Double cropping rice yield increasing method based on partial replacement of basal application chemical fertilizer with organic fertilizer

Abstract

The invention belongs to the technical field of agricultural planting, and particularly relates to a double cropping rice yield increasing method based on partially replacing basal application chemical fertilizer with organic fertilizer. In double cropping rice planting, an applied base fertilizer is a mixed mode of an organic fertilizer and a chemical nitrogen fertilizer; the mixing mode is that the milk vetch is mixed with the chemical nitrogen fertilizer, or the rice straw is mixed with the chemical nitrogen fertilizer, or the charcoal is mixed with the chemical nitrogen fertilizer, or the barnyard manure is mixed with the chemical nitrogen fertilizer, or the cake fertilizer is mixed with the chemical nitrogen fertilizer; the application amount of different organic fertilizers and the proportion of chemical nitrogen fertilizers are limited, tillering fertilizers and panicle fertilizers are applied in a matched mode, the yield increasing purpose can be achieved, and the method is suitable for being applied and popularized in the double cropping rice area.

Description

[0001] This application is a divisional application with application date of June 9, 2018, application number 201810590634.5, and invention name "A method for increasing double-season rice yield based on partial replacement of base fertilizer with organic fertilizer". Technical Field

[0002] The invention belongs to the technical field of agricultural planting, and in particular relates to a double-season rice yield-increasing method based on partial replacement of base-applied chemical fertilizers with organic fertilizers. Background Art

[0003] Crop production is increasingly dependent on chemical fertilizers, and the application of organic fertilizers is becoming less and less important. The simple application of chemical fertilizers will lead to a series of problems such as soil quality deterioration, difficulty in maintaining high crop yields, and environmental pollution. Therefore, in the three-crop system double-season rice area, it is important to explore the selection of different organic fertilizers to partially replace the chemical nitrogen fertilizer base application to ensure the stable and increased yield of double-season rice, which is also of great significance to improving the quality of cultivated land.

[0004] In recent years, many scholars have studied the use of organic fertilizers to replace chemical fertilizers for soil fertilization. Related studies have shown that organic fertilizers can improve soil aggregate structure, increase soil organic matter content, and improve soil nutrient content and plant nutrient utilization efficiency to a certain extent. There are also many studies that show that the combination of organic fertilizers and chemical fertilizers can effectively promote rice growth and development and increase yields. Among them, some studies have shown that the perennial turning and returning of astragalus to the field can increase the fruiting rate and thousand-grain weight to a certain extent, thereby increasing rice yields. Some studies have shown that the perennial application of organic fertilizers (early rice astragalus and late rice pig manure) can increase the leaf area index of rice heading period by 47% compared with conventional fertilization. Previous researchers have also found that biochar can optimize the root morphology of rice, enhance physiological functions, and significantly increase yields; compared with the application of chemical fertilizers alone or cake fertilizers alone, the combination of cake fertilizers and inorganic nitrogen fertilizers can promote rice growth and significantly increase yields. Some studies have shown that the treatment of partial replacement of chemical fertilizers with organic fertilizers increases rice yield by 5.56% compared with the treatment of pure fertilizers.

[0005] Previous studies have mostly focused on the proportion of organic fertilizer application. However, there are many types of organic fertilizers, and different organic fertilizers have different effects. In addition, most studies have focused on the impact of organic fertilizers on rice yield. There are few in-depth studies on its effects on the characteristics of rice yield formation, and even fewer related studies have been conducted in double-season rice areas with three-cropping system. Summary of the invention

[0006] In view of this, an embodiment of the present invention provides a method for increasing double-season rice production based on partially replacing base-applied chemical fertilizers with organic fertilizers. The main purpose is to provide a theoretical basis and technical support for selecting suitable types of organic fertilizers in double-season rice areas with three-cropping system, ensuring stable and increased grain production, and continuously fertilizing paddy field soil.

[0007] To achieve the above object, the present invention mainly provides the following technical solutions:

[0008] On the one hand, an embodiment of the present invention provides a method for increasing the yield of double-season rice based on partial replacement of basal fertilizer with organic fertilizer, comprising the following steps:

[0009] In double-season rice cultivation, the base fertilizer applied is a mixture of organic fertilizer and chemical nitrogen fertilizer; among them, the mixing methods are a mixture of astragalus and chemical nitrogen fertilizer, a mixture of rice straw and chemical nitrogen fertilizer, a mixture of biochar and chemical nitrogen fertilizer, a mixture of manure and chemical nitrogen fertilizer, and a mixture of cake fertilizer and chemical nitrogen fertilizer.

[0010] Preferably, the weight ratio of the organic fertilizer to the chemical nitrogen fertilizer when mixed is 0.8-1.2:2.8-3.2.

[0011] Preferably, the weight ratio of the organic fertilizer to the chemical nitrogen fertilizer when mixed is 1:3.

[0012] Preferably, the early rice basal fertilizer of the double-season rice is a mixture of the astragalus melastoma and chemical nitrogen fertilizer.

[0013] Preferably, the late rice basal fertilizer of the double-season rice is a mixture of the cake fertilizer and chemical nitrogen fertilizer, or a mixture of the stable manure and chemical nitrogen fertilizer.

