Rape-sweet potato rotation planting method

Abstract

The invention discloses a rape-sweet potato rotation planting method, and belongs to the technical field of agricultural planting. The method is suitable for hilly dry land and comprises the following steps: S1, rape planting; s2, returning oilseed rape to the field; performing oilseed rape field returning treatment 15 days before transplanting of the potato seedlings; the returning mode is full-amount returning to the field or stubble returning to the field; s3, ridging and fertilizing; base fertilizer is applied at a time before soil preparation and ridging; s4, transplanting potato seedlings; sweet potato transplanting is conducted through a horizontal cuttage method; the transplanting time is early transplanting: mid-to-late April; or suitable-period transplanting: early May; or late transplanting: mid-to-late May; s5, harvesting; and harvesting in four months after transplanting the sweet potato seedlings. According to the invention, grain and oil harvesting can be realized; the maximization of yield, quality and economic benefit can be realized; in addition, a planter can select a suitable planting period according to different targets.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of agricultural planting technology, in particular to a rape-sweet potato rotation planting method. BACKGROUND

[0002] The west of Henan province is a typical hilly dryland area, and sweet potato is the most characteristic high-yield and high-quality coarse grain crop in the west of Henan province, which has strong drought resistance and wide application. However, the soil condition in this region is relatively weak, and the long-term one-crop planting mode leads to low land resource utilization efficiency.

[0003] With the improvement of people's living standards and the optimization of dietary structure, the sweet potato industry is transforming from starch type to fresh type. Fresh sweet potato can be harvested flexibly according to market conditions and growth period, and put on the market early to relieve the pressure in the off-season, and significantly improve resource utilization efficiency and economic value by shortening the planting cycle. Among them, the "early planting and early harvesting" mode with transplanting in late April and harvesting in mid-August has outstanding benefits. However, this mode does not make full use of light, heat, water and soil resources, especially the potential of winter fallow land needs to be tapped, and it is urgent to establish an efficient rotation system with sweet potato as the core.

[0004] Reasonable rotation is an effective way to improve crop yield and quality. At present, sweet potato-wheat rotation is more common. However, sweet potato is transplanted late, which is difficult to meet the demand of fresh sweet potato "early planting and early harvesting" to seize the market. Compared with wheat, rape is an ideal crop for developing winter fallow land as a winter oil crop, which has the characteristics of not competing with grain for land and significant multifunctionality (oil, vegetable, fertilizer and feed). Its main ways of returning to the field include green manure and straw return. Rape green manure has large biomass, strong phosphorus activation capacity and low cost, and has more promotion potential in dry land, which can fertilize the soil by biological nitrogen fixation and organic matter input, improve the physical and chemical properties, and alleviate the continuous cropping obstacles; straw return can improve soil structure, increase organic matter content and soil fertility. The short growth period of fresh sweet potato provides the key basis for sweet potato-rape rotation, and the multifunctionality of rape makes it possible to diversify the application of this rotation mode.

[0005] Therefore, it is of great importance to build an efficient sweet potato-rape rotation mode for the sustainable development of regional grain and oil industry. SUMMARY

[0006] The purpose of the present application is to provide a rape-sweet potato rotation planting method to improve agricultural output value.

[0007] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0008] A rape-sweet potato rotation planting method suitable for hilly dry land, comprising the following steps:

[0009] S1, planting rape;

[0010] S2, rape is returned to the field; rape is returned to the field 15 days before the potato seedlings are transplanted;

[0011] The returning method is: returning all the amount or returning the root stubs;

[0012] S3, ridge fertilization; base fertilizer is applied at one time before the soil is plowed and ridged;

[0013] S4, potato seedling transplanting; horizontal cutting method is used for potato transplanting;

[0014] The transplanting time is: early transplanting: middle and late April; or suitable transplanting: early May; or late transplantating: middle and late May;

[0015] S5, harvesting; the potato seedlings are harvested four months after being transplanted.

[0016] Preferably, in step S1, the rape is fertilized with N 180 kg / hm 2 , P2O5 75 kg / hm 2 , K2O 120 kg / hm 2 and borax 15 kg / hm 2 ; wherein the nitrogen fertilizer is urea, the phosphorus fertilizer is calcium superphosphate, and the potassium fertilizer is potassium chloride.

[0017] Preferably, in step S2, the potato is fertilized with N 75 kg / hm 2 , P2O5 75 kg / hm 2 , K2O 150 kg / hm 2 ; wherein the nitrogen fertilizer is urea, the phosphorus fertilizer is calcium superphosphate, and the potassium fertilizer is potassium sulfate.

[0018] Preferably, in step S2:

[0019] Returning all the amount means that the rape plants are directly plowed into the soil at the beginning of flowering or at the peak of flowering or at the mature stage, and the soil is fertilized through biological nitrogen fixation and organic matter input;

[0020] Returning the root stubs means that the rape is harvested at the beginning of flowering or at the peak of flowering or at the mature stage, only the root stubs are left, and the root stubs are plowed into the soil.

[0021] Preferably, in step S4: single ridge double row triangular equidistant planting, ridge distance is 0.8-1.0 m, and plant distance is 0.4-0.5 m.

