Effect of Plant Population and Row Spacing on Evapotranspiration and Water‐Use Efficiency by Soybeans
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SUMMARYProductivity and water resource usage efficiency are crucial issues in sustainable agriculture. The aims of the present research were to compare and evaluate the soil moisture content (SMC), evapotranspiration (ETa), yield, water-use efficiency (WUE), and net return of winter wheat (Triticum aestivum L.) and soybean [Glycine max (L.) Merr.] under different plant population distribution patterns and to identify the possible ways to improve water utilization. Using the same plant population for a given crop, the experiments consisted of four spacings between rows (row spacings) for winter wheat (cvar Shannong 919) under both rainfed and irrigated conditions and five row spacings for summer soybean (cvar Ludou 4) under rainfed conditions. For winter wheat, the stem number with row spacing of 49 cm was the lowest in all treatments. The SMC was enhanced by irrigation, particularly at the 10–40 cm depth. The yield and WUE were negatively correlated with row spacing and were greater with narrower row spacing than with wider rows. For soybean, SMC in uniform distribution (spacing between plants) treatments was greater at lower depths than at shallower depths for each row spacing treatment. A high yield, WUE and net return of winter wheat and soybean can be achieved with narrower row spacing. Combining winter wheat row spacing of 14 cm with soybean row spacing of 18 cm and soybean row spacing of 27 cm is a highly suitable planting system for the plains of Northern China.

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Row spacing fails to modify soil evaporation and grain yield in spring wheat in a dry Mediterranean environment

Australian Journal of Agricultural Research ◽

10.1071/ar9930661 ◽

1993 ◽

Vol 44 (4) ◽

pp. 661 ◽

Cited By ~ 21

Author(s):

IAM Yunusa ◽

RK Belford ◽

D Tennant ◽

RH Sedgley

Keyword(s):

Solar Radiation ◽

Grain Yield ◽

Water Use Efficiency ◽

Water Use ◽

Ground Cover ◽

Soil Types ◽

Row Spacing ◽

Crop Canopy ◽

Mediterranean Environment ◽

Use Efficiency

The loss of moisture by evaporation from soil under crop canopies (Esc) has been recognized as a major cause of poor water use efficiency (WUE), and hence poor grain yield, in crops grown in environments with limited rainfall. Agronomic approaches to restrain Esc aim to reduce the transmission of solar radiation to the soil beneath the crop by improving ground cover by the crop canopy. However, the sparse canopies produced in these environments have a limited effect on evaporation during the energy dependent first stage (Es1); much of the evaporation is independent of energy at the soilsurface (Es2), and therefore less sensitive to the influence of the crop canopy. Manipulating plant arrangement, primarily by changing row spacing, may provide a simple approach for improving ground cover and restraining E,, without changing GAI, and thus improving WUE and grain yield. To explore the potential benefit of variable row spacing on Esc and grain yield in the dry (300 mm) Mediterranean environment of the eastern wheatbelt of Western Australia, spring wheat was grown in 0.09, 0.18, 0.27 and 0.36 m row spacings on coarse textured and fine textured soil types at Merredin in 1989. Esc was determined with an empirical model and measured with microlysimeters. Row spacing had no significant effect on the development of green area index (GAI), dry matter (DM) accumulation and evapotranspiration (ET) throughout the season. However, in mid-season, the proportion of ground covered by the canopy was higher and transmission of solar radiation was reduced in the 0.09 m row spacing compared with the 0.36 m row spacing. These effects did not restrain E,,, which was similar in all treatments. Esc was not restrained even when the plant density was doubled in the 0.09 m row spacing treatment. Esc during the season averaged 88 mm across all row spacings on both soils; this accounted for 56% and 48% of the mean seasonal ET on the coarse textured and fine textured soils respectively. Consequently, neither water use efficiency nor grain yield were affected by variation in row spacing; water use efficiency averaged 25 kg DM ha-1 mm-1 on both soil types. For dry Mediterranean environments of Western Australia, it was concluded on the basis of these results, and yield data from other row spacing trials in the same districts, that there are no significant yield benefits to be obtained by reducing the row spacing from the current spacing of 0.18 m.