[0014] Preferably, the nitrogen content of the astragalus is 3.2%, the nitrogen content of the stem of the early rice straw is 0.81%, the nitrogen content of the leaf of the early rice straw is 1.99%, the nitrogen content of the manure is 0.5%, and the nitrogen content of the cake fertilizer is 3.15%.

[0015] Preferably, the cake fertilizer is rapeseed cake fertilizer; the chemical nitrogen fertilizer is compound fertilizer, wherein the mass ratio of N:P:K is 15:15:15.

[0016] Preferably, the early rice variety of the double-season rice is Zhongzao 39, and the late rice variety of the double-season rice is Hyou 518.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention studies the effects of partial replacement of chemical nitrogen fertilizers with different organic fertilizers on the growth, nitrogen accumulation and yield of double-season rice, and finds that under the same nitrogen fertilizer application level, each organic fertilizer promotes the growth and development of rice and the later nitrogen accumulation to a certain extent, which is further manifested as an increase in yield; among them, astragalus membranaceus has the most obvious effects on early rice, and cake fertilizer and stable manure have the most obvious effects on late rice. This technology is suitable for promotion and application in double-season rice areas, and provides a theoretical basis and technical support for soil fertilization and farming system development of double-season rice fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0020] Figure 1 A graph showing the gradual increase in dry matter accumulation of early rice in 2016 as the growth period progresses, provided in an embodiment of the present invention;

[0021] Figure 2 A graph showing the gradual increase in dry matter accumulation of late rice in 2016 as the growth period progresses, provided in an embodiment of the present invention;

[0022] Figure 3 The dry matter accumulation of early rice in 2017 provided by the embodiment of the present invention gradually increases with the growth period

[0023] Figure 4 A graph showing the gradual increase in dry matter accumulation of late rice in 2017 as the growth period progresses, provided in an embodiment of the present invention;

[0024] Figures 1 to 4 Different lowercase letters indicate significant differences at the 5% level. DETAILED DESCRIPTION

[0025] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, technical solutions, features and effects of the present invention application are described in detail below with preferred embodiments. The specific features, structures, or characteristics of the multiple embodiments in the following description can be combined in any suitable form.

[0026] Example

[0027] Experimental materials: Early rice variety Zhongzao 39 and late rice variety Hyou 518 were used as test materials; the nitrogen content of the selected organic fertilizers was: astragalus 3.2%, early rice straw stem 0.81%, leaf 1.99%, stable manure 0.5%, cake fertilizer 3.15%;

[0028] Test location: From 2016 to 2017, the test was conducted at Sifen Farm, Liling City, Zhuzhou (E113°29′52″, N27°32′42″), located in the subtropical monsoon humid climate zone, with an average temperature of 18.58℃ and an annual precipitation of 1489mm in 2016; the average temperature in 2017 was 18.71℃ and an annual precipitation of 1605mm; the test soil type was paddy soil with red and yellow mud; the test land farming system was typical: rice-rice-fertilizer three-crop system; the pH value of the tillage layer soil was 5.61, total nitrogen was 1.66g / kg, total phosphorus was 0.66g / kg, total potassium was 10.9g / kg, organic matter was 43.25g / kg, alkaline nitrogen was 136.5mg / kg, available potassium was 56mg / kg, and available phosphorus was 42.55mg / kg;

[0029] Experimental design: Under the conditions of nitrogen (N) application of 150 kg / ha and nitrogen base fertilizer: tillering fertilizer: panicle fertilizer = 5:3:2, 100% chemical nitrogen fertilizer treatment was used as the control (T5), and 4 organic fertilizer + chemical nitrogen fertilizer treatments were set up: T1 (Astragalus (early rice) / rice straw (late rice) + chemical fertilizer), T2 (biochar + chemical fertilizer), T3 (stable manure + chemical fertilizer), T4 (rapeseed cake fertilizer + chemical fertilizer). Among them, the proportion of organic fertilizer replacing chemical nitrogen fertilizer in T1, T3 and T4 treatments was 25%, T2 treatment was biochar + 100% chemical fertilizer, and the biochar application rate was 15 t / ha; in the experiment, the basal chemical nitrogen fertilizer was compound fertilizer (N:P:K was 15:15:15), and the topdressing chemical nitrogen fertilizer was urea (containing N 46%), phosphorus and potassium fertilizers were uniformly applied according to local fertilization habits, and the fertilization schemes between early and late rice in each treatment were consistent. The specific fertilization schemes are shown in Table 1. The experiment adopted a large-area design without replication, and each large area was 220m 2 ; Ridges are set up between the areas and covered with film to prevent water and fertilizer from mixing. Each area has an independent water inlet and outlet. The early rice varieties in 2016 were sown on March 23 and transplanted on April 22; the late rice varieties were sown on June 27 and transplanted on July 25; the early rice varieties in 2017 were sown on March 21 and transplanted on April 26; the late rice varieties were sown on June 23 and transplanted on July 20.

