AGRAVIS recommends: Do not make false economies with regard to fertiliser
There is uncertainty regarding future developments in all agricultural sectors. What product prices can we expect during the medium term? Which strategy is the correct one for the company orientation? Usually, the production costs are the first thing to be reviewed in the light of such a background. Measures that do not appear to have a clear purpose are then questioned and stopped. With regard to crop cultivation this is often, unfortunately, the liming process.
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- In times where agricultural product prices leave little room for error, liming is necessary.
It is tempting to do aside with the costs for liming in a year, even if these are only responsible for 1 to 2 per cent of total variable costs. However, what are the consequences of long-term omission of liming?
Usually, the need for agricultural lime in arable soils is undisputed in most regions. The use of mineral fertilisers that leach lime from the soil, and the natural acidification due to precipitation, soil respiration, and soil conversion processes up to root exudates from the cultivated plants that were grown all contribute to a considerable loss of lime.
In order to maintain soil fertility and therefore maintain the foundation of production, the pH value must be used as an indicator and calcium as a nutrient must be kept at the optimum level. If these are not at optimum levels, then workability of the soil is more demanding, the availability of all nutrients fades, soil life is thwarted, and in the worst-case scenario, the solubility of heavy metals that are toxic to plants increases. All of these factors have a greater effect on yield than the last kilogram of nitrogen or the correct choice of fungicide strategy.
Falls in yield of up to 10 per cent
Investigations clearly show that insufficient lime can lead to falls in yield of 30 to 40 per cent with regard to maize, barley, and sugar beet. Wheat, rye, and potatoes have shown themselves to be less susceptible in the investigations. Nevertheless, no operating manager can take responsibility for falls in yield of 10 per cent due to not carrying out liming during this current period.
Feed efficiency is of decisive importance
Even on grassland liming is just as important as farmland and should take place to the same extent. With regard to milk production, feed efficiency is the most important factor. Also, it is this feed efficiency that is determined by the quality of pasture land growth. In addition, liming has an effect on the species composition of the sward. Value-determining and high-quality feed plants require a weakly acidic to neutral pH value. On the other hand, low-quality feed plants dominate on acidic grassland soils. Rushes and sedges, the marsh marigold, and the creeping buttercup are regarded as indicator plants for acidic soils.
Amendments to fertilisation regulations
With regard to the topic of crop nutrition, the frequently described and regularly discussed amendments to fertilisation regulations will be a matter requiring much focus. This requires all participants to focus even more intensely on the use of nutrient sources. The objective must be to ensure that the highest possible proportion of applied nutrients are absorbed by the cultivated plants and that this is manifested in yield. If an adequate supply of lime on the farmland or grassland is not ensured, then the provision of important macro- and micronutrients is suboptimal and general use is not efficient. A sound strategy in line with crop rotation against the backdrop of stricter legislation is therefore a key lever in this system.
Every three to four years: Perform soil analysis
Alongside a spade test, soil analysis is the most important monitoring tool for determining the state of soil. The latter should not only be carried out every six years to fulfil legal obligations, but every three or four years instead. The results can be used to monitor the fertilisation strategy. If sampling is repeatedly carried out at the same point of time in crop rotation, then comparisons can be made with older samples and conclusions can be drawn regarding how values have developed. If there are serious imbalances or extremely low supply values, then an annual inspection can provide information regarding the success of measures that were undertaken.
The site-specific soil sample leads to greater significance for the sample and therefore to a considerable increase in efficiency regarding the fertilisers used.
In order to further increase the benefit of soil analysis and to improve relevance site-specific approaches can also be used. Geo-referenced sampling (GPS location of the sample is recorded) enables samples to be compared far more effectively over time.
The company AGRAVIS NetFarming GmbH provides the option of defining individual sites where samples are taken. Management zone cards are the foundation of the system, which mirror the yield potential of the section in the broadest sense of the term. The differences in the profitability of agricultural land can be established based on satellite data from previous years. In this case no quantitative statements are made, it cannot be stated whether 70 or 90 decitonnes of grain were harvested. However, qualitative statements are made, covering areas in which the highest yields are possible and the zones where yields will be lower.
The objective of the procedure: Homogenisation of soil content categories
The soil sample is now taken from the individual yield zones. This means, on the one hand, that a fault in the supply of nutrients could be discovered that may prevent higher yields. On the other hand, the quantities of nutrients to be spread including lime could be adjusted in line with extraction of feasible yield levels. In this case, provision of nutrients in the relevant yield zones is taken into account.
