Van Eerd, L. L., Congreves, K. A., Hayes, A., Verhallen, A. and Hooker, D. C. 2014. Long-term tillage and crop rotation effects on soil quality, organic carbon, and total nitrogen. Can. J. Soil Sci. 94: 303–315. Long-term studies allow for quantification of the effects of crop production practices, such as tillage and crop rotation, on soil quality and soil C and N stores. In two experiments at Ridgetown, ON, we evaluated the long-term (11 and 15 yr) effect of tillage system and crop rotation on soil quality via the Cornell Soil Health Assessment (CSHA) at 0–15 cm and soil organic C (SOC) and total N at 5-, 10-, and 20-cm increments to 120 cm depth. The CSHA soil quality score and SOC and total N were higher with no-till (NT) than fall moldboard plough with spring cultivation (conventional tillage, CT) and rotations with winter wheat [soybean–winter wheat (S-W) and soybean–winter wheat–corn (S-W-C)] compared with rotations without winter wheat. In both long-term trials, NT had ca. 21 Mg ha−1 more or 14% higher SOC than CT in the 0- to 100-cm soil profile, a trend which contrasts previous research in eastern Canada. Thus, the two long-term trial results at Ridgetown suggest that to improve soil quality and storage of C and N, growers on clay loam soil in southwestern Ontario should consider adopting NT production practices and including winter wheat in the rotation.

, L. L. 2012. Nitrogen cycling, profit margins and sweet corn yield under fall cover crop systems. Can. J. Soil Sci. 92: 353Á365. In order to improve N best management practices in southwestern Ontario vegetable farming, the effect of cover crops on N dynamics in the fall and spring prior to sweet corn planting and during sweet corn season was assessed. The experiment was a split plot design in a fresh green pea Á cover crop Á sweet corn rotation that took place over 2 site-years at Bothwell and Ridgetown in 2006Á2007 and 2007Á2008, respectively. The main plot factor was fall cover crop type with five treatments including oat (Avena sativa L.), cereal rye (Secale cereale L.), oilseed radish (OSR; Raphanus sativus L. var. oleoferus Metzg Stokes), mixture OSR plus cereal rye (OSR&rye) and a no cover crop control. Compared with no cover crop, sweet corn profit margins were higher by $450 ha (1 for oat at Bothwell and $1300 and $760 ha (1 for OSR and OSR&rye, respectively, at Ridgetown. By comparing plant available N over the cover crop season, the cover crops tested were more effective at preventing N loss at Bothwell than at Ridgetown likely due to higher precipitation and sandier soil at Bothwell. Despite differences in site characteristics, cover crops did not result in increased plant available N compared with no-cover during the sweet corn season at either site, indicating that these cover crops will not provide an N credit to the following crop and growers should not modify N fertilizer applications based on cover crops. n te´moin, soit l'absence de culture-abri. Comparativement au traitement te´moin, la marge de profit du maı¨s sucre´a augmente´de 450 $ par hectare avec l'avoine, a`Bothwell, ainsi que de 1 300 $ et de 760 $ par hectare avec le radis et le me´lange radis/seigle, respectivement, a`Ridgetown. Quand on compare la quantite´de N a`la disposition des plantes durant la croissance de la culture-abri, on constate que les cultures teste´es pre´viennent mieux les pertes de N a`Bothwell qu'aR idgetown, sans doute a`cause de pre´cipitations plus abondantes et d'un sol plus sablonneux. En de´pit des diffe´rences observe´es au niveau des particularite´s du site, la culture-abri n'a accru la quantite´de N disponible pour les plantes a`aucun des deux endroits pendant la saison de croissance du maı¨s sucre´, comparativement au traitement te´moin, signe que les cultures teste´es n'ajoutent pas du N au sol pour la culture subse´quente et que les cultivateurs ne devraient pas modifier leurs applications d'engrais N en fonction de la culture-abri.Mots clé s: É conomique, culture de´robe´e, perte de nitrates, avoine, seigle, radis, bilan azoteẂ ith over 30 000 ha of land in production, sweet corn is the most widespread field-grown vegetable crop in Canada. With approximately 50% of the national acreage, Ontario is the largest sweet corn producing province with a farm value of $25.5 million in 2007 (Mailvaganam 2008). With such a large acreage, it is important that sweet corn production not only optimizes returns b...

