Coping with Nitrates and Cross Compliance Regulations in Tillage

Farmyard management

For tillage farmers with no livestock this section has little relevance. Washings from vegetables and from farm machinery are considered to be soiled water. This soiled water has to be contained for 10 days within the closed period (see appendix 1 & 2) and land-spread in the correct manner.

Nutrient management

Effective nutrient management is a commonsense and economic approach to farming. Nutrients are becoming increasingly expensive as raw materials and energy costs rise and the misuse of nutrients has environmental consequences. The vast majority of farmers have been using nutrient management techniques successfully for years; however, previous fertilizer guidelines are now legal maxima.

Organic nitrogen – ‘the 170 kg/ha limit’

Each livestock farmer has received a statement of their organic nitrogen from the Dept of Agriculture, Food & Forestry (DAFF). Organic nitrogen is determined by the stocking rate of animals on a farm and quantities of organic manures imported onto a farm. The maximum permitted limit is 170 kg organic N/ha. On livestock farms it is effectively a stocking rate limit. It is not a limit on chemical N fertilizer. A livestock farmer must apply to the DAFF for a derogation to farm above this level, but only up to 250 kgs organic N/ha (the full details on the derogation process have yet to be announced by the DAFF). Tillage farmers importing organic manures are limited to 170 kg organic N/ha. For example you are limited to spreading 15.5t /ha of broiler litter per year (see appendix 4).

Crop fertilizers

SI 378 strives to ensure that the crop’s requirement for nutrients are satisfied. The fertilizer levels in the directive are maximum permitted levels and not recommended rates for a given set of circumstances. You are not obliged to spread the levels outlined in the directive. REPS farmers are obliged to follow their plans for fertilizer advice.

SI 378 uses four criteria to determine what chemical fertilizer a crop requires:

Soil phosphorus index

The phosphorus (P) advice for cereal crops is shown in appendix 3. No chemical fertilizer P is permitted at soil P index 4 unless potatos or beet are being grown. Soil analysis is the basis to determine the crops P requirement. In the absence of a soil test taken in the last 5 years, soil P is assumed to be at soil P index 3.

Potash (K) is not included under SI 378 but should be part of any nutrient plan.

Soil nitrogen index

The soil nitrogen (N) index system indicates the soils ability to supply N during the growing season and depends on the previous cropping history and previous organic manure applications. There are four N indices ranging from 1 to 4 - index 1 soils containing small soil nitrogen reserves and index 4 soils having the largest soil nitrogen reserves. Within SI 378 the nitrogen index table is split into two (see appendix 5). The upper half of the table applies to tillage crops grown in land more than 5 years ‘away’ from long term grass leys and is the most common situation found on farms. The lower half of the table applies to tillage crops grown in land less than 5 years ‘away’ from long term grass leys. In appendix 5, the crop within the columns is the previous crop. For example, in the case of land being in tillage more than 5 years, where oilseed rape was the previous crop, the soil is classed as being in N index 2.

Previous cereal crop yields

Additional nitrogen is allowable under SI 378 for high yielding cereal crops. The higher yield is based on the best yield in any one of the three previous harvests at 20% moisture content. For every 1 tonne/ha above reference yields (see appendix 6), a farmer may apply an extra 20 kg N/ha. Records (weighbridge dockets, etc) should be used to support farm reference yields.

For example, a farmer averaged 11 t/ha (@ 20 % mc) for winter wheat in 2006. This is 2t/ha more than the reference yield. Therefore he is allowed to spread the standard 190 kg/ha + 40kg/ha for extra yield giving a total of 230 kg N/ha for 2007-2009 on his winter wheat crops.

Organic manures

The nutrient value (N & P) of all organic manures is specified in SI 378. The phosphorus contained in organic manures is deemed to be 100% available to the crop. The nitrogen in organic manures has varying rates of availability, increasing up to 2010 in order to encourage better and novel use of manures. If land has received dressings of organic manure in two successive years, it is deemed to be soil N index 2. Transitional provisions allow that imported pig, poultry and spent mushroom compost can be applied to P index 4 soils up until 2011. However, the 170 kg organic N/ha limit still applies and all the imported phosphorous is assessed on a whole farm basis.

Application of fertilizers

There is a detailed section in SI 378 on the best practice methods of applying chemical and organic fertilizers. These are already being implemented by farmers under the ‘Code of Good Farming Practice’ with some additional measures. In general these rules detail how close you can spread organic and chemical fertilizers to watercourses and drinking water abstraction points. The amounts and the permitted spreading times of organic and chemical fertilizers are outlined also. A major change from the ‘Code of Good Farming Practice’ is that the country is now divided into 3 distinct zones each with its own set of dates during which it is prohibited to spread organic and chemical fertilizers. These zones, and the periods during which you cannot spread fertilizers, are set out in appendices 1 & 2.

