Facility secondary NO3− salinized soil modifier, preparation method and modification method

Abstract

A facility secondary NO.sub.3.sup. salinized soil modifier and a modification method are disclosed. The present invention involves the preparation processes of two biological soil modifiers A and B and application methods thereof, which are specifically described as follows: (1) soil modifier A: solid, obtained by microbial fermentation with straw powder and rice bran and the like as raw materials, C/N between 30-50, applied by uniformly mixing at 1-1.4 by mass with facility ploughing soil, co-culturing at 35-50 C. for 5-7 days, and then returning to fields; and (2) soil modifier B: liquid, subjected to salt tolerance acclimation to have effective microbial populations, and used in the crop growth period. Based on the microbial techniques, the present invention can improve soil structureness, enhance microbial activity and promote biological immobilization on inorganic nitrogen in soils, significantly increasing the facility cultivation crop yield, and improving the product quality.

Claims

1. A facility secondary NO.sub.3.sup. salinized soil modifier, comprising a soil modifier A and a soil modifier B, wherein the soil modifier A comprises the following components by weight: 30-50 parts of straw powder, 10-40 parts of rice bran, 5-20 parts of rapeseed cake, and also an EM stock solution and red sugar, and the weights of the EM stock solution and the red sugar both are 1.2-4.5% of the total weight of the straw powder, the rice bran and the rapeseed cake; and the soil modifier B is obtained by acclimation of the EM stock solution by gradually increasing a salt solution concentration, wherein the C/N ratio of the straw powder is 65-85:1, the C/N ratio of the rice bran is 18-22:1, and the C/N ratio of the rapeseed cake is 9-13:1.

2. A method of preparing the facility secondary NO.sub.3.sup. salinized soil modifier of claim 1, comprising: preparing the soil modifier A, which comprises the steps of uniformly mixing the straw powder, the rice bran, and the rapeseed cake, adding the EM stock solution and the red sugar into the resulting mixture and then adding water to reach about 35% of a water content (by mass); and performing closed fermentation at a temperature of above 22 C. for 10-26 days; and preparing the soil modifier B, which comprises the steps of: mixing Ca(NO.sub.3).sub.2, KNO.sub.3, NaCl and KCl in a 5:3:1:1 ratio by mass, formulating 0.5 wt % of an inorganic salt solution from the resulting mixture of inorganic salts, and performing acclimation by gradually increasing the concentration, wherein a concentration of an inorganic salt is successively increased to 4% by 0.5% gradient, and wherein the C/N ratio of the straw powder is 65-85:1, the C/N ratio of the rice bran is 18-22:1, and the C/N ratio of the rapeseed cake is 9-13:1.

3. The method of claim 2 wherein after the last step, the C/N ratio of the biological soil modifier A is adjusted to be 30-50 using the straw powder.

4. A soil modification method based on the facility secondary NO.sub.3.sup. salinized soil modifier according to claim 1, by comprising: applying the soil modifier A by adding the soil modifier A into a facility ploughing soil for planting; co-culturing at 35-50 C. for 5-7 days after being fully mixed; covering onto the soil surface 1 day before crop planting with a thickness of 0-10 cm; applying the soil modifier B by diluting 500-1000 and spraying onto the root surface during the crop growth period.

5. The soil modification method based on the facility secondary NO.sub.3.sup. salinized soil modifier according to claim 4, wherein the amount of the soil modifier A is 1-1.4 of the soil weight.

6. The soil modification method based on the facility secondary NO.sub.3.sup. salinized soil modifier according to claim 4, wherein the amount of the soil modifier B after dilution is 3000-4500 kg/ha.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(1) The present invention is further described below with reference to specific examples. The examples are only used to illustrate the present invention and not limit the present invention.

(2) The present invention is directed to a facility secondary salt salinized soil modification method by applying the soil modifier A and the soil modifier B. The use methods of the modifiers are also included. The soil modifier A comprises the following components by weight: 30-50 parts of straw powder, 10-40 parts of rice bran, 5-20 parts of rapeseed cake, and also an EM stock solution and red sugar. The weights of the EM stock solution and red sugar both are 1.2-4.5 of the total weight of straw powder, rice bran and rapeseed cake.