beet (Beta vulgaris L.) storage quality in large outdoor piles is impacted by pile management but not by nitrogen fertilizer or cultivar. Can. J. Plant Sci. 92: xxxÁxxx. Even though storage results in lower sucrose recovery from sugar beets, physical constraints dictate that a significant proportion of the sugar beet crop can be stored up to 120 d before processing. From 2006From to 2010 (1 ), sugar beet cultivar, and pile management method were independently evaluated to determine their effects on sugar beet storability in large outdoor piles. At harvest, five representative sugar beet samples from the N and cultivar field trials were placed in a large outdoor storage pile. Sugar beet quality assessments were taken at harvest and three times over the storage season. On the last retrieval date only, sugar beet samples were retrieved from piles managed via the length-vs. end-removal method. Although there were differences among N treatments and cultivars in sugar beet quality at harvest, there were no storage date by N treatment or storage date by cultivar interactions for any parameters measured indicating that N fertilization or cultivar did not influence the ability to maintain sugar beet quality in large outdoor piles. The lengthremoval method of pile management had better quality sugar beets compared with the standard end-removal method. Hence, sugar beet producers do not need to modify production practices to optimize storability, but sugar beet processors can improve sucrose recovery by removing sugar beets lengthwise along both sides of large piles as opposed to the standard end-removal method.Key words: Sucrose, pile removal, ammonium nitrogen fertilizer, variety, EuroMaus Van Eerd, L. L., Congreves, K. A. et Zandstra, J. W. 2012. La qualite´de la betterave sucrie`re (Beta vulgaris L.) durant le stockage exte´rieur en tas importants est affecte´e par la me´thode de gestion des stocks, mais pas par l'usage d'engrais azote´s ni le cultivar. Can. J. Plant Sci. 92: xxxÁxxx. Bien que le stockage re´duise la quantite´de sucrose extraite de la betterave sucrie`re, les contraintes physiques ne´cessite l'entreposage d'une part importante de la re´colte avant transformation pendant un maximum de 120 jours. De 2006 a`2010, les auteurs ont e´value´se´pare´ment la fertilisation avec des engrais azote´s (0 a`220 kg de N par hectare), le cultivar et la me´thode de gestion des stocks en vue d'e´tablir l'incidence de ces parame`tres sur la capacite´d'entreposage des betteraves sucrie`res en gros tas exte´rieurs. À la re´colte, ils ont pre´leve´cinq e´chantillons repre´sentatifs de betteraves dans les parcelles soumises aux essais de fertilisation N et de cultivar, et les ont de´pose´s dans des amas importants stocke´s a`l'exte´rieur. Ils ont ensuite e´value´la qualite´des betteraves a`la re´colte et a`trois autres moments, durant l'entreposage. À la dernie`re date seulement, ils ont re´cupe´re´les e´chantillons des tas ge´re´s selon la dure´e d'entreposage ou par re´cupe´ration a`une extre´mite´de l'amas. Bien que l'us...

