Method for preventing and controlling late blight of potatoes planted in red soil slope cropland

Abstract

The invention provides a late blight control method for planting potatoes in red soil slope cropland, and the used fertilizer comprises urea, calcium superphosphate and potassium sulfate according to a mass ratio of 15: 12-13.5: 16.5. According to the method, in the breeding period, phosphite is used for completely or partially replacing pesticide to prevent and control potato late blight. Compared with local conventional fertilization, the optimized fertilizer has the advantages that the use amount of the chemical fertilizer is reduced, and the content of soil nutrients and the accumulation of plant nutrients cannot be obviously influenced. In addition, phosphite replaces pesticides and has a prevention and treatment effect on potato late blight. The fertilizer with the optimized formula and the method for preventing and treating the late blight by using the phosphite have important significance on good development of the potato industry.

Description

Technical Field

[0001] The invention belongs to the technical field of crop planting, and particularly relates to a method for preventing and controlling late blight of potatoes planted on red soil sloping farmland. Background Art

[0002] potato( Solanum tuberosum ) originated from the Andes Mountains in South America. It is an annual herbaceous plant of the Solanaceae family, the fourth largest food crop in the world, and China ranks first in potato cultivation worldwide. Research on potatoes is not only related to the efficiency and output of agricultural production, but also closely related to global food supply and environmental sustainability. Research on potatoes is not only related to the efficiency and stability of agricultural production, but also closely related to food supply, environmental protection and scientific innovation, and has important social and economic significance. Potatoes are used as both food and vegetables. For food security, potatoes are the main source of food in many regions, and optimizing production will directly affect food supply and human nutrition; for economic development, potatoes are an important commercial crop that helps farmers increase their income and promote agricultural economic development; from the perspective of environmental protection, reducing the use of pesticides and improving drought and disease resistance will help protect the ecological environment and soil health.

[0003] Fertilization is an effective means to increase potato yields. The nitrogen, phosphorus and potassium required for potato growth, except for a small part obtained from the soil, are mainly provided by fertilization. When soil nutrients are insufficient, fertilization is needed to supplement soil nutrients. Due to the prominent problems of unreasonable fertilizer formula, imbalance of nitrogen, phosphorus and potassium ratio, insufficient application of organic fertilizer, etc. in potato fertilization, the nitrogen, phosphorus and potassium nutrient ratio in soil nutrients is imbalanced, the soil organic matter content is reduced, the soil is compacted, and the fertilizer utilization rate is low, resulting in increased fertilization costs and deterioration of quality. Optimizing fertilization is to seek a reasonable nitrogen, phosphorus and potassium ratio, improve the physical and chemical properties of the soil without affecting soil nutrients, and thus achieve the effect of increasing production.

[0004] Potato late blight is caused by Phytophthora infestans. Late blight is highly destructive and can cause 100% yield loss, causing serious damage to potato cultivation worldwide. The rapid spread and high destructiveness of this disease make it one of the major challenges in agricultural production. Late blight is mainly transmitted by spores. Wet and cool climatic conditions provide the most ideal environment for its spread. Rain and wind can spread spores to healthy plants and cause new infections. The symptoms of late blight first appear on the leaves of potatoes, showing water-soaked spots and black moldy patches. As the disease worsens, the leaves of the plants gradually wither and rot, and the stems and tubers may also be infected, resulting in a decrease in yield.

[0005] For a long time, researchers have conducted in-depth research on the characteristics of its pathogens, the law of transmission, and prevention and control measures. At present, there is a deep understanding of the biological characteristics of late blight pathogens, the disease resistance of host plants, and the disease resistance mechanism. From the perspective of the mechanism of action, the mechanism of action of existing agents is relatively concentrated on the interference or obstruction of mitochondrial respiration, the destruction of membrane structure, the influence of material metabolism and synthesis, and the inhibition of related functional enzymes. Most of them are highly selective and have a single target. However, due to the obvious physiological differentiation and rapid genetic variation of oomycetes, single-target fungicides are prone to resistance and affect the fungicide effect. For example, pyraclostrobin, cyazofamid, and metalaxyl are already facing serious resistance problems. New agents such as fluthiazide and fluopicolide also have high resistance risks. Therefore, the development of agents with new mechanisms of action is a hot spot for the prevention and control of potato late blight in the future. In addition, the use of mixed agents to improve the prevention effect and delay the occurrence of resistance is also a practical and effective means. Therefore, finding a reasonable and effective new mixed agent solution is another research hotspot for the prevention and control of potato diseases in the future. At the same time, since biogenic agents such as eugenol and sinomenine have good prevention and control effects, and most biogenic agents have the advantages of being green and safe, low in toxicity, and not easy to develop drug resistance, but there are relatively few types of biogenic agents at this stage, finding and developing new biogenic agents is also an important research direction for the prevention and control of potato late blight in the future. Summary of the invention

[0006] The purpose of the invention is to provide a method for preventing and controlling late blight of potatoes planted on red soil sloping farmland, thereby solving the problem of excessive fertilization during potato planting on sloping farmland, which leads to the prevalence of late blight.