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Influence of row spacing on water use and yield of rain-fed wheat (Triticum aestivum L.) in a no-till system with stubble retention

Crop and Pasture Science ◽

10.1071/cp10124 ◽

2010 ◽

Vol 61 (11) ◽

pp. 892 ◽

Cited By ~ 6

Author(s):

S. G. L. Kleemann ◽

G. S. Gill

Keyword(s):

Grain Yield ◽

Water Use Efficiency ◽

Water Use ◽

Vegetative Growth ◽

Growing Season ◽

Light Interception ◽

Row Spacing ◽

Spike Density ◽

Stubble Retention ◽

Use Efficiency

A 3-year field study was undertaken to investigate the effect of row spacing on vegetative growth, grain yield and water-use efficiency of wheat. All 3 years of the study experienced 21–51% below-average rainfall for the growing season. Widening row spacing led to reduced biomass and tillers on per plant basis which could be related to the reduction in light interception by the wheat canopy in the wide rows which in turn could have reduced assimilate production. Reduction in vegetative growth in 54-cm rows translated into a significant reduction in grain yield which was strongly associated (r2 = 0.71) with the loss of spike density. The pattern of crop water use (evapotranspiration, ET) during the growing season was very similar for the three row-spacing treatments. However, there was some evidence for slightly lower ET (~5%) in 54-cm rows in two growing seasons. More importantly, there was no evidence for increased ET during the post-anthesis phase in wide rows as has been speculated by some researchers. Over the 3 years of the study, grain yield declined by 5–8% as row spacing increased from 18 to 36 cm and by a further 12–20% as row spacing increased from 36 to 54 cm. There was a consistent decline in water-use efficiency for grain (WUEG) with increasing row spacing over the 3 years. WUEG declined by 6–11% as crop spacing increased from 18 to 36 cm and declined further by 12–15% as row spacing increased to 54 cm. Lower light interception at wider row spacing could have reduced assimilate production by wheat as well as increased soil evaporation due to lower shading of the soil surface in more open canopies. Growers adopting wider row spacing on these relatively heavy textured soils are likely to experience some reduction in grain yield and WUEG. However, some growers may be prepared to accept a small yield penalty from intermediate row spacing as a trade-off for increased stubble retention and soil health.

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Deficit Irrigation and Plant Population Effects on Leaf Quality and Yield of Spinach

HortScience ◽

10.21273/hortsci.40.4.1095d ◽

2005 ◽

Vol 40 (4) ◽

pp. 1095D-1095

Author(s):

Daniel I. Leskovar ◽

Giovanni Piccinni ◽

Darrin Moore

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Deficit Irrigation ◽

Spinacia Oleracea ◽

Plant Population ◽

Lower Percentage ◽

Marketable Yield ◽

Plant Populations ◽

Leaf Quality ◽

Use Efficiency

A two-year experiment was conducted to determine yield, water use efficiency, and leaf quality responses to deficit irrigation and plant population of spinach (Spinacia oleracea L.). Three irrigation regimes were imposed with a center pivot system, 100%, 75%, and 50% crop evapotranspiration rates (ETc). Spinach seeds were planted on 11 Nov. 2003 at three plant populations: 494 (P-1), 618 (P-2), and 741 (P-3) thousand seeds/ha on cvs. DMC 16 and ASR 157, and on 15 Oct. 2004 at four plant populations: 655, 815, 988, and 1149 thousand seeds/ha on cv. DMC 16. Harvests were done on 3 Mar. 2004 and 26 Jan. 2005. In the first season, marketable yield was not reduced by deficit irrigation, but water use efficiency was significantly higher for 50% ETc compared to 100% ETc. The cv. DMC 16 had a significantly lower percentage of stem weight than ASR 157 (8.3 vs. 16.4%). The cv. ASR 157 had an excess of stem weight at 100% and 75% ETc compared to 50% ETc at P-1, but similar at P-2 and P-3. The cv. DMC 16 had a trend of reduced stem weight for P3 at 50% ETc. In the second season, marketable yield was reduced by deficit irrigation. However, water use efficiency was significantly higher for 50% ETc compared to 100% ETc, but similar to 75% ETc. Deficit irrigation also decreased the percentage of stem weight. Despite a slight increase in the percentage of of yellow leaves, but not in percentage of of stem weight, marketable yield and water use efficiency were significantly higher at 1149 thousand seeds/ha. This study showed that deficit irrigation in combination with increased plant population has the potential to increase yield and water savings, without adversely affecting leaf quality.

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