Slurry Wizard. Introduction

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1 Slurry Wizard Introduction Before you use the Slurry Wizard you should read the guidance below on how to use them. The report is best viewed by pressing F11 on your keyboard to view as full screen. AHDB Dairy seeks to ensure that the information contained within this guide and the Slurry Wizard is accurate. However, AHDB Dairy shall not in any event be liable for loss, damage or injury howsoever suffered directly or indirectly in relation to the information and reports provided, and no liability will be accepted for errors or omissions. Copyright, Agriculture and Horticulture Development Board All rights reserved. No part of this publication may be reproduced in any material form (including by photocopy or storage in any medium by electronic means) or any copy or adaptation stored, published or distributed (by physical, electronic or other means) without the prior permission in writing of the Agriculture and Horticulture Development Board, other than by reproduction in an unmodified form for the sole purpose of use as an information resource when the Agriculture and Horticulture Development Board is clearly acknowledged as the source, or in accordance with the provisions of the Copyright, Designs and Patents Act All rights reserved. All other trademarks, logos and brand names contained in this publication are the trademarks of their respective holders. No rights are granted without the prior written permission of the relevant owners. 1

2 Slurry Wizard Start You may need to adjust your Excel security settings for the Slurry Wizard to work. Save the Slurry Wizard to your hard drive and always work from the saved version and save any changes with a new file name, so that you can go back to the original version if needed. On opening the Slurry Wizard you will see the screen below. You need to enter your own data in the white boxes as this will be carried forward to other pages. Enter your farm name or reference as this will be printed on each report, together with the date and time. Changing the depreciation rates could have a large impact on your results, so use the values shown unless you have a good reason to use a different value. Slurry Wizard Data entry Farm name/reference Herd size 120 cows Milk yield/cow 8000 litres Depreciation buildings 5 % Depreciation plant 10 % Interest rate 5 % Electricity cost p/kw hr Water cost 1.00 m3 Labour cost 10 /hr Tractor + man cost 25 /hr Test Use the buttons to move around the wizard. User guide - click on the button to link to the guide, which can be printed once open with a right click. EXCEL SECURITY You may need to alter your excel security settings to enable the functions of the Housing Wizard to work. Once you have entered your own data you can click on the Go to Slurry Wizard button on the right to take you to the next stage of data entry. The Slurry Wizard The main aim of the Slurry Wizard is to identify whether there is adequate slurry storage and to allow for different strategies to be explored. The AHDB Dairy booklet Cost effective slurry strategies on dairy farms should be read before using the Slurry Wizard. The Slurry Wizard has three key components. 1 To calculate the existing slurry capacity 2 To calculate the existing slurry production 3 A report to look at the monthly production compared to existing storage The Slurry Wizard includes the typical costs of slurry storage and associated operating costs for slurry spreading. If you wish to you can change some of the operating costs and the capital costs to refine the report for your own situation. 2

3 DATA ENTRY The first stage is to enter data specific to your own situation as shown below: The total farmable area is used to calculate the farm nitrogen loading. The telephone STD code is used to select the relevant monthly rainfall data for your location. The cows in herd are used in the slurry calculation. The cows in milk are used to calculate the volume of parlour washings. The depreciation and interest rates are used to look at the cost of new investment. The water cost is used to calculate the benefit of harvesting roof water. The slurry spreading cost is used to calculate the benefit of reduced slurry production. The cost of water storage, water diversion, roofing cost and slurry storage are used in calculating the cost:benefit of slurry production/storage options. It is very important for you to review the costs which might apply to your farm. SLURRY STORAGE CAPACITY The Slurry Wizard allows you to calculate the capacity of existing slurry stores. You should deduct freeboard from the height of the store to provide adequate capacity for exceptional rainfall. Deduct 0.3 metres for a steel or concrete store and 0.75 metres for a lagoon. For a slurry lagoon the area should allow for the sloping bank by taking the average width and length from the base of the lagoon to the freeboard level. 3

