Irrigation management of soybean (Glycine max (L.) Merrill) in a semi-arid tropical environment. II. Effect of irrigation frequency on soil and plant water status and crop water use

1992 ◽  
Vol 43 (5) ◽  
pp. 1019 ◽  
Author(s):  
AL Garside ◽  
RJ Lawn ◽  
RC Muchow ◽  
DE Byth

Plant and soil water status, crop water use and water use efficiency, as affected by irrigation treatment, were monitored over two seasons for soybean cv. Ross, sown in the late wet season in the Ord Irrigation Area in north Western Australia. Irrigation treatments were, in both seasons, furrow irrigation after cumulative open pan evaporative losses of 30, 60 120 and 240 mm, and in the second year, an additional treatment, saturated soil culture (continuous furrow irrigation, analogous to irrigation after 0 mm pan evaporation). As expected, during periods of strong evaporative demand plant water status, as indicated by leaf water potential and leaf conductance of water vapour, was consistently greater in the more frequently irrigated treatments, while soil water depletion occurred to greater extent and depth in the less frequently irrigated treatments. However, total soil water use was directly proportional to crop growth, so that there was little evidence that water use efficiency was enhanced by restricting water supply in this environment. Indeed, efficiency of water use even under the continuous furrow irrigation system was comparable with that from other irrigation treatments. The responses are interpreted to imply that there is unlikely to be any economic advantage to the use of limited supplemental irrigation in this environment.

2018 ◽  
Vol 10 (11) ◽  
pp. 1682 ◽  
Author(s):  
Kelly Thorp ◽  
Alison Thompson ◽  
Sara Harders ◽  
Andrew French ◽  
Richard Ward

Improvement of crop water use efficiency (CWUE), defined as crop yield per volume of water used, is an important goal for both crop management and breeding. While many technologies have been developed for measuring crop water use in crop management studies, rarely have these techniques been applied at the scale of breeding plots. The objective was to develop a high-throughput methodology for quantifying water use in a cotton breeding trial at Maricopa, AZ, USA in 2016 and 2017, using evapotranspiration (ET) measurements from a co-located irrigation management trial to evaluate the approach. Approximately weekly overflights with an unmanned aerial system provided multispectral imagery from which plot-level fractional vegetation cover ( f c ) was computed. The f c data were used to drive a daily ET-based soil water balance model for seasonal crop water use quantification. A mixed model statistical analysis demonstrated that differences in ET and CWUE could be discriminated among eight cotton varieties ( p < 0 . 05 ), which were sown at two planting dates and managed with four irrigation levels. The results permitted breeders to identify cotton varieties with more favorable water use characteristics and higher CWUE, indicating that the methodology could become a useful tool for breeding selection.


Author(s):  
G Genemo ◽  
T Seyoum

Flow rate and furrow length are the main irrigation decision variables currently affecting yield and water productivity at farm level. Improper selection of these variables produces an over use of water and loss in crop production. The general objective was to investigate the effect of decision variables on yield and water productivity of onion under conventional furrow irrigation system, with specific objective to analyze the effect of flow rate, furrow length and their interaction on yield and water productivity of onion. The field experiment was laid out in randomized complete block design with factorial arrangement of three levels of flow rate (0.7, 0.98 and 1.3 L/S) and three levels of furrow length (25, 35 and 50 m) with three replications. Inflow out flow method was used to determine the infiltration characteristics of the soil and Irrigation depth was controlled by using 3-inch Parshall flume. The maximum non-erosive flow rate to the experimental site was fixed through design equation considering soil textural class and furrow bed slope. Effect of furrow length and flow rate on yield and water productivity of the onion were used for evaluation. Their analyses indicated that effect of furrow length and their interaction with flow rate on yield were not significant (p<0.05). However, the flow rate showed highly significant (p<0.01) effect on yield of onion. The ranges of mean yield gained from furrow length and flow rate were F1 (14.75 ton ha-1) to F3 (15.96 ton ha-1) and Q1 (13.59 ton ha-1) to Q3 (19.69 ton ha-1), respectively. The effect of furrow length on crop water use efficiency and field water use efficiency was not significant (p<0.05). However, the flow rate has showed highly significant (p<0.01) effect on crop water use efficiency and field water use efficiency. The range of mean crop water use efficiency and field water use efficiency from furrow length and flow rate were F1 (33.65 kg/ha/mm) to F3 (36.41 kg/ha/mm) and Q1 (30.99 kg/ha/mm) to Q3 (38.65kg/ha/mm) and F1 (2.06 kg/m3) to F3 (2.23 kg/m3) and Q1 (1.89 kg/m3) to Q3 (2.36 kg/m3), respectively. Therefore, it can be concluded that a furrow length of 50 m is suitable to use 1.3 L/S of flow rate for better onion yield and water productivity under similar soil type of study area. Int. J. Agril. Res. Innov. Tech. 11(1): 92-100, June 2021


