Summary of research project: |
Objective and technical fields:
Efficient organization of irrigation and agricultural activities on cotton growing through determination of optimal elements of an irrigation technique for concentrated irrigation, planning the irrigation and nutrition regime according to the programmed yield. Objectives: improvement of planning and management of in-farm water use, raising the efficiency of fertilizing and use of other resources for cotton growing.
Scientific and technical approach:
Raising the efficiency of water, land, labor, material and technical resources use for cotton growing through organization of more efficient irrigation in the farm, determination of optimal irrigation technique elements, planning the irrigation and nutrition regime according to the programmed yield, carrying out argotechnical activities in coordination with irrigation for each field. Studies included elaboration and testing of organizational, meliorative, technical, operational measures for water, fertilizers, labor and technics saving during cotton growing.
Environment characteristics:
The pilot plot is situated in Hissar valley with sharply continental climate. Maximum temperature in July is 43oC-44oC, minimum temperature is -24oC-30oC, average annual temperature is 14,1oC-15,1oC. Sum of positive temperatures (above 10 0C) is 2192-2510oC. Average annual relative air humidity is 46-53%, it reduces down to 31-42% in summer. Duration of the frost-free period is 220-240 days. Precipitation falls mostly in late autumn, winter and spring, annual precipitation is 595-610 mm, total solar radiation is 607,55-628,50 kJ/cm2, evaporativity is 1252-1597 mm. Annual average wind speed is 1,5-2,8 m/sec, number of days with strong wind (up to 15 m/sec) is 5-15 days.
The valley is slightly dismembered by the gully and river system. Valley is made of sick alluvial-proluvial deposits with underlying conglomerates and sandstones. Soils are old-irrigated light gray and cinnamon-colored-calcareous. Depth of water table is big, ground waters are fresh with slight salinity. Permeability of 1 m soil layer is 10-20 mm/hour, coefficient of permeability of the underlying layer is 1250-2000 mm/hour. Inclination is mostly 0,01-0,03, more seldom it is 0,003-0,007. Soils are old-irrigated, non-salinized, cinnamon-colored-calcareous, heavy, middle and light slightly-stony. Volume weight of 1 m soil layer is 1,6-1,35 t/m3, minimum moisture capacity is 24,0-18,6%, depth of water table is more than 80 m, ground waters are fresh. Source of irrigation is Big Hissar Canal, water salinity is not more than 0,7 g/l.
Analysis of the existing irrigation technology for cotton in different irrigation schemes showed that water gifts were dispersed in many of them. Under such regime 10-15 ha were assigned to 1-2 irrigators in a brigade, irrigation was made simultaneously on several irrigation plots, irrigation flow given to a brigade (100-200 l/sec) was dispersed for small flows (15-30 l/sec) in accordance with the number of irrigated plots. Irrigation dispersed among small plots, manual water distribution, low labor productivity of irrigators hampered timely mechanized inter-row cultivation because of nonuniform post-irrigation soil readiness in one place and caused irregular employment of tractors, increased fuel expenditures, reduced labor productivity, broken technology of agricultural activities and reduced efficiency of irrigation. In the experimental brigade with dispersed irrigation the extension of the operating part of brigade ditches and water losses for filtration from earthen system increased by 6,4 times comparing with concentrated irrigation increased from 0,3 l/sec to 5,9 l/sec or 400-500 m3 per irrigation period. Irrigation and nutrition regimes for crops were determined irrespective of obtained yield. Irrigation norm was 13,0-14,0 th. m3/ha, 3-4 water gifts were made.
Parameters of Pilot Projects and Technical Solutions:
Net irrigated area was 76 ha, specialization was cotton-growing, irrigation was made through furrows from a surface earthen system, canal efficiency was 0,85-0,90, total length of permanent canals was 4870 m, specific length was 64 m/ha, canal capacity was 200-350 l/sec. Surface release was made by surface escape. Water turbidity was 4-0,5 g/l.
Furrows were 100-150 m long, the area of a brigade was divided into 8 plots with concentrated irrigation 12-7 ha each, a group of 11 irrigators was made. Irrigation norms and depths of irrigation were calculated for obtaining the yield of 3,5-4,5 t/ha with 6-8 water gifts, gross depth of irrigation was 1070-1860 m3/ha, irrigation norms were 10500-9850 m3/ha. Taking into account programmed yield, nutrition regime was determined. For obtaining the programmed yield of 3,5-4,5 t/ha of raw cotton with due regard for the content of nutrients in soil of each plot, coefficients of using nutrients from soil and fertilizers differently for each plot annual doses of fertilizers and schedules of their application were calculated.
Methodology:
Improved irrigation technology with the elements of programmed yield included: organization of concentrated irrigation and determination of optimal irrigation technique elements; calculation of the optimal irrigation regime for obtaining the programmed yield; diagnosis and correction of an irrigation schedule; calculation of the optimal nutrition regime for obtaining the programmed yield; perfection of the irrigation technique; elaboration of the technological schedule for carrying out the agricultural operations in coordination with irrigation.