(3) The preparation of the soil modifier A comprises the following steps:

(4) Step 1, uniformly mixing straw powder, rice bran and rapeseed cake, adding into the resulting mixture the EM stock solution and red sugar and then adding water to reach about 35% of a water content; and

(5) Step 2, performing closed fermentation at a temperature of above 22 C. for 10-26 days.

(6) After the preparation is completed, it is preferred to adjust the C/N ratio of the modifier. Preferably, the C/N ratio is adjusted to be 30-50 using straw powder, with N+P.sub.2O.sub.5+K.sub.2O5%.

(7) In this embodiment, straw powder (C/N of 65-85:1), rice bran (C/N of 18-22:1), and rapeseed cake (C/N of 9-13:1) all are commercially available. A product having the C/N ratio of 30-50 is preferably prepared in this embodiment. The C/N is selected based on the following facts: essential nutrients and energy are required to maintain microbial vital activity and reproduction, and 1 part nitrogen generally needs to be consumed in order to absorb 25-30 parts carbon for microorganisms, and thus when an organic substance applied to soils has a C/N<25:1, microorganisms cannot utilize available nitrogen in soils and rather, relatively complete decomposition of the organic substance results in release of mineral nitrogen, so that nitrate nitrogen effect cannot be reduced; when the C/N ratio is too large, N element required for microbial cell proliferation is absent, which is unfavorable to microbial activity. Thus, the substance having a C/N ratio of 30-50 is co-cultured with the facility soil in the present invention, the ploughing soil can provide sufficient available carbon source for the modifier.

(8) The preparation of the biological modifier B is as follows: step 1, mixing Ca(NO.sub.3).sub.2, KNO.sub.3, NaCl and KCl in a 5:3:1:1 ratio by mass, formulating 0.5 wt % of an inorganic salt solution from the resulting mixture of inorganic salts, with glucose as carbon source, seeding 1-2 mL of the EM stock solution to a 250 mL triangular flask containing 100 mL of the mixture of inorganic salts, and performing enrichment culture at 30 C. with stirring at 170 r/min (usually, the culture is completed within 5-12 days), wherein the concentration of NO.sub.3.sup. in culture is determined every 2 d, and when the cutting rate is 230% and the amount of seeds reaches 10.sup.7-10.sup.8 cfu/ml, the next culture is performed; step 2, taking 1-2 mL of the solution obtained from the last culture and adding 100 mL 1.0 wt % of the inorganic salt solution (the concentration is increased at 0.5% gradient) and performing enrichment culture under the same conditions as those described above; next, the concentration of the inorganic salt solution is successively increased to 4% at 0.5% gradient.

(9) The soil modifier A is solid and is used by co-culture with the ploughing soil before crop planting. The soil modifier B is liquid, is subjected to salt tolerance acclimation to have effective microbial populations as main component, and is sprayed onto the root surface during the crop growth period.

(10) For the facility secondary NO.sub.3.sup. salinized soil modification method, the soil modifier A is applied by stacking the facility ploughing soil for planting having a thickness of about 0-10 cm of the surface layer to be 35-40 cm high. The soil modifier A is added at 1-1.4 by mass, fully mixed, co-cultured at 35-50 C. for 5-7 days, covered onto the soil surface layer to 0-10 cm 1 day before crop planting. The soil modifier B is applied by diluting 500-1000 and then spraying onto the root surface in an amount of 3000-4500 kg/ha during the crop growth period depending on the growth conditions. The soil has good drainage ability, or is provided with an underground drainage system. Taking tomato as an example, reasonable irrigation manner is drip irrigation or common irrigation. The upper irrigation limit is the field moisture capacity, the lower irrigation limit is 45% (seedling period)-65% (flowering and fruit setting period)-60% (fruiting period), and designed wetted layer is 0.2 m (seedling period)-0.4 m (flowering and fruit setting period and fruiting period).

(11) The EM stock solution used in this embodiment is available from Love Harmony Music Environmental Biotechnology (Nanjing) Co., Ltd. It contains more than 80 effective active microorganisms such as photosynthetic bacteria, lactic acid bacteria, yeasts, has the live bacterial count 0.1 billion/ml at pH3.8, and is a tan, translucent liquid with thick sour or tart odor.

