Method for measuring water consumption of test rice

Abstract

The invention discloses a test rice water consumption measuring method, and relates to the technical field of agricultural water saving, and the method comprises the following steps: before tests of different drought degrees in each growth period, transplanting rice into a test pot, after the drought degrees in each growth period are reached and a water layer exists in the test pot, using a measuring instrument to measure the water level of the test pot before and after two days, calculating daily water consumption by using a water consumption balance formula, weighing rice and wet soil by using an electronic platform scale in a fixed time every day when no water layer exists in the test pot, calculating the soil moisture content at the fixed time, supplementing water to the level of the soil moisture content in the previous day by using a measuring cylinder, and weighing the fresh weight of the randomly cut plants by using the electronic scale after each growth period is ended; calculating the fresh weight change coefficients of the rice in different stages, and obtaining the field water consumption of the rice according to the difference between the initial soil mass and the final soil mass, the water supplementing amount, the fresh weight change coefficients and the surface area of the test pot. The method is simple to operate, low in measurement cost and high in measurement precision, and can be widely applied to wide occasions in a large area.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural water saving, and in particular to a method for measuring water consumption of experimental rice. Background Art

[0002] Research on water consumption at various growth stages of rice has always been a hot topic in the field of rice water-saving technology. The feedback information provided by rice water consumption is usually used to guide irrigation or other research. Therefore, the acquisition of rice water consumption and the quantitative expression of its characteristics are of great significance to precision irrigation and sustainable development of rice farms.

[0003] At present, crop evapotranspiration is mainly obtained through two ways: model simulation and measurement. Many scholars at home and abroad have proposed a variety of models for estimating crop evapotranspiration, such as the PM model and Prierstley-Taylor model for calculating evapotranspiration on a daily time scale or even smaller scale, the Thornthwaite model for calculating evapotranspiration on a monthly scale, and the Penman-Monteith (PM) single-source model for calculating actual evapotranspiration under dense canopy conditions and the Shuttleworth-Wallace (SW) dual-source model under sparse canopy conditions. These models are relatively complex and require many parameters that are not easy to obtain, which has certain limitations on the application of the models. The methods for measuring crop evapotranspiration can be roughly summarized as hydrological methods, micrometeorological methods, plant physiological methods, remote sensing and telemetry methods, etc.

[0004] However, most of the current weighing measurement methods do not take into account the accumulation of dry matter in each growth stage of the crop, as well as the changes in fresh weight of the crop during the reproductive growth stage, which can easily lead to large errors in water consumption in each stage after measurement, and cannot be used for overall research on large-scale crops. Summary of the invention

[0005] The embodiment of the present invention provides a method for measuring water consumption of experimental rice, which can solve the problem of large error in the measured water consumption during the growth period in the prior art.

[0006] The present invention provides a method for measuring water consumption of rice, comprising the following steps:

[0007] Obtain the presence or absence of water layer in rice experimental pots;

[0008] When there is no water layer in the rice test pot:

[0009] Obtain the initial soil moisture content at the beginning of the rice growth stage; irrigate the rice at different growth stages so that the soil moisture content at a fixed time every day is consistent with the initial soil moisture content, and record the irrigation amount at a fixed time every day to calculate the irrigation amount at different growth stages;

[0010] At the end of the rice growth stage, the above-ground part of the rice is cut and weighed, and the underground part of the rice is weighed; and the coefficient of change of the fresh weight of rice at different growth stages is calculated by using the improved formula of the coefficient of change of the fresh weight of rice; the improved formula of the coefficient of change of the fresh weight of rice is as follows:

[0011]

[0012] Where: f represents the coefficient of variation of rice fresh weight during the growth stage; n represents the number of potted rice; m ag Represents the fresh weight of aboveground rice in the treatment group; m s represents the fresh weight of rice seedlings; α represents the ratio of the fresh weight of rice in the upper and lower parts of the control group. m ck-ug Represents the fresh weight of the underground part of the control group, m ck-ag Represents the fresh weight of above-ground parts;

[0013] According to the irrigation amount and the coefficient of change of rice fresh weight at different growth stages, the water consumption of rice at different growth stages is calculated by using an improved rice water consumption formula; the improved rice water consumption formula is as follows:

[0014]

[0015] Among them: ET i represents the field water consumption at the ith growth stage; m 0 Represents the initial potting soil weight; m t represents the weight of potted soil at the end of the growth stage; t represents the number of days of water stress during the growth stage; m i represents the irrigation amount in the ith growth stage; T i represents the number of days in the ith reproductive period; ρ w represents the density of water; S p Represents the area of ​​the potted plant.

