Planting method for improving yield and quality of sweet potatoes

Abstract

The invention discloses a planting method for improving the yield and quality of sweet potatoes, and relates to the technical field of crop planting and cultivation, the key points of the technical scheme are as follows: deep ploughing is performed on land, ridging planting is performed during planting, furrowing is performed in the middle of a ridge, organic fertilizer is applied, sweet potatoes are planted on two sides, and the organic fertilizer is prepared by anaerobic fermentation of organic household garbage; in the fruit expanding period of the sweet potatoes, selenium fertilizer is sprayed on leaf surfaces for four times. According to the method, the physicochemical properties of soil can be improved, the yield and quality of sweet potatoes can be improved, and the fertility of the soil can be improved by remarkably increasing the content of organic carbon, total nitrogen and total phosphorus in the soil, reducing the volume weight, adjusting the pH value to be alkalescent, enriching functional florae mainly including Proteobacteria and Bacteroida and reducing the content of heavy metals such as Cd, Cr and Pb, so that the yield and quality of the sweet potatoes can be improved, and the yield and quality of the sweet potatoes can be improved. Meanwhile, the selenium content and crude protein content of the sweet potatoes are improved under the condition of ensuring high yield.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of crop planting and cultivation, more particularly, it relates to a planting method for improving the yield and quality of sweet potatoes. BACKGROUND

[0002] Due to long-term application of chemical fertilizers, single cropping, and overexploitation, among other factors, China's farmland soil has experienced acidification, compaction, decreased fertility, and nutrient imbalance, among other degradation problems, affecting crop yield and quality, threatening national food security, and leading to significant losses in soil carbon storage, further exacerbating climate change (Zhang et al., 2006; Jin et al., 2000; Wang et al., 2023). Organic fertilizers are considered one of the effective measures to improve degraded soil, increase soil organic carbon storage, and improve crop yield and quality (Ren et al., 2021; Xie et al., 2021). At the same time, the production of municipal solid waste is also on the rise, with organic waste accounting for about 60% of the total amount of municipal solid waste (Gu et al., 2017). Its treatment and resource utilization have become an urgent environmental and social problem. By using reasonable classification and treatment technology to convert organic household waste into organic fertilizer for field application, not only can carbon emissions be reduced and environmental pollution be reduced, but also can replace part of the chemical fertilizer input, thereby alleviating climate change and soil degradation to some extent, and promoting the green and sustainable development of cities and agriculture (Randolph et al., 2017; Sardarmehni et al., 2020). However, there is still a lack of systematic research on how organic household waste organic fertilizer affects soil physical and chemical properties, nutrient content, microbial structure, and crop yield and quality.

[0003] Selenium, as one of the essential trace elements for the human body, its deficiency or excess will affect health. In some areas of China, the soil is deficient in selenium, and selenium fertilizer is of great concern because it can effectively increase the selenium content of crops and is often used to produce selenium-rich agricultural products to improve the dietary quality and health status of residents.

[0004] Sweet potato (Ipomoea batatas L.) is an important food and economic crop worldwide, with characteristics such as high yield, strong adaptability, and rich nutrition. It is not only one of the main sources of human food, but also has wide applications in feed, industrial raw materials, and bioenergy. Improving the yield and quality of sweet potatoes is of great significance for ensuring food security, promoting sustainable agricultural development, and adjusting energy structure.

[0005] In view of this, the present application provides a planting method for improving the yield and quality of sweet potatoes.

[0006] Therefore, through field experiments, organic fertilizer, compound fertilizer, selenium fertilizer and their combination treatments are set to observe the changes of soil physical and chemical properties, nutrient content and microbial community structure under different fertilization strategies, as well as the growth performance and nutrient component differences of sweet potato, aiming to systematically analyze the effects of organic household garbage organic fertilizer and selenium fertilizer under different fertilization strategies on soil fertility and soil microbial community structure, sweet potato yield and quality, so as to optimize the fertilization strategy, improve the yield and quality of sweet potato, promote soil health and realize the sustainable development of agriculture and the resource utilization of organic household garbage. SUMMARY

[0007] The purpose of the present application is to provide a planting method for improving the yield and quality of sweet potato, improving the physical and chemical properties of soil and improving the yield and quality of sweet potato.

[0008] The above technical purpose of the present application is realized by the following technical scheme:

[0009] The present application provides a planting method for improving the yield and quality of sweet potato, comprising the following steps: deep ploughing the land, planting in ridges, applying organic fertilizer in the middle of the ridge, planting sweet potato on both sides, and the organic fertilizer is prepared by anaerobic fermentation of organic household garbage.

