A cold-resistant agent for double-season rice planted in southern Hunan and its use method

Abstract

The present invention belongs to the technical field of cold-resistant agents, and the present invention provides a cold-resistant agent for double-season rice planted by machine in southern Hunan and a method for using the same. The cold-resistant agent for double-season rice planted by machine in southern Hunan provided by the present invention is composed of the following raw materials in parts by weight: 1 to 3 parts of zinc sulfate, 1 to 3 parts of manganese sulfate, 1 to 3 parts of ammonium chloride, 0.5 to 1.5 parts of β-cyclodextrin and 0.5 to 1.5 parts of anti-drop agent. The cold-resistant agent provided by the present invention and the method for using the same solve the problems faced by early rice production in Hunan, such as "late spring cold", the failure of rice seedlings to take root, and the reduction of late rice production due to "Cold Dew Wind", and provide technical and theoretical support for further increasing rice production in southern Hunan and achieving stable rice production.

Description

Technical Field

[0001] The invention relates to the technical field of cold-resistant agents, and in particular to a cold-resistant agent for machine-transplanted double-season rice in southern Hunan and a use method thereof. Background Art

[0002] Early spring cold damage occurs frequently in southern Hunan, and late rice is often invaded by "Cold Dew Wind", which has a great impact on the safe production of double-season rice, especially machine-transplanted double-season rice. At present, machine transplanting of rice is developing rapidly, but the regreening period of machine transplanting is long, which greatly increases the risk of double-season late rice encountering "Cold Dew Wind". Therefore, it is particularly necessary to study a cold-resistant agent suitable for machine-transplanted double-season rice. Summary of the invention

[0003] In order to overcome the above defects in the prior art, the present invention provides a cold-resistant agent for machine-transplanted double-season rice in southern Hunan and a method for using the same.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The invention provides a cold-resistant agent for machine-transplanted double-season rice in southern Hunan. The cold-resistant agent is composed of the following raw materials in parts by weight: 1 to 3 parts of zinc sulfate, 1 to 3 parts of manganese sulfate, 1 to 3 parts of ammonium chloride, 0.5 to 1.5 parts of beta-cyclodextrin and 0.5 to 1.5 parts of anti-drop agent.

[0006] The present invention also provides a method for using a cold-resistant agent for machine-transplanted double-season rice in southern Hunan, comprising the following steps:

[0007] (1) mixing the Xiangnan machine-planted double-season rice cold-resistant agent with water to obtain a mixed solution;

[0008] (2) Spraying the mixture obtained above at the one-leaf-one-heart stage of early rice or after turning green, and spraying the mixture obtained above at the heading stage of late rice.

[0009] Preferably, the mixing ratio of the Xiangnan machine-planted double-season rice cold-resistant agent and water in step (1) is 45-55 g: 35000-45000 mL.

[0010] Preferably, the spraying amount in step (2) is 35000-45000 mL / mu.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] The cold-resistant agent and the use method thereof provided by the present invention solve the problems faced by early rice production in Hunan Province, such as "late spring cold", failure of rice seedlings to take root, and reduction in late rice production due to "Cold Dew Wind", and provide technical and theoretical support for further increasing rice production in southern Hunan and achieving rice stress resistance and stable production. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram showing the effects of the cold-resistant agent of the present invention and the spraying period on the dynamics of early rice stem tillers. DETAILED DESCRIPTION

[0014] The invention provides a cold-resistant agent for double-season rice planted by machine in southern Hunan, which is composed of the following raw materials in parts by weight: 1-3 parts of zinc sulfate, 1-3 parts of manganese sulfate, 1-3 parts of ammonium chloride, 0.5-1.5 parts of beta-cyclodextrin and 0.5-1.5 parts of anti-drop agent, wherein the anti-drop agent is p-chlorophenoxyacetic acid.

[0015] In the present invention, the cold-resistant agent for Xiangnan machine-transplanted double-season rice is preferably composed of the following raw materials in parts by weight: 1 to 3 parts of zinc sulfate, more preferably 1.5 to 2.5 parts, and more preferably 2 parts; 1 to 3 parts of manganese sulfate, more preferably 1.5 to 2.5 parts, and more preferably 2 parts; 1 to 3 parts of ammonium chloride, more preferably 1.5 to 2.5 parts, and more preferably 2 parts; 0.5 to 1.5 parts of β-cyclodextrin, more preferably 0.8 to 1.2 parts, and more preferably 1 part; 0.5 to 1.5 parts of anti-drop agent, more preferably 0.8 to 1.2 parts, and more preferably 1 part.

