No-till strip row farming using yearly maize-soybean rotation increases yield of maize by 75 %

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1 Agron. Sustin. Dev. (2015) 35: DOI /s y RESEARCH ARTICLE No-till strip row frming using yerly mize-soyen rottion increses yield of mize y 75 % Rfiq Islm & Den C. Glenney & George Lzrovits Accepted: 20 Jnury 2015 /Pulished online: 27 Ferury 2015 # INRA nd Springer-Verlg Frnce 2015 Astrct Development of gronomic prctices tht mximize the use of nturl resources to improve soil helth nd crop productivity is criticl for long-term sustinility of griculturl technologies. In Ontrio, Cnd, the most conventionl mize production prctice follows 3-yer rottion with soyens nd ploughing of the lnd efore plnting nd fter hrvesting. This technology yields 8 10 t h 1 of mize. We ecme wre of long-term no-till strip row frming system developed y n Ontrio grower where mize yields re doule tht of the verge for the province. This study set out to identify wht fctors contriute to such mssive yield increse nd the sis for this superior method of mize production. In 2-yer field study, we compred vriety of iotic nd iotic fctors ssocited with yields t this highly productive site with those of two verge yielding sites. The notill strip row frming system grew mize nd soyens in lternte strips rotted yerly nd hd higher plnt popultions, etter root rchitecture, higher plnt iomss, nd 75 % greter (18.35 t h 1 ) grin yield compred to nery frm tht used conventionl production prctices. Aout 21 % of the yield increse resulted from erly plnting, greter numer of seeds plnted, nd helthier ers/seeds. The remining 54 % increse ws linked to lrger ers, which we tenttively ttriute to eneficil effects conferred y the microorgnisms tht develop in this unique gro-ecosystem. The verge net return t the no-till site ws estimted to e CDN (Cndin) $2000 h 1, which ws 400 % higher thn the net returns of the conventionl sites. The study concludes tht no-till mngement where soil remins undistured when comined with yerly rottions of n pproprite legume crop, growing crops exctly on the sme cropping rows every yer, nd R. Islm (*): D. C. Glenney : G. Lzrovits A&L Biologicls, Agroecologicl Reserch Services Centre, 2136 Jetstrem Rd, London, ON N5V 3P5, Cnd e-mil: rfiq@lcnd.com optimiztion of plnt density cretes sustinle technology for mximizing mize yields. Keywords Long-term no-till. Strip row frming. Conventionl production prctice. Yerly mize-soyen rottion. Optimum plnt density. Mize yield improvement. Incresed net return 1 Introduction Technologicl innovtions tht increse crop yield, reduce frmers cost, improve soil helth, nd protect the environment re necessry for the next genertion of griculturl production systems (Hos et l. 2008). Agriculturl prctices tht rely on chemicls nd tillge re not considered to hve much potentil for contriuting to future yield increses (Edgerton 2009). Mny components of such prctices hve ecome costly to growers while degrding soil physicl structure nd negtively impcting the environment (Svci 2012). Cropping prctices such s no-tillge systems comined with crop rottion using pproprite plnt species nd retention of crop residues on the soil re known to minimize mny of the dverse effects cused y current crop production prctices (Hos et l. 2008). Advntges of the no-till cultivtion systems include cost, protection of soil integrity, reduction in erosion, conservtion of soil moisture, reduced soil tempertures during summer, nd fewer emissions of greenhouse gses (Hos et l. 2008; Piv et l. 2012). No-till systems lso improve physicl, chemicl, nd iologicl properties of soil (Mrtinez et l. 2013), including the evolution or mintennce of eneficil microil communities tht rise from miniml soil disturnce nd pproprite crop rottions (Peters et l. 2003). In Ontrio, Cnd, mize is grown under rin-fed conditions, nd conventionl mize production relies on ploughing

