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Conflicting results have been reported in the literature concerning the effects of narrow row spacings on soybean [Glycine max (L). Merr.] production in the southern USA. The objective of this study was to revisit the issue by evaluating some economic implications of alternative row spacing arrangements on soybean performance under both irrigated and nonirrigated conditions. Data from 3‐yr continuous soybean experiments conducted at the Northeast Research and Extension Center, Keiser, AR, between 1990 and 1992 were used for this purpose. Enterprise budgeting was employed to determine the nature of costs and returns associated with alternative production systems. Simple variability and break‐even analyses were used to provide preliminary insights into the probable sensitivities of alternative practices to fluctuations in production and economic environments. The results indicated that narrow row systems (usually between 10 and 20 in.) could enhance yields and net returns either under nonirrigated or irrigated conditions. A yield increase of between 15 and 30% was obtained under nonirrigated conditions, while an improvement in yields ranging from 10 to 17% was obtained under irrigation. Furthermore, results from break‐even analysis supported the use of narrow row systems for enhancing net returns relative to wide row arrangements under a production environment that is characterized by fluctuations in yields and output prices. Research Question Using a new set of experimental data concerning the response of soybean to different production and row spacing systems in the South, the objective of the study was to evaluate some economic implications of alternative production practices and row spacing arrangements on the performance of soybean under both irrigated and nonirrigated conditions. Literature Summary Narrow row (NR) arrangements, which generally refer to spacings that are less than 30 in., have been shown to produce higher yields with indeterminate soybean than the conventional wide row arrangements in the midwestem USA. However, results with determinate cultivars in the south have been inconclusive. This is often attributed to the disparities in canopy closure and light interception abilities of determinate and indeterminate cultivars. Although one of the major limitations of NR is its poor ability to allow effective mechanical weed control through inter‐row cultivation, it is becoming evident that crops under such spacing arrangements may be able to shade weed seedlings and interfere with weed development more effectively than their wide row counterparts. As a result, such crops may require less herbicides or post‐plant cultivation for an equally effective weed control than other alternative row spacing systems. Study Description Data were obtained from 3‐yr row spacing experiments on Sharkey silty clay soils that were conducted at the Northeast Research and Extension Center, Keiser, AR, between 1990 and 1992. An enterprise budgeting approach was employed to determine the costs and returns associated with alt...

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I\bst t llct 111< ,,9'515 PLI So1 0/97/$17.00 © 1997 Elsevier Science B.V. Ali rights reservcd. 69-5150(97)00012_1

I\bst t llct 111< ,,9'515 PLI So1 0/97/$17.00 © 1997 Elsevier Science B.V. Ali rights reservcd. 69-5150(97)00012_1