[0022] Preferably, it further includes: selecting the transplanting period according to different planting targets;

[0023] The planting target is: yield advantage, or high commercial potato rate, or high starch content, or high soluble sugar content.

[0024] Preferably:

[0025] When the planting objective is to maximize output value, early transplanting should be chosen.

[0026] When the planting target is high starch content, transplanting should be done at the appropriate time.

[0027] When the planting target is high soluble sugar content, late transplanting should be selected;

[0028] When the planting goal is to achieve a high rate of marketable potatoes, the transplanting time for full return to the field is early transplanting, and the transplanting time for stubble return to the field is appropriate transplanting.

[0029] Preferably, when the planting objective is to increase output value, in addition to considering yield factors, time price differences should also be considered to enable earlier market entry and avoid the concentrated harvest period.

[0030] Preferably, when calculating output value and marketable potato rate:

[0031] The grading standards for sweet potato tubers are as follows: Grade 1 tubers weigh 200-400g, Grade 2 tubers weigh 100-200g, Grade 3 tubers weigh 50-100g, and ungraded tubers weigh less than 50g or more than 400g.

[0032] Marketable potato rate (%) = (Grade 1 potato tubers + Grade 2 potato tubers + Grade 3 potato tubers) / Total number of potatoes × 100.

[0033] Compared with the prior art, the present invention provides a rapeseed-sweet potato rotation planting method, which has the following beneficial effects.

[0034] 1. This invention can achieve a double harvest of grain and oil.

[0035] 2. This invention can maximize yield, quality and economic benefits; and growers can choose the appropriate planting period according to different objectives.

[0036] Other advantages, objectives and features of the invention will be set forth in part in the description which follows; and in part will be apparent to those skilled in the art upon examination of the following description; or may be learned from practice of the invention. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the process of the present invention.

[0038] Figure 2 Correlation analysis of sweet potato yield with planting date, yield components and agronomic traits under different return-to-field methods.

[0039] Figure 3 To investigate the impact of planting time on sweet potato quality under different sap return methods.

[0040] Figure 4The correlation between the yield and quality of the sweet potato planted at different planting times and the different returning methods of the soil. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application.

[0042] Reference Figure 1 The oilseed rape-sweet potato rotation planting method is suitable for hilly dry land, and comprises the following steps.

[0043] S1, planting oilseed rape;

[0044] S2, returning the soil with the oilseed rape; the returning treatment is performed 15 days before the sweet potato seedling transplanting;

[0045] The returning method is: returning all the amount of the soil (Q) or returning the root stubble (R);

[0046] S3, ridge forming and fertilizing; the base fertilizer is applied at one time before the land preparation and ridge forming;

[0047] S4, sweet potato seedling transplanting; the sweet potato is transplanted by using the horizontal cutting method;

[0048] The transplanting time is: early transplanting (D1): the middle and late April; or suitable time transplanting (D2): the early May; or late transplanting (D3): the middle and late May;

[0049] S5, harvesting; the sweet potato is harvested four months (120 days) after the sweet potato seedling transplanting.

[0050] In the step S2, the returning method further comprises: winter idle field (W).

[0051] That is to say, the field is idle in winter, and the oilseed rape is not planted in the field, and the returning is not performed, and only the transplanting time is controlled, so as to guide the planting of the sweet potato in some cases where the oilseed rape cannot be planted in time.

[0052] In the step S2, the returning method further comprises: winter idle field (W).

[0053] The early transplanting (D1) is preferably performed around April 15;

[0054] The suitable time transplanting (D2) is preferably performed around May 1;

[0055] The late transplanting (D3) is preferably performed around May 15.

[0056] In some embodiments, in the step S1, the fertilizing amount of the oilseed rape is: N 180 kg / hm 2 ; P2O5 75 kg / hm 2 ; K2O 120 kg / hm 2and borax 15 kg / hm 2 .

[0057] Wherein, nitrogen fertilizer is urea (containing N 46%), phosphorus fertilizer is superphosphate (containing P2O5 12%), and potassium fertilizer is potassium chloride (containing K2O 60%).

[0058] Preferably, in step S2, the fertilization amount of sweet potato is: N 75 kg / hm 2 ; P2O5 75 kg / hm 2 ; K2O 150 kg / hm 2 .

[0059] Wherein, nitrogen fertilizer is urea (containing N 46%), phosphorus fertilizer is superphosphate (containing P2O5 12%), and potassium fertilizer is potassium sulfate (containing K2O 52%).

[0060] Through reasonable fertilization control, different fertilizer supplies are given in the rape period and the sweet potato period, which not only meets the respective needs, but also cooperates to provide a more suitable soil environment for the rotation of the preceding and subsequent periods.

[0061] It can be understood that the field management measures all adopt the recommended methods of local agricultural technology popularization departments to be more suitable for small regional environment.

[0062] In step S2: full amount of returning to field refers to directly pressing the rape plants into the soil at the beginning of flowering period or full flowering period or mature period, realizing soil fertilization through biological nitrogen fixation and organic matter input; root stubble returning to field refers to harvesting the aboveground part of rape at the beginning of flowering period or full flowering period or mature period, only leaving root stubble, and pressing into the soil.

