METHOD FOR DEVELOPING AND INCREASING , RESP . THE FERTILITY OF SOIL

Technical field

The invention relates to a method for developing and increasing, resp. the soil fertility.

Background of the Invention

It is known that the lack of the natural productivity of skeletal soils such as waste land, waste stockpiles is traceable decisively to the lack of humus materials and to the unfavourable economy of water-supplies. In case of the traditional irrigation

- "water culture" - of the soils of inferior fertility, several problems arise, as a result of the irrigation the soil becomes leached, secondary salinization begins, the humus materials and plant nutrients get eroded which result in the further decrease of the fertility and unprofitable cultivation.

The economy of water supplies of the soil of deserts , semi-deserts and waste stockpiles, respectively, is generally poor which is traceable to the lack of humus . A further problem can be caused by die absence of suitable irrigation water. The environment contaminating effect of some waste stockpiles appears also in the contamination of the receptive waters and subsoil water, resp. as by washing the surface the infiltrating water and sub soil water become contaminated.

By the cultivation of these waste stockpiles this contaminating effect can only be moderated.

In the developing countries it is very difficult to carry out the traditional complex ground recultivation method /drawing areas into cultivation/ because of different technical and economic problems. The problems connected with the recultivation are the following:

- the lack of suitable irrigation water,

- the natural soil productivity decreasing effect of irrigation farming, leaching of the humus materials,

- in case of irrigation farming on poor quality soils the plant nutrients get eroded by water, they are poorly utilized,

- by the cultivation of waste stockpiles the problem of environment contamination in a given case is only partially solved. The object of present invention is to develop and steadily increase the soil fertility and to decrease the environment contaminating effects in a technological process /irrigation/.

Disclosure of the Invention

The process according to the present invention is based upon tie recognition that the combination of the irrigation technology and the multiplication of soil-algae lead to surprising, unexpected good results.

According to the present invention the crude water is optionally pre-treated, namely if it is needed, it is transformed into water suitable for irrigation purposes, then on the soil humus is formed or enriched by soil-algae, that is a soil-alga having the required fertility is propagated on the area to be treated, the irrigation water is optionally enriched with humus materials prior to, during or after the treatment of the soil with the algae. The presence of the plant nutrients in the irrigation water and the nutrient supply, resp. , are preferably continuously ensured in synthesized form, which can be reached by the multiplication of algae on the plant nutrients. There are several well-known biotechnical procedures which solve some parts of the given complex problem.

According to the present invention a procedure with large variational possibility is elaborated which is suitable to solve the whole problem and not only certain parts and which can be widely used except the cold climatic zones.

The basic requirement of the present procedure is a water suitable for irrigating purposes and any other crude water which is poor in sodium and chlorid ions, resp. According to the invention optionally a water cleaning operation is carried out as a pre -treatment according to the Hungarian patent specification /No. 174 397/. This procedure must be done in case of waters which do not contain NaCl and the essence of the treatment is that the crude water to be cleaned is led into an aquatic plant stand, thus an irrigation water of suitable quality is obtained.

Our results show that the aquatic plant stand is suitable for decreasing the total salt content of waters, adjusting the neutrality of water, enriching the humic matters to a certain degree but its fundamental function is to make "living water" from crude-water. The efficiency of the procedure is verified by experiments but in each case the material to be extracted or neutralized must be tested and the spreading of the absorbing, accumulating plant species must be assured. In given case in the lack of other possibilities a marsh controlled or developed for this purpose can be suitable as well.

In the course of the procedure according to the present invention optionally the irrigation water is subsequently enriched with humus materials. The fertilization with organic materials in certain cases involves difficulties, in case of nomadic stock-raising or at recultivation processes the enrichment of organic substances is very expensive. If the water of irrigation water quality is allowed to flow through an organic material, e. g. compost, soluble organic and inorganic materials are dissolved from the organic material and solid pieces of the size suitable for irrigation technology are taken along as well. By treating the organic material with artificial fertilizer the inorganic plant nutrients will be also spread with the irrigation water. The enrichment can be advantageously carried out with a grated container. In a simpler environment the saprobity of water can be enhanced by the enrichment of organic material in a lake regulated for this purpose. The enrichment of the organic material can be carried out e. g. by the addition of a dilute manure. Before this procedure it is to be examined that what kind of water quality and organic material content are needed by the plant to be cultivated.

