Plant husbandry – Process
Reexamination Certificate
1997-06-17
2001-03-27
Bui, Phuong T. (Department: 1638)
Plant husbandry
Process
C047S048500, C071S001000, C071S011000, C071S054000
Reexamination Certificate
active
06205707
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for the fertilization of soil for cultivated plants, whereby nitrogen fertilizer is spread over the cultivated area in conjunction with the sowing of cultivated plants and more fertilizer is spread over the cultivated area later during the growing season.
In particular, the present invention relates to nitrogen fertilization carried out in conjunction with the cultivation of cereals, although the method can be applied in conjunction with the fertilization of soil for other plants as well by making corresponding changes in the amounts of fertilizer, In this context, ‘cereals’ refers to all known cereals, such as wheat, barley, oats, rye, rape, turnip rape, maize, rice, etc. ‘Other plants’ refers to other useful plants cultivated on fields and corresponding cultivation areas. In the present application, 1 kg of nitrogen fertilizer specifically means an amount of fertilizer that contains 1 kg of nitrogen.
BACKGROUND OF THE INVENTION
In field husbandry, in principle the soil should be fertilized with nitrogen used in amounts corresponding to the quantity of nitrogen removed from the soil via harvesting. Fertilization recommendations are based on long-term average crop yields obtained from extensive test material. The recommendations ignore the fact that there are large variations between growing seasons in respect of the formation of crop yields. Water supply is often a minimum factor restricting growth, and when water is in short supply, the crops per hectare fall below the long-term averages. Furthermore, because Finland is situated at the northern limits of the cultivable area, from time to time there are fail-years, e.g. due to cold weather conditions, in which the crops remain considerably be-low long-term averages. In other countries as well, the crops per hectare vary correspondingly, due to variations in the growing conditions, in the first place weather conditions.
According to the fertilization recommendation for Finland, the average amount of nitrogen fertilizer to be spread on the cultivated area in mineral soil is 90-110 kg/ha. If the amount of fertilizer used is 110 kg/ha, the crop yield should be over 5000 kg/ha for the amount of nitrogen removed from the soil with the crop to correspond to the amount of nitrogen spread over the cultivated area in conjunction with sowing. Very often, however, e.g. when growth is limited by insufficient water supply, the crops per hectare fall as low as below 3000 kg/ha. In this case, a large overdose of nitrogen remains in the soil, and this nitrogen is liable to be washed away, denitrified, or it may combine with the soil in a form unusable for plants. The average crops in Finland in recent years have been slightly over 3000 kg/ha. Therefore, in the long term, the fields have been over-fertilized. In other countries, too, there are large variations in crops, depending on the weather and other conditions prevailing in each country and their changes. However, the problem resulting from over-fertilization is encountered in other countries as well, especially when there are unexpected changes in weather conditions and in the case of drought.
The fertilizer left unused because of over-fertilization, i.e. the production investment corresponding to the excess amount of fertilizer, has not yielded any returns In cultivation. In addition, the excess nitrogen is mainly washed away into water systems, resulting in a significant increase in the nitrogen load on water systems and therefore pollution. Moreover, in this case the fodder and food industries cannot get raw material of a quality consistent with the aim.
SUMMARY OF THE INVENTION
The object of the present invention is to eliminate the drawbacks described above.
Thus, the object of the invention is to develop methods for fertilizing the soil for cultivated plants in such a way that the grower will get a better return on the production investment made in the form of fertilization and that the amount of fertilizer washed away into water systems and polluting them will be substantially reduced.
A specific object of the invention is to develop fertilizing methods so that the fertilization carried out in conjunction with the sowing should better correspond to realistic crop prospects in the light of the average crops per hectare obtained in recent years. A further object of the invention is to develop methods for fertilizing the soil for cultivated plants in such a way that the amount of fertilizer spread on the cultivated area should more effectually correlate with possible larger crops as well.
As for the features characteristic of the invention, reference is made to the claims.
The invention is based on extensive investigations, during which it was unexpectedly established that the growth and/or nitrogen nutrient situation of cultivated plants, i.e. the need for nitrogen fertilization and the utilization of fertilizer by the plants can be measured during the growing season and, based on the measurement results, supplementary fertilization can be carried out as needed. In particular, the method is based on measuring the growth and/or nitrogen nutrient situation, e.g. the chlorophyll concentration, of cultivated plants during a certain period of time from the beginning of the growing season when an amount of fertilizer corresponding to a basic crop smaller than the local maximum crop is used and, similarly, on measuring the growth of cultivated plants in the same growing conditions in an area with supplementary fertilization, e.g. an over-fertilized area (e.g. a limited part of the cultivated area), where an overdose of fertilizer has been added so that the plants in this limited fertilizer window area can take as much nitrogen as they are able to take and utilize in the prevailing conditions; the amount of nitrogen fertilizer added in the fertilizer window may be e.g. 30-50% above the amount used in the rest of the cultivated area. A particularly advantageous approach is to determine the chlorophyll concentration in the plant leaves in the fertilizer window and outside it; it has been established that the chlorophyll concentration correlates quite well with the amount of nitrogen contained in the plant leaves, and so the chlorophyll concentration in the fertilizer window and outside it gives a relatively accurate indication of the amount of nitrogen fertilizer used by the plants and therefore of the amount of nitrogen needed in the production area. From the measurement of the growth of the plants in the cultivated area as compared with the growth in the area with supplementary fertilization, it is thus possible to establish whether the plants in the cultivated area are suffering from under-fertilization, and if so then this can be corrected via general supplementary fertilization of the cultivated area if the growth in the extra-fertilized area significantly exceeds the growth in the cultivated area.
The amount of growth in a given area can be measured by any method known in itself, e.g. by weighing the growth per unit area that has taker. place in the area, e.g. the amount of aerial growth, i.e. phytomass, or if desired, the entire growth, i.e. biomass (comprising aerial parts and roots).
The growth of cultivated plants can thus be monitored by measuring the nitrogen nutrient situation of the plants, e.g. by determining the chlorophyll concentration in the plants in a cultivated area with basic fertilization and in an area with supplementary fertilization. Supplementary fertilization is carried out if the growth and/or the amount of nitrogen, e.g. the chlorophyll concentration in the plants in the area with supplementary fertilization is substantially, e.g. over 10%, preferably over 20%, greater than in the cultivated area without supplementary fertilization.
In conjunction with the investigations, methods for predicting the crop yield at a given time in the growing season so that it is possible already during the growing season to relatively accurately determine the prospective crop yield and the supplementary fertilizatio
Altera Law Group LLC
Bui Phuong T.
Suomen Rehu Oy
LandOfFree
Method for the fertilization of soil for cultivated plants does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for the fertilization of soil for cultivated plants, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for the fertilization of soil for cultivated plants will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2472340