[0016] The present invention also provides a method for using a cold-resistant agent for machine-transplanted double-season rice in southern Hunan, comprising the following steps:

[0017] (1) mixing the Xiangnan machine-planted double-season rice cold-resistant agent with water to obtain a mixed solution;

[0018] (2) Spraying the mixture obtained above at the one-leaf-one-heart stage of early rice or after turning green, and spraying the mixture obtained above at the heading stage of late rice.

[0019] In the present invention, the mixing ratio of the Xiangnan machine-transplanted double-season rice cold-resistant agent and water in step (1) is preferably 45-55 g: 35000-45000 mL, and more preferably 50 g: 40000 mL.

[0020] In the present invention, the spraying amount in step (2) is preferably 35,000 to 45,000 mL / mu, more preferably 38,000 to 42,000 mL / mu, and even more preferably 40,000 mL / mu.

[0021] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0022] Example 1

[0023] The invention provides a cold-resistant agent for machine-transplanted double-season rice in southern Hunan, which is composed of the following raw materials in parts by weight: 1 part of zinc sulfate, 1 part of manganese sulfate, 1 part of ammonium chloride, 0.5 part of beta-cyclodextrin and 0.5 part of anti-drop agent.

[0024] Example 2

[0025] The invention provides a cold-resistant agent for machine-transplanted double-season rice in southern Hunan, which is composed of the following raw materials in parts by weight: 2 parts of zinc sulfate, 2 parts of manganese sulfate, 2 parts of ammonium chloride, 1 part of beta-cyclodextrin and 1 part of anti-drop agent.

[0026] Example 3

[0027] The invention provides a cold-resistant agent for machine-transplanted double-season rice in southern Hunan, which is composed of the following raw materials in parts by weight: 3 parts of zinc sulfate, 3 parts of manganese sulfate, 3 parts of ammonium chloride, 1.5 parts of beta-cyclodextrin and 1.5 parts of anti-drop agent.

[0028] Experimental Example 1

[0029] Experimental materials: Early rice is Zhongjia Zao 17, which is a conventional early rice of indica type, with a full growth period of 109 days; late rice is Hyou 518, which is a three-line hybrid rice of indica type, with an average full growth period of 112.9 days. The cold-resistant agent is Ai Lidun (uniconazole powder, 20% active ingredient) produced by Tuyouta Company, S-inducing agent (abscisic acid aqueous solution, 0.1% active ingredient) produced by Zhifu Company, and the Xiangnan machine-transplanted double-season rice cold-resistant agent in Example 2 of the present invention.

[0030] Experimental location: A double-season rice experiment was conducted in Xidu Town, Hengyang County, Hunan Province in 2018. The basic physical and chemical properties of the soil in the test field were: organic matter 25.20g / kg, total nitrogen 1.50g / kg, alkaline nitrogen 162.30mg / kg, total phosphorus 0.64g / kg, available phosphorus 9.60mg / kg, total potassium 19.30g / kg, available potassium 102.43mg / kg, pH 6.22. The specifications of the test seedling tray were 58cm×28cm.

[0031] Experimental design: The test sets up two factors of cold-resistant agent type and spraying period. The types of cold-resistant agents are Ai Lidun (C1), S-inducing element (C2) and Xiangnan machine-transplanted double-season rice cold-resistant agent (C3) in Example 2 of the present invention. The application concentrations are all the recommended concentrations in the product manual (C1 seed soaking concentration is 1000 times liquid, and the spraying concentration is 30g per mu with 30 kg of water; C2 seed soaking and spraying concentrations are both 200 times liquid; C3 seed soaking and spraying concentrations are both 50g with 40 kg of water). The early rice spraying period is set to soak seeds (D1), spray one leaf and one heart (D2), spray two leaves and one heart (D3), spray before transplanting (D4), spray after returning to green (D5) and other 5 periods, and the late rice spraying period is set to booting stage (F1), initial booting stage (F2), full booting stage (F3), and one week after full booting (F4) and other 4 periods. In addition, in order to ensure that late rice encounters low temperature adversity, a late rice delayed sowing experiment is set. The seeds of early rice were soaked on March 24 (the seeds of D1 were soaked according to the concentration recommended in the product manual, and the seeds of the other treatments were soaked in water), sown on March 28 (dry seeds 105g / tray), and transplanted on April 20; the seeds of late rice were soaked in water on June 28, sown on July 1 (dry seeds 90g / tray), and transplanted on July 21; the seeds of late rice delayed sowing experiment were soaked on July 16, sown on July 19, and transplanted on August 8. The machine transplanting density was 30cm×11cm, and each treatment was transplanted 100m 2 The amount of fertilizer applied to each treatment was the same, and the amount of nitrogen (N) applied to early rice was 180 kg / hm 2 The nitrogen application rate for late rice is 210 kg / hm 2 , according to N:P 2 O 5 :K 2 O=1:0.5:1 with phosphate fertilizer (superphosphate, containing P 2 O 5 12%) and potash fertilizer (potassium chloride, containing K 2 O 60%), nitrogen fertilizer (urea, containing 46.4% pure nitrogen) was applied at a ratio of 5:3:2 for base fertilizer, tillering fertilizer and ear fertilizer, all phosphorus fertilizer was applied as base fertilizer at one time, and potassium fertilizer was applied at a ratio of 6:4 for base fertilizer and tillering fertilizer. Other management was carried out according to local high-yield habits.

