of any tillage farming enterprise and has been a focus for the Teagasc, Tillage Crop BETTER Farms programme. This programme has being running since 2009 in conjunction with three farms in Cork, Meath and Wexford. The programme was established to provide a platform for technology transfer and for demonstrating best practice concerning many aspects of tillage farming in Ireland. On the three farms being monitored there is a history of soil sampling and targeted fertiliser applications to meet crop requirements. Over the past three years the fields on these farms have been intensively soil sampled to assess changes in soil nutrient status and to evaluate the fertiliser application programmes in relation to the soil type and crop rotation on each farm. Over the last number of decades nutrient requirements for individual crops have changed as new higher yielding varieties have increased crop nutrient demand. In addition, on these farms, the cropping rotations have also changed over the last decade, and the crop nutrient advice has needed to evolve in order to satisfy the demands for these new crops. In order to support changes in nutrient management practice a number of N,, and trace element field trials have also been conducted on all three farms to measure crop yield response to these nutrients. Williamsons in Wexford Traditionally, George and enneth Williamson practiced a spring cereal and sugar beet crop rotation on moderately well drained heavy textured soils on their farm in south Co. Wexford. Care must be taken to cultivate these soils at the correct time, and not too early for the preparation of a suitable seedbed at sowing, in order to ensure satisfactory crop establishment as these soils are prone to capping says George. These clay loam soils are moisture and nutrient retentive and have the potential to produce very high yielding crops. Since the introduction of the Tillage BETTER Farm rogramme local Teagasc tillage advisor John ettitt has worked closely with Williamsons to integrate best crop management practices on the farm. More winter cereals have been included in the crop rotation in order take advantage of this high yield potential and also to spread the workload over a longer period at planting and harvest times. The soils on the Williamsons farm have been intensively sampled in 2009 & Table 1 shows the percentage of soils in the different soil and indexes and the trends in soil fertility across the farm over this time period. The numbers of soils at index 1 have decreased from 50 to 25%, soils at index 2 have increased from 25

2 to 50%, soils at index 3 have decreased from 25 to 12.5% and soils at index 4 have increased from 0 to 12.5%. These results show that the overall fertility across the farm has improved with fewer soils at very low levels ( index 1). Changes in soil fertility on the farm have been more variable. While there has been an increase in soils at very low levels (Index 1: 0 to 12.5%), there has also been an increase in soils with sufficient levels (Index 4: 0 to 12.5%). Table 1: ercentage (%) of soils in each & index in 2009 and 2011 for the Wexford farm Soil Index & (very low) (low) (optimum) (sufficient/excess) Over the last 3 years the crop rotation on the Williamsons farm has changed to included more winter cereals with a reduction in the land area devoted to spring barley production. During this time the main fertiliser compounds used also changed from a fertiliser supplying a to ratio of 1:2 (e.g. N--: / ) to a : ratio of 1:2.4 type fertilisers (e.g. N--: ) which better matches the crops annual and requirements. For example, in 2009 an average of 33kg/ha and 76kg/ha was applied compared to 39kg/ha and 96kg/ha in Table 2: Wexford farm & balance over the 2010 and 2011 cropping seasons Nutrient 2 yr Nutrient Removal (kg/ha) 2 yr Nutrient Applied (kg/ha) 2 yr Farm Balance (kg/ha) Soil Test Change mg/L mg/L The farm and balance (table 2) shows the average nutrients removed compared to the average nutrient applied for the 2010 and 2011 cropping seasons and its effect on soil fertility levels. Over the 2 years a total of 65kg/ha was removed (at harvest) and 77kg/ha was applied resulting in a surplus of 12kg/ha being applied. As 75 % of the soils on the farm were below optimum soil levels (i.e. index 1 & 2) this surplus helped to build soil levels on the farm resulting in an average soil test increase of 0.3mg/L over the 2 years. Over the same period a total of 196kg/ha was removed and 173kg/ha was applied, resulting in a deficit of 23kg/ha (i.e. more removed than was applied). This resulted in an average drop in soil test levels of 5mg/L over the 2 years. Very high cereal crop yields were achieved on this farm in 2011 resulting in high removals (116 kg/ha) in grain and straw. Table 3: Typical & removal over 5 yr crop rotation Crop Crop Crop Yield Nutrient Removal per Crop Rotation Year otential t/ha kg/ha (units/ac) kg/ha (units/ac) Yr 1 Winter Wheat (30) 98 (78) Yr 2 Winter Oats (27) 130 (104) Yr 3 Winter Wheat (30) 98 (78)

