136 Dr Köpke how do you know if soil is healthy First of all by its loose consistency Is it mel lowing as we say In oth er words is it all porous and crumbly Does it hold moisture Do you see any earthworms Is it fragrant Is it living soil or do added plant residues remain undigested by microorganisms for a long time And how do you bring life into the soil Mainly by incorporating lots of organic primary matter such as slightly decomposed plant residues from a di verse crop rotation that includes legumes which cap ture nitrogen Even better composted crop residues And what really stimulates the development of soil fertility and soil quality is livestock manure from ruminants like cattle sheep and goats In Germany there used to be contests for the best manure heap until well into the 1940s In villages in the region of Württemberg farmers kept heaps of solid dung on racks right in front of their hous es with a cesspit below to collect the liquid phase The dung heaps were all very nicely and precisely arranged On Sundays neighbours would stroll by and size them up If a dung heap was well tended then all was well in the barn and in the entire household too So nice dung heaps mainly served a social function Yes he laughs the neighbourhood watch kept an eye on the dung heaps And by the way it was very sensible to separate the solid and liquid manure even if people didn t understand that in detail Liquid manure is rich in potassi um If as often happened in the past dung is simply piled somewhere like at the edge of a field then the potassium and other plant nutrients just seep into the ground under that spot and are lost to the crops in the field Does organic agriculture build and expand upon such traditional knowledge Of course and that s easiest for organic farmers who run mixed operations That is when they raise crops and live stock ideally ruminants like cattle and create a practically self contained farm organism Cultivating forage crops with their great mass of roots and shoots improves and main tains soil fertility The forage crops are then consumed by livestock transformed into dung and liquid manure and re turned to the fields in a targeted manner as needed main taining a virtually closed loop Organic farmers pay particu lar attention to soil quality as the basis for the quality of the food they produce Humus is a key word in organic agriculture What exactly is that First off it s the mixture of humic acids and humic substanc es which gives fertile topsoil its dark colour But I have to ad mit that we don t fully understand what humus is and how it forms So that term is often avoided and we speak of soil organic matter instead This refers to all plant animal and microorganism detritus in various stages of decay in and on the soil and is a product of decomposition The level of or ganic matter in the soil is gauged by means of an extreme ly simple technique We measure the soil s organic carbon content If there s lots of this carbon in the soil then we say it contains lots of humus Granddad s walking stick buried in Prof Dr Ulrich Köpke Professor at the Institute for Organic Agriculture IOL at the University of Bonn founder and president of the International Society of Organic Agriculture Research member of the German Federal Environmental Agency s Soil Protection Commission 6 Nature and people A POT OF TEA WITH

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