[0032] Measurement items and methods:

[0033] Leaf area and dry matter accumulation: The leaf area and dry matter weight of the key growth stages (tillering peak stage, booting stage, full heading stage, milky stage and mature stage) were investigated. Six replicates were taken from each plot, with 3 holes in each replicate. The leaf area was determined by the length-width coefficient method. The leaves, stems, and ears were bagged, withered at 105°C for 30 minutes, and dried at 80°C to constant weight. The dry matter weight of each part was weighed.

[0034] Yield and its components: During the maturity period, three points were selected diagonally in each region. The number of effective panicles of 60 consecutive rice stalks was investigated at each point. The number of effective panicles per hole was calculated. Five stalks were sampled at each point according to the average number of effective panicles. The samples were taken back to the laboratory to investigate the number of grains per panicle, fruit setting rate and thousand-grain weight. 2 (Every 2m 2 The actual yield was calculated based on a moisture content of 13.5%.

[0035] Physiological characteristics: The seedlings of each treatment were collected at the three-leaf and one-heart stage, and the antioxidant enzyme activities were determined according to the "Principles and Techniques of Plant Physiological and Biochemical Experiments" edited by Li Hesheng. The peroxidase (POD) activity was determined by the guaiacol method, with the change of OD470 of 0.1 / min as one relative enzyme activity unit U; the superoxide dismutase (SOD) activity was determined by the nitroblue tetrazolium (NBT) photochemical reduction method, with 50% inhibition as one enzyme activity unit U; the catalase (CAT) activity was determined by the hydrogen peroxide method, with the change of OD240 of 0.1 / min as one relative enzyme activity unit U.

[0036] Data processing:

[0037] Excel 2010 was used for statistical analysis and DPS 7.05 was used for variance analysis.

[0038] (1) The effects of cold-resistant agents and spraying time on the dynamics of early rice stem tillering were studied. Figure 1 shown.

[0039] Depend on Figure 1 It can be seen that among the cold-resistant agent treatments, the maximum tiller number of C1 treatment was slightly higher, and the average effective ear number of C2 treatment was higher. Among the treatments during the spraying period, the maximum stem tiller number of D2 and D4 treatments was higher, but most of them were invalid tillers, and the effective ear number of each treatment was basically the same. Among the combination treatments, the tillering ability of C1D3 and C3D3 was weak, and the effective ear number of each combination treatment of D2 was higher. In addition, the effective ear number of each C2 treatment was higher than that of C1 and C3. Overall, the cold-resistant agent was treated with C2, and the tillering ability of the D2 treatment during the spraying period was stronger, and the final effective ear number was higher.

[0040] (2) The effects of cold-resistant agents and spraying period on the physiological characteristics of early rice were studied. The activities of various antioxidant enzymes are shown in Table 1.

[0041] Table 1 Effects of cold-resistant agents and spraying time on the antioxidant system of early rice leaves

[0042]

[0043] Note: Different lowercase letters indicate significant differences at the 0.05 level. The same below.

[0044] As shown in Table 1, there was no significant difference in POD activity among the three treatments of cold-resistant agents. The activities of CAT and SOD in C3 treatment were at a high level, while those in C1 treatment were significantly lower. In the spraying period treatment, the SOD activity in D2 treatment was slightly lower, and the activities of CAT and POD were very high. The POD activity in D5 treatment was slightly lower, and the activities of the other two enzymes were high. The activities of each enzyme in D3 and D1 treatments were low, and only the CAT activity was high in D4 treatment. In the combined treatment, the activities of various enzymes in C3D2 were at a high level, the POD activity in C3D5 treatment was low, and the activities of CAT and SOD were extremely high. The activities of each antioxidant enzyme in C2D3, C2D4, and C3D1 were very low, and the rules of other treatments were not obvious. In general, cold-resistant agents can improve the antioxidant capacity of rice, and C3>C2>C1. During the spraying period, the D2 and D5 treatments were better, and the D3 treatment was worse.