[0063] It should be noted that: rape returning to field can be divided into straw returning to field and green manure returning to field according to the maturity state of rape, and the difference in the mechanism of regulating crop growth will directly affect the yield, quality and economic benefit of the subsequent crops.

[0064] Full amount of returning to field (straw and green manure returning to field) refers to directly pressing the rape plants into the soil at the beginning of flowering period or full flowering period or mature period, realizing soil fertilization through biological nitrogen fixation and organic matter input.

[0065] As an excellent biological fertilizer, the core value of green manure lies in effectively improving the organic matter content in the soil and actively improving the physical and chemical properties of the soil. In addition, green manure can effectively cope with the challenges of soil degradation and the intensification of pests and diseases caused by crop continuous cropping, thereby realizing the double leap of crop yield and quality.

[0066] Green manure rape at the beginning of flowering or full flowering period can increase the content of soil organic matter, total nitrogen, alkali-hydrolyzable nitrogen and available potassium. Green manure rape with full amount of pressure green cultivation measures can not only benefit the growth of the following crops, but also effectively reduce the use of fertilizers. Compared with traditional green manure such as Chinese milk vetch and hairy vetch, rape green manure has greater potential for promotion in dry land rotation system due to its large biomass, strong phosphorus activation ability and low planting cost.

[0067] Straw rape at the mature stage is returned to the field, containing a variety of organic materials, which plays an important role in crop growth, yield, and agricultural development. Straw return can also improve soil structure, increase organic matter content and soil fertility, and provide a better soil environment for crop growth, thereby improving crop yield and quality.

[0068] Root stubble return refers to the rape at the beginning of flowering or full flowering period or at the mature stage, only leaving the root stubble, and turning it into the soil.

[0069] In some embodiments, in step S4: single ridge double row triangular equidistant planting, ridge distance is 0.8-1.0 meters, plant distance is 0.4-0.5 meters, and density is 40020-62531 plants per hectare.

[0070] The growth of sweet potato is not only restricted by its variety characteristics, but also deeply affected by multiple factors such as cultivation techniques and ecological environment. Under the condition that the variety characteristics and cultivation techniques remain relatively stable, by adjusting the planting period of crops in time, the key climatic factors such as temperature, light, accumulated temperature and rainfall that crops face at each growth and development stage can be effectively changed, and the yield and quality of crops can be improved.

[0071] Previous studies have extensively explored the influence of planting period on the yield, quality and economic benefits of sweet potato. Xiao Qingquan selected "Pusuo 32" as the test material in the autumn sweet potato production research in Datian County, Fujian Province, and found that the planting period should be set before the middle of July, and the growth period should be no less than 120 days, which can harvest high yield and high quality. Liu Qian et al. used edible sweet potato variety "Yanshu 25" as the test material in the agricultural demonstration garden of Qingdao Agricultural University, and found that the yield of sweet potato at harvest time increased with the advance of transplanting time, but the incidence of skin tendons increased and the appearance quality decreased. Zhan Xiangdong et al. used "Shangshu 19" and "Jixu 23" as test materials, focusing on the northern potato area of China, and the results showed that the number and yield of tubers were significantly different under different transplanting times. In the case of pursuing fresh food commodity potato as the main target, the best transplanting time should be selected in late May.

[0072] The most suitable transplanting time of sweet potato varies in different regions and types.

[0073] In the planting method of the present application, further comprising: selecting the transplanting period according to different planting targets.

[0074] Among them, the planting target is: yield advantage, or high commercial potato rate, or high starch content, or high soluble sugar content.

[0075] When the planting target is yield advantage, the transplanting time is selected as early transplanting.

[0076] When the planting target is high starch content, the transplanting time is selected as suitable transplanting.

[0077] When the planting target is high soluble sugar content, the transplanting time is selected as late transplanting.

[0078] When the planting target is high commercial potato rate, the whole amount of still field selects the transplanting time as early transplanting, and the root stubble still field selects the transplanting time as suitable transplanting.

[0079] It should be noted that when the planting target is yield advantage, in addition to considering yield factors, time price difference is also considered; in order to be able to go on the market in advance and avoid the concentrated harvesting period.

[0080] In the yield calculation and commercial potato rate calculation:

[0081] The grading standard of sweet potato tubers is: first-class tubers 200-400g, second-class tubers 100-200g, third-class tubers 50-100g, and no-class tubers less than 50g or more than 400g.

[0082] Commercial potato rate (%)=(first-class tuber block+second-class tuber block+third-class tuber tuber block) / total tuber number x 100.

[0083] The effects of different still field methods of rape on the agronomic characters of sweet potato under the transplanting period, including: stem length, base stem diameter, branch number; on the yield and constituent factors of sweet potato, including: sweet potato yield composed of unit area plant number, single plant tuber number and average single tuber weight; on the quality characters of sweet potato, including: soluble sugar content, starch content.

[0084] Experimental example.

[0085] Test site overview.

[0086] From April to September 2023, a field experiment was conducted at the Henan University of Science and Technology Experimental Farm (33°49′N, 112°8′E) in Ruyang County, Luoyang City. This area has a warm temperate continental monsoon climate with abundant sunshine, mild temperatures, and distinct seasons. The average annual sunshine duration is 2177.3 hours, the average annual temperature is 14℃, the average annual precipitation is 690 mm, and the frost-free period is 213 days. The physicochemical properties of the topsoil (0-20 cm) in the experimental field were as follows: pH 7.56, organic matter 6.90 g / kg, available nitrogen 20.07 mg / kg, available phosphorus 7.67 mg / kg, and available potassium 345.32 mg / kg.