[0010] In the fruit bulking stage of sweet potato, selenium fertilizer is sprayed on the leaves for 4 times.

[0011] The present application is further provided that: the ridge distance of the ridge planting is 1-1.2 m.

[0012] The present application is further provided that: the plant spacing of the sweet potato planting is about 25 cm.

[0013] The present application is further provided that: the interval time of the selenium fertilizer spraying is 5-7 days.

[0014] The present application is further provided that: the application amount of the selenium fertilizer is 500 mg / hm 2 .

[0015] The present application is further provided that: the application amount of the organic fertilizer is 20 t / hm 2 .

[0016] In summary, the present application has the following beneficial effects:

[0017] The planting method provided by the application has great advantages in improving soil physical and chemical properties and improving sweet potato yield and quality by using organic household waste organic fertilizer combined with selenium fertilizer (OSe). The fertilization measure can significantly improve the content of soil organic carbon, total nitrogen and total phosphorus, reduce the bulk density and adjust the pH to weak alkaline, enrich the functional flora mainly composed of Proteobacteria and Bacteroidota, reduce the content of heavy metals such as Cd, Cr and Pb, and improve the soil fertility, while improving the selenium content and crude protein content of sweet potato under the condition of ensuring high yield. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is the experimental sample plot in the embodiment of the application;

[0019] Figure 2 is the soil physical and chemical properties in the embodiment of the application (different lowercase letters represent the significance (P < 0.05) of differences between different treatments);

[0020] Figure 3 is the content of soil metal and metalloid elements in the embodiment of the application;

[0021] Figure 4 is the influence of different fertilization strategies on bacterial community composition in the embodiment of the application;

[0022] Figure 5 is the influence of different fertilization strategies on sweet potato yield and quality in the embodiment of the application;

[0023] Figure 6 is the relationship between sweet potato yield, quality and soil fertility in the embodiment of the application. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0025] Test sample plot

[0026] The test sample plot is located in Jiangjiang Village, Sanmen County, Taizhou, with geographical coordinates of 121.699°E, 28.939°N, and the sample plot covers an area of about 4000 square meters. The sample plot is composed of three irregular terraces from high to low. It is located in the subtropical monsoon region, with mild and humid climate, distinct seasons, and basic synchronization of light, heat and water. The average annual temperature is 17℃, the annual sunshine is 1600 hours, the frost-free period is 244 days, the annual rainfall is 1700 millimeters, and the soil is yellow soil.

[0027] The experiment adopts a field random block design. According to the soil fertility conditions in the field, the plots with similar fertility are set as a block group, and a total of 3 block groups are set. 6 plots (treatments) are set in each block group, which are: no fertilization, single application of compound fertilizer (1.5 t / hm 2 ), single application of organic household waste organic fertilizer (20 t / hm 2 ), single application of selenium fertilizer (500 mg / hm 2 ), compound fertilizer combined with selenium fertilizer, and organic household waste organic fertilizer combined with selenium fertilizer. Each treatment has 3 repetitions, a total of 18 plots. The area of each plot is 100 m 2 , and the interval is 1 m

[0028] Example 1:

[0029] The land is plowed before planting, and the planting is done on the ridge with a ridge distance of 1-1.2 m. The organic fertilizer 20 t / hm 2 is applied in the middle of the ridge, and sweet potatoes are planted on both sides with a plant spacing of about 25 cm. The planting is done in an inclined manner. In the fruit swelling period of sweet potato, i.e. from the 70th day after planting sweet potato, the selenium fertilizer is sprayed on the leaves for 4 times (with an interval of 5-7 days between each spraying), and the selenium fertilizer is 200 mL, 100 L of water is added, and 0.2 hm 2 can be sprayed.

[0030] The organic fertilizer used in the application is prepared by anaerobic fermentation of organic household waste by Wengling Huayuan Biological Technology Co., Ltd. The selenium fertilizer is a liquid organic selenium-rich fertilizer produced by Aobang Biology, and the selenium content is ≥500 mg / L.

[0031] Comparative Example 1:

[0032] The difference from Example 1 is that no fertilizer treatment is done, i.e. no organic fertilizer and selenium fertilizer is applied.

[0033] Comparative Example 2:

[0034] The difference from Example 1 is that only compound fertilizer (1.5 t / hm 2 ) is applied, and no selenium fertilizer is applied.