2 838 R. Islm et l. the lnd in the fll followed y second tillge in the spring to incorporte the crop residue. Seeds re most commonly plnted in rows with cm spcing, nd crop sequences follow 3-yer rottion of cerels, forges, or soyens (Glycine mx L. Merr). No-tillge frming usully involves miniml soil opening in nrrow nd, followed y seeding into the nds using plnter-mounted coulters nd/or residue clering devices. The crop rottions re similr for oth methods nd they generlly otin similr yields verging 9.2 t h 1 (153.5 u c 1 ) (Bgg et l. 2009; Anonymous ). An Ontrio grower, Mr. Den C. Glenney, developed no-till strip row frming system, which he termed Fence Row Frming ( MAGAZINE.spx?id=572). While Mr. Glenney ws working t the fmily frm t young ge, he noticed tht the plnts growing long the undistured fence rows hd etter growth thn the crops in rest of the ploughed field. This oservtion encourged him to grdully convert his conventionl mize field to no-till strip row frming. Mize yields egn to increse in his field fter 5 to 6 yers of inititing the prctice nd hve kept incresing s the system continues to e refined (Rhoton 2000; Mrtinez et l. 2013). He plnts seeds exctly on the sme cropping rows every yer y pssing through the mulch using plnter he designed. The plnter wheels never roll over the cropping rows; thus, the rows hve remined undistured since this prctice egn. Mize nd soyens re grown in strips nd lternte yerly (Fig. 1). Now, fter 15 yers of this prctice, verge yields re t h 1 (300 u c 1 ), more thn doule the verge of 9. 2th 1 found in Ontrio (Anonymous ). Soyen yields verge 4.0 t h 1 (60 u c 1 ), slightly higher thn the Ontrio verge. It is possile tht llelopthic effects ssocited with mize-soyen rottions my limit the yield increses expected with soyens t the no-till site (Mmolos nd Klurtji 2001). An understnding of wht chnges rought out the incresed mize yield is of gret interest to oth the grower nd the industry. The im of our study ws to identify key iologicl nd non-iologicl fctors involved in the yield increses y compring fctors to those found t nery frm where conventionl production prctices were used. 2Mterilsndmethods 2.1 Estlishment of field experiments This study ws conducted t two frmers fields locted in Dunnville, Ontrio, Cnd, during 2012 nd 2013 crop sesons. The no-till strip row mize frm is 75 h re of lnd t " N nd " W. The size of ech strip is 4 m wide nd 80 m long. Two nery conventionl production sites owned y the sme frmer re locted t " N nd " W. The strip frm is 5 km from the conventionl mize fields. Soils of the experimentl sites re chrcterized y BRR5 nd TLD2, Berrien nd Toledo. The prent mteril for the experimentl site is cm sndy texture over lcustrine silty cly nd cm sndy sediments over lcustrine cly nd silty cly. The two conventionl production sites, termed conventionl-1 site (in 2012) nd conventionl-2 site (in 2013), re oth out 50 h ech. In 2012, the no-till strip row site ws designted s no-till-1 site nd ws compred with the conventionl-1 site. In 2013, s regulr prctice, the mize nd soyen strips were lternted with ech other nd the plot ws designted s no-till-2 site nd compred with conventionl-2 site. Lnd preprtion, plnting, nd crop mngement were done y the frmers without chnging their norml prctices, except tht we Soy strip Soy strip Mize strip Twin rows Fig. 1 Long-term no-till mize-soyen (soy) strip row frming prctice locted in Dunnville, Ontrio, Cnd. Left, lternte mize nd soyen strips. Right, experimentl site in June 2013 demonstrtes tht crops re grown in twin rows nd retin crop residues on the soil surfce. The mize nd soyen strips shown here were plnted with lternte crop in In 2013, plnting ws done exctly on the previous cropping rows