[0087] Experimental materials.

[0088] The sweet potato variety tested was the fresh-eating variety 'Pushu 32', bred by the Puning Municipal Academy of Agricultural Sciences in Guangdong Province and provided by Luoyang Shuxiang Potato Industry Science and Technology Innovation Park Co., Ltd.; the rapeseed variety tested was 'Shuangyou 195', provided by the Institute of Economic Crops of the Henan Academy of Agricultural Sciences.

[0089] Experimental design.

[0090] A two-factor split-plot experimental design was used. The main plot represented three planting periods: early transplanting (D1: April 15), timely transplanting (D2: May 1), and late transplanting (D3: May 15). The subplot represented two rapeseed return-to-field methods: full return (Q) and stubble return (R), with a winter fallow field (W) as a control. A total of nine treatments were included, with each treatment replicated three times. The plot area was 90.80 m². 2 The full-scale rapeseed return treatment involved mechanically crushing the rapeseed and returning it to the field, followed by deep plowing. The stubble return treatment involved harvesting the rapeseed at ground level, leaving only the stubble in each plot. Other tillage practices were the same as the full-scale rapeseed return treatment. Potato seedlings were transplanted 15 days after the rapeseed treatment for each treatment, and samples were taken and harvested 120 days after transplanting.

[0091] Rapeseed was sown in rows with a row spacing of 0.2m and a plant spacing of 0.11m, resulting in a planting density of 454,545 plants / hm². 2 Sweet potatoes were propagated by horizontal cuttings and transplanted in a triangular pattern with double rows on single ridges at equal intervals. The ridge spacing was 0.9m, the plant spacing was 0.44m, and the density was 50,505 plants / hm². 2 .

[0092] The fertilizer application rate for rapeseed is 180 kg / hm². 2 P2O5 75kg / hm 2 and K2O 120kg / hm 2 15 kg / hm of borax 2 The fertilizer application rate for sweet potatoes is 75 kg / hm². 2 P2O5 75kg / hm 2 and K2O 150kg / hm2 .

[0093] The nitrogen fertilizer for both crops was urea (containing N 46%), and the phosphorus fertilizer was common superphosphate (containing P2O5 12%); the potassium fertilizer for rape was potassium chloride (containing K2O 60%), and the potassium fertilizer for sweet potato was potassium sulfate (containing K2O 52%).

[0094] All fertilizers were applied as base fertilizer at one time, and other field management measures were carried out according to local conventional practice.

[0095] Measurement content and method.

[0096] 1.1.1 Agronomic traits

[0097] After 120 days of transplanting of the seedlings, 3 representative plants with consistent growth and no diseases and pests were randomly selected in each plot as samples for indoor measurement and field investigation. The basal stem diameter was measured by vernier caliper, the length of stem and vine was measured by tape measure, and the branch number was counted manually.

[0098] 1.1.2 Yield traits

[0099] After 120 days of transplanting of the seedlings, 15 plants were randomly selected in each plot, and the number of tubers and the weight of single tuber of sweet potato were measured, and then the yield per hectare was calculated according to the planting density.

[0100] 1.1.3 Quality traits

[0101] 1-2 tubers with uniform size were selected for each treatment, washed and sliced, then placed in an oven at 105°C for 30 min, and then transferred to an oven at 75°C until constant weight, and the dry matter weight was recorded, and then ground and sieved for determination of nutritional quality.

[0102] Among them, the soluble sugar content was determined by anthrone sulfuric acid colorimetry, and the starch content was determined by 3,5 dinitrosalicylic acid colorimetry.

[0103] 1.1.4 Commercial traits

[0104] 15 sweet potato plants were selected for each treatment for determination of commercial traits.

[0105] The 15 sweet potato plants were divided into 3 sample groups by random sampling method, and each sample group was a repetition. According to previous research, field investigation and market research, the root grading standard was: first-class tuber (200-400 g), second-class tuber (100-200 g), third-class tuber (50-100 g), and no-class tuber (less than 50 g or more than 400 g).

[0106] Data analysis.

[0107] 1.2.1 Relevant calculation formula

[0108] Marketable tuber rate (%) = (first grade tuber + second grade tuber + third grade tuber) / total tuber number x 100.

[0109] 1.2.2 Data processing

[0110] All data in this experiment were entered and analyzed using Microsoft Excel 2022, variance analysis was performed using SPSS 26.0 software, Duncan's method was used to test the significance of differences at the levels of a = 0.05 and a = 0.01, and Origin 2024 software was used for plotting. The data in the chart are mean ± standard deviation.

[0111] Table 1 - Effects of different rape residue incorporation methods on main agronomic traits of sweet potato at planting time

[0112]

[0113] Note: Different lowercase letters in the same column indicate that the difference between treatments is significant at the 5% level; different capital letters in the same column indicate that the difference between different residue incorporation methods of rape at the same planting time is significant at the 5% level. S, D, and S x D represent rape residue incorporation methods, planting time, and their interaction, respectively. * and ** represent significant differences at P < 0.05 and P < 0.01, respectively, and ns represents no significant difference.