Great significance of soil samples
This procedure leads, in the long term, to standardisation of soil content categories. The various yield areas are dependent on the type of soil, amongst other things, and therefore cannot be changed. The application card that is derived from this always remains heterogeneous – even with content category "C" for all nutrients. This is deliberate. More fertiliser should be used in areas where more is harvested, and less should be used where less is harvested. This system means that the significance of a soil sample takes on a whole new dimension and leads to a considerable increase of efficiency in the use of fertilisers.
Cost-effective retrofitting options
The use of this system is possible with far more operations than one would suspect. Processing application cards is possible for all fertiliser spreaders on which the spreading can be adjusted depending on speed with little additional equipment. Within the field of limespreaders the technology is certainly not as widespread, however cost-effective retrofitting options are still provided by manufacturers. Many contractors are already well prepared in this regard.
Lime products are distinguished by means of their speed of action.
When selecting agricultural lime the decisive factor is that the properties of the product are in harmony with the location's requirements and the desired objectives of fertilisation. In general, the product used must correspond to the requirements in laws for use of fertilisers. This means that there is a minimum content of important substances and that the minimum requirements of reactivity and grinding coarseness have been achieved.
Establishing the neutralisation value is necessary to compare various lime products and their performance. Fertiliser recommendations are generally given in "CaO". As well as "CaO", the basic constituents of lime can also be stated as "CaCO3", "MgCO3", or "MgO". All statements must be converted into CaO for a comparison to take place. The resulting neutralisation value states what quantity of acid can be neutralised for each quantity unit of agricultural lime.
Distinguishing according to origin and its speed of action
It is possible to distinguish lime products on the basis of their origin and their speed of action. The latter is more expedient in practice. If following this consideration, burnt lime is the first type that comes to mind. The effect occurs directly after contact with the soil water. It is particularly suitable for liming extremely acidic soils, especially when the focus is on improving the soil structure of heavy clayey or silty soils. On lighter soils with less buffering capability burnt lime should only be used with great caution. It should only be used on grassland and existing stock if this is dried out, otherwise there is a risk of chemical burns.
Converter lime is sustainable
Calcium carbonate has a slower, more sustainable effect. Implementation in the soil is strongly dependent on the bedrock and the grinding coarseness. The finer it is, the quicker the effect. As the lime does not immediately react upon contact with water, earth-moist goods can be delivered, which has benefits for transportation, storage, and application. The risk of chemical burns to plant stock is non-existent. The calcium carbonate primarily acts as maintenance liming for all soils, including extremely light soils with little buffering. Usage on grassland is possible at any time provided that the land can be driven on. Mixed lime is at a stage between burnt lime and calcium carbonate and is available in the trade; it combines the properties of both varieties and can be assigned to one area or the other, depending on the proportions of ingredients in the mixtures.
Converter lime as slow-acting and sustainably-acting lime
Converter lime is seen as a slow-acting and sustainably-acting lime in the same broad manner as natural calcium carbonate. They can be used on all soils, for all cultures, and at any time. Auxiliary parts include silicic acid, phosphate, and trace elements. The positive effects of silicic acid include stabilisation of the crumb structure, release of phosphate available in the soil through the use of exchangers, and stabilising tissue in the plant, therefore improving the immune system (including mildew) and stability. Storage is simple and possible in a flat store as well as on the edge of the field. Due to the high specific weight and the earth-moist nature, the spread pattern is very even and free of dust.
Greatest benefit through liming
In summary it can be said that precisely in times where agricultural prices provide little margin for error, liming is imperative. This is the only way in which capital invested in resources can gain maximum benefit. Investigations show that the drops in yield due to not carrying out liming are not in proportion to the costs of such soil maintenance. Liming on grassland is just as important as on arable land in order to ensure feed efficiency. Soil investigations remain the means of choice for monitoring the fertilisation strategy. In order to gain the maximum possible benefit from the capital that has been invested, and to maximise the value of the analysis results, area-specific basic fertilisation and liming from AGRAVIS NetFarming GmbH provides very effective solutions. The correct lime product is ultimately chosen based on the demands of the location. From the range of quality limes from burnt lime to calcium carbonate to converter lime it is possible to plan a tailored recommendation for any location.
More information about this topic is available from Arne Klages (crop cultivation sales consultancy), tel. 0049 152 01810283, firstname.lastname@example.org, Stefan Hanebrink (crop cultivation sales consultancy), 0049 251 682-2067, email@example.com, and Christian Carl (AGRAVIS NetFarming GmbH), 0049 172 5303459, firstname.lastname@example.org.