[0045] (3) The effects of cold-resistant agents and spraying period on dry matter accumulation of early rice were studied. The results are shown in Table 2.

[0046] Table 2 Effects of cold-resistant agents and spraying period on the accumulation dynamics of dry matter in the aboveground part of early rice

[0047]

[0048]

[0049] As shown in Table 2, among the cold-resistant agent treatments, the C3 treatment was at the highest level in all periods, and the C2 treatment was higher than the C1 treatment except at the booting stage, and the difference was significant in all other periods; among the different spraying periods, the D5 treatment was higher in all periods, the D1 treatment accumulated dry matter faster in the early and middle stages, and the level was lower at the beginning of the milky stage, while the D2 treatment was just the opposite, with a lower level in the peak stage, but the dry matter accumulation rate accelerated at the booting stage, and it was at a higher level in all subsequent periods, and the D4 treatment had a lower dry matter weight in all periods. Among the various combination treatments, the C2D2, C3D2, and C2D5 treatments had a lower dry matter weight in the early stage, but the accumulation rate accelerated in the middle and late stages, and it was always at an extremely high level until the maturity stage. The C2D5 combination had a higher dry matter weight in all periods, the C3D1 treatment had a lower dry matter weight in the booting stage, and it was very high in other periods, and the C1D1 treatment had a lower dry matter weight in all periods. In general, the effect of cold-resistant agents on increasing dry weight is C3>C2>C1. During the spraying period, the dry weight of treatments D2 and D5 was higher.

[0050] (4) The effects of cold-resistant agents and spraying period on the leaf area of ​​early rice were studied. The results are shown in Table 3.

[0051] Table 3 Effects of cold-resistant agents and spraying period on leaf area index of early rice

[0052]

[0053]

[0054] As shown in Table 3, among the treatments of cold-resistant agents, the LAI of C3 treatment was the highest in all periods, and the difference was significant, followed by C2 treatment, but the difference was not significant in the heading stage and milky stage; among the treatments of spraying period, the LAI of D2 treatment was lower in the early and middle stages, but higher in the milky stage, the LAI of D3 treatment was lower in the booting stage, but very high in other periods, the LAI of D5 treatment was lower in the tillering stage and milky stage, and very high in other periods; among the combined treatments, the LAI of C1D2, C2D1, and C2D4 treatments was lower in all periods, the LAI of C1D3 and C2D2 treatments was lower in the early and middle stages, but higher in the milky stage, the LAI of C3D2 treatment was lower in the tillering stage, and higher in other periods, the LAI of C3D3 treatment was lower in the heading stage, and higher in other periods. In general, the cold-resistant agents C3>C2>C1, and the D2 treatment was better in the spraying period.

[0055] (5) The effects of cold-resistant agents and spraying period on early rice yield and its components were studied. The results are shown in Table 4.

[0056] Table 4 Effects of cold-resistant agents and spraying period on early rice yield and yield components

[0057]

[0058]

[0059] As shown in Table 4, among the different cold-resistant agents, the yield of C3 treatment was significantly higher than that of other treatments. Compared with C1 and C2 treatments, the yield of C3 treatment was 7.6% and 7.1% higher, respectively. Through analysis, it was found that the levels of each yield component were very high, and the yield and yield component levels of C1 and C2 treatments were relatively consistent, with no significant difference. During the spraying period, the yield of D2, D4, and D5 treatments was higher. The yield of D1 treatment was lower due to the lower number of grains per ear, and the yield of D3 treatment was lower due to the lower fruit setting rate. Among all the combined treatments, C3D2 and C3D5 treatments had the highest yields. The effective panicle number per unit area of ​​C3D2 treatment was low, but the extremely high number of grains per panicle and the fruit setting rate had significant compensatory effects. The levels of various yield components of C3D5 treatment were very high. The yields of C1D1, C2D5, and C3D3 treatments were low. The reason for C1D1 treatment was that the levels of various yield components were low. The reasons for C2D5 and C3D3 treatments were similar. Both had high effective panicle numbers per unit area, but the fruit setting rate was too low, resulting in low yields. In general, cold-resistant agents and spraying periods had a great impact on early rice yields. Among cold-resistant agents, C3 treatment had the most obvious increase in yield. During the spraying period, D2, D4, and D5 treatments had higher yields.