[0114] As shown in Table 1, both residue incorporation methods and planting time had significant effects on stem length (P < 0.05). Under each planting time, the stem length of sweet potato under the full residue incorporation (Q) treatment was significantly higher than that under the winter fallow (W) condition, while there was no significant difference in stem length between the root residue incorporation (R) treatment. Under the winter fallow condition, compared with early planting (D1) and late planting (D3), on-time planting (D2) was beneficial to the growth of sweet potato stems; under Q and R conditions, the stem length of D1 was higher than that of D2 and D3. Among them, the stem length of QD1 was the largest, reaching 255.0 cm, which was increased by 207.9% and 38.6% compared with WD1 and QD3, respectively.

[0115] Stem diameter affects the transport of water and nutrients during the growth and development of sweet potato. Residue incorporation methods and planting time had significant effects on basal stem diameter (P < 0.05). Under each planting time, the basal stem diameter of sweet potato under the Q treatment was significantly higher than that under the W treatment, while there was no significant difference in basal stem diameter between the R treatment. Under all rape residue incorporation methods, different planting times had different effects on the basal stem diameter of sweet potato, with D1 > D2 > D3, and the difference between D1 and D3 was significant. Among them, the stem diameter of QD1 was the largest, reaching 12.60 mm, which was increased by 93.85% and 82.61% compared with WD1 and QD3, respectively.

[0116] The branch number affected the morphology and yield of sweet potato. The way of returning the field had a significant effect on the branch number (P<0.01), while the planting period had no significant effect on the branch number (P>0.05). Under each planting period, the branch number of sweet potato under Q treatment was significantly higher than that under R and W treatments. Under the conditions of winter fallow and root stubble returning, different planting periods had no significant effect on the branch number of sweet potato; while under the condition of full amount returning, the branch number of D1 treatment was significantly higher than that of D2 and D3 treatments. The branch number of all treatments ranged from 3.0 to 16.0 per plant, among which the branch number of QD1 treatment was the highest, with an average of 16.0 per plant, and the branch number of WD1 treatment was the lowest, with an average of 3.0 per plant.

[0117] Table 2 - The effect of planting period on the yield and constituent factors of sweet potato under different returning methods of oilseed rape

[0118]

[0119] Note: The same column and different lowercase letters represent a significant difference of 5% between treatments; the same column and different capital letters represent a significant difference of 5% between different returning methods of oilseed rape under the same planting period. S, D and SxD represent oilseed rape returning method, planting period and their interaction, respectively. * and ** represent significant difference at P<0.05 and P<0.01, respectively, and ns represents no significant difference.

[0120] As shown in Table 2, the returning method and planting period had a significant effect on the yield of sweet potato tubers (P<0.01). Under each planting period, the effect of different returning methods of oilseed rape on the yield of sweet potato tubers was full amount returning (Q)>root stubble returning (R)>winter fallow (W), and there was a significant difference between each returning method.

[0121] Compared with winter fallow, the average yield of full amount returning increased by 19.43%, and the average yield of root stubble returning increased by 7.50%. Under each returning method, the yield gradually decreased as the planting period delayed (D1→D3). In D1 period, compared with WD1 treatment, RD1 and QD1 treatments increased by 5.66% and 26.75%, respectively. In D2 period, RD2 and QD2 treatments were 3.32% and 16.62% higher than WD2 treatment, respectively. In D3 period, RD3 and QD3 treatments were 5.69% and 13.04% higher than WD3 treatment, respectively. Among all treatments, the yield of QD1 treatment was the highest, which was 23.98 t / hm 2 , QD1 was 19.96% and 26.75% higher than RD1 and WD1, respectively.

[0122] The yield of sweet potato was composed of the number of plants per unit area, the number of tubers per plant and the average weight of single tuber. When the number of plants per unit area was consistent, the yield of sweet potato depended on the number of tubers per plant and the average weight of single tuber. As shown in Table 2, the number of tubers per plant was significantly affected by the different residue management methods (P<0.01), and the order was Q>R>W, and the difference between each residue management method was significant.

[0123] With the delay of planting time, the number of tubers per plant of W treatment showed an upward trend, while the number of tubers per plant of Q and R treatments had no significant change. The number of tubers per plant of QD1 treatment was the highest, reaching 4.83 per plant, which was significantly higher than that of WD1 treatment (1.83 per plant) and RD1 treatment (3.17 per plant), with an increase of 163.9% and 52.4%, respectively.

[0124] The residue management method and planting time had no significant effect on the average weight of single tuber (P>0.05). Only in the winter fallow field, D3 was significantly lower than D1 by 49.0%. The average weight of single tuber of each treatment was in the range of 113.28-249.18 g / plant, in which WD1 was the highest (249.18 g / plant), and RD3 was the lowest (113.28 g / plant).