Congreves, K. A., Smith, J. M., Németh, D. D., Hooker, D. C. and Van Eerd, L. L. 2014. Soil organic carbon and land use: Processes and potential in Ontario’s long-term agro-ecosystem research sites. Can. J. Soil Sci. 94: 317–336. Soil organic carbon (SOC) is crucial for maintaining a productive agro-ecosystem. Long-term research must be synthesized to understand the effects of land management on SOC storage and to develop best practices to prevent soil degradation. Therefore, this review compiled an inventory of long-term Ontario studies and assessed SOC storage under common Ontario land management regimes via a meta-analysis and literature review. In general, greater SOC storage occurred in no-till (NT) vs. tillage systems, in crop rotation vs. continuous corn, and in N fertilizer vs. no N fertilizer systems; however, soil texture and perhaps drainage class may determine the effects of tillage. The effect on SOC storage was variable when deeper soil depth ranges (0–45 cm) were considered for NT and rotational cropping, which suggests an unpredictable effect of land management on SOC at depths below the plough layer. Therefore, researchers are encouraged to use the presented inventory of nine long-term research sites and 18 active experiments in Ontario to pursue coordinated studies of long-term land management on SOC at depths extending below the plough layer.

. 2015. Response of four spring-seeded cover crops to residues of selected herbicides. Can. J. Plant Sci. 95: 303Á313. Although herbicide labels provide crop rotation restrictions, information is limited on the influence of herbicide residues on cover crops. Field experiments were conducted in 2011/2012 and 2012/2013 in Ontario, Canada, to characterize the effects of soil residues of selected herbicides on establishment and growth of buckwheat (Fagopyrum esculentum Moench), annual ryegrass (Lolium multiflorum Lam.), sorghum sudangrass [Sorghum bicolor (L.) Moench )Sorghum sudanense (P.) Stapf], and spring wheat (Triticum aestivum L.) spring-seeded cover crops planted 1 yr after application. Imazethapyr (100 and 200 g ha ) was applied pre-emergence (PRE) to processing peas (Pisum sativum L.), while S-metolachlor/atrazine plus mesotrione (2880'140 and 5760'280 g ha (1 ) and saflufenacil/ dimethenamid-P (735 and 1470 g ha(1 ) were applied PRE to sweet corn (Zea mays L.). Imazethapyr residues from 200 g ha(1 caused 75 and 48% visible injury in buckwheat and sorghum sudangrass, respectively. Plant light attenuation, shoot dry weight, and nitrate-nitrogen content were reduced up to 82, 64 and 67% in buckwheat, and 40, 11 and 24% in sorghum sudangrass, respectively, by residues from imazethapyr. S-metolachlor/atrazine plus mesotrione residues caused up to 53% visible injury to annual ryegrass and reduced plant light attenuation, shoot dry weight, and nitrate-nitrogen content by as much as 59, 48, and 55%, respectively. There were no observable adverse effects of visible injury, light attenuation, shoot dry weight, and nitrate-nitrogen content on spring wheat regardless of herbicide or rate. These results indicate that buckwheat and sorghum sudangrass should not be grown in the year following imazethapyr, and that annual ryegrass should not be grown in the year after application of S-metolachlor/atrazine plus mesotrione. However, no restrictions are needed for growing spring wheat following these herbicides. 0, 11 et 24 % chez le sorgho. Les re´sidus de S-metolachlor/atrazine et de mesotrione engendrent jusqu'a`53 % de dommages visibles chez le ray-grass annuel et diminuent l'atte´nuation de la lumie`re, le poids sec des pousses et la teneur en azote-nitrate de jusqu'a`59, 48 et 55 %, respectivement. L'herbicide et son taux d'application n'ont aucun effet ne´faste apparent au niveau des dommages visibles, de l'atte´nuation de la lumie`re, du poids sec des pousses et de la teneur en azote-nitrate pour le ble´de printemps. Ces re´sultats indiquent qu'on ne devrait pas cultiver du sarrasin ni du sorgho l'anne´e suivant l'application d'imazethapyr et qu'on ne devrait pas semer du ray-grass annuel l'anne´e suivant l'application de S-metolachlor/atrazine et de mesotrione. Toutefois, aucune restriction ne s'applique au ble´de printemps apre`s l'utilisation de ces herbicides.Mots clé s: Cultures-abris, re´sidus d'herbicide, absorption de l'azote, atte´nuation de la lumie`re Crop rotation is one of the major factors conside...