Growing interest in American Kinsey-Albrecht soil analysis RE SEARCH when steps 1 to 3 have been properly implemented can you make adjustments for any necessary trace elements and nitrogen’, says Van Gurp. 'We map the EC of each location in the plot, which gives us a picture of the variation in the electrical conductivity', Van Gurp explains. creates the optimum conditions for soil life and root development. Furthermore, make sure that there’s sufficient organic material to feed the soil life, for example Sampling in a square metre. He then touches on another important aspect in soil analysis and that’s the fact that a plot is rarely homogeneous. ‘Yet we test the soil of a plot with one composite sample. We carry out the fertilisation and recommendations for the entire plot on the basis of the analysis of this composite sample. Fertilising according to this advice will result in parts of the plot receiving too little, just enough, or too much of the fertiliser. A shortage or an excess of fertiliser means a loss of quality and therefore a financial loss. So our expensive farmland is not used to the full, while land use is very intensive in the Netherlands, the land and lease prices are high and every square metre counts. By mapping the soil fertility of each square metre, we can fertilise more precisely and so cut our losses. Taking a soil sample from every square metre of a plot is an impossible and costly task, but we can use an indirect method to determine the soil fertility of every square metre. For this we use an electromagnetic induction (EMI) sensor that measures the electrical conductivity (EC) of the soil. Here we make use of the fact that all kinds of soil properties such as clay, loam and sand (texture), organic matter, CEC and minerals influence the electrical conductivity. We map the EC of each location in the plot, which gives us a picture of the variation in the electrical con‘And a balanced plant ration can only be achieved with a good soil balance’ with green manure. Only then will the nitrogen fertilisers come into play in step 5, including both the basic application on the soil and the possible extra via the haulm. What we always underline is that steps 4 and 5 are most ecologically effective if the first three steps have been carried out correctly. In other words, only ductivity. This variation can be summed up in four main EC categories. We then take a soil sample from each EC category, which produces an analysis. The soil properties we then obtain per EC category lead to much more accurate advice and recommendations based on the actual soil fertility per square metre. The only drawback at the moment is the location-specific applications of the advice. These can’t yet always be carried out by the farmer or the contractor, but with the current speed of developments in precision farming, this could be much closer for individual farmers than we think’, says Van Gurp. Incidentally, an EC map of your plots provides a lot of insight into their homogeneity and can reveal much more about them, such as patches of weed, yield differences and oftenunexplainable growth patterns. This soil scan has been developed by N-xt Soil Services in cooperation with Fleuren Tree Nurseries, says Van Gurp. Working on an ideal nutrient balance ‘The Kinsey-Albrecht soil analysis and the related soil improvement advice concentrates on a combination of measures’, summarises Van Gurp. ‘It starts with working on an ideal nutrient balance in the soil, whereby the percentage and the ratio of calcium/magnesium and the percentage of potassium are in order. This ensures for an optimal balance between water and air (oxygen) in the soil. What’s important next is to activate the soil life and keep it active. Bringing the trace elements up to level plays a major role in this, step 4’. The level and importance of micronutrients in many soils are severely underestimated, says Van Gurp which contributes strongly to biological processes in the soil. ‘Because you won’t get there simply by increasing the organic matter content, by applying the correct fertiliser or green manure, and by leaving crop debris. Crop rotation also plays a key role here. And when it comes to actively keeping useful fungi, bacteria and insects alive in the soil, it’s also important to pay attention to the sometimes disastrous effect of crop protection chemicals and certain artificial fertilisers. By extension, we also need to consider soil tillage. As little disturbance as possible to soil life and structure is best, which requires minimal tillage, preferably to a shallow depth and without turning, as far as possible.’ ● Leo Hanse Potato World 2020 • number 2 31 Pagina 30

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