UA144098U - METHOD OF DETERMINATION OF WATERING TIME BY DAILY SOIL MOISTURE STOCKS - Google Patents

Abstract

The method of determining the term of irrigation on the daily reserves of soil moisture (W) under crops includes a set of actions for daily calculation on a PC of a complex indicator of previous weather conditions (P), namely: the total daily weighted precipitation (hD), the amount of average daily air temperature for the period from the date of sowing or restoration of vegetation to the estimated date (t1, ° C), the amount of average daily humidity deficit for the period from the date of transition of average daily air temperature through +5 ° C in autumn in the previous year to the estimated date ((d, mb The date of irrigation is set when the calculated daily values of moisture reserves fall below the natural pre-irrigation threshold of moisture reserves.

Description

The useful model belongs to agricultural crops and, in particular, concerns methods of determining soil moisture reserves when prescribing irrigation of agricultural crops using monitoring of agroclimatic indicators of meteorological stations closest to the field.

There is a known method of determining soil moisture reserves by the thermostatic weight method.

The disadvantage of the method is the significant expenditure of resources and the delay in determining the amount of moisture for 2-3 days.

The proposed method of determining the watering period based on daily soil moisture reserves does not have the above-mentioned disadvantages and is the closest to a useful model in terms of achieving the desired result.

The purpose of the useful model is to improve the process of determining soil moisture reserves and increase the efficiency and accuracy of irrigation timing due to the use of monitoring meteorological indicators of weather stations closest to the field.

This goal is achieved by choosing empirical parameters (a, b and c) for the selected agricultural crop and estimated soil layer based on the monitoring of weather observations at the nearest weather station (Table 1).

Table 1

Empirical parameters of formula (3) for corn and spring barley

Agricultural crop, soil layer (cm) corn

Weather station 0-100 0-100 a|rv|i|s/|a|rv|s a|j|s a || with

ashes | 61 |348|178| 95 337) 340| 69 / 126 | 162 | 125 | 166 | 297 (Melitopol | 85 | 327 |162|144 337) 310| 79 96 | 167 | 149 | 96 | 326

Berezanka | 95 | 382|168|152 434| 313) 87 103 172 | 147 | 98 | 327

Odesa | 72 |476|157|120 475) 314) 80 | 141 | 164 | 133 | 168,316

The sum of the average daily deficits of air humidity (ha) for the period preceding the date of determination is found from the date of transition of the average daily air temperature through 5 C above the previous year to the calculation date. The sums of time-weighted atmospheric precipitation "9 are calculated according to formula (2), and the sums of effective temperatures (ha) are taken into account during the transition

In ХУ due to the biological minimum in the spring of the calculation year. In formula (2) 1 and C, etc. - the sum of p

The amount of precipitation, respectively, for the first and second, third - tenth, etc. days before the calculation date, and 71 - the sum of atmospheric precipitation from the date of transition of the average daily air temperature through 5 "C in autumn to the date that ends 51 days before the calculation date , mm.

Daily soil moisture reserves in the calculated soil layer (MM) are determined by formula (3) depending on the complex indicator of previous weather conditions, which is calculated by formula (1):

Coo)

r 1000la ha(x ; (1) 2 10 20 30 40 50 p pa - Ul; OVU y; obu; odu y; -0OZU y; 02 Ul; Ou Ya, 1 3 TV 21 31 A1 51 , (g)

In -c-aechr(-b P) and (3)

Calculated (for each day) values of soil moisture reserves are compared with permissible (pre-irrigation or minimum) moisture reserves for the selected agricultural crop and irrigation is prescribed on the day when the calculated moisture reserves are less than permissible.

The irrigation rate applied to the field is taken into account in formula (2) as atmospheric precipitation.

