A PLANT NUTRIENT PRODUCT

Abstract: A method of increasing the harvest yield in plant cultivation, the soil being supplied with plant nutrient depots comprising a mixture of bark, and peat, preferably provided with plant nutrient substances (N, P, K) and trace substances, said mixture being composted and pressed in an extruder press to the formation of pellets and dried to a water content of about 10-15 % by weight.

Description: A PLANT NUTRIENT PRODUCT DESCRIPTION In land utilization the consumption of inorganic plant nutri¬ ents, so-called commercial fertilizers, has greatly increased in recent years. Such fertilizers contain nitrogen, phospho¬ rous, potassium and trace substances essential to the plants. Normally, these chemical elements are present in chemical com pounds which are readily dissolved in water and which can the refore be rapidly leached out from the top soil layer by rain water and carried therewith into water-ways and lakes, creati serious environmental problems. Consequently, when plant nutri ents are administered in the form of commercial fertilizers great losses are often experienced. When commercial fertilizers are used annually over long period of " time, contaminants in the form of heavy metals are liable t collect in the ground, in a chemical form such as to be drawn into and be concentrated in the plants. Heavy metals can also be found in excessively high concentrations when untreated di- gested sewage sludge from sewage works is used as a fertilizer The present invention is based on the discovery that it is pos sible to create durable physical and chemical environment of such description that a plant nutrient can be supplied to the roots of the plants with a much greater efficiency (yield) tha was previously considered possible. By practicing the present invention it 'is possible to significantly improve the harvest yield, i.e. to produce larger harvests per ground area and amount of nutrients supplied than has previously been possible with earlier methods. The essential features of the invention reside in providing the soil not only with nutrients as such, but also simulta¬ neously with the chemical, physical, and biological environ- ment required in order for the plants, through their roots, to fully utilize the nutrients in an optimal manner, while any surplus of nutrients remain in the soil from one growing season to the next. OMPI In accordance with the invention, the nutrient substances are incorporated and adsorbed in pellets of a compostible and composted, ground biomaterial, such as the finely-divided bark of conifers, de-watered and shredded peat, disintegrated news- print, compostible and composted fractions of domestic waste, straw and common reed, either with or without the addition of fresh or digested sludge from communal sewage works. The surprisingly high yield which can be obtained when prati- cing the invention is illustrated in Figures 1 and 2. Figure 1 illustrates the harvest yield when administering various nitrogen additions, on one hand as commercial fertilizer;KAS, and on the other hand as plant nutient pellets, P1 , according to the present invention. It will be seen from Figure 2 that even when the nutrient substance according to the invention is administered in the Autumn, about six months before the seed is to be sown, the yield per hectar and amount of nitro¬ gen supplied is greater than when nitrogen is administered in the Spring under otherwise similar conditions. This shows that the present pellets create a depot effect in the soil with regard to distribution of plant nutrients, the addition of microbiological activities, and other factors, which are essential for a good harvest result. At the same time as the nutrient effect greatly increases in accordance with the illustrated diagram, any heavy metals present are bound to the bark in the form of insoluble so-called chelate com¬ pounds, which prevents the plants from taking up heavy metals, or reduces the extent to which such metals are taken up. EXAMPLE Bark having a dry substance contents of 250 kg was shredded to a particle size of at most 5 mm and was mixed thoroughly with de-watered peat having a dry substance contents of 250 kg and containing other disintegrated biomass. The mixing continued until a homogenous mass having an optimal water content with regard to composting was obtained. This mass was composted in a vertical reactor vessel, while continously aerating the mass and turning it over. During the composting OMPI process the mass is heated to 70°C for such a time that any patogenic bacteria present are killed off. Composting involves a biological degradation of the biologica mass involved, which leads to a stabilization of the organic material, and the mixture is made hygienic by the heat gene¬ rated, as mentioned above. This is particularly important in the case a digested sludge from a sewage work is included. Intended plant nutrients were added to the composted mass in a chemical form such as to prevent the nutrients from leaving during the manufacturing process. In certain cases, the plant nutrients can be added prior to the composting process. The thus enriched mixture having a moisture content of about 45 % was compressed to a relatively high density (about 0.8-1. and was formed into pellets in a pellet extruder or pelleti¬ zing " machine, the pellets being dried and cooled, whereby mechanically very strong pellets were obtained. Pelletizing also facilitates handling, transportation, and spreading of the product. The ready-to-use pelleted product has a moisture content of 10-15 % by weight, which is a reasonable level, at which no microbiological activities occur during storage. When compressing the mixture during the pelletizing process the nutrients are adsorbed on and bound with the organic ma¬ terial, and are slowly released in the soil in keeping with the take-up ability of the plants. Such trace elements as Mg, Mn, B, Co, and Cu can also be added to the homogenous mass together with the plant nutrients prior to the pelletizing process. The composted organic content of the pellets increases the biological activity when mixed with the soil, and provides for an extended fertilizing effect (aftereffect). The bio¬ logical material present, bark, and peat, shows moreover an ability to bind water, whereby the water-retention provides OMPI for an adequte environment for the nutrient uptake. In a preferred embodiment of the invention bark, peat, and sewagw sludge are mixed in the relation 25:25:50 with regard to dry substance content, and is provided with plant nutrients in a siutable form. The mixture is then pelletized, and intro¬ duced into a reactor to be composted by means of a continous aeration. After completed composting, spreading to the soil is carried out in known ways. Simultaneously with pelletizing seeds can be added to the mass which is to be pelletized, whereby a product is obtained which provides initially the best conditions for germination and nutrient emittion during the first period of time in the soil. By means of the water retention ability of the biomass opti¬ mal conditions for the seed is obtained, and the risk for a destroyed sowing by drying is eliminated. OMPI

Claims: CLAIMS 1. A method for increasing harvest yield in plant cultiva¬ tion, characterized by supplying to the soil plant nutrient depots comprising a mixture of bark and peat, preferably provided with plant nutrient substances (N,P,K,) and trace substances, which mixture subsequently has been composted and compressed in an extruder press to the formation of pellets having a water content of about 10-15 % by weight. 2. A method according to claim 1, characterized in that the plant nutrient substances are added after the composting process. 3. A method according to claim 1, characterized in that an organic sewage sludge is added to the mixture prior to said composting process. 4. A method according to claim 1, characterized in that bark, peat, and sewage sludge from a sewage work are mixed and formed into pellets in an extruder press, whereupon the pel¬ lets are composted, obtional plant nutrient substances being added prior to composting. 5. A method according to claims 1 to 4, characterized in that seeds for sowing are added to the mass prior to pelletizing in an extruder press. 6. A method according to claim 4, characterized in that bark, peat, and sewage sludge are mixed in the relations 25:25:50 with regard to dry substance contents.

Inventors: HAEFFNER ERIK, THRAP-OLSEN OLAV, HAEFFNER, ERIK, THRAP-OLSEN, OLAV
Applicants: INNOCAP AB, INNOCAP AKTIEBOLAG
Application year: 1983
Main classification: C05F11
IPC codes: C05F11, C05F15