CN1631098A - Insufficient irrigation forecast and control method - Google Patents

Abstract

The invention discloses an insufficient irrigation forecast and control method which consists of, determining crop objects, calling crop growth cycle L, divided growth phase, water requirement for crops at each phase and degree of priority of water demand from system data base, determining the zone and its size executed by the non-sufficient irrigation, calling the zone's soil and meteorological data, calculating each phase's maximum evaporating value ET[mi], determining the current water supply amount W[i], the current soil moisture content theta [i], calculating the water demand amount of the crop in phase I, utilizing a storage model to calculate the optimum water filling amount m[10] of the crop in phase I, irrigation predetermined amount M[0] and optimum water filling cycle t[0], transforming the calculated m[10], M[0] and t[0] into control value to special irrigation device controller.

Description

A kind of insufficient irrigation forecast and control method

Technical field

The present invention relates to the forecast control method that irrigation and water conservancy is irrigated, relate in particular to a kind of insufficient irrigation forecast and control method.The present invention is according to the concrete condition of zones of different, input by relevant parameter, according to insufficient irrigation technical indicator system, provide the forecast of regional agriculture water and the regional agriculture water is carried out certain adjusting and control according to this forecast, belong to the farmland water conservancy works field.

Background technology

Though China is a resource big country, because water is few per capita, factors such as water region imbalance make agricultural water-saving irrigation become an important breakthrough mouth of current agricultural production and even whole national economy development.Insufficient irrigation is meant when water resource is not enough to satisfy crop and generates required abundant water, a kind of irrigation program of existing water resource being carried out optimum allocation.When the water resource deficiency, in the time of can only adopting insufficient irrigation, how (Different Crop, different regions etc.) reasonably distribute limited duty on time (the different vegetative stages of crop) and space, to obtain the highest output or income, the underproduction loss that lack of water is caused is minimum, is one of problem of carrying out most critical in the insufficient irrigation.Theory, the technology of insufficient irrigation are combined, then the final purpose and the meaning of the abundant irrigation technique research of right and wrong with actual.

Though currently in the insufficient irrigation theoretical research, obtained many achievements, mainly be confined to angle qualitatively, be a kind of discussion of imperfect irrigation program.Therefore, these achievements in research obviously can not satisfy " deciding water to produce " or " with the water fixed output quota " that proposes in the irrigation management, drop into the water yield and the output that can gather in the crops between the quantitative relationship requirement; Or water distributes the quantitative requirement between the change of production that causes at different times.

Summary of the invention

The technical problem to be solved in the present invention is, at the deficiencies in the prior art, a kind of insufficient irrigation forecast and control method are proposed, need water index according to the different regions Different Crop, in conjunction with locality actual conditions then, provide insufficient irrigation forecast and control index, in order to the guiding agricultural production water or directly control the operation of this ground irrigation installation.

Technical problem to be solved by this invention is achieved by the following technical solution:

A kind of insufficient irrigation forecast and control method, this method comprises the steps:

Step 1: according to the crop object of determining, from system database, call the plant growth period L, divide vegetative stage, per stage water demand of crop V _iAnd need water degree of priority λ _iEtc. related data;

Step 2: determine zone and area size that insufficient irrigation is carried out, from system database, call this regional soil, meteorological data, comprise rainfall R _i, temperature T _i, soil types T _s, bulk density of soil ρ, field capacity h etc.;

Step 3: calculate maximum transpiration quantity ET of each stage _Mi

Step 4: determine current available water W _i, current soil soil moisture content θ _i

Step 5: calculate crop in i stage water requirement; Adopt inventory model, calculate this crop at best irrigating water quota m of i stage ₁₀, irrigation norm M ₀, and the best t irrigation frequency ₀

Step 6: will calculate m ₁₀, M ₀, t ₀Change into controlled quentity controlled variable and export to special-purpose irrigation installation controller.

Aforesaid method after the described step 6, is returned the available water that step 4 is calculated next stage, irrigates the back soil moisture content; Finish until all stages.