[0016] Preferably, it also includes:

[0017] When there is a water layer in the rice test pot:

[0018] Obtain the water level of the test basin at the same time point on the previous day and the next day;

[0019] According to the water level of the previous day and the next day, the water consumption of rice on the next day is obtained through the water balance formula, and the water consumption of rice at different growth stages is calculated;

[0020] The water balance calculation formula is as follows:

[0021] h 1 +P+m i -EC=h 2

[0022] Where: h 1 represents the water level in the potted plant the day before; h 2 represents the water level in the potted plant the next day; P represents the rainfall in the period, when there is no rainfall, P = 0; C represents the drainage, when there is no drainage, C = 0; m i represents the irrigation amount; E represents the water consumption of rice the next day.

[0023] Preferably, the soil moisture content calculation formula is as follows:

[0024]

[0025] Where: m i represents the fresh weight of rice on day i; m s represents the fresh weight of rice seedlings; T i represents the number of days in the ith reproductive period; W v Represents the soil moisture content of the potted plant; m b Represents the weight of the potted plants the day before; m a represents the weight of the potted plant on the next day; Δmfi represents the fresh weight increase of rice on the i-th day; md represents the mass of dry soil in the potted plant; γd represents the capacity of the soil.

[0026] Preferably, the step of obtaining a water-free layer in a rice test pot comprises the following steps:

[0027] Select several rice plants of the same variety and place them in a test pot;

[0028] When conducting growth period experiments, observe whether there is a water layer in the rice test pots.

[0029] Preferably, the above-ground part of the rice and the underground part of the rice are weighed using an electronic scale with an accuracy of 0.0001g, and the weight of the potted plant and the weight of the soil in the potted plant are weighed using an electronic scale with an accuracy of 0.1g.

[0030] Preferably, the irrigation amount at different growth stages is measured using a measuring cup, and the irrigation amount is converted into mass by taking a fixed value based on the density of water.

[0031] The embodiment of the present invention provides a method for measuring water consumption of test rice, which has the following beneficial effects compared with the prior art:

[0032] This method takes into account the transpiration of rice plants, evaporation between plants and the water required by the plant itself, and focuses on the incremental change in rice fresh weight. The improved calculation method can be more accurate and directly use conditions such as the number of days, rice fresh weight change coefficient, carrier weight, and irrigation amount to directly calculate the overall water consumption of rice at each stage, thereby improving accuracy and reducing workload, providing a sufficient theoretical basis for large-scale rice cultivation and overall research. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the principle steps of a method for measuring water consumption of rice provided in an embodiment of the present invention;

[0034] Figure 2 A schematic diagram of the structure before the evapotranspiration experiment at each growth stage of a method for measuring water consumption of rice provided in an embodiment of the present invention;

[0035] Figure 3 A schematic diagram of the structure of water level measurement before evapotranspiration experiment in each growth period of a method for determining water consumption of rice provided in an embodiment of the present invention;

[0036] FIG4 is an operation process diagram of an evapotranspiration test in each growth period of a method for measuring water consumption of rice provided in an embodiment of the present invention, wherein: FIG4(a) is an operation process diagram of the previous day in the evapotranspiration test in each growth period; FIG4(b) is an operation process diagram of the second day in the evapotranspiration test in each growth period;

[0037] FIG5 is an operation process diagram of a method for measuring water consumption of rice provided in an embodiment of the present invention after evapotranspiration test at each growth period, wherein: 5(a) is a schematic diagram after evapotranspiration test at each growth period; 5(b) is a schematic diagram of cutting the part above the soil surface of the rice paddy for weighing;

[0038] Figure 6 A schematic diagram of the structure of a test pot for testing a method for measuring water consumption of rice provided in an embodiment of the present invention;

[0039] Figure 7 A schematic structural diagram of a mudguard for testing a method for measuring water consumption of rice provided in an embodiment of the present invention.