3 Yr 4 Winter Barley (29) 108 (86) Yr 5 Winter Rape (24) 45 (36) Average & Removal (kg/ha) 35 (28) 96 (77) On average over the 5 year crop rotation 35kg/ha and 96kg/ha will be removed annually based on target crop yields in table 3. The aim of the fertiliser programme is to replace nutrients removed to maintain soil fertility. For example the current fertiliser programme applied 430kg/ha (3.5 bags/ac) of N--: For low fertility soils (Index 1 & 2) additional and will be applied annually to build soil fertility to optimum levels (index 3) over a number of years (see table 4). For the crop rotation in table 3, index 2 soils will receive 45kg/ha (35+10) and 111kg/ha (96+15) each year until the soils are re-sampled in 4 years time. Table 4:Additional & required for soil build up (kg/ha) Soil Index It is well recognised on the Wexford BETTER farm that there is no substitute for a soil with good and fertility. A stronger focus has been placed on crop nutrient requirements and crops that better suit soil type have contributed significantly to farm profitability over the past 3 years says John ettit, Teagasc, Tillage Advisor. Crowley s in Cork John and Denis Crowley farm on medium to heavy textured soil types in North Cork. Traditionally the farm was heavily involved in sugar beet production and the loss of this crop brought about substantial change in the farming system. Winter cereals (wheat and barley) are the main stay of the cereal crop rotation on the farm. The Tillage BETTER farms programme is facilitated by the Local Teagasc tillage advisor Ciaran Collins who works closely with the Crowley s on all aspects of tillage management. The whole farm was soil tested in 2009 and a large section which predominantly grows continuous winter barley was retested in 2011 to monitor soil fertility changes over this period. The soil type in this block of land is a well drained sandy loam and is very suitable for the production of winter barley. This land is not sown early as the soil type suits late sowing; as it dries out relatively fast in the autumn says John. Table 5 shows the percentage of soils in the different soil and indexes and the trends in soil fertility across this block over this time period. Soil test results reveal that soil and levels have changed significantly over the last 3 years. The percentage of soils with low levels (index 2) have increased from 12 to 53%, while soils with optimum levels (index 3) have decreased from 65 to 41% and none of the soils remained at index 4 in Soil levels show a similar trend in that the percentage of soils with very low and low levels (index 1 and 2) have increased, while the percentage of soils at index 3 decreased from 29 to 6% over this period. Overall the soil and fertility levels on this block of land have decreased in the last 3 years.

4 Table 5: ercentage (%) of soils in each & index in 2009 and 2011 for the Cork farm Soil Index & (very low) (low) (optimum) (sufficient/excess) There are a number of factors that may have contributed to the decline in soil fertility on this block of land on the Cork farm. Firstly, the soil type is a sandy loam which is likely to have less nutrient retention than a more clay rich loam or clay loam or clay soil type. In general soil test and levels are more responsive (will increase or decrease faster) to the levels of nutrient application on sandier soil types. Secondly, very high yields of winter barley (10t/ha plus) have been harvested off this block of land over the last 3 years, therefore mining significant quantities of and annually in the grain and straw. Thirdly, 370kg/ha (3 bags /ac) of N--: was applied in the previous fertiliser programme for winter barley. At these application rates there was a small shortfall of 1kg and large shortfall of 76 kg /ha over the last 2 years which had a negative impact on soil fertility levels. Table 6:Cork farm & balance over the 2010 and 2011 cropping seasons Nutrient 2 yr Nutrient Removal(kg/ha) 2 yr Nutrient Applied (kg/ha) 2 yr Farm Balance (kg/ha) Soil Test Change mg/l mg/l The and balance for the 2010 and 2011 cropping seasons is shown for this block of land in table 6. hosphorus removal in the harvested crop was broadly similar to inputs ( 75 v 74 kg/ha) over this period however, when soil storage and losses are taken into account the application was not sufficient to maintain soil test levels resulting in an average soil test decrease of -1.9 mg/l over the 2 years. This is a large drop in soil levels and may be related to the sandier nature and lower buffering capacity of the soil.. Crop removals were well in excess of applications (224 v 148kg/ha) and this is been reflected in the drop of 31mg/L of soil. In order to halt the decrease in soil levels on this soil type application rates will need to be increased to match crop removal rates. For example a 10t/ha crop of winter barley will remove 115kg/ha annually. In this case the application of an N-- compound (e.g ) should continue on a yearly basis to meet all the crop needs and most of the crop needs but additional could be applied rotationally as MO (50%) once every 2 years to supply the remainder to the required. The decline in soil and experienced on this soil type may not be typical on the majority of Irish soils as and levels tend to change more slowly over time. Additional soil sampling is planned for the end of the 2012 season in order to further investigate these trends in soil and levels. O Donoghue s in Meath Joe O Donoghue and his brother, Colm farm on moderately to well drained medium to heavy textured soils close to the Meath-Dublin border. These gravely clay loam