Aforesaid method also comprises, calculates the crop failure ratio according to following model;

$\frac{Y_a}{Y_m}=\underset{i=1}{\overset{n}{\mathrm{\Π}}}{\left(\frac{{\mathrm{ET}}_{\mathrm{ai}}}{{\mathrm{ET}}_{\mathrm{mi}}}\right)}^{{\mathrm{\λ}}_i}$

In the formula:

N is the number of dividing in the stage;

λ _iIt is i stage lack of water Sensitivity Index;

Ya is the crop actual production, kg/ mu or t/hm2;

Ym is the crop potential production, kg/ mu or t/hm2;

ETai is the actual transpiration quantity in i stage, mm/d or m3/ (mu d);

ETmi is the potential transpiration quantity in i stage, mm/d or m3/ (mu d).

The present invention is used for agricultural production, make the insufficient irrigation technology become possibility in the first-line practical application of agricultural production, accurately prediction the crop underproduction degree that may occur in water-stressed conditions, for carrying out of various work prepared sufficient information and time.The present invention can PDA be the hardware implementation platform, volume is little, easy to carry, have simple to operate, multiple functional, advantage such as adaptability is strong is fit to the technical staff and administrative staff's use of agricultural production one line, provide information and decision-making foundation accurately for it instructs industrial water, have vast market prospect.

Description of drawings

Fig. 1 is the flow chart of the method for the invention.

Embodiment

Below in conjunction with the drawings and specific embodiments technical scheme of the present invention is described in detail.

The present invention lays particular emphasis on the quantity of output and Relationship with Yield and expresses, and proposes a cover complete insufficient irrigation forecast and control method, and can calculate the different harvest fluctuations that cause of different growing water supply.The management objectives that are " with the water fixed output quota " or " deciding water to produce " are implemented, so the water yield full vegetative period distribute change with the output RESPONSE CALCULATION provide may with facility.

Technical scheme of the present invention as shown in Figure 1, this method comprises the steps:

With portable digital device, for example: PDA is a platform, is the insufficient irrigation forecast control method of core with the forecast of regional farmland insufficient irrigation water with control system, is divided into several steps:

Step 1: determine the crop object, such as wheat, corn, cotton etc.;

Step 2:, from system database, call plant growth period L, vegetative stage division (I stage altogether), per stage water demand of crop V according to the crop object of determining _iAnd need water degree of priority λ _iEtc. related data;

Step 3: determine zone and area size that insufficient irrigation is carried out;

Step 4: according to determined zone, from system database, call this regional soil, meteorological data, comprise rainfall R _i, temperature T _i, soil types T _s, bulk density of soil ρ, field capacity h etc.;

Step 5: according to crop and area information, determine the parameter of mathematical model, promptly calculate maximum transpiration quantity ET of each stage _Mi

Formula: ET is adopted in the calculating of maximum transpiration quantity _m=K _cET ₀

In the formula: K _cBe crop coefficient, ET ₀Utilize the Penman-Monteith formula to calculate,

${\mathrm{ET}}_0=\frac{0.408\mathrm{\Δ}(R_n-G)+\mathrm{\γ}\frac{900}{T+273}{U}_2(e_s-e_d)}{\mathrm{\Δ}+\mathrm{\γ}(1+{0.34U}_2)}$

Wherein: ET ₀Be reference crop water requirement (mm/d), R _nBe crop surface net radiation amount (MJ/m2d), G is soil heat flux (MJ/m2d), and Δ is saturation vapour pressure and temperature relation slope of a curve (kPa/ ℃), and γ is moisture meter constant (kPa/ a ℃), and T is an average temperature of air, with degree centigrade (℃) expression, U ₂Be the wind speed (m/s) of above 2m eminence, e on ground _sBe saturation of the air vapour pressure (kPa), e _dFor the air actual vapor is pressed (kPa);

Step 6: determine current out of Memory, comprise current available water W _i, current soil soil moisture content θ _i

The current soil soil moisture content adopts instrument directly to measure or uses formula:

${10\mathrm{\γH\θ}}_t=10\mathrm{\γ}{\mathrm{H\θ}}_0+\underset{0}{\overset{t}{\mathrm{\Σ}}}{P}_0+\underset{0}{\overset{t}{\mathrm{\Σ}}}\mathrm{\βET}$

In the formula, θ _tBe average soil moisture content in the t day crop root water accepting layer (degree of depth is H) (accounting for) in the heavy % of soil, down together; θ ₀Be the first soil moisture content of forecasting period; P ₀Be effective precipitation (mm); β=1-k/100, k are recharge of ground water coefficient (%), the dry density of soil in the γ plan wettable layer, t/m3;