[0030] Table 1 Specific fertilization scheme for early and late rice in each treatment (t / ha)

[0031]

[0032]

[0033] Growth and development characteristics of rice: At the tillering peak stage, booting stage, heading stage, milky stage and maturity stage, the front, middle and back three parts were selected from the region, three points were randomly surveyed in each part, and the number of rice tillers in ten holes were randomly selected from each point for continuous investigation, and the average number of tillers in a single hole was calculated. According to the average number of tillers in a single hole, three representative plants were selected, and three repeated samples were taken from each region. The leaf area of ​​rice was measured by a leaf area meter, and the leaf area index (LAI) was calculated; the leaves, stems, ears and other parts were bagged, placed in an oven (DHG-9246A) at 105℃ for 30 minutes, and then dried at 80℃ to constant weight, and the dry matter weight of rice was measured.

[0034] Leaf area decay rate [LAI d -1 ]=[LAI2-LAI1] / (t2-t1); LAI2-LAI1 is the difference between the leaf area index measured twice, and t2-t1 is the time interval between the two measurements.

[0035] SPAD value of rice leaves: A chlorophyll meter (SPAD-502) was used to measure the SPAD value of flag leaves at the booting stage, heading stage and milky stage. Thirty rice holes were measured in each area, with 10 holes as one replicate. Ten flag leaves were measured in each rice hole, and each flag leaf was measured at three positions: upper, middle and lower. The average was taken as the leaf SPAD value of the area.

[0036] Rice yield and yield composition: The front, middle and back three parts were selected from each region. The number of effective rice panicles in 100 consecutive holes was investigated in each part, and the number of effective panicles per hole was calculated. Then, 15 holes were sampled in each region according to the average number of effective panicles (every 5 holes was repeated once), and the samples were taken back to the laboratory to investigate the number of grains per panicle, fruit setting rate and 1000-grain weight. Three points were randomly collected in each region, and each point was 1m 2 Rice is harvested and dried separately, and the actual yield is calculated based on a moisture content of 13.5%.

[0037] Plant nitrogen accumulation: The plant samples were measured by dry weight, crushed and sieved, digested by the H2SO4-H2O2 method, and the total nitrogen content of each part of the aboveground part of the plant was measured using a continuous flow analyzer (San++system) produced by Skalar Analytical Instruments of the Netherlands. The sum of the total nitrogen content of each part multiplied by the dry weight of the corresponding aboveground part is the aboveground nitrogen accumulation.

[0038] Data processing: Excel 2007 software was used for data statistical analysis, and SPSS22.0 was used for variance analysis.

[0039] Effects of different organic fertilizers on double-season rice yield and yield components - Yield: As shown in Table 2, the early rice yield (actual yield) in 2016 and 2017 showed that the organic fertilizer treatments (T1-T4) were higher than the T5 treatment to varying degrees, and the results were basically consistent with the theoretical yield. In 2016, the yield of early rice in different organic fertilizer treatments (T1-T4) was significantly higher than that in the single chemical fertilizer treatment (T5). The yield of each organic fertilizer treatment was T3>T1>T2>T4, and the yield of T5 increased by 4.81% to 7.74% compared with the single chemical fertilizer treatment (T5) of 7.62t / ha. In 2017, the yield of early rice in different organic fertilizer treatments (T1-T4) increased by 0.12% to 3.50% compared with the single chemical fertilizer treatment (T5). Among them, the yields of T1, T2, and T4 were significantly higher than those of T3 and T5, and T4 had the highest yield of 8.29t / ha among all treatments. The average yield of early rice in 2016 was 8.01t / ha, and the average yield of early rice in 2017 was 8.17t / ha, and the yield of early rice in 2017 increased by 1.97% compared with that in 2016. The late rice yield (actual yield) in 2016 and 2017 showed that each organic fertilizer treatment (T1-T4) was higher than that of T5 treatment to varying degrees, and the theoretical yield showed basically the same results. In 2016, the yields of late rice T1, T3 and T4 were significantly higher than those of T5, and the yield of T2 was greater than that of T5 but not reaching a significant level. The yields of each organic fertilizer treatment were T1>T3>T4>T2, which were 9.34t / ha, 9.12t / ha, 9.08t / ha and 8.75t / ha, respectively, which were 8.10%, 5.56%, 5.09% and 1.27% higher than the T5 yield of 8.64t / ha, respectively. In 2017, the yields of late rice T3 and T4 were significantly higher than those of T5, and the yields of T1 and T2 were higher than those of T5 but not reaching a significant level. The yields of each organic fertilizer treatment were T3>T4>T1>T2, which were 8.47t / ha, 8.46t / ha, 8.19t / ha and 8.13t / ha, respectively, which were 6.27%, 6.15%, 2.76% and 2.01% higher than the T5 yield of 7.97t / ha, respectively.

[0040] Table 2 Effects of different organic fertilizers on rice yield and yield components

[0041]

[0042] Note: Different lowercase letters in the same column indicate significant differences at the 5% level, the same below.

