Row Width and Weed Management Systems for Early Soybean Production System Plantings in the Midsouthern USA

Heatherly, Larry G.; Spurlock, Stan R.; Elmore, C. Dennis

doi:10.2134/agronj2002.1172

Cited by 12 publications

(10 citation statements)

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“…Costs for POST applied to GR cultivars were less than for POST applied to non‐GR cultivars. This cheaper weed management with postemergent glyphosate compared with non‐glyphosate postemergent herbicides over the course of this study agrees with results of Nelson and Renner (1999) and Heatherly et al (2002a)(2002b). Over the 3 yr of this study, POST for GR cultivars cost the least, and PRE + POST for GR cultivars cost the most.…”

Section: Resultssupporting

confidence: 88%

“…In the irrigated experiments, water was applied by the furrow method through gated pipe whenever soil water potential at the 30‐cm depth, as measured by tensiometers, decreased to between −50 and −70 kPa. The effect of irrigation on yield of soybean in the midsouthern USA is well documented (Heatherly, 1999b), but irrigation environment can also affect infestation levels of some weed species (Heatherly et al, 1994, 2001, 2002a). Amounts of irrigation water applied and irrigation starting and ending dates each year were 360 mm applied between 7 July and 24 August in 1999, 355 mm applied between 28 June and 23 August in 2000, and 160 mm applied between 19 June and 24 July in 2001.…”

Section: Methodsmentioning

confidence: 99%

“…This small profit margin dictates that all inputs associated with production must be evaluated with respect to their likelihood of increasing profitability and that yield losses due to controllable pests such as weeds must be prevented within economic constraints. The objective of the producer is to control weeds adequately to maximize profits; however, inputs used for weed management in soybean represent a significant cost (Buhler et al, 1997; Johnson et al, 1997; Reddy and Whiting, 2000; Heatherly et al, 2001, 2002a). Weed management expenditures are almost always made before the onset of drought and without knowledge of ensuing moisture status for subsequent crop and weed development.…”

mentioning

confidence: 99%

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Influence of Early‐Season Nitrogen and Weed Management on Irrigated and Nonirrigated Glyphosate‐Resistant and Susceptible Soybean

Heatherly

Spurlock

Reddy³

2003

Agronomy Journal

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Field studies were conducted on Sharkey clay soil (very‐fine, smectitic, thermic Chromic Epiaquert) at Stoneville, MS (33°26′ N lat). The objectives were to determine the effect of application of 0 and 35 kg N ha−1 applied early in the growing season to glyphosate‐resistant (GR) and non‐GR soybean [Glycine max (L.) Merr.] cultivars using two weed management systems in irrigated and nonirrigated environments. Weed management systems were (i) pre‐emergent followed by postemergent weed management using nonglyphosate herbicides applied to both GR and non‐GR cultivars (PRE + POST) and (ii) postemergent weed management using glyphosate on GR cultivars and nonglyphosate herbicides on non‐GR cultivars (POST). Applied N had no effect on weed management in or yield from soybean and lowered average net returns by $28 to $50 ha−1. Average seed yields from the highest‐yielding GR cultivar in 1999 and 2000 were 135 and 270 kg ha−1 more than 1999 and 2000 yields from a non‐GR cultivar in the nonirrigated environment (all net returns were negative and yields <1500 kg ha−1). In the irrigated environment, use of a non‐GR cultivar compared with a GR cultivar resulted in a significant 200 and 250 kg ha−1 greater yield and greater profits in 2 of 3 yr. Use of PRE + POST compared with POST‐only was not necessary for achieving greatest yield or net return with either non‐GR or GR cultivars. Use of postemergent glyphosate always resulted in the cheapest weed control ($43 to $81 ha−1), even with the greater cost for seed of GR cultivars included. There was no measured effect of glyphosate compared with nonglyphosate herbicides on GR cultivar yield.

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Section: Resultssupporting

confidence: 88%

Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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Influence of Early‐Season Nitrogen and Weed Management on Irrigated and Nonirrigated Glyphosate‐Resistant and Susceptible Soybean

Heatherly

Spurlock

Reddy³

2003

Agronomy Journal

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“…The effect of irrigation on yield rates with recommended adjuvants and in recommended tank mixes (Table 1). Pre-emergent herbicides and infestation levels of some weed species (Heatherly et al, 1994(Heatherly et al, , 2002a. Pre-emergent herbicides and infestation levels of some weed species (Heatherly et al, 1994(Heatherly et al, , 2002a.…”

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confidence: 99%

Influence of Early-Season Nitrogen and Weed Management on Irrigated and Nonirrigated Glyphosate-Resistant and Susceptible Soybean