(12) The facility agriculture is dryland farming, and substantial accumulation of nitrate nitrogen in the ploughing layer soil, particularly 0-10 cm soil, is a main cause of soil secondary salinization. The mechanisms by which the present invention decreases the soil NO.sub.3.sup. content are described as follows: a high concentration of nitrates has strong inhibition effect on microorganisms themselves, which affects microbial metabolism, and the microbial agent in the present method is subjected to salt tolerance acclimation, and after being applied to the crop root system, causes quick formation of beneficial microbial populations, accelerates assimilation on soil nitrates, and converts nitrogen element into microbial nitrogen, thereby reducing the content of soluble nitrogen element in soil; and meanwhile, the presence of denitrifying microorganisms accelerates the denitrifying process, NO.sub.3.sup. is reduced to release molecular nitrogen (N.sub.2) or nitrous oxide (N.sub.2O), leaving the soil.

Examples 1-4: Preparation of Soil Modifiers

(13) For the soil modifier A of the present invention, the raw materials were mixed in different proportions, adjusted to a water content of about 35% (w/w), and charged into a lidded plastic tub for closed fermentation at above 22 C. for 10-26 days. When a fragrant odor was diffused, it was indicated that the fermentation was completed, and straw powder was used to adjust the C/N ratio to be 30-50. The composition of the raw materials is as follows:

(14) TABLE-US-00001 Ex. No. Item 1 2 3 4 straw powder (kg) 40 42 48 50 rice bran (kg) 36 33 24 20 rapeseed cake (kg) 24 25 28 30 EM stock solution (kg) 0.12 0.27 0.30 0.45 red sugur (kg) 0.12 0.27 0.30 0.45 days 10 15 20 26 N + P.sub.2O.sub.5 + K.sub.2O (%) 5.53 5.31 5.3 5

(15) The preparation of the soil modifier B comprises the following steps:

(16) Step 1, mixing Ca(NO.sub.3).sub.2, KNO.sub.3, NaCl and KCl in a 5:3:1:1 ratio by mass, formulating 0.5 wt % of an inorganic salt solution from the resulting mixture of inorganic salts, with glucose as carbon source, seeding 1-2 mL of the EM stock solution to a 250 mL triangular flask containing 100 mL of the mixture of inorganic salts, and performing enrichment culture at 30 C. with stirring at 170 r/min, wherein the concentration of NO.sub.3.sup. in culture was determined every 2 d, and when the cutting rate of NO.sub.3.sup. was 30% and the amount of seeds reached 10.sup.7-10.sup.8 cfu/ml, the next culture was performed; step 2, taking 1-2 mL of the solution obtained from the last culture and adding 100 mL 1.0 wt % of the inorganic salt solution and performing enrichment culture under the same conditions as those described above, wherein the concentration of the inorganic salt solution was successively increased to 4% at 0.5% gradient.

(17) Examples 1-4 were formulated with the same batch of the soil modifier B and were subjected to soil planting and modification tests described below.

Example 5

(18) The resulting soil modifiers from example 1 were selected for tomato planting on various types of soils.

(19) Soil 1 was normal facility soil without soil secondary salt salinization.

(20) Soil 2 was soil with mild-to-moderate facility secondary salt salinization having a total salt content of 2.10 g/kg, soil nitrate nitrogen of 0.44 g/kg and pH 6.1.

(21) Soil 3 was soil modified from soil 2 using the soil modifiers in example 1. The modification was performed by stacking the facility ploughing soil for planting (0-10 cm) to be 35-40 cm high, adding the soil modifier A at 1 by mass, fully mixing, co-culturing at 35-50 C. for 5-7 days, covering onto the soil surface layer to 0-10 cm 1 day before crop planting, planting tomato seedlings, and 7 days later, spraying the soil modifier B diluted 500 (3000 kg/ha) onto the root system; afterwards, the soil modifier B was sprayed once during flowering period and during fruit expanding period.

(22) The soils were provided with an underground drainage system (depth of drainage pipe of 0.7 m, spacing of 8 m). The facility tomato irrigation manner was drip irrigation, and the upper irrigation limit was the field moisture capacity and the lower irrigation limit was 45% (seedling period)-65% (flowering and fruit setting period)-60%/o (fruiting period), and the designed wetted layer was 0.2 m (seedling period)-0.4 m (flowering and fruit setting period and fruiting period).