[0043] Yield components: The results of the effect of organic fertilizer application on the yield components of early and late rice in two years are shown in Table 2. Among the treatments of early rice in 2016, the effective panicles of T1 and T5 treatments were significantly higher, but the number of grains per panicle and the fruit setting rate of T5 treatment were lower overall, so the comprehensive yield was lower than that of other treatments. The number of grains per panicle of T3 treatment was significantly higher than that of other treatments. The fruit setting rate of T1, T2 and T3 treatments was significantly higher. There was no significant difference in 1000-grain weight among the treatments. In 2017 early rice, the effective panicles of T2 treatment were significantly higher, but its fruit setting rate was relatively low. The effective panicles of T1 and T4 treatments were relatively low, but their fruit setting rates were relatively high, with a certain compensation effect, and the comprehensive yield was higher. There was no significant difference between T3 treatment and T5 treatment. Overall, T1 and T3 treatments significantly improved the fruit setting rate of early rice in the two years. There was no obvious pattern in other components.

[0044] In 2016, the effective panicles of late rice in T2 and T3 treatments were significantly higher than those in other treatments, and the number of grains per panicle in T1 treatment was significantly higher. The thousand-grain weight in T1 and T4 treatments was significantly higher than that in other treatments, and there was no significant difference in the fruit setting rate of late rice in 2016 among the treatments. In 2017, the effective panicles of late rice in T4 treatment were significantly higher than those in other treatments, but the number of grains per panicle was significantly lower. There was an opposite pattern in T2 and T5 treatments. There was a certain complementary effect between the two. There was no significant difference in thousand-grain weight among the treatments. The fruit setting rate of T1, T3, and T4 treatments was significantly higher than that of T2 and T5. In terms of the two-year late rice, organic fertilizer has a certain effect on improving the fruit setting rate of late rice. The two-year late rice treatments of T1, T3, and T4 showed a consistent pattern. This is related to the fact that the above three organic fertilizer treatments release nutrients slowly, providing relatively sufficient nutrient elements for the later rice grain filling.

[0045] Effects of different organic fertilizers on leaf area index and leaf area decay rate of double-season rice: As shown in Table 3, the leaf area index of early and late rice in the two years showed an overall trend of first increasing and then decreasing as the growth period progressed, reaching the maximum at the booting stage and gradually decreasing after the booting stage; the leaf decay rate of the two years in the T5 treatment was significantly higher than that of the other treatments. In the early rice of 2016, the leaf area index of the T4 treatment was significantly lower than that of the other treatments at the peak tillering stage, the leaf area index of the T2 treatment was significantly higher than that of the other treatments at the booting stage, the leaf area index of the T3 and T4 treatments at the heading stage was significantly lower than that of the other treatments, and there was no significant difference between the treatments at the milky stage, but T5 was the lowest. The leaf area decay rates of the early rice treatments in 2016 were T5>T2>T3>T4>T1, and the leaf decay rate of the T5 treatment was the fastest at 0.0828LAID -1 The average decay rate of leaves treated with other treatments is 0.0071 LAID faster -1. In the 2017 early rice, the leaf area index of T3 and T5 treatments was significantly higher than that of other treatments at the peak tillering stage, while T4 was significantly lower than that of other treatments. The leaf area index of T1, T2, and T5 treatments was higher than that of T3 and T4 at the booting stage, among which T2 and T5 reached significant levels, while T4 was significantly lower than that of other treatments. The leaf area index of T4 treatment was still significantly lower than that of other treatments at the heading stage and milky stage. The leaf area decay rates of each treatment of early rice in 2017 were T5>T2>T1>T3>T4, and the fastest leaf decay rate of T5 treatment was 0.1342LAID -1 The average decay rate of the leaves is 0.0332LAID faster than that of the other treatments. -1 .

[0046] In 2016 late rice, the leaf area index of treatments T1 and T2 at the peak tillering stage was significantly lower than that of other treatments, the leaf area index of treatment T2 at the booting stage was significantly higher, the leaf area index of treatment T5 at the full heading stage was significantly lower, and the leaf area index of treatment T5 at the milky stage was lower, and there was no significant difference among treatments. The leaf area decay rate of each treatment of late rice in 2016 was T5>T2>T3>T4>T1. In 2017 late rice, the leaf area index of treatments T2 and T3 at the peak tillering stage was significantly higher, the leaf area index of treatment T1 at the booting stage was significantly lower, there was no significant difference among treatments at the full heading stage, and the leaf area index of treatments T1 and T5 at the milky stage was significantly lower. The leaf area decay rate of each treatment of late rice in 2017 was T5>T3>T2>T4>T1.

[0047] Comprehensively considering the leaf area index and leaf area decay rate data of early and late rice in two years, the leaf area decay rate of T5 treatment is the fastest, which is not conducive to the photosynthesis of leaves in the later stage. The leaf area index of early and late rice in T2 treatment is relatively high, but its leaf area decay rate is second only to T5 treatment. T4 treatment has no obvious advantage in the early leaf area index of early and late rice, but its leaf area decay rate is slower in the later stage, which is conducive to delaying leaf senescence, thereby maintaining the effective photosynthetic area. In the later stage, it can produce relatively more photosynthetic products, effectively ensuring sufficient grain filling. Combined with yield, it is one of the factors for cake fertilizer to increase yield. From the perspective of leaf decay rate, both T1 and T3 treatments have a certain effect in delaying leaf senescence.

