ISHS Acta Horticulturae 145: Symposium on the Use of Fertilizers in Protected Vegetable Production
P - S /PLANT-SAP/ ANALYSES. ANOTHER WAY TO REGISTRE THE NUTRIENT UPTAKE IN PLANTS |
| Author: | L. Mansson |
| Abstract:
It has often been said that the plant is a factory producing a lot of products from simple raw materials plus energy. The grower has to see to, that all necessary rawmaterials are always optimally supplied to make the energy and production capability fully used. In a real factory we cannot count the amount of different ready products and on basis of that make a list of what has to be supplied in the nearest future. We must go to the store of fresh rawmaterials. In the normal plant tissue analyses a mixture of raw materials and ready products are measured instead of concentrating on the real inorganic, still moveable nutrients. Since 1948 we have in Helsingborg tried to separate the inorganic nutrients from the already used or precipitated nutrients. These levels we have found to be a much better base for the feeding-recommendation than the common total tissue analyses. Shortly explained we measure nitrate - and ammonium-nitrogen instead of protein-nitrogen; only phosphate -P instead of both protein- and phosphate -P; only sulphate -S instead of total S etc. As there is no known organic potassium in the plant, both methods measure the same K, but we declare it in mg K per liter plant sap /=press-sap, Pflanzen-Saft or PS/ instead of % K in dry matter. As the processes in the cells first of all must be influenced by what is in the cell-sap, we cannot find any reason why fluctuating amounts of sugar, starch, cellulose a.s.o. should have an influence on the registered figures. After our normal sample processing we in the PS also measure Ca, Mg, Na, Cl, Fe, Mn, Zn, B, Cu, Mo, Al, Ni, Cr, Cd, Si, Sr etc. For Fe our aim is to measure both the two-valid | |
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