What is a good soil to manure ratio

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  • Straw fertilization - how straw becomes a valuable fertilizer
As the picture shows, the first combine harvesters were on the road in many regions in the light locations. The straw that arises during the grain harvest is a plant-based, proprietary fertilizer with considerable nutrient content - especially potassium (100 to 150 kilograms per hectare of potassium (K2O) for 100 quintals of wheat straw). Its sensible use is of great importance. The amount of straw remaining in the field during the grain harvest is calculated at around 80 percent of the grain yield, i.e. 80 quintals per hectare of grain yield leaves around 65 quintals per hectare of straw. High yields are therefore synonymous with large amounts of straw, which is often a problem. So that it does not have a disruptive effect on the subsequent crop, after the harvest, all efforts must be concentrated on ensuring that the straw can be moved quickly in the soil.
Straw consists mainly of cellulose. It contains only about 0.5 percent nitrogen (N) and has a ratio between carbon (C) and nitrogen of 80 to 1. The soil microorganisms have a high N requirement when building up their body substance, that of a C / N ratio of is determined under 20 to 1. In the soil there is therefore an acute nitrogen deficiency when straw is incorporated without additional fertilization, since all the available nitrogen is required for straw decomposition. If nitrogen is not additionally administered, only a limited and slow conversion of the straw takes place. It may be that the subsequent crop then suffers from an N deficiency. Root formation and water flow in the soil can be restricted by leftover straw mats. In order to ensure microbial degradation, nitrogen can therefore also be fertilized. In addition to chopping up and evenly distributing the straw, the prerequisite for rapid implementation is not too deep incorporation in order to offer the soil organisms optimal conditions in terms of moisture and ventilation. This will become all the more important after the new fertilizer ordinance comes into effect, since then fertilization after the harvest in general and with straw in particular will be severely restricted. This will only be limited to rapeseed and winter barley (60 kilograms per hectare of total N, 30 kilograms per hectare of ammonium N) by September 30th. will still be possible according to the current status. In all other crops, what bacteria do comparatively quickly today must then be taken over by soil fungi, as is often the case today with plowless tillage or mulch sowing.
In the context of the current fertilizer ordinance, both liquid manure / digestate and mineral fertilizers can be used for straw fertilization. N-liquid fertilizers, such as PIASANĀ® 28, are particularly suitable for this, as they evenly wet the straw. The C / N ratio is increased to a level that ensures rapid microbial degradation. In this case, it is not the soil but the straw that should come into direct contact with the N fertilizer. The amount is calculated with around one kilogram of N per deciton of straw. Any residual amounts of readily available nitrogen remaining in the soil after harvest and from mineralization should be taken into account. In the case of high N balance surpluses and good mineralization conditions, additional N addition should be avoided or at least significantly reduced. The best biodegradation is achieved when the straw is worked into the soil immediately after the fertilizer has been applied (in the case of liquid manure, within four hours). This creates the best conditions for the development and income generation of the subsequent crop.