[0048] Table 3 Leaf area index and leaf area decay rate of rice population under different treatments

[0049]

[0050] Effects of different organic fertilizers on the relative chlorophyll content (SPAD value) of double-season rice leaves: As shown in Table 4, the SPAD values ​​of early and late rice leaves in 2016 and 2017 showed a trend of first rising and then falling, reaching the maximum value at the heading stage and tending to decline after the heading stage. In 2016 early rice, the SPAD value of the leaves in the T5 treatment at the heading stage was significantly higher than that of other treatments, while T2 and T4 were significantly lower. The SPAD value of the leaves in the T1 treatment at the heading stage was higher, while that in the T4 treatment was lower. At the milky stage, the SPAD values ​​of the leaves in the T1 and T3 treatments were significantly higher than those in the T5, and the SPAD values ​​of the leaves in the T2 and T4 treatments were higher than those in the T5, but the differences were not significant. In 2017 early rice, the SPAD value pattern of the leaves between the treatments at the heading stage was basically consistent with the SPAD value of the leaves in the 2016 early rice. The SPAD values ​​of the leaves in the T1, T2, and T3 treatments at the heading stage were significantly higher than those in the T5, and there was no significant difference between the T4 and T5 treatments. At the milky stage, the SPAD values ​​of leaves in treatments T3 and T4 were significantly higher than those in treatment T5, while the SPAD values ​​of leaves in treatments T1 and T2 were not significantly different from those in treatment T5.

[0051] In 2016 late rice, at the booting stage, the SPAD values ​​of leaves in treatments T1 and T5 were significantly higher than those in other treatments, and T5 was the highest. At the heading stage, the SPAD value of leaves in treatment T1 was significantly higher than that in other treatments, and that in treatments T2 and T3 was significantly lower than that in treatment T5. At the milky stage, the SPAD values ​​of leaves in treatments T1, T4, and T5 were significantly higher than those in treatments T2 and T3, and the SPAD value of leaves in treatment T2 was the lowest. In 2017 late rice, the SPAD value of leaves in treatment T5 was significantly higher than that in other treatments at the booting stage, the SPAD value of leaves in treatment T1 was significantly higher at the heading stage, the SPAD value of leaves in treatment T1 was significantly higher at the milky stage, and the SPAD value of leaves in treatment T4 was significantly lower, and there were no significant differences among other treatments.

[0052] Based on the results of SPAD values ​​of early and late rice leaves in the two years, the SPAD value of leaves in the early and late rice T5 treatment was significantly higher during the booting stage, with a smaller increase in the heading stage and a larger decrease in the middle and late stages. This shows that the application of chemical fertilizers alone has an obvious advantage in promoting the formation of chlorophyll in the sword leaves of rice in the early stage, but has a weak effect on alleviating the decline in chlorophyll content in the leaves in the later stage. The SPAD values ​​of early rice T1 and T3 treatments were higher in the middle and late stages, which can better maintain the photosynthetic activity of leaves, promote the full filling of grains, and thus increase the yield of early rice. The overall SPAD value of leaves in the T4 treatment was lower in the early stage, and it could effectively alleviate the decline in SPAD value in the middle and late stages. The effect of T2 treatment on leaf SPAD value was not obvious. The SPAD value of sword leaves in the late rice T1 treatment in 2016 was higher overall, and was lower in the booting stage of the late rice T1 treatment in 2017, and maintained at a higher level from the heading stage. The rules of other organic fertilizer material addition treatments were not obvious.

[0053] Table 4 Relative chlorophyll content (SPAD value) of rice leaves under different treatments

[0054]

[0055] Effects of different organic fertilizers on dry matter accumulation of double-season rice: Figure 1 and Figure 3 It can be seen that the dry matter accumulation of early and late rice in the two years showed a gradual increase trend as the growth period progressed. For early rice, the dry matter accumulation of T1-T4 treatments before the milky stage of early rice in 2016 was lower than that of T5, among which T3 and T4 treatments were significantly lower than T5. At the milky stage, T1, T2, and T3 treatments were all higher than T5, among which T2 treatment reached a significant level, and T4 treatment was significantly lower than T5. There was no significant difference in dry matter accumulation among the treatments during maturity ( Figure 1 ). In 2017, the dry matter accumulation of early rice T2 treatment was higher than that of other treatments at each growth stage. The dry matter accumulation of T1, T3, and T4 was lower than that of T5 to a certain extent before the milky stage, and higher than that of T5 to varying degrees during the milky stage. The dry matter accumulation of T1-T4 treatments was higher than that of T5 during the maturity stage, but it did not reach a significant level ( Figure 3 ).

[0056] Depend on Figure 2 and Figure 4 It can be seen that for late rice, the dry matter accumulation of the late rice T2 treatment in 2016 was higher than that of other treatments at each growth stage. There was no significant difference in dry matter accumulation among the treatments at the peak tillering stage, and the dry matter accumulation of the T1 treatment from the peak tillering stage to the milky stage was significantly lower than that of the other treatments. The dry matter accumulation of the T1-T4 treatments at the maturity stage was higher than that of T5, but did not reach a significant level ( Figure 2 ). In 2017, the dry matter accumulation of late rice T2 treatment before milky stage was significantly superior to that of other treatments. The dry matter accumulation of T4 treatment was not obvious before heading stage, but was higher than that of other treatments to a certain extent after heading stage. The dry matter accumulation of T1-T4 treatments at maturity was higher than that of T5 to a certain extent, but did not reach a significant level ( Figure 4 ).