Example. According to the monitoring of the data of the meteorological indicators of the Velikoy Alexandrov Meteorological Station for 2018, the amount of time-weighted precipitation 9 calculated according to the formula - on May 22 is 28.5 mm, the sum of the daily air humidity deficits is 6236 mb, the sum of the effective temperatures is up to 316, "С , then the complex indicator of previous weather conditions is calculated according to (1) RT,

Hence, according to formula (3), the calculated moisture reserves // 7297-114 ехр 544-143) 250 m exceed the permissible moisture reserves at 70 9o of the lowest moisture capacity, which for southern low-humus chernozems in a meter-long soil layer are (331770)/100-5231.7 mm, which indicates no need for watering. Similarly, for each day of vegetation, moisture reserves were calculated and compared with the permissible ones (Table 2). At the end of the decade, that is, on May 29, the calculated moisture reserves pass through the allowable (pre-irrigation) reserves, which means that on May 30, the first irrigation of corn must be carried out.

Table 2

The results of comparing the calculated soil moisture reserves with the allowable ones in the corn fields near the Velyka Oleksandrivka weather station in 2018.

KPPPU PYHI PESEN POS I POOLOS NYA PO SONNYA PO NIN KON 22.05.2018 623.6 316.2 1,443 245.0 231.7 23.05.2018 637.0 328.4 1,363 242.7 231.7 24.05.2018 647.8 340.7 1,294 240.6 231.7 05/25/2018 661.3 353.2 1,223 238.4 231.7 05/26/2018 670.7 362.6 1,163 236.5 231.7 05/27/2018 684.4 37 0 1,099 234.3 231.7 05/28/2018 700.1 379.9 1,037 232.1 231.7 05/29/2018 715.8 390.4 0.077 230.0 231.7 05/30/2018 731.0 4,902.3 0 228.0 231.7 -1 17 1

Therefore, the application of the proposed method of determining the daily soil moisture reserves for the purpose of irrigation ensures prompt and timely implementation and improvement of the process of determining soil moisture reserves and can be recommended for the purpose of determining the timing of irrigation of agricultural crops in the steppe and forest-steppe of Ukraine.

Sources of information: 1. Recommendations on operational control and management of the water regime of soils on irrigated lands using tensiometers / Romashchenko M.I., Koryunenko V.M., Muromtsev

From M.M. - K.: IHIM of the Ukrainian Academy of Sciences, 2007. - 24 p. 2. Lytovchenko A.F. Regime and calculation of soil moisture in the mountains of Zailiysky Alatau.

The issue of hydrology of mountain districts. Alma-Ata, 1971. P. 172-189. 3. Lytovchenko A.F., Dotsenko V.Y., Rudakov L.N., Tkachuk A.V. The selection of the observed period for calculating the norm of soil moisture reserves under crops of agricultural crops in

The steppe zone of Ukraine // Bulletin of the Dnipropetrovsk State Agrarian University. - 2001. - Mo 1. P. 78-84. 4. Lytovchenko A.F.

Agro-hydrometeorological method for calculating soil moisture and water-saving modes of irrigation of irrigated crops in the Steppes and Forest-Steppes of Ukraine!:

monograph / A.F. Lytovchenko. - Dnipropetrovsk: "Svidler A.L." Publishing House, 2011. - 244 p.

Claims (1)

USEFUL MODEL FORMULA The method of determining the period of irrigation based on the daily reserves of soil moisture (MU) under crops, which includes a set of actions from the daily calculation on a personal computer of a comprehensive indicator of previous weather conditions (Р), namely: the total amount of daily time-weighted precipitation (Pd), sums of the average daily air temperature for the period from the date of sowing or restoration of vegetation to the calculation date (hy, "C), sums of the average daily air humidity deficit for the period from the date of the transition of the average daily air temperature by 5 "C in the autumn of the previous year to the calculation date (ha, mb) according to the data of the meteorological station closest to the field, at the same time, the irrigation date is set when the calculated daily values of moisture reserves fall below the natural pre-irrigation threshold of moisture reserves.