[0007] The present invention first provides a fertilizer for planting potatoes on red soil sloping farmland, wherein the fertilizer contains urea, superphosphate and potassium sulfate, and the mass ratio thereof is 15:12-13.5:16.5; As a specific record of the embodiment, the fertilizer, wherein the mass ratio of urea, superphosphate and potassium sulfate is 15:13.5:16.5 or 15:12:16.5; In another aspect, the present invention provides a method for planting potatoes on red soil sloping farmland, wherein the method comprises applying the above-mentioned fertilizer during the planting process; The method is to apply 1200-1500 kg of fertilizer per hectare, wherein two-thirds are applied as base fertilizer and one-third are applied as topdressing; Among them, top dressing is applied when potatoes enter the tuber swelling period.

[0008] Furthermore, the method is to use phosphite to completely or partially replace pesticides to prevent and control potato late blight during planting.

[0009] As a specific description of the embodiment, the treatment is carried out by leaf spraying; wherein the concentration of the phosphite used is 2.5mM.

[0010] The optimized fertilizer of the present invention reduces the amount of chemical fertilizer used compared to local conventional fertilization, without significantly affecting the content of soil nutrients and the accumulation of plant nutrients. Moreover, phosphite replaces pesticides and has a preventive and therapeutic effect on potato late blight. The fertilizer with optimized formula and the method for preventing and controlling late blight with phosphite of the present invention are of great significance to the good development of the potato industry. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 : Total phosphorus content in soil at different growth stages of potato, including CK (no fertilizer + pesticide), T1 (local conventional fertilization: 15-15-15 + pesticide), T2 (optimized fertilization 1 (15-13.5-16.5 + pesticide), T3 (optimized fertilization 2 (15-12-16.5 + pesticide), T4 (local conventional fertilization + phosphite), T5 (optimized fertilization 1 + phosphite), T6 (optimized fertilization 2 + phosphite). Different lowercase letters a, b, c represent the same growth stage, and the differences among different treatments are significant (P<0.05). Capital letters A, B, C represent tuber formation period, tuber expansion period, and starch accumulation period, respectively. The numbers in each figure below are the same as those in the figure below. Figure 1 Consistent.

[0011] Figure 2 : Total potassium content of potatoes at different growth stages; Figure 3 : Soil organic matter content diagram of potato in different growth and nutrition stages; Figure 4 : Soil alkaline nitrogen content at different potato growth stages; Figure 5 : Available phosphorus content in soil at different growth stages of potato; Figure 6 : Available potassium content of potatoes at different growth stages; Figure 7 : A diagram of the total content of potato plants, where Figures A, B, and C represent the total nitrogen content of the plant, the total phosphorus content of the plant, and the total potassium content of the plant, respectively. DETAILED DESCRIPTION

[0012] The present invention studies the effect of phosphite as a substitute for pesticides on the nutrient, yield and occurrence and development of late blight of potatoes in red soil sloping farmland under the condition of reducing the dosage of different chemical fertilizers for potatoes, and determines that phosphite can be used as a green fungicide to prevent and control late blight of potatoes. In addition, a new plant phosphorus and weed control system is established, which can simultaneously solve practical problems in agricultural production such as excessive application of phosphorus fertilizers and herbicides, low utilization rate of soil phosphorus, super weeds, etc., and effectively achieve weight loss and efficiency improvement.

[0013] Sloping farmland refers to dry land distributed on hillsides with poor surface flatness, prominent water, fertilizer and soil runoff, and low crop yields. The concept of "sloping land" is generally a landform type with an angle of 6 to 25 degrees (after reclamation, it is often called sloping farmland).

[0014] Red soil, also known as red soil or brick red soil, refers to soil rich in iron oxide and aluminum oxide, and is generally believed to be formed in hot and humid tropical regions. Due to the high iron oxide content, almost all red soils are rusty red. Red soil has a distinct structure and is well ventilated and drained. The soil is acidic and not suitable for growing crops. It is rich in stickiness and plasticity, and has poor productivity, but it can be cultivated and managed with appropriate fertilizers to increase yields.