[0035] The compound fertilizer used in the application is a Stanley compound fertilizer, and the total nutrient content is ≥45%, and the N-P2O5-K2O content ratio is 14-16-15.

[0036] Comparative Example 3:

[0037] The difference from Example 1 is that only organic fertilizer (organic fertilizer 20 t / hm 2 ) is applied, and no selenium fertilizer is applied.

[0038] Comparative Example 4:

[0039] The difference from Example 1 is that only selenium fertilizer is applied, without organic fertilizer.

[0040] Comparative Example 5:

[0041] The difference from Example 1 is that compound fertilizer (1.5 t / hm 2 ) is applied, and selenium fertilizer is applied.

[0042] I. Sample collection

[0043] Soil samples were collected at the time of sweet potato harvest. Three points were randomly selected in each treatment plot, and soil samples were collected in the 0-20 cm soil layer using a soil drill and a cutting ring, avoiding boundary and trench areas. After collection, the soil samples were taken back to the laboratory, and the soil was divided into three parts. One part was weighed and placed in an aluminum container and dried in an oven along with the cutting ring to determine the moisture content and bulk density. One part was frozen for the determination of microbial biomass carbon and nitrogen, nitrate nitrogen, and ammonium nitrogen, as well as DNA extraction, sequencing, and microbial community composition analysis. The remaining part was air-dried, ground, and passed through a 2 mm sieve for the determination of soil pH, nutrient and heavy metal content, and organic carbon content. At the time of sweet potato harvest, 10 m 2 of sweet potato mass was collected and weighed, and three sweet potato tubers were randomly selected from each treatment, peeled, and dried. One part was ground for the determination of sweet potato crude protein quality, and the other part was frozen in liquid nitrogen and ground for the determination of vitamin C, crude fiber, soluble sugar, and starch.

[0044] II. Laboratory analysis

[0045] The determination of soil physical and chemical properties and sweet potato quality indicators was based on national standard determination methods. Soil moisture content was determined using the aluminum box drying method; soil bulk density was determined using the cutting ring method; total organic carbon (TOC) content was determined using the potassium dichromate oxidation-spectrophotometric method; total nitrogen (TN) content was determined using the Kjeldahl method; nitrate nitrogen (NO3 - -N) and ammonium nitrogen (NH4 +- N) was determined using potassium chloride solution extraction-spectrophotometry; total phosphorus (TP) content was determined using ammonium molybdate spectrophotometry; metal and selenium element contents (TK, Na, Mg, Al, Cr, Mn, Fe, Cu, Zn, Se, As, Mo, Cd, Pb) were determined using microwave digestion-inductively coupled plasma-mass spectrometry; soil pH was determined using a mercury-mercury electrode; for sweet potato quality, organic carbon and total nitrogen contents were determined using potassium dichromate oxidation-spectrophotometry and Kjeldahl nitrogen determination; crude protein was calculated as total nitrogen x 6.25; soluble total sugar content was determined using anthrone-H2SO4 colorimetry at a wavelength of 620 nm; starch content was determined using enzyme-acid double hydrolysis; crude fiber content was determined using acid-base digestion-weight loss. The root-shoot ratio was calculated using dry weight for the above- and below-ground parts of sweet potato. The composition and structure of soil bacterial communities were studied using 16S rDNA amplicon sequencing technology (Hess M et al., 2011).

[0046] III. Data analysis

[0047] One-way ANOVA was used to test the significance of differences in soil physicochemical properties, sweet potato yield, and quality under different fertilization treatments (p = 0.05). Pearson correlation analysis was used to evaluate the relationship between soil physicochemical properties and sweet potato yield and quality indicators. SPSS 27.0 was used for data processing and statistical analysis, and the ggplot2 software package in R was used for plotting.

[0048] IV. Experimental results

[0049] A comprehensive comparison of nine soil physicochemical indicators (Figure 2) showed that fertilization strategies significantly affected soil water retention, structural stability, and nutrient storage patterns. The C, CK, O, and Se treatments had higher soil water content. Compared with CK, the CSe treatment significantly increased soil bulk density, while the O and OSe treatments significantly reduced soil bulk density, thereby improving soil structure and increasing soil permeability. The application of compound fertilizer led to more compact soil. The soil pH increased to 7.3 under Se treatment, indicating that weakly basic selenate had a certain regulating effect on acidic soil. In terms of soil nutrient effects, the O and OSe treatments significantly increased TN, TP, and TOC content, with the addition of selenium promoting the increase in TN content, increasing from 8.33 g / kg (O treatment) to 9.02 g / kg (OSe treatment), possibly due to the promotion of soil microbial nitrogen fixation by selenium (Lei et al., 2022). The CSe treatment significantly increased TP but had limited contribution to TOC, indicating that compound fertilizer had weak ability to promote soil organic carbon fixation. The OSe treatment significantly increased NH4 +The highest N content (7.19 mg / kg) was observed in treatment C, which used compound fertilizer to directly add nitrate - The highest TK content (70 mg / kg) was observed in treatment O, and it decreased significantly after the addition of selenium, which indicated that the addition of organic fertilizer could directly increase the potassium content and enhance the fixation of potassium, but the addition of selenium might exchange a part of the potassium and form K + And loss (LI et al., 2012).