(23) The results indicated that for one season of tomato planting, the present modification method resulted in decrease of total salt content in soils (0-15 cm) by 37% and increase of tomato yield by 33%.

(24) Specific soil types and test results are shown in table 1 below:

(25) TABLE-US-00002 TABLE 1 Relative quantity of Soil total Soil leaf nitrate salt nitrate Fruit reductase Tomato content/g nitrogen/g nitrates/g genes yield/t Treatment kg.sup.1 kg.sup.1 kg.sup.1 (HQ616893) ha.sup.1 Soil 1 0.06 0.015 0.10 0.81 80.1 Soil 2 2.10 0.440 0.12 1.34 63.8 Soil 3 1.32 0.172 0.074 6.07 84.9

(26) It can be seen from the table that, after being soil modified, soil 3 produces a tomato yield significantly higher than that of non-modified soil 2 and better than that of normal soil.

Example 6

(27) Similar to example 5, the resulting soil modifiers from example 1 were selected for tomato planting on various types of soils.

(28) Soil 1 was normal facility soil without soil secondary salt salinization.

(29) Soil 2 was soil with serious facility secondary salt salinization having a total salt content of 3.90 g/kg, soil nitrate nitrogen of 1.35 g/kg and pH 5.7.

(30) Soil 3 was soil modified from soil 2 using the soil modifiers in example 1. The modification was performed by stacking the facility ploughing soil for planting (0-10 cm) to be 35-40 cm high, adding the soil modifier A at 1.4 by mass, fully mixing, co-culturing at 35-50 C. for 5-7 days, covering onto the soil surface layer to 0-10 cm 1 day before crop planting, planting tomato seedlings, and 7 days later, spraying the soil modifier B diluted 1000 (4500 kg/ha) onto the root system; afterwards, the soil modifier B was sprayed once every 10 days.

(31) The soils were provided with an underground drainage system (depth of drainage pipe of 0.7 m, spacing of 8 m). The facility tomato irrigation manner was drip irrigation, and the upper irrigation limit was the field moisture capacity and the lower irrigation limit was 45% (seedling period)-65% (flowering and fruit setting period)-60% (fruiting period), and the designed wetted layer was 0.2 m (seedling period)-0.4 m (flowering and fruit setting period and fruiting period).

(32) The results indicated that for one season of tomato planting, the present modification method resulted in decrease of total salt content in soils (0-15 cm) by 45% and increase of tomato yield by 73%.

(33) Specific soil types and test results are shown in table 2 below:

(34) TABLE-US-00003 TABLE 2 Relative quantity of Soil total Soil leaf nitrate salt nitrate Fruit reductase Tomato content/g nitrogen/g nitrates/g genes yield/t Treatment kg.sup.1 kg.sup.1 kg.sup.1 (HQ616893) ha.sup.1 Soil 1 0.06 0.015 0.10 0.81 80.1 Soil 2 3.90 1.350 0.12 1.34 43.2 Soil 3 2.13 0.389 0.074 6.07 74.9

(35) It can be seen from the table that, after being soil modified, soil 3 produces a tomato yield significantly higher than that of non-modified soil 2.

Comparative Example 1

(36) The resulting soil modifiers from example 1 were selected for tomato planting on various types of soils. The difference from example 5 was that the biological modifier B was not used in the soil modification process.

(37) Soil 1 was normal facility soil without soil secondary salt salinization.

(38) Soil 2 was soil with mild-to-moderate facility secondary salt salinization having a total salt content of 2.10 g/kg, soil nitrate nitrogen of 0.44 g/kg and pH 6.1.

(39) Soil 3 was soil modified from soil 2 using the soil modifier in example 1. The modification was performed by stacking the facility ploughing soil for planting (0-10 cm) to be 35-40 cm high, adding the soil modifier A at 1 by mass, fully mixing, co-culturing at 35-50 C. for 5-7 days, covering onto the soil surface layer to 0-10 cm 1 day before crop planting, and planting tomato seedlings.

(40) Soil 4 was soil modified from soil 2 using the biological modifier A (in the preparation, the C/N ratio was adjusted to be 80) and applied by the same procedure as soil 3.

(41) Soil 5 was soil modified from soil 2 using the biological modifier A (in the preparation, the C/N ratio was adjusted to be 12) and applied by the same procedure as soil 3.