[0040] Among them: 1. mudguard, 2. test pot, 3. test rice, 31. the part of the test rice above the soil surface, 32. the part of the test rice below the soil surface, 4. electronic platform scale (50kg / 0.1g), 5. measuring cup, 6. electronic scale (accuracy of 0.001g), 7. ruler. DETAILED DESCRIPTION

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0042] See also Figure 1 As shown, the embodiment of the present invention provides a method for measuring water consumption of experimental rice, comprising the following steps:

[0043] Before conducting water consumption experiments at different growth stages (tillering stage, jointing and booting stage, heading and flowering stage, and milky stage) with different drought degrees (soil moisture content of light drought is 70%, soil moisture content of moderate drought is 60%, soil moisture content of severe drought is 50%, and soil moisture content of extreme drought is 40%), the rice seedlings were transplanted into soil with saturated moisture content, the whole plant was transplanted into a sealed test pot, and the test pot was placed in the test field.

[0044] When conducting water consumption experiments at different drought levels in different growth stages, after reaching the drought level, when there is a water layer on the field surface, use a steel ruler to measure the water level of the test pot two days before and after, and use the water balance formula to calculate the daily water consumption; when there is no water layer on the field surface, use an electronic scale 4 to weigh the rice and humidified soil at a fixed time every day, calculate the soil moisture content at the fixed time, and use a measuring cup 5 to add water to the soil moisture level of the previous day and record it.

[0045] After conducting water consumption tests at different drought levels at different growth stages, randomly cut the rice plant above the soil 31 in the test pot and place it on an electronic scale 6 to weigh the plant fresh weight, and calculate the coefficient of change of rice fresh weight at different growth stages λ f , combined with the difference in wet soil quality at the beginning and end of the test (m 0 -m t ), water volume of measuring cup m i , fresh weight variation coefficient λ f And the inner surface area of ​​the pot cm 2 , calculate the field water consumption after the introduction of changes in rice fresh weight.

[0046] The water balance formula is used to calculate daily water consumption without considering infiltration and rainfall. The specific water balance formula is as follows:

[0047] h 1 +P+m i -EC=h 2

[0048] Where: h 1 represents the water level in the potted plant the previous day (mm); h 2represents the water level in the potted plant the next day (mm); P represents the rainfall in the period (mm) and P = 0; C represents the drainage in the period (mm) and C = 0; m i Irrigation volume during the period (mm); E represents field water consumption during the period (mm).

[0049] After the soil moisture content is calculated, add water to the level of the previous day and record it. The specific soil moisture content calculation formula is as follows:

[0050]

[0051] Where: W v Represents the soil moisture content of potted plants (%); m b represents the weight of the potted plant the day before (g); m a Represents the weight of the potted plant the next day (g); Δm fi Rice fresh weight increment on day i (g); m d represents the mass of dry soil in the pot (g); γ d Represents the volume of soil (g / cm 3 ).

[0052] After weighing the fresh weight of the plants, the coefficient of change of rice fresh weight at different waterlogging degrees in each growth period was calculated. The specific calculation formula for the coefficient of change of rice fresh weight at different water stress degrees in each growth period is as follows:

[0053]

[0054] Where: m i represents the fresh weight of rice on day i (g); m s represents the fresh weight of rice seedlings (g); T i represents the number of days in the ith growth period (d); λ f represents the coefficient of variation of fresh weight during the growth period; n represents the number of potted rice plants i (plants); m ag represents the fresh weight of the aboveground rice in the treatment group (g); α represents the fresh weight ratio of the aboveground and belowground rice in the control group (where m ck-ug represents the fresh weight of underground part of the control group (g), m ck-ag Represents the fresh weight of above-ground parts (g).