This task was solved with field observations and elaboration of the model for organization of irrigation by a brigade. Studies were carried out in 4 stages:
1. Study of the current condition of water use and irrigation technology on the studied area, registration of brigade work on the fields, determination of water expenditures, measurement of water-physical properties of soil and inclination, content of nutrients in soil.
2. Elaboration of an irrigation technology: determination of the borders of plots with concentrated irrigation, determination of the line for cutting temporary ditches with due regard for optimal length of irrigation furrows, places of water release from them, expansion of a canal section for concentrated flow, training of irrigators. Determination of the programmed yield, calculation of irrigation and nutrition regimes, determination of irrigation norms and depths of irrigation, elaboration of an irrigation schedule for a brigade, determination of water application duration for each plot. Elaboration of a technological scheme for cotton growing in a brigade in coordination with irrigation.
3. Realization of the irrigation technology, measurement of water expenditures, irrigation norms and depths of irrigation, observations over irrigation schedule and duration, registration of activities on cotton cultivation on all plots with concentrated irrigation.
4. Systems analysis of obtained data, correction of algorithms for solution of tasks and feasibility study of implemented measures.
Results:
Application of concentrated irrigation and optimal elements of an irrigation technique in a brigade provided simultaneous increase of irrigated and cultivated area up to 8-12 ha and resulted in improvement of irrigation showing on the plots:
- water application duration was 2-3 days (3-5 days on the control plot);
- duration of the cycle of cultivation during water application was 10-13 days (15-22 days on the control plot);
- surface release was 15-20% (30-40% on the control plot).
According to the optimal irrigation regime elaborated with the field water balance equation using biophysical coefficients for obtaining the programmed yield, 6-8 water gifts were made depending on soil texture. On middle-loam soils 7 water gifts were made with net average depth of irrigation equal to 1065 m3/ha; net irrigation norm was 7470 m3/ha, gross irrigation norm was 9750 m3/ha. On the control plot 4 water gifts were made with net average depth of irrigation equal to 2250 m3/ha; net irrigation norm was 9000 m3/ha, gross irrigation norm was 13315 m3/ha. Water expenditures per unit of production on the experimental plots were 40% less than on the control plot.
Calculated fertilizer dose was 220-245 kg/ha of nitrogen, 165-200 kg/ha of phosphorus and 80-100 kg/ha of potassium. Fertilizers were applied 6 times: 1st time - into ploughed soil (70% of phosphorus and 50% of potassium), 2nd time - during presowing soil treatment (30% of nitrogen), 3rd time - during sowing (10 kg/ha of nitrogen and 20 kg/ha of phosphorus), 4th time - during the stage of 2-3 real leaves (20% of nitrogen, 15% of phosphorus), 5th time - during the bud-formation period (25% of nitrogen, 5% of phosphorus and 25% of potassium), 6th time - during blooming (25% of nitrogen, 10% of phosphorus and 25 of potassium). Fertilizers were applied into soil before water application according to calculated doses and schedules.
Implementation of calculations with elaborated algorithms, training of brigade members, organization of work on cotton growing in the brigade according to the technological schedule of the agricultural activities in coordination with irrigation (irrigation schedules for each plot) gave the possibility to raise the labor productivity in the brigade by 27-30%, to reduce gross irrigation norm by 15-20% and raise cotton yield by 10-15%.
In 1983-1987 the area of introduction of the new development was 14,772 th. ha and involved cotton-growing districts of the Republic with different environmental conditions (Lenin, Yavan, Kolkhozabad and Ashtsky districts). As a result of this introduction average increase of raw cotton yield was 0,36 t/ha or 11%, cost of the unit of production reduced by 4,7 ruble/ha, total profitability for the whole territory was 11,38 mln. rubles in prices of 1984.
For automation of initial data gathering, their processing, storage and calculation of the technology elements “Automated system of timely planning and management of water saving irrigation technology for cotton” was created by name “Meliorator”. This system consists of 5 blocks with the following tasks:
1. Block of storage, processing and preparation of initial data.
2. Selection of optimal elements of an irrigation technique and calculation of canal section parameters.
3. Calculation of nutrition norms and regime for cotton.
4. Calculation of irrigation norms and regime for cotton.
5. Elaboration of an irrigation schedule for plots of each brigade.
Introduction of “Meliorator” program in 1988-1989 on the area of 18 000 ha increased the yield of raw cotton by 0,2-0,4 t/ha, improved raw cotton sort and raised its price by 15-25%. 1600 m3/ha (or 28,8 mln m3/ha for the whole territory) of irrigation water was saved.
On being revised “Meliorator” program can be used for all the crops of cotton crop rotation.
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