[0050] In summary, OSe had advantages in improving soil carbon, nitrogen and phosphorus storage, reducing soil bulk density and adjusting soil pH, but its potential negative effects on soil water content needed to be concerned. Treatment O also significantly improved soil fertility. Treatment CSe faced the problems of high bulk density and poor water retention. Considering the nutrient supply and physical properties, we suggested that the organic fertilizer should be the main body, and appropriate selenium fertilizer should be supplemented to achieve the dual optimization of soil function.

[0051] Effects of different fertilization strategies on the contents of metals and selenium in soil

[0052] For example Figure 3As shown, the contents of 12 metal and metalloid elements in soil decreased to different degrees when selenium was added (Se, Ose, CSe) (Tian et al., 2024). Among them, the contents of heavy metal elements (Cr, Mn, Fe, Cu, Zn, Mo, Cd, Pb) and metalloid elements (As, Se) decreased by 30-85% compared with CK (Cd > Pb, Cu > As, Cr, Zn > Fe > Mn), and the content of Cd decreased from 0.045 mg / kg (C) to 0.006 mg / kg (OSe). Compared with CK, the content of Mg, Mn, Mo and Cd elements slightly increased in the soil treated with organic fertilizer (O). After determining the elements contained in the fertilizer, we found that the high heavy metal content in the organic waste led to the high heavy metal content in the fertilizer (Mn 340 mg / kg, Mo 151 mg / kg, Cd 27.74 mg / kg). In normal soil, the concentrations of selenium (Se) and cadmium (Cd) are often positively correlated (Yang et al., 2021; Guo et al., 2024). Studies have shown that the addition of Se in soil can reduce the content of Cd in soil leachate, thereby reducing the availability of Cd and reducing the accumulation of Cd in plants (Huang et al., 2018). However, in this study, the detection of Se content in soil treated with Se decreased with the content of heavy metal elements, but the Se content in sweet potato plants and tubers treated with Se was higher and the content of heavy metal elements was generally lower, so the reduction of heavy metal elements may be related to rainwater leaching. Overall, the addition of Se significantly reduced the content of harmful elements in soil, while also ensuring that essential trace elements remained within the normal concentration range. Reasonable addition of selenium fertilizer in heavy metal contaminated soil remediation may be beneficial to the remediation of contaminated soil, but the mechanism of its effectiveness still needs further study.

[0053] Bacterial community composition structure under different fertilization strategies

[0054] Effect of fertilization mode on soil bacterial community structure as Figure 4The relative abundance of Proteobacteria was the highest in all treatments, but was affected by the fertilization treatments, with the highest value in CSe (55%) and the lowest in O (45%). Bacteroidota reached the highest value in CSe and OSe (15%), and the lowest value in the other treatments (10%-12%). Acidobacteriota was the highest in O (11%) and the lowest in CSe (6%). Actinobacteriota and Gemmatimonadota were relatively stable (6%-8%) in all treatments. The relative abundance of “others” was 10%-13%. The differences among the treatments were mainly reflected in the changes in the relative abundance of Proteobacteria, Bacteroidota, and Acidobacteriota. Proteobacteria, which prefer to use readily available nutrients, were enriched in CSe, which accelerated the rate of nutrient mineralization (Dai et al., 2018). Bacteroidota, which are involved in the decomposition of sugars such as lignin, were also enriched in CSe and OSe. These enriched bacterial groups can increase the rate of soil nutrient cycling to some extent and provide nutrients for plants (Wolińska et al., 2017).