4 You must make a separate entry for circular stores (5 & 6) to allow the correct calculation of the capacity and the area. If the slurry store is covered you should tick the box so that the area is deducted from the total. The total slurry capacity is copied through to the report so that you can see how this compares with monthly slurry production. SLURRY SEPARATOR If you already have a slurry separator you should select Yes providing it is used to separate all the slurry produced on the farm and entering the store(s). You can adjust the % reduction in slurry entering the store. The default value is 20%, with the typical range from 15 to 25%. You need to be realistic about the reduction in volume achieved to avoid wrongly calculating the volume of storage required. PARLOUR WASHINGS TO SLURRY STORE The Slurry Wizard allows you to calculate the amount of water from parlour washing. If this water does not go in to the slurry store then click the No option. If Yes then click either High or Low volume washing or enter your own value if known. The total monthly volume of parlour washings will then be calculated and copied through to the report. UNCOVERED DIRTY YARD AREA TO SLURRY STORE There are many sources of dirty water from uncovered yards, e.g. feed areas, collecting yards, silage clamps, loafing areas, etc. 4

5 The Slurry Wizard allows you to calculate the area of the various dirty yards. The total area is copied through to the report. ROOF WATER AREA TO SLURRY STORE Roof water which drains in to the slurry store can significantly increase the volume of slurry. You will need to look at all roofs around the dairy unit and determine where the roof water drains to. If the water drains to the slurry store then include in the table. The area of the roof should be based on the floor area covered by the roof. LIVESTOCK DATA ENTRY The Slurry Wizard allows you to enter all livestock on the farm to provide a farm nitrogen loading calculation and to calculate the amount of slurry produced. Part of the table is shown below: 5

6 You should enter the annual average number of livestock in to each category and then enter the % collected as slurry, e.g. in the example above there are 120 cows in herd, but with dry cows housed on straw reduces the amount collected as slurry to 85%. For cows housed on straw the typical amount collected as slurry would be 50%, i.e. half of the cow excreta goes on the straw and the other half goes on the yard areas (feed, collecting, loafing, etc.). The farm nitrogen loading calculation is shown at the bottom of the livestock data entry table: In this example the total nitrogen output of 14,042 kg is divided by the farmable area of 106 hectares to give a farm nitrogen loading of 132 kg nitrogen per hectare. This figure is before export/import of manure. You should consider the farm nitrogen loading in relation to the requirement for Nitrogen Vulnerable Zones and/or Cross Compliance. THE REPORT The Slurry Wizard report provides a monthly profile of slurry production based on the information that has been entered as shown in the example report below. Slurry Report Cubic metres Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Total Days Total excreta as slurry % excreta to slurry store Excreta to slurry store Slurry separated Yes / 20% Parlour washings Yes Typical rainfall (metres) Own value rainfall (metres) Yard run off area to slurry store Slurry store area Roof water area to store Total cubic metres Cumulative production Total storage capacity Capacity less production You will need to enter the % excreta to the slurry store in the white cells, depending on when the cows would normally be at grazing, e.g. if cows go out to grass by day in the first week of March and then fully grazing by day and night by the third week of March then you would enter 50% in March. During the main grazing period you would expect around 20% of the slurry to fall on yards associated with milking. The report will show the typical monthly rainfall amount in metres based on the STD telephone code that you entered. You can enter your own values in the row below and must be entered in metres per month. The monthly rainfall value will be used to calculate the volume of water entering the store from roofs, yards and the slurry store. If you have entered your own values these will be used instead of the typical values. 6

7 The report also shows the slurry production compared to the capacity. This assumes that the store is empty at the 1 st October. In this example there is only enough storage for 4 months slurry. The shortfall in capacity is 3 cubic metres. The next step is to consider alternative options. You should consider diverting all roof water and/or diverting dirty water to a separate store. The report provides some cost:benefit information, which is based on the data entered: The net benefit is based on the total area of roof water and dirty yard area, either with or without water harvest. In this example the benefit of diverting all the roof water is 3,177/year, which increases to 4,119/year if the water is stored and used on the farm. In this example there is a loss from roofing the dirty yards of - 3,063/year, which even with water harvest reduces to a loss of - 2,416/year. The use of a slurry separator is not included in the Slurry Wizard as this is a more complex decision. Action points may display based on your own data. Once you have established the current situation you can save this as existing and then consider alternative strategies, which can then be examined using the Slurry Wizard and saved as alternative options. DISCLAIMER AHDB Dairy recommends seeking clarification of the specific requirements of Nitrate Vulnerable Zones (NVZ) regulations for your farm. The calculations carried out using this tool will be based on figures provided by the user and AHDB Dairy cannot take responsibility for decisions made as a result. 7