[0015] The present invention is described in detail below in conjunction with embodiments and drawings.

[0016] Example 1: Materials and methods information related to the present invention 1. Overview of the test site The field test was conducted in Chaotie Village, Xiaobaihu Town, Luliang County, Qujing City, Yunnan Province from August to December 2023. The soil type in the area is red soil, the pH of the test site is 4.85, the average altitude is 1870m, the average annual temperature is 14℃-14.7℃, and the annual rainfall is about 1000mm.

[0017] 2. Test materials The test variety: "Lishu No. 6", a winter potato variety with the advantages of high yield, high efficiency and high quality.

[0018] Test soil: red soil. The basic physical and chemical properties of the tillage layer (0-20 cm) are shown in Table 1.

[0019] Fertilizer types tested: urea, superphosphate and potassium sulfate.

[0020] Table 1: Basic physical and chemical properties of the tested soil 3. Experimental design This example adopts the field test method and is carried out from August 1, 2023 to December 10, 2023. The test adopts a randomized block design, and each treatment is repeated 3 times (n=3), with a total of 21 plots. Each plot has an area of ​​55m 2 A total of 16 rows of potatoes (320 plants, 27 cm plant spacing, 62 cm row spacing) were planted. A 2-meter protective row was reserved around the experimental site.

[0021] The experiment set up 7 treatments, namely: CK (no fertilizer + pesticide), T1 (local conventional fertilization: 15-15-15 + pesticide), 1500 kg / ha, one-time basal application; T2 (optimized fertilization 1: 15-13.5-16.5 + pesticides) 1200 kg / ha, 2 / 3 as basal fertilizer, 1 / 3 as topdressing; T3 (optimized fertilization 2: 15-12-16.5 + pesticides), 1200 kg / ha, 2 / 3 as basal fertilizer, 1 / 3 as topdressing; T4 (local conventional fertilizer + phosphite), 1500 kg / ha, one-time basal application; T5 (optimized fertilization 1 + phosphite), 1200 kg / ha, 2 / 3 as basal fertilizer, 1 / 3 as topdressing; T6 (optimized fertilization 2 + phosphite), 1200 kg / ha, 2 / 3 as base fertilizer and 1 / 3 as top dressing.

[0022] T4, T5, and T6 completely replace chemical pesticides with phosphite.

[0023] Among them, 15-15-15, 15-13.5-16.5 and 15-12-16.5 of T1, T2 and T3 represent the mass ratios of urea, superphosphate and potassium sulfate.

[0024] When potatoes enter the tuber swelling period, topdressing should be done. The formula of topdressing should be the same as that of base fertilizer, and topdressing should be done once in the whole process.

[0025] Application of pesticides and phosphites: When potatoes enter the tuber formation growth period (4 weeks after sowing), late blight prevention and control work begins. The commonly used pesticide in the local area is Silver Farid (Bayer), the main ingredients of which are fluazifop-butyl and cymoxanil. The brand of phosphite used is Capella, and the application concentration is 2.5mM (PO 3 3- ). Pesticides and phosphites were sprayed on leaves. Since autumn potato diseases are relatively serious, the control of pesticides in this experiment was relatively frequent, with spraying once every 7 days, and each spraying was done until the leaves were completely wet (run off). A total of 13 applications were made throughout the experiment.

[0026] 4. Sample preparation Samples of potato plants were collected during the vegetative growth period, i.e., tuber formation period, tuber expansion period, starch formation period, and harvest period. According to the random principle, three plots were set up for each treatment, and ten plants were randomly collected from each plot (excluding plants used for disease observation), and a total of 210 potatoes were collected in each growth period. After collection, the samples were naturally air-dried, and then ground through a 0.5 mm sieve for the determination of nitrogen, phosphorus, and potassium nutrient content of the plants.

[0027] 5. Measurement indicators 1) Plant sample measurement The total nitrogen content of the plants was determined by Nessler colorimetry, the total phosphorus content was determined by vanadium molybdenum yellow colorimetry, and the total potassium content was determined by flame photometry.

[0028] 2) Yield determination At harvest time, four ridges without destructive sampling were randomly selected in each plot for theoretical yield measurement.