[0125] Further analysis of the correlation between the yield of sweet potato and its constituent factors and agronomic traits under different rape residue management methods showed that under all residue management methods, the planting time was negatively correlated with the yield and underground biomass. Under the conditions of whole residue and root residue, the planting time was significantly negatively correlated with the stem diameter, vine length and other agronomic traits. Under the condition of winter fallow, the yield was only positively correlated with the underground biomass; under the conditions of whole residue and root residue, the yield was positively correlated with the stem diameter, vine length, branch number and underground biomass, indicating that under these conditions, the planting time significantly affected the yield formation by regulating the agronomic traits.

[0126] See Figure 2 , the correlation analysis of the yield of sweet potato and the planting time, yield constituent factors and agronomic traits under different rape residue management methods. The bubbles and numbers in the figure are symmetrical, * indicates significant at P<0.05 level, and ** indicates significant at P<0.01 level. Y: tuber yield; D: planting time; NSR: number of tubers per plant; ASRW: average weight of single tuber; BSD: base stem diameter; VL: vine length; BN: branch number; UB: underground biomass.

[0127] See Figure 3 , the effect of planting time on the quality of sweet potato under different rape residue management methods; in the figure, W, R and Q represent winter fallow, root residue and whole residue, respectively, and different lowercase letters indicate that the difference between all treatments reaches the 5% significant level; S, D and SxD represent the rape residue management method, planting time and their interaction, respectively. * and ** represent significant difference at P<0.05 and P<0.01, respectively, and ns represents no significant difference.

[0128] See Figure 4 , the correlation analysis of yield and quality of sweet potato under different rape residue management methods. The bubbles and numbers are symmetrical, * indicates significant at P < 0.05 level, and ** indicates significant at P < 0.01 level. D: planting period; SSC: soluble sugar; SC: starch.

[0129] Soluble sugar content is an important indicator of edible quality and processing performance of sweet potato tubers.

[0130] As Figure 3 shown, the rape residue management method had a significant effect on the soluble sugar content of sweet potato tubers (P < 0.05), and the planting period had a very significant effect on the soluble sugar content of sweet potato tubers (P < 0.01). Under each planting period, the total residue was higher than the root stubble residue and the winter fallow field, with an increase of 23.63% and 18.83%, respectively. Under the same residue management method, the soluble sugar content of D3 planting period was generally higher, with an increase of 18.8%-46.8% and 105.0%-158.9% compared with D1 and D2 planting periods, respectively. The soluble sugar content of QD3 treatment was the highest, reaching 19.78%, which was 8.74% and 11.06% higher than WD3 and RD3 treatments, respectively.

[0131] Starch is the most important chemical component in sweet potato tubers after water and is an important indicator of sweet potato quality.

[0132] As Figure 3 shown, the rape residue management method had no significant effect on the starch content of sweet potato tubers (P > 0.05), and the planting period had a very significant effect on the starch content of sweet potato tubers (P < 0.01). Under each residue management condition, the starch content of sweet potato tubers reached a peak value at D2 planting period, with an increase of 6.3%-7.1% and 26.2%-49.0% compared with D1 and D3 planting periods, respectively. The starch content of WD3 treatment was the highest, reaching 52.96%, which was 13.97% and 1.05% higher than RD3 and QD3 treatments, respectively.

[0133] Further analysis of the correlation between sweet potato tuber yield and quality under different rape residue management methods Figure 4 .

[0134] Under the condition of winter fallow, the planting time was significantly positively correlated with the soluble sugar content and negatively correlated with the starch content. Under the condition of root stubble returning, the planting time was not significantly correlated with the soluble sugar and starch contents. Under the condition of whole amount returning, the planting time was significantly negatively correlated with the starch content. Under the conditions of different returning, the tuber yield was significantly negatively correlated with the planting time and the soluble sugar content, and positively correlated with the starch content. Under the conditions of root stubble returning and whole amount returning, the tuber yield was significantly positively correlated with the starch content. Under the condition of whole amount returning, the tuber yield was significantly negatively correlated with the soluble sugar content. It was indicated that the planting time could realize the synchronous improvement of the yield and quality of sweet potato by regulating the changes of soluble sugar and starch.

[0135] Table 3 - Effects of planting time on the number and rate of marketable tubers of sweet potato under different returning methods of oilseed rape

[0136]

[0137] Note: The same column and different lowercase letters represent that the difference between all treatments reached 5% significant level; the same column and different capital letters represent that the difference between different returning methods of oilseed rape under the same planting time reached 5% significant level.

[0138] The yield proportion of different grades of sweet potato tubers was calculated according to weight. It was known from Table 3 that there was no significant difference in the first grade tubers among the returning methods. Among them, the first grade tubers of QD1 treatment were the highest, reaching 3.67, which was increased by 83.5% and 22.3% compared with WD1 and RD1 treatments, respectively. Under the same returning method, there was no significant difference in the first grade tubers between D1 and D2 planting times, and the first grade tubers of D1 planting time were significantly higher than those of D3 planting time under the conditions of root stubble returning and whole amount returning.

[0139] In terms of the second grade tubers, Q treatment was significantly higher than W treatment under the same planting time (P<0.05), while R and W treatments had no significant difference. The second grade tubers of all treatments ranged from 1.0 to 6.33. Among them, the second grade tubers of QD1 treatment were the highest, reaching 6.33, and the second grade tubers of RD3 treatment were the lowest, reaching 1.00. Under the same returning method, the second grade tubers of D1 and D2 planting times were higher than those of D3 planting time.