Heatherly

Spurlock

Reddy³

2003

Agronomy Journal

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cause glyphosate has no carryover or soil persistence, producers can use a glyphosate-only weed management Field studies were conducted on Sharkey clay soil (very-fine, smecprogram with no concern for choice of rotational or titic, thermic Chromic Epiaquert) at Stoneville, MS (33؇26 N lat).following crops.The objectives were to determine the effect of application of 0 and 35 kg N ha Ϫ1 applied early in the growing season to glyphosate-Glyphosate-resistant cultivars offer producers the resistant (GR) and non-GR soybean [Glycine max (L.) Merr.] cultiflexibility to control a broad spectrum of weeds in soyvars using two weed management systems in irrigated and nonirrigated bean with no concern for crop safety (Reddy, 2001). environments. Weed management systems were (i) pre-emergent fol-Cost of weed control using a postemergence managelowed by postemergent weed management using nonglyphosate herbiment program for GR cultivars should be less, even cides applied to both GR and non-GR cultivars (PRE ϩ POST) andwith the greater cost for seed of most GR cultivars (ii) postemergent weed management using glyphosate on GR cultivars (Reddy et al., 1999;Heatherly et al., 2002b). This could and nonglyphosate herbicides on non-GR cultivars (POST). Applied translate to increased profits if yields from GR cultivars N had no effect on weed management in or yield from soybean and are equal or nearly equal to those from non-GR cultilowered average net returns by $28 to $50 ha Ϫ1 . Average seed yields vars. Use of GR cultivars should preempt the use of from the highest-yielding GR cultivar in 1999 and 2000 were 135 and 270 kg ha Ϫ1 more than 1999 and 2000 yields from a non-GR cultivar tillage and pre-emergent herbicides for weed managein the nonirrigated environment (all net returns were negative and ment. The flexibility of using either nonglyphosate heryields Ͻ1500 kg ha Ϫ1 ). In the irrigated environment, use of a nonbicides or glyphosate on GR cultivars increases manage-GR cultivar compared with a GR cultivar resulted in a significant ment options for weed control when GR cultivars are 200 and 250 kg ha Ϫ1 greater yield and greater profits in 2 of 3 yr. Use used. Nonglyphosate herbicides applied to GR soybean of PRE ϩ POST compared with POST-only was not necessary for in monocrop or corn (Zea mays L.)-soybean rotation achieving greatest yield or net return with either non-GR or GR systems do not adversely affect GR soybean (Nelson cultivars. Use of postemergent glyphosate always resulted in the and Renner, 1999; Webster et al., 1999). cheapest weed control ($43 to $81 ha Ϫ1 ), even with the greater costGlyphosate inhibits 5-enolpyruvylshikimate-3-phosfor seed of GR cultivars included. There was no measured effect of phate synthase (EPSPS) and thus blocks aromatic amino glyphosate compared with nonglyphosate herbicides on GR cultivar yield.

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“…The effect of irrigation on yield of soybean in the the same ones each year) and their combinations was dictated by expected weed populations (PRE) or actual populations midsouthern USA is well documented (Heatherly, 1999c), but irrigation environment can also affect infestation levels (POST). Expert opinion during the growing season was used to determine when weed population within each WMS was of some weed species (Heatherly et al, 1994(Heatherly et al, , 2001(Heatherly et al, , 2002. Amounts of irrigation water applied and irrigation starting sufficient to justify application of POST herbicides and what herbicides to use.…”

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Weed Management Systems for Conventional and Glyphosate‐Resistant Soybean with and without Irrigation

2002

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almost always made before the onset of drought and without knowledge of ensuing moisture status for subse-Management inputs that maximize economic return from the early quent crop and weed development. This presents a chalsoybean [Glycine max (L.) Merr.] production system have not been evaluated fully. The objective was to determine the effect of weed man-lenge, especially in NI production systems that often agement on yield and net return from early planted maturity group result in low yield in the midsouthern USA. (MG) IV and MG V glyphosate [N-(phosphonomethyl)-glycine]-resis-A majority of the soybean hectarage in the midsouthtant (GR) and conventional (CONV) soybean cultivars grown in the ern USA is NI even though past research has shown early soybean production system with (IRR) and without (NI) irrigathat yield and net return will increase from irrigation tion. Field studies were conducted from 1996 through 1999 on Sharkey (Heatherly, 1999a). The small profit margin and large clay (very-fine, smectitic, thermic Chromic Epiaquert) at Stoneville, start-up costs associated with land leveling to accommo-MS (33؇26 N lat). Weed management systems were (i) pre-emergent date furrow or flood irrigation, or the initial purchase (PRE) broadleaf followed by postemergent (POST) broadleaf and cost associated with overhead irrigation systems, can grass weed management (PRE ϩ POST) and (ii) POST broadleaf make capitalization of irrigation capability prohibitive. and grass weed management (POST). Use of POST-only weed management was cheaper, yielded more, and resulted in greater net returns Thus, most land used for soybean production in the than did use of PRE ϩ POST weed management with both CONV midsouthern USA presently is committed to either an and GR cultivars. Under the conditions of this study, use of GR vs. IRR (start-up costs absorbed in past) or NI production CONV cultivars in an NI or low-yield environment resulted in greater system. Management of NI and IRR plantings of soyprofit ($52 vs. Ϫ$17 ha Ϫ1 3-yr average, respectively). Use of CONV vs. bean in the midsouthern USA entails different sets of GR cultivars resulted in greater profit in an IRR or high yield environproduction practices, especially for weed management ment ($382 vs. $266 ha Ϫ1 3-yr average, respectively). These results (Heatherly et al., 2002), because the opportunity for indicate that use of GR cultivars with POST-only weed management profit is different between the two systems (Heatherly will result in greater profit in an NI environment while use of CONV and Spurlock, 1999). cultivars with POST-only weed management will result in greater Many weed management systems (WMSs) provide profit in an IRR environment.is a nonselective herbicide that kills both annual and

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Row Width and Weed Management Systems for Early Soybean Production System Plantings in the Midsouthern USA

Cited by 12 publications

References 30 publications

Influence of Early‐Season Nitrogen and Weed Management on Irrigated and Nonirrigated Glyphosate‐Resistant and Susceptible Soybean

Influence of Early‐Season Nitrogen and Weed Management on Irrigated and Nonirrigated Glyphosate‐Resistant and Susceptible Soybean

Influence of Early-Season Nitrogen and Weed Management on Irrigated and Nonirrigated Glyphosate-Resistant and Susceptible Soybean

Weed Management Systems for Conventional and Glyphosate‐Resistant Soybean with and without Irrigation

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