[0057] Based on the data from two years, the dry matter accumulation of the T5 treatment before early rice grain filling was higher than that of other treatments to a certain extent, indicating that the T5 treatment had certain advantages in the early nutritional growth of rice and promoted the early growth of rice. After the milky stage, the dry matter accumulation of the T1-T4 treatments was higher than that of T5 to varying degrees, indicating that the T1-T4 treatments could fully provide the nutrients required for grain filling and had certain advantages for the later reproductive growth of rice. The T1 treatment of late rice showed certain disadvantages to rice growth in the early stage compared with other treatments. The T2 treatment had certain advantages in promoting the accumulation of dry matter in rice.

[0058] Effects of different organic fertilizers on nitrogen accumulation in the aboveground part of double-season rice plants: As shown in Table 5, the nitrogen accumulation of plants in the T2 and T5 treatments was significantly higher during the tillering period of early rice in 2016, and the T1 treatment was the lowest. However, as the growth period progressed, the nitrogen accumulation of plants in the T1 treatment increased significantly, and its nitrogen accumulation at the heading stage was significantly higher than that of the T2, T3, and T4 treatments. In contrast, the nitrogen accumulation of plants in the later stage of the T2 and T5 treatments decreased significantly compared with the early stage. The effect of the T3 and T4 treatments was not obvious in the early stage, but the nitrogen accumulation of plants increased significantly in the later stage. At the maturity stage, the nitrogen accumulation of plants in the T3 and T4 treatments was significantly higher than that of other treatments. The T2 and T5 treatments of early rice in 2017 showed the same pattern as the early rice in 2016, with a higher nitrogen accumulation of plants in the early stage and a significant decrease in the later stage. The nitrogen accumulation of plants in the T4 treatment was less in all growth stages. The effect of the T1 treatment was not obvious. The nitrogen accumulation of plants in the T3 treatment was relatively low in the early stage, but as the growth period progressed, the nitrogen accumulation of plants in this treatment was significantly higher than that in other treatments, which was basically consistent with the pattern in 2016.

[0059] In 2016, the nitrogen accumulation of plants in the T2 and T5 treatments was basically consistent with that of early rice. The nitrogen accumulation was high in the early stage, and decreased significantly in the middle and late stages. The nitrogen accumulation of plants in the T1 treatment was significantly lower at the tillering peak and heading stages, and increased more in the maturity stage than that of the T5 treatment. The nitrogen accumulation of plants in the T4 treatment at the heading and maturity stages was significantly higher than that of other treatments. Compared with the T5 treatment, the T3 treatment also had a trend of lower nitrogen accumulation in the early stage and increased nitrogen accumulation in the late stage. In 2017, the nitrogen accumulation of plants in the T1 treatment was significantly lower at the tillering peak, and higher at the T2 and T5 treatments at the tillering peak, of which T5 was significantly higher than other treatments. The accumulation of plants in T5 was significantly lower after the heading stage. The overall trend of nitrogen accumulation of plants in the T2 and T5 treatments was basically consistent with that of late rice in 2016. The accumulation of nitrogen in the T3 treatment was low in the early stage, but significantly higher than that in other treatments at the heading stage and maturity stage. Compared with the T5 treatment, the nitrogen accumulation of the T4 treatment showed no obvious advantage in the early stage, but a significant increase in the nitrogen accumulation in the later stage.

[0060] Based on the results of nitrogen accumulation of early and late rice plants in the two years, the nitrogen accumulation of plants in the T2 and T5 treatments was higher in the early stage and less in the later stage. T1, T3, and T4 showed that the nitrogen accumulation of plants was lower in the early stage and higher in the later stage. There were also some differences between the early and late rice treatments of T1, T3, and T4. The nitrogen accumulation of plants in the early stage of T1 treatment was lower than that of plants in T2 and T5 treatments. T3 treatment manure had a more prominent advantage in nitrogen accumulation in plants than T4 treatment cake fertilizer.

[0061] Table 5 Effects of different organic fertilizers on nitrogen accumulation in double-season rice (kg / ha)

[0062]

[0063] The following conclusions were drawn from the above experimental process and experimental data:

[0064] Effects of different organic fertilizers on rice yield and yield components: Rice yield is composed of four major factors: number of panicles, number of grains per panicle, thousand-grain weight and fruit setting rate. Suitable light, temperature, water, air and fertilizer conditions are inseparable from rice growth. If any of these conditions cannot be met, it will directly affect the yield formation of rice. In the two-year results of the present invention, the early rice astragalus was turned over and returned to the field, and the late rice cake fertilizer and stable manure treatments increased production significantly, and all showed a significant increase in fruit setting rate, which was basically consistent with the results of previous studies. The main reason may be that astragalus, cake fertilizer, and stable manure all have a certain decomposition cycle, have a certain nitrogen backward shift effect, and have sufficient nutrient supply to the rice grain filling period, thereby showing a higher fruit setting rate. From the perspective of the early and late rice yields in the present invention in two years, compared with the single application of chemical fertilizers, the early rice yield increased by an average of 4.35% and the late rice yield increased by an average of 4.33%, which is consistent with the results of previous studies. Specifically, the return of early rice straw to the field significantly increased the yield of early rice in the past two years. Cake fertilizer, stable manure, and biochar all increased the yield to a certain extent, but there was no obvious pattern in the two-year results. For late rice, cake fertilizer and stable manure treatments had a significant effect on increasing the yield based on the two-year results. Biochar had no significant effect on increasing the yield of late rice. The impact of returning early rice straw to the field on the yield of late rice showed inconsistent patterns from the two-year results, but there was a certain degree of increase.