[0140] In terms of the third grade tubers, Q treatment was significantly higher than W treatment under the same planting time (P<0.05), while R and W treatments had no significant difference. Under the same returning method, the third grade tubers of sweet potato reached a higher value under D2 planting time. Among them, the third grade tubers of QD2 treatment were the highest, reaching 4.33, and the third grade tubers of WD1 treatment were the lowest, reaching 1.33.

[0141] There was no significant difference in the rate of marketable tubers among the different returning methods. Under the same returning method, the rate of marketable tubers in D1 planting period was significantly higher than that in D3 planting period, and there was no significant difference between D1 and D2 planting periods. Under all returning methods, the rate of marketable tubers in D1 and D2 planting periods was significantly higher than that in D3 planting period, and compared with D3 planting period, the rate of marketable tubers in D2 and D1 planting periods increased by 47.1%-100.9% and 47.4%-82.2%, respectively.

[0142] Table 4: The influence of planting period on the economic benefits of crops under different returning methods of oilseed rape

[0143]

[0144] Note: The same column represents significant difference (P<0.05) between treatments; different capital letters represent significant difference (P<0.05) between different returning methods of oilseed rape. The price data of sweet potato was obtained from the big data platform of sweet potato industry.

[0145] Due to the influence of the concentrated marketing of sweet potato in October, the price of sweet potato showed a gradual downward trend from August to November.

[0146] From Table 4, under the same returning method, with the delay of planting period, the total yield per hectare of sweet potato showed a downward trend. Compared with winter fallow field (W), under the condition of full returning, the total yield of sweet potato increased by 26.75%-51.33%, and under the condition of root returning (R), the yield increased by 5.66%-6.98%. Under the conditions of full returning, root returning and winter fallow field, the total yield of sweet potato in D1 planting period was the highest, among which, under the condition of full returning, the yield in D1 planting period increased by 27.27% and 58.33% compared with D2 and D3 planting periods, respectively, under the condition of root returning, the yield increased by 19.96% and 10.73%, respectively, and under the condition of winter fallow field, the yield increased by 17.42% and 30.00%, respectively. Under all returning methods, the influence of planting period on the total yield of sweet potato showed the following trend: D1>D2>D3.

[0147] In D1 planting period, compared with WD1 treatment, the total yield of QD1 and RD1 treatments increased by 26.75% and 5.66%, respectively; in D2 planting period, compared with WD2 treatment, the total yield of QD2 and RD2 treatments increased by 16.62% and 3.32%, respectively; in D3 planting period, compared with WD3 treatment, the total yield of QD3 and RD3 treatments increased by 13.04% and 5.69%, respectively. Among all treatments, the total yield of sweet potato in QD1 treatment was the highest, which was 94001.60 yuan / hm 2 , followed by RD1 and WD1 treatments.

[0148] The influence of planting period on the growth and yield of sweet potato under different returning methods of oilseed rape.

[0149] Straw and green manure are important measures to improve soil fertility and increase the yield of the following crops. In this study, compared with winter fallow (W), the whole amount of rape (Q) and root stubble (R) increased the average yield of sweet potato tubers by 19.33% and 7.50%, respectively, which was mainly due to the mineralization of organic matter and the promotion of soil structure for tuber growth. Correlation analysis showed that the yield was positively correlated with the stem diameter, length, and underground biomass under the conditions of whole amount of rape (Q) and root stubble (R), indicating that rape can improve agronomic traits and promote yield formation. This is consistent with the conclusion of Zhang Shuntao et al. that rape can improve the yield of the following crops. In addition, regardless of the way of returning, early transplanting (D1) can harvest relatively high tuber yield, and the yield is increased by 5.9% and 33.6% under the conditions of moderate transplanting (D2) and late transplanting (D3), respectively. This is due to the matching of light and heat resources with the demand of tuber expansion, which maintains a high value of tuber number and underground biomass, verifying the yield-increasing mechanism of early transplanting.

[0150] Effect of transplanting time on the quality of sweet potato under different rape returning methods.

[0151] Crop quality is affected by environmental and cultural practices. In this study, under all returning methods, the starch content of sweet potato tubers was the highest under moderate transplanting (D2), which was increased by 26.2%-49.0% compared with late transplanting (D3), which was related to the expansion of day-night temperature difference promoting the transformation of photosynthetic products into storage substances. At the same time, the soluble sugar content was significantly increased under late transplanting (D3), which was increased by 18.8%-46.8% and 105.0%-158.9% compared with early transplanting (D1) and moderate transplanting (D2), respectively, due to the inhibition of respiration consumption by low temperature at harvest time, which promoted the retention of sugar in tubers. Correlation analysis revealed that the effect of transplanting time on quality was regulated by the returning method. Under winter fallow (W), transplanting time was positively correlated with soluble sugar content and negatively correlated with starch content, indicating that late transplanting promotes sugar accumulation but inhibits starch synthesis under low fertility conditions. Under root stubble returning (R), transplanting time was not significantly correlated with soluble sugar and starch content, confirming that it maintains stable quality by improving soil fertility and buffering carbon allocation fluctuations. Under whole amount of rape returning (Q), transplanting time was only negatively correlated with starch content, and early transplanting combined with the continuous mineralization of nutrients under whole amount of rape returning promoted the synthesis and accumulation of starch.