The essential feature of the process according to the invention is the humus forming, the enrichment with soil-algae.

This operation is the process of natural humus forming, caused articially and in a way which is most favourable from the point of view of the intentions of the process. By the multiplication of a soil alga strain having suitable productivity the formation of natural organic substances begins.

If the demand on moisture of the soil-alga and the nutritive material is insured, a coating is formed by the soil-alga on the surface in a short time. This coating makes the intensive production of organic material possible. In case of suitable alga strains the saving of nutritive material and energy can be assured. As a consequence of the thickening of the "alga lawn" the production gradually decreases but it can be made intensive again with a shallow-ploughing. Beyond humus forming the multiplication and growing of the soil-alga have an erosion decreasing effect and thereby a more advantageous economy of water-supplies is ensured on the area by the development of "alga-lawn" . It is practical to give this step of procedure a start on the area to be recultivated before the settlement of the land.

Under suitable circumstances this process and the growing of the cultivated plants can be assured at the same time . This step of the pro cedure according to the present invention is carried out by passing irrigation water and nutrient solution to the area and inoculating with alga strains, the irrigation /moisturing/ is passed to the field through a temporary or a stable irrigation system and the nutrient solution is passed through a nutrient solution feeding apparatus. The humus enrichment described previously which was mentioned before the humus enrichment with algae, can be carried out optionally in an inverted order that is after the enrichment with the algae or both can be carried out at the same time.

After the enrichment with the algae - or in a given case after the enrichment - the presence of plant nutrients and the replacement of the nutritive material in an organic material synthesized form /for irrigation method/, resp. , are ensured.

This step of the procedure is not indispensable but this is more expedient than the traditional artificial fertilizing. This step of the process is useful by itself in the irrigation farming.

It is known that the nutrition retain capability of the skeletal soil is unfavourable. The inorganic fertilizers get eroded or leak into the deeper layers of the soil. It is known furthermore that the plants synthesize organic substances from inorganic fertilizers in the presence of light. Consequently, if algae are formed on the plant nutrients in basins or pools the nutrient or a part of it can be passed to the fields in the form of organic substances. For this purpose the appropriate floating alga strain has to be selected or alga strains which can be multiplicated on the soil are used. The alga producing basin or pool can be used as a secondary utilization for fish breeding, where the metabolites of the fishes increase the organic substance content of the irrigation water. The advantage of some sort of blue /green algae is that they absorb the air nitrogen, so their use results in nutrition saving. A further amount of energy can be saved by adding the nutritive element phosphorus in the form of phosphoric acid or crude phosphate instead of a fertilizer.

The result of this step of the process is that a slowly decomposing nutrient is ensured to the crop plants, leaching is decreased, the humus content is increased and the soil structure is improved.

For carrying out the procedure simple alga producing basins or a lake constructed for this purpose should be made which can be combined, e. g. with a fish pond. The use of the procedure according to the invention is especially advantageous if the so called "nutrition peg" method is used and the plant nutrition of the plantations should be replaced.

As a preparatory operation our previous solution for cleaning subsoil water and infiltrating water, resp. , can be preferably used, which is described in Hungarian Patent Application No. 3601/83.

The figures serve the better understanding of the process.