5 soils have good moisture holding capacity but are prone to compaction as they have weak structure and sticky consistency. Soil fertility is an important component when growing cereal crops but it is also critical to maintain good soil structure, establish crops in good condition, carry out timely field operations, and most importantly know your land and match crops to suitable soils says Joe. With a proportion of the farmed area rented over longer periods the challenge is to establish a good foundation for future crop production on this land in the first few years. Local Teagasc tillage advisor Shay helan works closely with the O Donoghues on all aspects of crop production and facilitates the adoption of new technology through the Tillage BETTER farms programme. Table 6 shows the percentage of soils in the different soil and indexes and the trends in soil fertility across this farm between 2009 and The soil test results show no change in soil levels over this period. Soil levels show a positive change with the percentage of low soils (index 1) decreasing from 44 to 22%, soils and the percentage of soils in index 2 and 3 increasing by 12% and 11% respectively. The soils on this farm have been formed from calcium rich till with soil ph ranging from even though little lime has been applied over the years.. Table 6: ercentage (%) of soils in each & index in 2009 and 2011 for the Meath farm Soil Index & (very low) (low) (optimum) (sufficient/excess) The crop rotation on the Meath farm consists mainly of continuous winter wheat, or spring barley and break crops such as oilseed rape. In 2011 high yields of spring barley were achieved (8.1 t/ha) which removed high levels of 31kg/ha and 92 kg/ha similar to some moderately yielding winter crops. In the past high and compounds were used to build soil fertility (e.g. N--: ), however with high fertiliser prices in 2009 fertiliser programme relied on more traditional fertiliser compounds such as N--: The aim for these years was to supply just enough and to meet crop off-take and control production costs. Table 7: Meath farm & balance over the 2010 and 2011 cropping seasons Nutrient Av. Nutrient Removal(kg/ha) Av. Nutrient Applied (kg/ha) 2 yr Farm Balance (kg/ha) Soil Test Change mg/L mg/l The Meath farm two year and balance is shown in table 7. The average removed in grain and straw was 64kg /ha and the average applied was 44 kg /ha, resulting in a deficit of 20kg/ha over the last 2 years. However the effect of this deficit on soil levels was relatively small with an average soil test decrease of -0.1 mg/l over the 2 years. These heavy textured soils have the capacity to retain applied and within the root zone and maintain a constant supply of these nutrients throughout the growing season. In this way the effects of the undersupply of applied

6 were minimised as the crops were able to draw on the soil reserves. Similarly crops removed 177kg/ha compared to 143kg/ha applied over the last 2 years. This resulted in a deficit of 34kg/ha over this period, however, contrary to the balances soil levels increased by 19mg/L. This can be explained by the historic application on these fields where surplus was applied as a high compound (N--: ) to crops in the previous two years (2007 and 2008). This surplus sustained soil reserves over the 2009 to 2011 period. In order to maintain high crop yields on this farm going forward this borrowed soil and reserves will need to be replenished in the near future. Summary Over the past number of years there has been change on all three farms, in particular changes in crop type and sequence within the rotation has been a factor that has helped to maximise the yield potential and profitability on each farm. Soil fertility is one of the key factors in the production of high yielding crops and the farm fertilizer programme must be aligned with the nutrient requirements of the new cereal varieties. Fertilizers now represent a significant cost in the production of tillage crop and they need to be managed as efficiently as possible. Soil testing is the cheapest and most effective tool to base sound fertilizer decisions on. During the period that the Tillage BETTER farm programme has been in place nutrient requirements on these three farms have changed. Good soil fertility information through regular soil sampling has played a key role in fine tuning nutrient advice on each farm. Fertiliser practice has evolved over the last number of years to meet the nutrient demands depending on soil type and crop yield potential in each field. On the Wexford BETTER farm more winter cereals are now grown which suit the heavy soil type. The fertiliser strategy has changed to include fertilisers that better match both soil and crop and requirements. On the Cork BETTER farm continuous winter barley production on a sandy loam has shown that additional and is required to maintain soil fertility levels. On the Meath BETTER farm crop types are suited to the soil types and soil fertility levels. On this farm soil fertility levels have remained relatively stable despite any shortfalls in nutrient inputs in any one year, as adequate nutrients are being supplied when appropriate on a longer term basis. One of the key messages from the programme regarding soil fertility is to look backwards as well as looking forwards when formulating fertilizer strategies for farms. In particular years (e.g. 2011) exceptionally high crop yields will result in higher and removals which need to be replenished in future years. Soil testing is an important tool to identify soil fertility trends and results should be used to adjust fertilizer programmes where required.