[0152] Effect of transplanting time on the economic traits of sweet potato under different rape returning methods.

[0153] The experiment shows that the full amount of returning (Q) and root stubble returning (R) treatment is 19.60% and 4.88% higher than winter idle field (W) sweet potato yield, which significantly improves the yield of sweet potato. The continuous nutrient supply provided by the rape returning promotes the accumulation of root dry matter and yield formation, thereby improving the yield of sweet potato. Under all returning modes, early transplanting (D1) can harvest relatively more considerable yield, which is 17.06%-27.23% and 42.83%-60.20% higher than suitable period transplanting (D2) and late transplanting (D3), respectively. The core is to effectively avoid the market saturation during the concentrated harvesting period within 15-30 days of early marketing, so as to realize the price premium. In addition, compared with winter idle field (W), the full amount of returning (Q) significantly increases the proportion of secondary and tertiary potatoes, and the nutrient release rate of rape straw returning is higher than that of root stubble. Among them, the highest commercial potato rate appears in QD1, RD2 and WD2 treatments, which shows that the returning mode needs to be matched with the suitable transplanting period to optimize the commerciality of sweet potato. The internal mechanism is the difference in the influence of straw or root stubble decomposition rate on soil physical and chemical properties under different returning modes.

[0154] In the dryland rape-sweet potato rotation in western Henan, the full amount of returning mode (QD1) with early transplanting can maximize yield, agronomic traits and economic benefits, and is recommended as the main promotion mode in the region. According to the difference of production goals, root stubble returning with suitable period transplanting (RD2) or winter idle field with suitable period transplanting (WD2) can be used as alternative choices. This method provides a theoretical and practical basis for the optimization of dryland rotation system.

[0155] The above describes only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes to the technical solutions and inventive concepts of the present application within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

[0156] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms is not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or features of the embodiments or examples described in the present specification without contradiction.

Claims

1. A method of planting oilseed rape-sweet potato crop rotation, characterized by, Suitable for hilly dry land; including the following steps: S1, rape planting; S2, rape returning to field; rape returning to field treatment is carried out 15 days before potato seedling transplanting; The returning to field mode is: full amount returning to field, or root stubble returning to field; S3, ridge raising and fertilization; base fertilizer is applied once before land preparation and ridge raising; S4, potato seedling transplanting; horizontal cutting method is used for potato transplanting; Transplanting time: early transplanting, middle and late April; or suitable transplanting, early May; or late transplanting, middle and late May; S5, harvesting; four months after potato seedling transplanting.

2. The method according to claim 1, wherein, In step S1, the rape fertilization amount is: N 180 kg / hm 2 ; P2O5 75 kg / hm 2 ; K2O 120 kg / hm 2 and borax 15 kg / hm 2 ; wherein the nitrogen fertilizer is urea, the phosphorus fertilizer is superphosphate, and the potassium fertilizer is potassium chloride.

3. The method according to claim 1, wherein In step S2, the sweet potato fertilization amount is: N 75 kg / hm 2 ; P2O5 75 kg / hm 2 ; K2O 150 kg / hm 2 ; wherein the nitrogen fertilizer is urea, the phosphorus fertilizer is superphosphate, and the potassium fertilizer is potassium sulfate.

4. The method according to claim 1, wherein In step S2: Full amount returning to field refers to directly plowing rape plants into the soil at the beginning of flowering period or flowering period or mature period, realizing soil fertilization through biological nitrogen fixation and organic matter input; Root stubble returning to field refers to harvesting the aboveground part of rape at the beginning of flowering period or flowering period or mature period, leaving only root stubble, and plowing into the soil.

5. The method according to claim 1, wherein In step S4: single ridge double row triangular equidistant planting, ridge distance is 0.8-1.0 m, and plant distance is 0.4-0.5 m.

6. The method of claim 1, wherein, Also including: According to different planting targets, the transplanting period is selected; Among them, the planting target is: yield value advantage, or high commercial potato rate, or high starch content, or high soluble sugar content.

7. The rape-potato crop rotation planting method according to claim 6, characterized in that: When the planting target is yield value advantage, the transplanting time is selected as early transplanting; When the planting target is high starch content, the transplanting time is selected as suitable transplanting; When the planting target is high soluble sugar content, the transplanting time is selected as late transplanting; When the planting target is high commercial potato rate, full amount returning to field selects early transplanting time, and root stubble returning to field selects suitable transplanting time.

8. The method according to claim 7, wherein When the planting target is yield value advantage, in addition to considering yield factors, time price difference is also considered; in order to be able to go on the market in advance and avoid the concentrated harvesting period.

9. The method according to claim 1, wherein In yield value calculation and commercial potato rate calculation: The grading standard of potato tubers is: first-class potatoes 200-400 g, second-class potatoes 100-200 g, third-class potatoes 50-100 g, and no-class potatoes less than 50 g or more than 400 g; Commercial potato rate (%) = (first-class potato tubers + second-class potato tubers + third-class potato tubers) / total potato number x 100.

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