[0055] Effects of different fertilization strategies on sweet potato yield and quality

[0056] Effects of fertilization strategies on sweet potato yield and quality Figure 5 Compared with the control, the addition of selenium fertilizer (Se, CSe, OSe) increased the Se accumulation in crops. The average yield of Se treatment was 38 t / ha, and the starch content was 600 mg / kg. CSe maintained a high yield and high crude protein content (4%-5%). Se treatment maintained a high yield (38.27 t / ha) by increasing the root-shoot ratio to enhance the absorption of nutrients in the rhizosphere. C treatment reduced the root-shoot ratio of sweet potato, resulting in a decrease in yield (26.25 t / ha), which was alleviated by the addition of selenium. O treatment maintained the yield and quality of sweet potato at a certain level and promoted the accumulation of starch. In summary, the application of selenium fertilizer with organic fertilizer or compound fertilizer can improve the soil environment and increase the yield of sweet potato to some extent. The Se element provided by selenium fertilizer can improve the nutritional value of sweet potato.

[0057] Relationship between sweet potato yield, quality, and soil physical and chemical properties

[0058] The correlation analysis results of sweet potato yield, quality indicators and soil physical and chemical properties showed that the correlation between soil organic carbon and sweet potato yield and single plant tuber weight was not significant, while the correlation between soil microbial biomass carbon and sweet potato yield and single plant tuber weight was significant, with correlation coefficients of 0.35 and 0.36 respectively Figure 6 ), indicating that the content of organic matter alone has limited effect on crop yield, but microorganisms promote the decomposition of organic matter, increase the content of available nutrients in soil, and thus increase the yield of sweet potato. The crude protein content of sweet potato and the total phosphorus and available phosphorus content of soil showed significant correlation, with correlation coefficients of 0.43 and 0.45 respectively, indicating that when phosphorus supply is sufficient, plants can more effectively use nitrogen to synthesize proteins and other nitrogen-containing compounds. Soil total nitrogen and microbial nitrogen showed significant negative correlation with sweet potato crude fiber, with correlation coefficients of -0.33 and -0.38 respectively. It may be due to the fact that under conditions of sufficient soil nitrogen, plants tend to use the absorbed nutrients for growth and reproduction rather than synthesizing a large amount of fiber, and less fiber can improve the taste of sweet potato. In addition, soil microbial biomass carbon and microbial biomass nitrogen showed negative correlation with soluble sugar content, with correlation coefficients of -0.34 and -0.42 respectively.

[0059] In summary, the application of organic household waste organic fertilizer combined with selenium fertilizer (OSe) has great advantages in improving soil physical and chemical properties and enhancing sweet potato yield and quality. This fertilization measure can significantly increase the content of soil organic carbon, total nitrogen and total phosphorus, reduce bulk density and adjust pH to weak alkaline, enrich functional bacteria groups mainly composed of Proteobacteria and Bacteroidota, reduce the content of heavy metals such as Cd, Cr and Pb, and improve soil fertility, while ensuring high yield and increasing the content of selenium and crude protein in sweet potato. Compound fertilizer combined with selenium fertilizer (CSe) can also obtain high yield, but may cause soil compaction. Single application of selenium fertilizer (Se) can maintain stable yield by optimizing root-shoot ratio and reduce the risk of heavy metal toxicity. Single application of organic household waste organic fertilizer (O) may have limitations in its use due to the risk of heavy metal pollution. Therefore, it is recommended to promote the fertilization mode of applying organic household waste organic fertilizer as the base and combining with appropriate amount of selenium fertilizer in southern regions to realize the resource utilization of organic household waste and the management of soil degradation.

[0060] Finally, it should be noted that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some technical features. Any modification, equivalent substitution, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A planting method for improving sweet potato yield and quality, characterized by: The process includes the following steps: Deep plowing of the land, planting on raised beds, applying organic fertilizer in the middle of the raised beds, and planting sweet potatoes on both sides. The organic fertilizer is prepared by anaerobic fermentation of organic household waste. During the fruit enlargement period of sweet potatoes, apply selenium fertilizer to the leaves four times.

2. The planting method for improving sweet potato yield and quality according to claim 1, characterized in that: The spacing between the raised beds is 1-1.2 m.

3. The planting method for improving sweet potato yield and quality according to claim 1, characterized in that: The spacing between sweet potato plants is 23-27 cm.

4. The planting method for improving sweet potato yield and quality according to claim 1, characterized in that: The interval between spraying the selenium fertilizer is 5-7 days.

5. The planting method for improving sweet potato yield and quality according to claim 1, characterized in that: The application rate of the selenium fertilizer is 500 mg / hm. 2 .

6. The planting method for improving sweet potato yield and quality according to claim 1, characterized in that: The application rate of the organic fertilizer is 20 t / hm. 2 .

Images