3 No-till strip row frming using yerly mize-soyen rottion 839 requested tht oth frmers plnt the identicl mize hyrid. We rndomly chose four replicte plots (10 m 4 m ech) in ech field nd designted these s the experimentl plots. The history of the no-till frm nd the culturl prctices etween the experimentl sites were recorded. 2.2 Soil properties, moisture content, nd plnt popultion At 30, 60, nd 90 dys (d) fter seed sowing, 20 whole plnts were rndomly selected from ech of the four replicte plots nd removed using clen shovel. The plnts were rought ck to the lortory for further nlyses. The soil ttched to the roots (pproximtely cm depth soil) ws shken off from ll hrvested plnts nd used for nlysis of soil texture, soil orgnic mtter content, ph, nd nutrients. Two hundred grms of ech soil smple ws oven-dried t 80 C for 24 h to determine the moisture content. The plnt popultions of 4 m 2 m res plot 1 were determined t 30 d. The collected plnts nd soils were used for nlyses s descried in the following sections. 2.3 Nutritionl sttus of root zone soil nd plnt tissues Chemicl nlyses of soils included ville NO 3 -N, essentil micro-/mcro-nutrients (in μg ml 1 ), se (K, C, Mg) sturtion (%), ction exchnge cpcity (in meq 100 g 1 ), nd K/Mg rtio s descried ove (Jones 1999; Rice et l. 2012). Individul plnt roots, stems, leves, nd cos (if ny) were seprted. Stem nd lef tissues of the 20 plnts t ech growth stge were lso nlyzed for micro-/mcro-nutrients, nd the vlues were compred to expected vlues pulished for soil nd mize plnts y Bgg et l. (2009), Anonymous (2001), Mills nd Jones (1997), nd personl communiction to Mr. Greg Ptterson, Certified Agronomist with A&L Cnd Lortories Inc. 2.4 Lef chlorophyll content, shoot height, nd dry plnt iomss Chlorophyll content of three young leves from ech of the 20 mize plnts t three growth stges ws mesured using SPAD-502 meter (Konic Minolt, Osk, Jpn) in the field sites. Shoot heights were mesured fter the plnts were rought to the lortory. Roots were clened y wshing with running tp wter. The roots, stems, nd leves of individul plnts were chopped into smll pieces nd dried for 24 h t 80 C, nd their dry iomsses were mesured. 2.5 Root nd co diseses nd yield losses Before tking the dry weight, the numer of nodl roots per plnt nd numer of plnts which hd roots tht reched/ penetrted the plough pn lyer (>35 cm) were determined t 90 d. Root helth of plnts t the three growth stges ws determined y visul exmintion under inoculr microscope, nd the incidence of root dmge ws recorded. Five months fter sowing, 400 mize plnts were rndomly hrvested from ech site for determintion of yield nd the impct of disese on grin qulity. The incidence nd severity of disesed ers were grouped into the following ctegories; helthy (0 4.9 % infection t the co tip), mild (5 9.9 %), moderte ( %), nd severe (20 30 %). Disesed grins from ech of 400 ers from ech site were counted nd converted to grin loss from ech er s percentge sed on the totl seeds counted, nd the vlues were verged to determine yield losses. 2.6 Grin yields, nutritionl vlues of kernels, cost of crop production, nd net return The length nd dimeter of 100 rndomly chosen ers from ech field were mesured. The totl numer of kernels per er ws determined, nd 50 kernels from ech plot were rndomly chosen nd weighed. The weights per plot of the totl hrvested grin were determined sed on 15.5 % moisture content. The nutritionl sttus of hrvested kernels from no-till nd conventionl sites ws lso determined (Jones 1999; Horwitz 2003). Totl cost of production included input, lor, mchinery, crop insurnce, hndling/processing grins, nd mrketing. The gross return ws clculted from the yield (kg) per hectre multiplied y the price per kilogrm. Net income ws determinedysutrctingtotlcost from gross return. 2.7 Sttisticl nlysis The dt were nlyzed using SigmPlot 12.0 softwre (Systt Softwre Inc., Sn Jose, CA, USA). The results were verges of 20 replictions, stted s men±stndrd error. Differences etween mens were considered significnt t proility (p) vlue lower thn 5 % ccording to Tukey s HSD test. 3 Results nd discussion 3.1 Differences of soil properties, soil moisture, nd culturl prctices etween no-till nd conventionl sites Soil properties nd moisture levels t different plnt growth stges The soils of no-till nd conventionl-1 nd -2 sites were identified to e sndy lom, sndy cly lom, nd lomy snd, respectively (Tle 1). The soils elonged to the corse texture clss nd were considered to hve good internl dringe cpcity. The root zone soil (10 30 cm depth) from no-till site contined 3.0 % orgnic mtter, the verge found in most

