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Objective and technical fields:
To develop technological process of irrigation by sprinkler -unit “Kuban” and give recommendations on irrigation technology. Objectives: To perfect technology of irrigation by sprinkler-unit “Kuban”, irrigation network elements, reduce water expense and increase irrigated land productivity.
Scientific and technical approach:
Development of irrigation technical parameters providing sprinkler irrigation without runoff, given irrigation regime and irrigation water saving.
Meaning: Development of recommendations on cotton sprinkler irrigation.
Environment characteristics:
Climate is sharply continental. Average annual air temperature is 13 oC, maximum is 43 oC, minimum - 26 oC. Precipitation is 391 mm per year; total evaporativity is 670 -750 mm. Relative air humidity is 32 -48 %.
Relief is slightly corrugated, slope is 0.003 -0.009 to south -west.
Lithology: alluvial sediments: cover loam (0.5 -2.3 m) and gravel. Cover layer is constituted by middle and heavy loam. Sand particles content is 13.4 %, clay particles -25.8 %.
Groundwater level is 1.1 -1.5 m. Easy soluvable salts content is 0.059 -0.113 mg/ekv. Water salinity is 0.38 -0.39 g/l. Permeability is high (A=22 -38 mm, B=1.3 -2.2). Volume mass is 1.6 g/cu.cm. Normal moisture is 23 %.
Parameters of Pilot Projects and Technical Solutions:
Irrigated area is 61.1 ha (net). Land use efficiency is 0.97. Main crop is cotton. Water suply is performed by canal KP, collector K-1 with discharge 500 l/sec and collector B -3 -6 with discharge 650 l/sec. Collector specific extent is 12 m/ha. Sprinkler is supplied from concrete lined canal with parameters: length -850 m, width -2.9 m, width across the bottom -0.6 m. Canal efficiency is 0.94. Irrigation of cotton, alfalfa, kenaf was performed by “Kuban” with characteristics: discharge -170 l/sec, width of seizure -778 m, width of rain torch -12 m, rain intensity -1.1 mm/min., drop diameter -1.0 mm, movement speed -0.2 -2.0 m/min.
Methodology:
Soil air - water regime was studied by thermostat -weight method and neutron moisture meter. Water balance was calculated on basic of field test data. Phenological observations were undertaken on crop growth, germination and biological yield. Data processing was executed by statistical and theory of chances methods.
Results:
Within field 3 -4 waterings were performed. Average depth was 690 cu.m/ha. Average norm irrigation was 2760 cu.m/ha. Moisture before irrigation was 56 -71 % of full field moisture capacity, average value within growing season was 63 %. After irrigation moisture content was 85 -92 % (average was 88 %). Surface release was absent, deep release was 6 %. Relative evaporation during irrigation was 15.2 %. Sprinkler irrigation efficiency taking into account evaporation was 0.79. Time of irrigation was 7 hours. Relative air humidity at 2 m altitude was 40 % before irrigation and 85 % 6 minutes after its beginning. Humidity within the torch was 43 %. Initial temperature at 2 m altitude was 38 0 C and 6 minutes after its beginning was + 28 0 C. Rain drop evaporation within the torch was less than 1 %. Permitted layer of precipitation was 43 mm under initial moisture 60 % and 28 mm under initial moisture 70 %. On leaves about 0.08 mm water was settled which evaporated within 1.1 hour. Total evaporation from leaves was 2.3 %. Evaporation rate was 0.2 mm/hour, from rain -meters -0.42 mm/hour, from rain -meters under bush -0.11 mm/hour, the same under cone -0.08 mm/hour. Transpiration from wetted leaf was 0.13 min/hour. Soil moisture at the beginning of vegetation was 22.9 %, at the end -12.8 %. Moisture stock decreased on 1292 cu.m/ha or 17 % of total water consumption. Inflow from groundwater was 1964 cu.m/ha or 26 %. Precipitation was 1610 cu/m/ha (21 %). Total water consumption was 7626 cu.m/ha. Cotton plant density was 130 th.plant/ha, number of boxes -7.7 (1 bush), one box weight -4.35 g; biological yield - 4.35 t/ha. Within the field irrigated by furrows (distance between furrows 0.6 m, depth -25 cm, average discharge into furrow -0.6 l/sec, slope -0.0055, lag time -5 hours, absorption rate -52.3 mm/hour). Norm of irrigation was 5817, release -1662 cu.m/ha, duty net was 3660 cu.m/ha. Water consumption was 7534 cu.m/ha, number of irrigations -3. Average water duty was 1220 cu.m/ha. Irrigation efficiency without regard to evaporation was 0.56, with regard to -0.49. Average evaporation was 4.2 mm/day. Yield was 3.15 t/ha. Density was 118.4 th. plants/ha, number of boxes -6.5; box weight -4.1 g.
Comparison showed that yield growth within sprinkler irrigated site was 1.2 t/ha (27 %), water saving -40 %. Economic efficiency was 1368.2 rouble/ha. Additional effect due to water saving was 420 rouble/ha.
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