Figure 1 shows the treatment of crude water according to Hungarian Patent Specification No. 174 397;

Figures 2a and 2b show the scheme of water introduction suitable for the irrigation process; Figure 3 shows the system of the humus formation, enrichment with soil algae ;

Figure 4 shows the replacement of plant nutrients; Figure 5 shows the "peg" plantations for the nutrient replacement; Figure 6 shows the cleaning of subsoil water and infiltrating water;

Figures 7a to 7h show the combinations of the process according to the invention. Figure 1 shows the treating and cleaning of the crude water which is unsuitable for irrigation according to the Hungarian Patent Specification No. 174 397. In accordance with Figure 1 the crude water to be treated - marked with an arrow on the Figure - is led into the aquatic plant - stand 1. The cleaned water which leaves the aquatic plant-stand is also marked with an arrow. In this way the salt content of the crude water which is unsuitable for irrigation, decreases, the pH reaches the normal level, the water is enriched in humic materials namely after all a "living water" is obtained which is suitable for irrigation. This pre-cleaning procedure which has to be done when required is marked as step I.

Figure 2a shows that the nutrient water /marked with arrow/ of irrigation quality is passed - practically through the divided water intake 2 - into the organic material, e . g. compost storing grated container system - between them, there is a carrier plate 4, then from the filter container 5 it is led in the direction of the arrows.

Figure 2b shows a slightly different embodiment of the system.

This is step II of the procedure according to the present invention which shows the humus enrichment ; the water applied to irrigation technology in this step is enriched with soluble organic and inorganic materials /eventually liquid manure may be added/. In this step we ensure the application of the solid pieces of a size suitable for irrigation technology and by inorganic fertilizing the needed inorganic material content.

Figure 3 shows step III, namely the humus forming and enriching carried out by means of soil-algae. It is visible on the

Figure the irrigation water intake 6, the nutrient solution feeding 7, the inoculating place of the alga 8 and the temporary or stable irrigation system 9 serving the purpose of irrigating and moisturing. This step results in natural humus forming. In case of the use of blue alga which has a nitrogen-fixing capacity, nutritive material /energy/ can be saved. A further favourable effect which can be reached with this step, is the decreasing of losses due to soil-erosion and wind-erosion which is realized through the development of "alga-lawn" .

In step IV are replaced the plant nutrients, the replacement of the nutritive material in a synthesized form of the organic materials

The nutrient water is passed through the water feeder 10, the nutritive material through the material feeder 11 into the alga breeding pools 12 or lake. The irrigation water /with alga/ leaves the pools in the direction of the arrow. In this step the nutritive material is synthesized in the form of decomposing organic material. The advantages of this solution are that the erosion decreases, the humus content increases, the inclination to secondary solodization decreases, and the water treated in this way promotes and improves the development of the soil structure , respectively.

Figure 5 shows step V of the procedure, namely the case when it is intended to replace the plant nutrition on the nutrient "peg" plantations. On the Figure the level of the vegetation covering the soil is marked with reference number 13, the position of "peg" 14 and root zone 15 are also visible. The advantage of the procedure according to the invention is in this case that most of the nutrition is received by the crop plant, the nutrition is explored by the demand, leaching decreases, the plants covering the soil decrease the erosion. On Figure 6 step VI of the process is shown. This step shows our former method for cleaning the contaminated infiltrating water 16 and subsoil water 17. As it can be seen on the Figure above the producing plant 20 a pebble well 18 is placed which contains an additive for retaining the toxic or harmful materials. The collected and upwards flowing contaminated infiltrating water 16 and subsoil water 17 are led over the producing plant 19 and the material layered on it and so they are led into the cleaning pond or water-basin 19 wherein the cleaning process takes place as the toxic materials have previously been extracted from the water. In addition to the extraction of the toxic materials, the materials which can be utilized, can be extracted as well. By the combination of the cleaning process and the recultivation water can be saved.

Figures 7a to 7h illustrate the various variations of the steps of the process according to the invention, the ring drawn with continuous line around the steps marked with Roman numbers means that the given operation is obligatory and the ring drawn with broken line means that the operation can be carried out optionally but it is not absolutely necessary. The combinations of the obligatory and optional steps can be adapted to theglven field and its problems.