[0065] Effects of different organic fertilizers on rice growth and development: The growth and development of rice is significantly affected by fertilizers. The application of chemical fertilizers can quickly provide the nutrients required for rice growth and development in the short term, but long-term application will reduce soil fertility, degrade quality, and deteriorate permeability, which will affect the depth of rice root development. Organic fertilizers can promote the growth of rice stems and tillers, increase leaf area index, and increase aboveground dry matter accumulation. Perennial positioning experiments have shown that the leaf area of ​​rice in red soil paddy fields with increased application of organic fertilizers has increased by nearly 47.0%, but there is a certain maturity cycle in the early stage of organic fertilizers. In the early stage of organic fertilizer application, there is a problem of insufficient nutrient supply for rice growth. In the early stage of growth after returning straw to the field, the SPAD value of rice leaves is lower than that of the non-returning treatment, but in the middle and late stages of growth, as the straw is fully decomposed, the SPAD value of the straw returning treatment is higher than that of the non-returning treatment. In the present invention, the early rice growth period of astragalus (early rice straw) is returned to the field, cake fertilizer, and stable manure treatment have no obvious effect on the growth promotion of rice leaves compared with the single application of chemical fertilizer treatment, but from the perspective of its leaf attenuation rate, each organic fertilizer treatment can effectively delay leaf senescence in the later stage, among which cake fertilizer treatment is more obvious, the main reason is that under the same nitrogen level, chemical fertilizer can quickly provide nutrients for rice growth, and organic fertilizer has a certain decomposition cycle in the early stage, especially the carbon-nitrogen ratio of early rice straw is large, and microorganisms must first fix soil nitrogen biologically before straw decomposition, and the nitrogen supply for early rice growth is lower than that of chemical fertilizer, and in the later stage of rice growth, organic fertilizer decomposes fully, can fully provide nutrients required for rice growth, and has a certain effect on alleviating leaf senescence and maintaining leaf chlorophyll content, so that the leaves maintain higher photosynthetic activity in the later stage. And the SPAD value also shows a similar rule, so that there are sufficient leaves for photosynthesis in the later stage, supplying more photosynthetic products for grain filling, improving the fruiting rate, and thus increasing rice yield. Biochar has certain advantages in promoting rice leaf growth in the early stage, but it has no obvious effect on delaying leaf senescence and alleviating the reduction of SPAD value, but it has obvious advantages in promoting rice dry matter accumulation. The main reason is that the main function of biochar is to improve the soil aggregate structure, promote the growth of rice roots, and then promote the early growth and rapid development of rice, but it itself has low nitrogen content and there is no effect of nitrogen backward movement. Compared with other organic fertilizer treatments, nitrogen is supplemented in the later stage, and the leaves age faster in the later stage.

[0066] Effects of different organic fertilizers on nitrogen accumulation in the aboveground part of double-season rice plants: The decomposition speed of organic fertilizer itself is divided into two stages, fast and slow, and the mineralization rate of organic nitrogen is significantly lower than that of organic carbon, so its residual rate is higher than that of organic carbon, which has a nitrogen backward shift effect, providing sufficient nitrogen for the later growth of rice. In the present invention, the nitrogen accumulation of the overall biochar and chemical fertilizer treatment plants is higher in the early stage, and the increase is less in the later stage. The reason is that there is sufficient nitrogen supply for rice growth in the early stage of chemical fertilizer treatment, which can effectively promote the early growth of rice. As the growth period of rice advances, the plant consumes and nutrients are lost, resulting in insufficient nitrogen supply in the later stage, so the advantage in yield is not as obvious as that of organic fertilizer treatment. Biochar itself is mainly carbon, so it has little effect on the nitrogen accumulation of rice. Astragalus (early rice straw) turning over and returning to the field, manure, and cake fertilizer show that the nitrogen accumulation of plants in the early stage is low, and the nitrogen absorption of plants in the later stage is high. The possible reason is that organic fertilizer has a decomposition cycle, and can fully provide the nitrogen required for rice growth in the later stage. Among them, the nitrogen accumulation and leaf area index of the whole growth period of early rice T4 treatment in 2017 were lower than those of T5 treatment, and the SPAD value of T4 to milky stage was higher than that of T5, and the leaf decay rate of T4 was slower than that of T5. Combined with the dry matter increase before and after T4 and T5 treatment, the possible reason is that T5 was early and fast in the early stage, and the stem and leaf growth advantage was more obvious than T4, but the soil fertilizer effect of T4 treatment was shifted later, and the SPAD value of rice leaves in the later stage was higher, aging was slower, and the functional period was long. More photosynthetic products can be accumulated in the later stage, and the nitrogen increase in the later stage is higher than that of T5 treatment. In terms of yield, T4 treatment is higher than T5 treatment. In the present invention, the total nitrogen accumulation of rice treated by organic fertilizer as a whole is higher than that of single fertilizer application. There are also certain differences between each organic fertilizer treatment. In the straw return field treatment, the nitrogen accumulation of plants in the early stage is relatively low, and its reason is that nitrogen fixation before straw decomposition supplies less nitrogen required for rice growth, so the nitrogen accumulation of plants in the early stage is relatively low. Among the treatments with manure and cake fertilizer, the advantage of manure on nitrogen accumulation in plants is more prominent.