[0029] 3) Determination of plant diseases A total of 36 potato plants were selected from each plot for disease investigation. The investigation was conducted every two weeks until harvest. According to the disease susceptibility level, the disease index and control effect were calculated using the McKinney disease index formula, and the control effect was tested for significance and the control effect of phosphite. The disease grading standard is shown in Table 2 The disease index calculation formula is: Disease index = ∑ (number of diseased plants at each level x corresponding level) / total number of plants surveyed × 5 × 100 Control effect (%) = ∑ (control disease index in treatment area - disease index in treatment area) / control disease index in treatment area × 100%.

[0030] Table 2: Potato late blight disease classification standard Grade disease characteristics 0 The whole plant has no visible disease signs, and the color is normal without fading; 1 Visible disease appears on less than 1 / 4 of the leaves and stems of the whole plant, and a small amount of tissue fades; 2. 1 / 4~1 / 2 of the leaves and stems of the whole plant show disease characteristics, and the tissues show moderate discoloration; 3. 1 / 2~3 / 4 of the leaves and stems of the whole plant faded a lot, and the leaves curled; 4 More than 3 / 4 of the stem of the plant turns black, and all the leaves on the stem die; 5 The whole plant died 6. Data statistics and analysis Data were sorted using Excel, and homogeneity and normality tests were performed using SPSS 13.0, followed by one-way analysis of variance, and Duncan's and LSD tests to test for significant differences ( P <0.05).

[0031] Example 2: Results and Data Analysis 1. Soil nutrient content at each growth and nutrition stage of potatoes Tuber formation period ( Figure 1 A) The total phosphorus content of T4 was 2.91 g / kg, which was significantly higher than that of conventional fertilization and CK. Compared with CK treatment and conventional fertilization, T4 increased by 263.75% and 304.16% respectively; during the tuber expansion period ( Figure 1B) There was no significant difference in soil total phosphorus among all treatments; starch accumulation period ( Figure 1 C), T3 and T6 were significantly higher than CK, and increased by 402.32% and 355.81% respectively compared with CK.

[0032] Tuber formation period ( Figure 2 A) Total soil potassium: there was a significant difference between T2 and T5, but no significant difference was found in other treatments; during tuber expansion period ( Figure 2 B) There was no significant difference in soil total potassium among all treatments. Figure 2 C) There was no significant difference among all treatments. The optimized fertilization formula increased the potassium content.

[0033] 2. Soil organic matter content at different potato growth and nutrition stages Tuber formation period ( Figure 3 A), T6 organic matter content was 29.17g / kg, there was a significant difference between CK and the treatments with optimized formula and phosphite for disease control (T4, T5, T6), the soil organic matter of T4, T5, T6 was significantly higher than that of CK treatment, and increased by 29.62%, 27.06%, and 33.13% respectively compared with CK. Tuber expansion period ( Figure 3 B) There was no significant difference among all treatments; starch accumulation period ( Figure 3 C) There were no significant differences among all treatments.

[0034] 3. Available nutrient content in soil during each growth and nutrition period of potato Tuber formation period ( Figure 4 A), there was a significant difference in soil alkaline nitrogen content between T6 and CK treatments, T6 increased by 53.98% compared with CK; Figure 4 B) There was no significant difference among all treatments; starch accumulation period ( Figure 4 C) There were no significant differences among all treatments.

[0035] Tuber formation period ( Figure 5 A), conventional fertilization, soil available phosphorus in T2 and T4 treatments was significantly higher than that in CK treatment, however, there was no significant difference in soil available phosphorus content between conventional fertilization and optimized fertilization; tuber expansion period ( Figure 5 B) The soil available phosphorus in conventional fertilization and T4 and T5 treatments was significantly higher than that in other fertilization treatments; and in the starch accumulation period, the soil available phosphorus in conventional fertilization, T1, T2, T5, and T6 treatments was significantly higher than that in CK and T3 treatments.

[0036] Available potassium content in soil at each growth stage ( Figure 6): In the tuber formation period, there was a significant difference in soil available potassium between the T2 treatment and the CK, conventional fertilization and T4 treatments, and there was no significant difference between the other treatments. There was no significant difference in all treatments during the tuber expansion period; in the starch accumulation period, there was a significant difference between CK and T4, T5, and T6, and T4, T5, and T6 increased by 60.82%, 39.96%, and 73.02% respectively compared with CK; there was a significant difference between conventional fertilization and T4 and T6, and T4 and T6 increased by 44.93% and 26.10% respectively compared with conventional fertilization.