[0060] (6) The effects of cold-resistant agents and spraying period on the physiological characteristics of late rice were studied. The results are shown in Table 5.

[0061] Table 5 Effects of cold-resistant agents and spraying period on the antioxidant system of late rice leaves

[0062]

[0063] As shown in Table 5, among the cold-resistant agent treatments, the enzyme activities of C3 treatment were the highest, and those of C1 treatment were the lowest, with significant differences among the treatments; among the spraying period treatments, the enzyme activities of F2 treatment were the highest, and those of F1 treatment were relatively low. Among the combination treatments, the enzyme activities of C3F2 treatments were relatively high, and those of C1 combination treatments and F4 combination treatments were not high. Overall, the type of cold-resistant agent and the spraying period had an important influence on the antioxidant enzyme activity of early rice, and the performance of improving the stress resistance of rice was C3>C2>C1, and F2 was more suitable for the spraying period.

[0064] (7) The effects of cold-resistant agents and spraying period on delayed sowing of late rice were studied. The results are shown in Table 6.

[0065] Table 6 Effects of cold-resistant agents and spraying time on the antioxidant system in leaves of delayed-sowing late rice

[0066]

[0067] As shown in Table 6, in the treatment of cold-resistant agent, the activity of each enzyme showed C3>C2>C1. In the spraying period, the activity of each enzyme in F1 treatment was the highest, and that in F4 treatment was the lowest. The enzyme activity tended to decrease gradually as the spraying period was delayed. In each combination treatment, the enzyme activity of C1 treatment was still relatively low, and only C1F1 and C1F4 treatments had slightly higher SOD activity, while C3F1, C3F2, and C3F3 treatments had relatively high enzyme activity. It can be seen that the type of cold-resistant agent and the spraying period had a significant effect on the stress resistance of late rice. The cold-resistant agent for double-season rice transplanted by Xiangnan machine in Example 2 of the present invention had the best effect on improving the stress resistance of late rice, followed by S-inducing agent, and Ai Lidun was the worst.

[0068] (8) The effects of cold-resistant agents and spraying period on late rice yield and its components were studied. The results are shown in Table 7.

[0069] Table 7 Effects of cold-resistant agents and spraying period on late rice yield and yield components

[0070]

[0071] As shown in Table 7, among the cold-resistant agent treatments, the C3 treatment had the highest yield, which was 20.2% higher than the C1 treatment and 8.8% higher than the C2 treatment. Its various yield formation factors were at a high level, while the C1 treatment had the lowest yield, mainly due to the low number of grains per ear. During the spraying period, there was no significant difference in the number of grains per ear, thousand-grain weight and number of grains per ear among the treatments. The F2 treatment had the highest yield and the F4 treatment had the lowest yield because of its low fruit setting rate. Among the combined treatments, the C2F2 and C3F2 treatments had the highest yield, while the C1F4, C2F4 and C1F1 treatments had low yields. From the perspective of yield composition, the number of grains per ear and the fruit setting rate of these two treatments were very low. In general, the cold-resistant agent and the spraying period had a great impact on the yield. The C3 treatment had the most significant increase in yield, and the F2 treatment had the best spraying period.

[0072] (9) The effects of cold-resistant agents and spraying period on the yield and yield structure of delayed-sowing late rice were studied. The results are shown in Table 8.

[0073] Table 8 Effects of cold-resistant agents and spraying period on yield and yield composition of delayed-sowing late rice

[0074]

[0075] As shown in Table 8, the delayed sowing test encountered obvious low temperature adversity during the heading and flowering period. In the cold-resistant agent treatment, C3 treatment had the highest yield, and there was no significant difference in the yield between C1 and C2. The reason for the lower yield of the two was that the number of grains per ear and the fruiting were low; in different spraying periods, F1 treatment had the highest yield, and F4 treatment had the lowest yield. The yield decreased with the delay of the spraying period. There was no significant difference in the number of effective ears and thousand-grain weight in each spraying period treatment. The main reason for the difference in yield was the huge number of grains per ear and the fruiting rate; in each combination treatment, the yield of C3 was still higher, and the yield of F4 treatment was the lowest, which was consistent with the law of physiological characteristics. When encountering low temperature and cold damage, the Xiangnan machine-transplanted double-season rice cold-resistant agent in Example 2 of the present invention has the best effect on improving the resistance of rice, and when low temperature comes, spraying the cold-resistant agent as early as possible can avoid yield losses as much as possible.