(42) The soils were provided with an underground drainage system (depth of drainage pipe of 0.7 m, spacing of 8 m). The facility tomato irrigation manner was drip irrigation, and the upper irrigation limit was the field moisture capacity and the lower irrigation limit was 45% (seedling period)-65% (flowering and fruit setting period)-60% (fruiting period), and the designed wetted layer was 0.2 m (seedling period)-0.4 m (flowering and fruit setting period and fruiting period).

(43) The results indicated that for one season of tomato planting, the biological modifier A, the modifier with high C/N and the modifier with low C/N resulted in decrease of total salt content in soils (0-15 cm) by 12%, 16% and 9% and increase of tomato yield by 13%, 5% and 6%, respectively.

(44) Specific soil types and test results are shown in table 3 below:

(45) TABLE-US-00004 TABLE 3 Relative quantity of Soil total Soil leaf nitrate salt nitrate Fruit reductase Tomato content/g nitrogen/g nitrates/ genes yield/t Treatment kg.sup.1 kg.sup.1 g kg.sup.1 (HQ616893) ha.sup.1 Soil 1 0.06 0.015 0.10 0.81 80.1 Soil 2 2.10 0.440 0.12 1.34 63.8 Soil 3 1.85 0.343 0.10 3.68 72.3 Soil 4 1.81 0.218 0.08 3.49 67.2 Soil 5 2.28 0.491 0.14 1.32 60.1

(46) It can be seen from the table that, after being soil modified, soil 3 produces a tomato yield superior to non-modified soil 2, but slightly inferior to example 5 because no synergistic effect with the biological modifier B occurs; and that the modification effect of soil 4 is slightly superior to soil 3, but the tomato yield increasing amplitude is relatively low; and that soil 5 further aggravates the degree of facility soil secondary salt salinization.

Comparative Example 2

(47) The difference between comparative example 2 and example 5 was that the modifier B was the EM stock solution without salt tolerance acclimation, for tomato planting on various types of soils.

(48) Soil 1 was normal facility soil without soil secondary salt salinization.

(49) Soil 2 was soil with mild-to-moderate facility secondary salt salinization having a total salt content of 2.10 g/kg, soil nitrate nitrogen of 0.44 g/kg and pH 6.1.

(50) Soil 3 was soil modified from soil 2 using the soil modifiers in example 1. The modification was performed by stacking the facility ploughing soil for planting (0-10 cm) to be 35-40 cm high, adding the soil modifier A at 1 by mass, fully mixing, co-culturing at 35-50 C. for 5-7 days, covering onto the soil surface layer to 0-10 cm 1 day before crop planting, planting tomato seedlings, and 7 days later, spraying the soil modifier B diluted 500 (3000 kg/ha) onto the root system; afterwards, the soil modifier B was sprayed once during flowering period and during fruit expanding period.

(51) The soils were provided with an underground drainage system (depth of drainage pipe of 0.7 m, spacing of 8 m). The facility tomato irrigation manner was drip irrigation, and the upper irrigation limit was the field moisture capacity and the lower irrigation limit was 45% (seedling period)-65% (flowering and fruit setting period)-60% (fruiting period), and the designed wetted layer was 0.2 m (seedling period)-0.4 m (flowering and fruit setting period and fruiting period).

(52) The results indicated that for one season of tomato planting, the present modification method resulted in decrease of total salt content in soils (0-15 cm) by 20% and increase of tomato yield by 12%.

(53) Specific soil types and test results are shown in table 4 below:

(54) TABLE-US-00005 TABLE 4 Relative Soil quantity of total Soil leaf nitrate salt nitrate Fruit reductase Tomato content/ nitrogen/ nitrates/ genes yield/t Treatment g kg.sup.1 g kg.sup.1 g kg.sup.1 (HQ616893) ha.sup.1 Soil 1 0.06 0.015 0.10 0.81 80.1 Soil 2 2.10 0.440 0.12 1.34 63.8 Soil 3 1.67 0.290 0.011 3.82 71.2

(55) It can be seen from the table that, when the EM stock solution is not subjected to acclimation, its effect on reduction of total salt content in soils and increase of tomato yield is slightly inferior to that of the soil modifier in example 5.