1997 ◽  
Vol 77 (1) ◽  
pp. 83-90 ◽  
Author(s):  
B. G. McConkey ◽  
D. J. Ulrich ◽  
F. B. Dyck

A study was conducted on a 4-m-high ridge in southwestern Saskatchewan to determine the relationship of slope position with the soil water regime and spring wheat (Triticumaestivum L.) production and to determine if those relationships were altered by subsoiling. In all years, available soil water in the spring to 120 cm increased significantly with distance upslope. This pattern was attributed to residual subsoil water in the rooting zone that had not been used by previous crops in a long-term crop-fallow rotation. After 3 yr of annual spring wheat production, soil water to 1.2 m at all slope positions approximately equalled the water content wilting point (4.0 MPa) water content, showing this residual water had been largely consumed. Apparent use of soil water between seeding and harvest at the upper slope positions was equal to or greater than that at the lower slope positions. Over-winter soil water conservation, using tall (≥ 30-cm-high) wheat stubble for snow trapping, at the upper slope positions was equal to or greater than that at the lower slope positions. In the non-drought years of 1987 and 1989, wheat yields and crop water use efficiency increased significantly with distance downslope. Since these slope effects were not related to water use or availability, they were attributed to higher soil productivity, probably related to more historical net erosion with distance upslope. During the drought year of 1988, wheat yields and water use efficiency were greatest at the upslope positions, but these results were confounded by uneven crop emergence. Subsoiling to 35 cm or deeper increased the amount and depth of infiltration of water in years with near-average November–April precipitation. Subsoiling had little effect on wheat yields and no effect on crop water use. Key words: Landscape, wheat, productivity, soil moisture


1990 ◽  
Vol 30 (6) ◽  
pp. 817 ◽  
Author(s):  
M Incerti ◽  
GJ O'Leary

In 1986 and 1987 wheat was sown in an experiment at the Mallee Research Station, Walpeup, at 2 times of sowing and with 3 rates of applied nitrogen. Soil cores were taken and trenches excavated to 1.5 m to measure wheat root growth and depth of rooting. Wheat roots penetrated to a maximum depth of 104 cm in crops sown in May, the optimum time of sowing for maximum yield, while delayed sowing reduced total root biomass and limited rooting depth to 73-83 cm. The application of nitrogen fertiliser did not affect either the rooting depth or growth and yield. Significant changes in total soil water content between sowing and harvest only occurred in 1987 with the early and late sown crops reducing the total soil water content by 47 and 99 mm respectively. In 1986, above average rainfall during the growing season caused the early sown crop to accumulate more water below 50 cm than the late sown crop. While total water use was increased only in 1986 with early sowing, crop water use efficiency and yield was greater in both years. The addition of nitrogen had no effect on crop water use or water use efficiency. A survey of wheat crops carried out in 1988 on 10 Mallee farms also found that shallow rooting is widespead. The field experiment and survey data show that, irrespective of sowing time, roots did not penetrate as far down the profile as might be expected, given reported rooting depths commonly in excess of 200 cm on similarly textured soils. This was shown to be associated with high soil pH and salt content. Poor rooting depth of wheat in this environment will restrict the use of stored water and accordingly, calls the practice of fallowing into question.


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