[0067] The two-year positioning results of the experiment of the present invention show that, under the same nitrogen application level, partial replacement of chemical nitrogen fertilizer with organic fertilizer can promote rice growth and development to a certain extent, and the nitrogen accumulation of the plants in the later stage increases, which is further manifested as an increase in the fruit setting rate and an increase in yield to varying degrees; among them, the early rice is turned over and returned to the field with astragalus, and the late rice is treated with cake fertilizer and stable manure. The effect is obvious, which can be used as an effective measure to ensure stable and increased rice yields and improve soil fertility in the double-season rice areas with three-cropping system.

[0068] For matters not covered in the embodiments of the present invention, those skilled in the art can select from the prior art.

[0069] The above disclosure is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the above claims.

Claims

1. A method for increasing the yield of double-season rice based on partial replacement of basal fertilizer with organic fertilizer, characterized in that: The following steps are involved: In double-season rice cultivation, the base fertilizer used is a mixture of organic fertilizer and chemical nitrogen fertilizer; the tillering fertilizer and panicle fertilizer used are urea respectively; The mixing method is mixing astragalus with chemical nitrogen fertilizer, or mixing rice straw with chemical nitrogen fertilizer, or mixing biochar with chemical nitrogen fertilizer, or mixing manure with chemical nitrogen fertilizer, or mixing cake fertilizer with chemical nitrogen fertilizer; When the astragalus sinensis is mixed with the chemical nitrogen fertilizer, the application amount of the astragalus sinensis is 15 t / ha, the application amount of the chemical nitrogen fertilizer is 0.25 t / ha, and the nitrogen content of the astragalus sinensis is 3.2%; When the rice straw is mixed with the chemical nitrogen fertilizer, the application amount of the rice straw is 7.5 t / ha, the application amount of the chemical nitrogen fertilizer is 0.25 t / ha, and the nitrogen content of the rice straw is 0.81%; When the biochar is mixed with chemical nitrogen fertilizer, the application amount of the biochar is 15 t / ha, the application amount of the chemical nitrogen fertilizer is 0.5 t / ha, and the nitrogen content of the biochar is 1.99%; When the manure is mixed with chemical nitrogen fertilizer, the amount of manure applied is 7.5 t / ha, the amount of chemical nitrogen fertilizer applied is 0.25 t / ha, and the nitrogen content of the manure is 0.5%; When the cake fertilizer is mixed with the chemical nitrogen fertilizer, the application amount of the cake fertilizer is 1.5 t / ha, the application amount of the chemical nitrogen fertilizer is 0.25 t / ha, and the nitrogen content of the cake fertilizer is 3.15%; The application amount of the tillering fertilizer is 0.1 t / ha, the application amount of the ear fertilizer is 0.065 t / ha, and the chemical nitrogen fertilizer is a compound fertilizer with a mass ratio of N:P:K of 15:15:

15.

2. The method for increasing double-season rice yield according to claim 1, characterized in that: The double-season rice planting is double-season early rice planting or double-season late rice planting; In the double-season early rice planting, the base fertilizer applied is a mixture of organic fertilizer and chemical nitrogen fertilizer, which is any one of a mixture of astragalus and chemical nitrogen fertilizer, a mixture of biochar and chemical nitrogen fertilizer, a mixture of manure and chemical nitrogen fertilizer, and a mixture of cake fertilizer and chemical nitrogen fertilizer; In the double-season late rice planting, the base fertilizer applied is a mixture of organic fertilizer and chemical nitrogen fertilizer; the mixing method is any one of a mixture of rice straw and chemical nitrogen fertilizer, a mixture of biochar and chemical nitrogen fertilizer, a mixture of manure and chemical nitrogen fertilizer, and a mixture of cake fertilizer and chemical nitrogen fertilizer.

3. The method for increasing double-season rice yield according to claim 2, characterized in that: In the double-season early rice planting, the base fertilizer applied is a mixture of astragalus melastoma and chemical nitrogen fertilizer.

4. The method for increasing double-season rice yield according to claim 2 or 3, characterized in that: The early rice includes Zhongzao 39.

5. The method for increasing double-season rice yield according to claim 2, characterized in that: In the double-season late rice planting, the base fertilizer applied is a mixture of cake fertilizer and chemical nitrogen fertilizer, or a mixture of manure and chemical nitrogen fertilizer.

6. The method for increasing double-season rice yield according to claim 2 or 5, characterized in that: The late rice includes Hyou518.

7. The method for increasing double-season rice yield according to claim 1, characterized in that: The cake fertilizer is rapeseed cake fertilizer.

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