Ploughing (incl. min-till)

There is much research to show that arable ground left ‘bare’ over winter is at more risk of nitrogen leaching than ground with a sown crop and it seems plausible that any practice that reduces soil nitrogen leaching will benefit the following crop. Under SI 378, autumn ploughing (1^st July – 15^th Jan) of arable land is only permitted if the following crop is emerged within 6 weeks after ploughing. With winter crops this is usually the case, but for spring crops, the practice of autumn ploughing and leaving the soil ‘bare’ over the winter is no longer possible. Grassland (incl. set-aside under grass) cannot be ploughed between 16 October and the 30th of November. Grassland can be ploughed after this date and crops can be sown at the grower’s convenience.

Use of total herbicides (e.g. glyphosate)

If you spray a total herbicide between the 1^st July and 15^th Jan, you must have a green cover emerged within 6 weeks after spraying. This may be from a sown crop or natural regeneration. In practice, natural regeneration occurs after a pre-harvest application of glyphosate, but a post-harvest application will prevent natural regeneration. Note that in the case of maize and root crops (potatoes, beet & vegetables) no action is required to establish a green cover over-winter.

Use of pesticides

Only use and keep in store, pesticides that are authorized by the Pesticide Control Service (PCS). The full list is published each year by the PCS and available from their website www.pcs.gov.ie . Pesticides should be used and handled in accordance with current labels.

Records of pesticides

Keep a record of pesticide application date, rate and quantity. The Irish Grain Assurance Scheme (IGAS) record book and the Teagasc E-crops program are acceptable for this purpose. Keep a record of the PCS registration number of any pesticides used.

Pesticide store

Ensure the pesticide store is leak-proof and have a bucket of sand available to soak small spillages. Keep pesticides in a signed, secure shed/press etc. Dispose of empty pesticide cans to an authorized body – keeping the disposal receipt.

Organic manures

Farmer B intends to apply 60 tonnes of broiler litter onto stubble ground in Feb 2007. He intends to plough it as soon as possible after application and sow a spring crop. Nutrient calculation for organic manures and its implication for total chemical fertilizer allowance are given in tables 5 and 6 respectively.

Farmer B will alternate poultry manure spread-areas around the farm, to ensure that each plot gets a maximum of one application every two years, to remain in soil N index 1

Poultry manure (& pig manure) contains high proportions of ammonia nitrogen which is readily available to the crop but also easily lost to the environment. In order to achieve the full benefit from poultry manure it should be incorporated as soon as possible (<24 hours) after application and used for spring crops. This strategy ensures that the crop demand for nitrogen is sufficient to take up the nitrogen in the manure, before it can be volatilized or leached. If it is applied in the autumn, crop demand is not sufficient to take up the nitrogen, putting it at increased risk of being lost over the winter period.

By using the high yields achieved in 2004 and 2006, farmer B will also have a sufficient total farm fertilizer allowance to meet his requirements and continue to grow profitable crops into the future. The crop rotation is changing from 2006 and the total nitrogen allowance is not comparable directly between the years. The poultry manure is valued at €14 per ton fertilizer (NPK) value (not incl. spreading charges). If profitable crops can be grown using poultry manure as part of the fertilizer strategy, farmer B intends to increase the amount imported onto the farm and save on his fertilizer bill.

Fertilizer

• Calculate total farm fertilizer allowance. The DAFF will inspect fertilizer records on a total farm basis not on a field by field basis. It is up to each farmer to allocate fertilizer to achieve maximum economic return, with due regard to environmental protection.
• Use high cereal yields to spread additional nitrogen. Growers are allowed to choose the top yield from any one of the 3 previous harvests.
• Apply organic manures at a maximum of “once every two years” basis to individual plots to remain under Nitrogen Index 1.
• Apply and incorporate organic manures as near to crop growth as possible to derive maximum benefit from organic nitrogen, with regard to environmental protection.
• Soil sample plots regularly (1 in 5 years) to take account of soil Phosphrus changes and keep the soil sample records.
• Growers will need to be more discriminating concerning timing and conditions when applying fertilizers to ensure maximum effect.
• Possibly delay top dressing very early sown (before end Feb) spring crops until after mid March due to limitations in applying nitrogen above SI 378 rates.

Records

• Keep records of cereal yields at harvest time. The DAFF will request weighbridge dockets to verify farm yield for each cereal crop. If no records are available, you will have to keep to maximum limits (appendix 6).
• Keep records of fertilizer purchases e.g. dockets. Fertilizer spreading records are not necessary, unless you are in a derogation situation.
• Keep Pesticides records. The I.G.A.S book or other suitable record format is acceptable.
• Calculate farm fertilizer allowance.

Ploughing and use of total herbicides

• Identify and treat fields with perennial weed problems e.g. scutch, pre-harvest (excluding seed crops).
• Apply post-harvest total herbicide before early October. Use stubble cultivation to encourage natural regeneration.
• When excessive stubble growth occurs, stubble ground may be grazed (GAEC regulations still apply).

Research

Many elements of the research programme deal with issue related to the current regulatory challenges. Nitrogen response trials and projects dealing with winter cover crops are continuing. Two major research projects are being carried out between Teagasc Research Centers to improve nutrient efficiency and lower ammonia emissions from animal manures. Teagasc Oak Park has started a five year project into improving the effectiveness of pig slurry onto cereal crops. Oak Park research staff will hold a major demonstration on current animal manure spreading technologies in early March 2007.