[0037] 4. Content of the whole potato plant Total nitrogen in plants ( Figure 7 A) There was no significant difference among all treatments, but the total nitrogen content of the optimized formula fertilizer was 45kg / ha lower than the local conventional fertilizer. Figure 7 B) There was no significant difference among all treatments, but the total phosphorus content was reduced in both optimized formulas, indicating that potatoes in this area have the potential to reduce phosphorus fertilizer. In addition, the spraying of phosphite did not significantly affect the total phosphorus content of the plants. Figure 7 C), there was no significant difference among the three treatments (T4, T5, T6) that applied phosphite as a late blight control agent, but the total potassium content of the T6 treatment was significantly lower than that of the T2 and CK treatments.

[0038] 5. Impact on potato late blight As shown in Table 3, compared with fertilization plus pesticide control, optimized fertilization and phosphite replacing pesticides have a control effect on potato late blight. During the tuber formation period, there was no significant difference in the disease index between conventional fertilization T1 and T3 under pesticide treatment and T5 under phosphite treatment, and both were significantly higher than the other treatments. There was no significant difference in the control effect of T4 and T6 under phosphite treatment on late blight between that of T2 under pesticide treatment. During the tuber expansion period, except for T2 and T3, the disease index of the other treatments increased significantly compared with that of the tuber formation period. In terms of control effect, there was no significant difference between T4 and T6 under phosphite treatment and T3 under pesticide treatment; but T2 with 15% phosphorus reduction in addition to pesticide spraying had the best control effect, and T5 had the least obvious effect. During the starch accumulation period, the disease index of each treatment increased significantly compared with the tuber expansion period. At this stage, T6 and T3 had the best control effect, which was significantly higher than other treatments, and T5 had the least obvious effect.

[0039] Table 3: Effect of using phosphite instead of pesticides on the control of potato late blight under different fertilization formulas Note: T1 (local conventional fertilization: 15-15-15 + pesticides), T2 optimized fertilization 1 (15-13.5-16.5 + pesticides), T3 optimized fertilization 2 (15-12-16.5 + pesticides), T4 (local conventional fertilization + phosphite), T5 (optimized fertilization 1 + phosphite), T6 (optimized fertilization 2 + phosphite). Different capital letters A, B, C indicate significant differences among different treatments in the same growth period ( P <0.05). Different lowercase letters a, b, and c indicate significant differences in the same treatment at different growth stages ( P <0.05).

[0040] The above results show that during the entire vegetative growth period of potatoes, the accumulation of quick-acting nutrients in the soil was reduced by reducing the use of chemical fertilizers; and the optimized fertilization formula increased the total nutrients in the soil and improved the physical and chemical properties of the soil. Spraying phosphite instead of pesticides during the entire vegetative growth period of potatoes has a good control effect on potato late blight. The optimized fertilization formula (T6) with a 30% reduction in phosphorus and spraying phosphite has the best control effect on late blight, and there is no significant difference between the control of late blight with pesticides; and the T6 treatment is significantly higher than the formula with a 15% reduction in phosphorus (T5), which shows that spraying phosphite also has a certain effect on reducing the input of phosphorus fertilizers.

[0041] In summary, compared with conventional fertilization, the optimized formula fertilization treatment of the present invention does not affect the content of soil nutrients and the accumulation of plant nutrients on the basis of reducing the amount of chemical fertilizers, indicating that the test site has the potential for reducing the amount of chemical fertilizers; and phosphite replaces pesticides and has a better control effect on potato late blight.

Claims

1. A method for planting potatoes on red soil sloping farmland, characterized in that: The method comprises applying fertilizer for potato planting on red soil sloping farmland during the planting process; the fertilizer comprises urea, superphosphate and potassium sulfate in a mass ratio of 15:12 to 13.5:16.5; and during the planting period, phosphite is used to completely or partially replace pesticides to prevent and control potato late blight.

2. The method for planting potatoes on red soil sloping farmland according to claim 1, characterized in that: The mass ratio of urea, superphosphate and potassium sulfate is 15:13.5:16.

5.

3. The method for planting potatoes on red soil sloping farmland according to claim 1, characterized in that: The mass ratio of urea, superphosphate and potassium sulfate is 15:12:16.

5.

4. The method according to claim 1, characterized in that The method is to apply 1200-1500 kg of the fertilizer per hectare.

5. The method according to claim 4, characterized in that The method described herein, wherein two thirds of the fertilizer is applied as basal fertilizer and one third of the fertilizer is applied as top dressing fertilizer.

6. The method according to claim 5, characterized in that The topdressing is carried out when the potatoes enter the tuber swelling stage.

7. The method according to claim 1, characterized in that The phosphite is sprayed on leaves to prevent and control potato late blight.

8. The method according to claim 7, characterized in that The phosphite is used at a concentration of 2.5 mM.

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