[0055] After introducing the change in rice fresh weight, the field water consumption was calculated. The specific calculation formula for field water consumption at different water stress levels in each growth period is as follows:

[0056]

[0057] Among them: ET i represents the field water consumption in the ith growth period (mm); m 0represents the initial potting soil weight (g); m t represents the weight of potted soil at the end of the growth stage (g); t represents the number of days of water stress during the growth period (d); m i represents the mass of the i-th irrigation (g); ρ w Represents the density of water, with a fixed value of 1.0g / cm 3 ; S p Represents the area of ​​the pot (cm 2 ).

[0058] The research area of ​​this embodiment was conducted in Jiangxi Irrigation Experiment Center (N38°39′27.97″, E104°04′58.66″), and the fresh weight of the aboveground and underground parts of rice at tillering stage (TL, TM, TS, TE), jointing and booting stage (BL, BM, BS, BE), heading development stage (FL, FM, FS, FE), milky stage (ML, MM, MS, ME) and treatments (CK, CM) were measured respectively. The changes in fresh weight at different growth stages are shown in the following table:

[0059] Table 1 Calculation table of fresh weight variation coefficients in different growth stages of rice pot experiment

[0060]

[0061]

[0062] like Figures 2 to 7 As shown, an embodiment of the present invention provides a method for measuring water consumption of experimental rice, and the measuring steps are as follows:

[0063] Before the water consumption test at different growth stages (tillering stage, jointing and booting stage, heading and flowering stage, and milky stage) with different drought degrees (soil moisture content of 70% for light drought, 60% for moderate drought, 50% for severe drought, and 40% for extreme drought), the rice seedlings 3 were transplanted into an experimental pot 2 with saturated moisture content. The experimental pot 2 was in a sealed state, and a mud guard 1 was provided at the bottom of the experimental pot 2. After the transplanting was completed, the experimental pot 2 was placed in the experimental field.

[0064] When conducting water consumption tests at different drought levels in different growth stages, when the drought level is reached, when there is a water layer on the field surface, use a steel ruler to measure the water level of the potted plants two days before and after, and use the water balance formula to calculate the daily water consumption; when there is no water layer on the field surface, place the experimental pots on an electronic scale 4 at a fixed time every day, weigh the rice 3 and the humidified soil, calculate the soil moisture content at the fixed time, and use a measuring cylinder 5 to add water to the moisture content of the previous day and record it.

[0065] After conducting the water consumption test at different growth stages under different drought conditions, randomly cut the rice above the soil 31 in the experimental pot 2 and place it on the electronic scale 6 to weigh the fresh weight of the plant and calculate the coefficient of change of the fresh weight of rice at different growth stages λf , combined with the difference in wet soil quality at the beginning and end of the test (m 0 -m i ), water volume of measuring cup m i , fresh weight variation coefficient λ f And the inner surface area of ​​the pot cm 2 , calculate the field water consumption after the introduction of changes in rice fresh weight.

[0066] The rice growth period in this experiment is divided into tillering period (June 28-August 2), jointing and booting period (August 3-August 26), heading and flowering period (August 27-September 7), and milky period (September 8-September 20). i The drought duration n in this experiment was 3 days, and the inner surface area of ​​the pot was 1200.0 cm 2 The coefficient of variation of rice fresh weight in each growth period is shown in Table 1. The amount of water in each growth stage (m i ) and the difference between the initial and final wet soil mass of the test (m 0 -m t ) are shown in Table 2 below:

[0067] Table 2 Irrigation amount and initial and final wet soil quality difference at different growth stages of rice pot experiment

[0068]

[0069] The calculation period is the tillering period of rice. The control treatment (CK) and drought treatment (CM) are calculated respectively. The initial conditions are known. i =36d, t=3d, S p =1200cm 2 According to Tables 1 and 2, we know that f-ck is 9.945, f-cm is 4.748, (m 0 -m t ) ck is 10.094kg, (m 0 -m t ) cm 5.378kg, (m i ) ck 51.920kg, (m i ) cm The weight is 35.781 kg. Substituting these known conditions into the formula for calculation, we can get:

[0070]

[0071]