Step 7:, calculate crop at i stage water requirement (i from 1 to I) according to above information.Adopt inventory model, the information that provides according to step 2, four, six is the model input parameter, calculates this crop at best irrigating water quota m of i stage ₁₀, irrigation norm M ₀, and the best t irrigation frequency ₀

Step 8: calculating m ₁₀, M ₀, t ₀After, this information is shown to the technical staff, instruct it carry out to irrigate, or change into controlled quentity controlled variable and export to special-purpose irrigation installation controller;

Best irrigation norm calculates and adopts formula: m=10 γ H (θ _Max-θ _Min)

θ wherein _MinBe the minimum moisture content that crop allows, θ _MaxThe high-moisture percentage that allows for crop.

Calculate best irrigation frequency and adopt formula: ${10\mathrm{\γH\θ}}_t=10\mathrm{\γH}{\mathrm{\θ}}_0+\underset{0}{\overset{t}{\mathrm{\Σ}}}{P}_0+\underset{0}{\overset{t}{\mathrm{\Σ}}}\mathrm{\βET},$ Work as θ _tDrop to θ _MinDate be the best and pour water the phase;

Step 9: calculate after executing this stage insufficient irrigation, calculate the available water W of next stage _I+1, irrigate back soil moisture content θ _I+1

Step 10: turn to next stage, continue execution in step seven, finish until all stages;

Step 11: calculate the crop failure ratio according to following model;

The model of this method: $\frac{Y_a}{Y_m}=\underset{i=1}{\overset{n}{\mathrm{\Π}}}{\left(\frac{{\mathrm{ET}}_{\mathrm{ai}}}{{\mathrm{ET}}_{\mathrm{mi}}}\right)}^{{\mathrm{\λ}}_i}$

In the formula: the number that the n stage divides;

λ _iI stage lack of water Sensitivity Index, the size of this value reflect the underproduction degree that causes after this stage lack of water, i.e. λ _iBe worth greatly more, underproduction rate is big more;

Ya crop actual production, kg/ mu or t/hm2;

Ym crop potential production, kg/ mu or t/hm2;

The actual transpiration quantity in ETai i stage, mm/d or m3/ (mu d);

The potential transpiration quantity in ETmi i stage, mm/d or m3/ (mu d).

To 2002 inclined to one side years of drought in arid and semi-arid area, North China, utilize testing data, formulate the irrigation strategy of winter wheat in breeding time.Experiment station's soil is light loam, unit weight 1.395g/cm, field specific retention 19.8% (it is heavy to account for dry ground).During calculated with mathematical model, at first calculate maximum transpiration quantity of each stage, and then carry out the water yield and distribute according to meteorological data.Now carry out water yield allocation optimized respectively by inventory model, result of calculation sees the following form.As can be seen from the table, the key water of winter wheat is jointing～heading～pustulation period, when water shortage, at first supplies with this two stage waters, obtains the output of maximum maximum to guarantee crop.

Growing stage sows～tillers～turns green～jointing jointing～heading heading～grouting grouting～maturation
	Plan depth of wetted soil (m) 0.5 0.7 0.8 1.0 1.2 1.2 Sensitivity Indexs, 0.0994 0.0406 0.0370 0.2896 0.2089 0.001 rainfalls (mm) 25.7 36.6 8.3 2.9 2.1 41.7 increments of groundwater 0.0 0.0 0.0 0.0 0.0 0.0 (m3/hm 2)
Can distribute the water yield) 300 300 (m 3/hm 2)?????600?????????????????????????????????300?????????300 ????????????????900?????????????????????300?????????300?????????300 ????????????????1200????????????????????300?????????300+300?????300 ????????????????1500????????????????????300+300?????300+300?????300

It should be noted last that: above embodiment is the unrestricted technical scheme of the present invention in order to explanation only, although the present invention is had been described in detail with reference to the foregoing description, those of ordinary skill in the art is to be understood that: still can make amendment or be equal to replacement the present invention, and not breaking away from any modification or partial replacement of the spirit and scope of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (3)

1, a kind of insufficient irrigation forecast and control method, it is characterized in that: this method comprises the steps:

Step 1: according to the crop object of determining, from system database, call the plant growth period L, divide vegetative stage, per stage water demand of crop V _iAnd need water degree of priority λ _iEtc. related data;

Step 2: determine zone and area size that insufficient irrigation is carried out, from system database, call this regional soil, meteorological data, comprise rainfall R _l, temperature T _l, soil types T _s, bulk density of soil ρ, field capacity h etc.;

Step 3: calculate maximum transpiration quantity ET of each stage _Mi

Formula: ET is adopted in the calculating of maximum transpiration quantity _m=K _cET ₀

In the formula: K _cBe crop coefficient, ET ₀Utilize following formula to calculate,

${\mathrm{ET}}_0=\frac{0.408\mathrm{\Δ}(R_n-G)+\mathrm{\γ}\frac{900}{T+273}{U}_2(e_s-e_d)}{\mathrm{\Δ}+\mathrm{\γ}(1+0.34U_2)}$

Wherein: ET ₀Be reference crop water requirement (mm/d), R _nBe crop surface net radiation amount (MJ/m2d), G is soil heat flux (MJ/m2d), and Δ is saturation vapour pressure and temperature relation slope of a curve (kPa/ ℃), and γ is moisture meter constant (kPa/ a ℃), and T is an average temperature of air, with degree centigrade (℃) expression, U ₂Be the wind speed (m/s) of above 2m eminence, e on ground _sBe saturation of the air vapour pressure (kPa), e _dFor the air actual vapor is pressed (kPa);

Step 4: determine current available water W _i, current soil soil moisture content θ _t

The current soil soil moisture content adopts instrument directly to measure or uses formula:

$10\mathrm{\γH}{\mathrm{\θ}}_t=10\mathrm{\γH}{\mathrm{\θ}}_0+\underset{0}{\overset{t}{\mathrm{\Σ}}}{P}_0+\underset{0}{\overset{t}{\mathrm{\Σ}}}\mathrm{\βET}$

In the formula, θ _tBe average soil moisture content in the t day crop root water accepting layer (degree of depth is H) (accounting for) in the heavy % of soil, down together; θ ₀Be the first soil moisture content of forecasting period; P ₀Be effective precipitation (mm); β=1-k/100, k are recharge of ground water coefficient (%), the dry density of soil in the γ plan wettable layer, t/m3;

Step 5: calculate crop in i stage water requirement; Adopt inventory model, calculate this crop at best irrigating water quota m of i stage ₁₀, irrigation norm M ₀, and the best t irrigation frequency ₀

Best irrigation norm calculates and adopts formula: m=10 γ H (θ _Max-θ _Min)

θ wherein _MinBe the minimum moisture content that crop allows, θ _MaxThe high-moisture percentage that allows for crop.Calculate best irrigation frequency and adopt formula: $10\mathrm{\γH}{{\mathrm{\θ}}_t=10\mathrm{\γH\θ}}_0+\underset{0}{\overset{t}{\mathrm{\Σ}}}{P}_0+\underset{0}{\overset{t}{\mathrm{\Σ}}}\mathrm{\βET},$ Work as θ _tDrop to θ _MinDate be the best and pour water the phase;

Step 6: will calculate m ₁₀, M ₀, t ₀Change into controlled quentity controlled variable and export to special-purpose irrigation installation controller.

2, insufficient irrigation forecast according to claim 1 and control method is characterized in that: after the described step 6, return the available water that step 4 is calculated next stage, irrigate the back soil moisture content; Finish until all stages.

3, insufficient irrigation forecast according to claim 1 and 2 and control method, it is characterized in that: described method also comprises, calculates the crop failure ratio according to following model:

$\frac{Y_a}{Y_m}=\underset{i=1}{\overset{n}{\mathrm{\Π}}}{\left(\frac{{\mathrm{ET}}_{\mathrm{ai}}}{{\mathrm{ET}}_{\mathrm{mi}}}\right)}^{{\mathrm{\λ}}_i}$

In the formula:

N is the number of dividing in the stage;

λ _iIt is i stage lack of water Sensitivity Index;

Ya is the crop actual production, kg/ mu or t/hm2;

Ym is the crop potential production, kg/ mu or t/hm2;

ETai is the actual transpiration quantity in i stage, mm/d or m3/ (mu d);

ETmi is the potential transpiration quantity in i stage, mm/d or m3/ (mu d).

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