[0076] In summary, CAT, SOD, and POD are important components of the plant tissue protection enzyme system. When plants encounter adversity, the system balance of the protective enzyme is broken, the oxygen free radical content increases, and the membrane system is damaged. SOD can eliminate excessive oxygen free radicals in cells and convert them into hydrogen peroxide. CAT and POD can decompose excess hydrogen peroxide to protect cells. The present invention is based on the activity of each antioxidant enzyme, combined with the yield formation characteristics of early and late rice, and studies the low temperature and cold damage problems faced by double-season rice production in southern Hunan. The results show that among the three cold-resistant agents, the cold-resistant agent for double-season rice transplanted by machine in southern Hunan in Example 2 of the present invention is the most effective for improving the stress resistance of early and late rice, followed by S-inducing agent, and paclobutrazol has the worst effect; during the spraying period, the cold-resistant agent for early rice is best sprayed with one leaf and one heart and after returning to green, and the late rice is sprayed at the initial heading stage, and the stress resistance is the strongest.

[0077] From the tillering dynamics, the spraying of the Xiangnan machine-transplanted double-season rice cold-resistant agent in Example 2 of the present invention has the most obvious effect on the tillering of early rice, the tillering occurs faster, and the final number of tillers is also larger. The effect of Ai Lidun and S-inducing agent on the tillering ability of rice is not obvious, and the spraying period should be selected at one leaf and one heart, which has the best effect. From the dry matter accumulation and leaf area dynamics, the Xiangnan machine-transplanted double-season rice cold-resistant agent in Example 2 of the present invention has the best effect, followed by S-inducing agent, Ai Lidun is the worst, and the cold-resistant agent is sprayed at one leaf and one heart or after turning green, which has a more obvious effect on the dry matter accumulation. The type of cold-resistant agent and the spraying period have a great influence on rice.

[0078] From the perspective of yield components, the Xiangnan machine-transplanted double-season rice cold-resistant agent in Example 2 of the present invention can better coordinate the contradictions between the various yield components of early rice. The indicators of each yield component are relatively high, and the final yield improvement effect is the best. Compared with the dwarf stand, the S-inducing agent has a more obvious effect on the improvement of the number of grains per panicle, and there is no significant difference in other indicators, and the final yield is higher. During the spraying period, spraying one leaf and one heart or spraying after turning green can obtain higher yields. From the perspective of late rice yield, the late rice S-inducing agent is better than the dwarf stand. Similar to early rice, the S-inducing agent has a greater effect on the improvement of the number of grains per panicle, and there is no significant difference in other indicators. In 2018, the Xiangnan machine-transplanted double-season rice cold-resistant agent in Example 2 of the present invention has a better yield-increasing effect. Compared with the dwarf stand, the yield increased by 20.2%, mainly because the number of effective panicles and the fruiting rate were increased; the spraying period should be selected at the beginning of the heading period, and the yield is the highest. In summary, the cold-resistant agent for double-season rice transplanted by machine in southern Hunan in Example 2 of the present invention has the greatest impact on yield improvement. The cold-resistant agent for early rice should be sprayed when the rice is one leaf and one heart or after it turns green, and the cold-resistant agent for late rice should be sprayed at the initial heading stage.

[0079] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for using a cold-resistant agent for machine-planted double-season rice in southern Hunan, characterized in that: The steps include: (1) mixing the Xiangnan machine-planted double-season rice cold-resistant agent with water to obtain a mixed solution; (2) spraying the mixture obtained above at the one-leaf-one-heart stage of early rice or after turning green, and spraying the mixture obtained above at the heading stage of late rice; The cold-resistant agent for double-season rice planted by machine in southern Hunan is composed of the following raw materials in parts by weight: 1-3 parts of zinc sulfate, 1-3 parts of manganese sulfate, 1-3 parts of ammonium chloride, 0.5-1.5 parts of beta-cyclodextrin and 0.5-1.5 parts of anti-drop agent.

2. The method of use according to claim 1, characterized in that: The mixing ratio of the Xiangnan machine-transplanted double-season rice cold-resistant agent and water in step (1) is 45-55 g: 35000-45000 mL.

3. The method of use according to claim 1 or 2, characterized in that: The spraying amount in step (2) is 35000~45000mL / mu.

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