[0072] According to the above calculation results, the water consumption of the control treatment (CK) and the drought treatment (CM) during the tillering period was 516.777 mm and 342.989 mm respectively. The same calculation method was used to bring the above parameters of the remaining growth periods into the formula to calculate the water consumption. The calculation results are shown in Table 3:

[0073] Table 3 Calculation results of water consumption during the growth period of rice pot experiment

[0074]

[0075] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for measuring water consumption of experimental rice, characterized in that: The following steps are involved: Obtain the presence or absence of water layer in rice experimental pots; When there is no water layer in the rice test pot: Obtain the initial soil moisture content at the beginning of the rice growth stage; irrigate the rice at different growth stages so that the soil moisture content at a fixed time every day is consistent with the initial soil moisture content, and record the irrigation amount at a fixed time every day to calculate the irrigation amount at different growth stages; At the end of the rice growth stage, the above-ground part of the rice is cut and weighed, and the underground part of the rice is weighed; and the coefficient of change of the fresh weight of rice at different growth stages is calculated by using the improved formula of the coefficient of change of the fresh weight of rice; the improved formula of the coefficient of change of the fresh weight of rice is as follows: Where: f represents the coefficient of variation of rice fresh weight during the growth stage; n represents the number of potted rice; m ag Represents the fresh weight of aboveground rice in the treatment group; m s represents the fresh weight of rice seedlings; α represents the ratio of the fresh weight of rice in the upper and lower parts of the control group. m ck-ug Represents the fresh weight of the underground part of the control group, m ck-ag Represents the fresh weight of above-ground parts; According to the irrigation amount and the coefficient of change of rice fresh weight at different growth stages, the water consumption of rice at different growth stages is calculated by using an improved rice water consumption formula; the improved rice water consumption formula is as follows: Among them: ET i represents the field water consumption at the i-th growth stage; m0 represents the initial pot soil weight; m t represents the weight of potted soil at the end of the growth stage; t represents the number of days of water stress during the growth stage; m i represents the irrigation amount in the ith growth stage; T i represents the number of days in the ith reproductive period; ρ w represents the density of water; S p Represents the area of ​​the potted plant.

2. The method for determining water consumption of rice according to claim 1, characterized in that: Also includes: When there is a water layer in the rice test pot: Obtain the water level of the test basin at the same time point on the previous day and the next day; According to the water level of the previous day and the next day, the water consumption of rice on the next day is obtained through the water balance formula, and the water consumption of rice at different growth stages is calculated; The water balance calculation formula is as follows: h1+P+m i -E-C=h2 Where: h1 represents the water level in the potted plant on the previous day; h2 represents the water level in the potted plant on the next day; P represents the rainfall in the period, when there is no rainfall, P = 0; C represents the drainage, when there is no drainage, C = 0; m i represents the irrigation amount; E represents the water consumption of rice the next day.

3. The method for determining water consumption of rice according to claim 1, characterized in that: The soil moisture calculation formula is as follows: Where: m i represents the fresh weight of rice on day i; m s represents the fresh weight of rice seedlings; T i represents the number of days in the ith reproductive period; W v Represents the soil moisture content of the potted plant; m b Represents the weight of the potted plants the day before; m a Represents the weight of the potted plant the next day; Δm fi The fresh weight increment of rice on the i-th day; m d Represents the mass of dry soil in the pot; γ d Represents the capacity of the soil.

4. The method for determining water consumption of rice according to claim 1, characterized in that: The method of obtaining whether the rice test pot plant has a water layer comprises the following steps: Select several rice plants of the same variety and place them in a test pot; When conducting growth period experiments, observe whether there is a water layer in the rice test pots.

5. The method for determining water consumption of rice according to claim 1, characterized in that: The above-ground part of the rice and the underground part of the rice are weighed using an electronic scale with an accuracy of 0.0001g, and the weight of the potted plant and the weight of the soil in the potted plant are weighed using an electronic scale with an accuracy of 0.1g.

6. The method for determining water consumption of rice according to claim 1, characterized in that: The irrigation amount at different growth stages is measured using a measuring cup, and the irrigation amount is converted into mass after taking a fixed value based on the density of water.

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