4 840 R. Islm et l. rle soils in this region. Soil ph of plots t the no-till site ws 7.0, which is suitle for mize growth. The conventionl-1/2 site soils hd 5.3/7.2 % orgnic mtter nd ph of 7.5/ 7.4, respectively. The higher orgnic mtter in the root zone soils of conventionl sites could enefit the crops, ut the ph vlues were slightly ove the optimum rnge for mize, which might negtively impct yields t these sites. Some possile resons for higher orgnic mtter t the conventionl sites could e the differences of soil type nd tillge prctice compred to the no-till site. A numer of studies reveled tht the deposition of orgnic mtter in the top soil (0 10 cm depth) ws higher in long-term no-till soil compred to conventionl fields. In contrst, orgnic mtter content t the depth of cm ppered to e higher in tilled soil thn tht in no-tilled soil (Deen nd Ktki 2003; Frnzlueers nd Stuedemnn 2014; Liu et l. 2014). We were unle to find ny pulished reltionship etween soil orgnic mtter nd crop productivity nd thus did not ssign ny role for this fctor to yield impcts t ny site used. Moisture levels in the root zone soils were determined to e very similr t no-till-1/ conventionl-1 nd no-till-2/conventionl-2 sites, suggesting tht yield vritions were not relted to moisture deficiency or wterlogging conditions Culturl prctices A vriety of fctors were found to e similr nd dissimilr in the culturl prctices used t the no-till nd conventionl sites over the 2 yers of this study (Tle 1). Similrities included the following: growing the identicl mize hyrid (P0216 AM-R), est to west crop row direction, nd no folir pesticide ppliction. The mjor differences etween the two frming systems were s follows: At the no-till site, the lnd ws not ploughed, mize nd soyen strips (ech 4 m wide) were lternted, crops were grown exctly on the previously grown rows, nd crop residues were retined on the soil surfce. In contrst, soil t the conventionl sites ws ploughed efore sowing, crop residues were incorported into the soil, nd 2 yers of mize production ws followed y 1 yer of soyens. Seeding t the no-till site ws done on My 5th, the recommend dte (efore or on My 7th) for this climtic zone, wheres sowing occurred 1 week lter thn the recommend dte t the conventionl sites.. According to Bgg et l. (2009), one cn expect 1 % yield reduction per dy of lte plnting; thus, we ssume tht this led to 7 % yield loss t this site. Mize t the no-till site ws grown in 20 cm twin rows nd the seeds were plced 25 cm prt, with 55 cm gp etween the twin rows (Fig. 1). At the conventionl sites, the row spcing ws 75 cm nd seeds were plced 15 cm prt. As result, the numers of stnding mize plnts t the no-till-1/2 sites were 79,500/80,400 h 1, compred to the conventionl- 1/2 sites where 72,300/72,200 h 1 plnts were counted. The extr 7,000 8,000 plnts re expected to increse the yield difference out 10.5 %. The row spcing my lso contriute to higher yields. Gozuenli et l. (2004) found tht mize when grown in twin rows often yielded significntly etter thn those in single-row systems when there were 90,000 plnts h 1. The fertilizer rtes t the no-till nd conventionl-1/2 sites differed only slightly (Tle 1), ut nding fertilizer hs een shown to enefit yields. However, we re unle to ssign yield fctor to fertilizer plcement. 3.2 Anlysis of micro- nd mcro-nutrients in soils nd mize stem/leves from no-till nd conventionl sites Plnt ville minerl nutrients in root zone soil At ll sites, NO 3 -N in soils from the root zone t 30 d ws found to e in the optimum rnge (10 25 μg ml 1 )(Tle2- A). NO 3 -N levels in other sites decresed s the seson Tle 1 Comprisons of the soil properties nd mize mngement prctices etween no-till nd conventionl fields Crop field Soil texture SOM (%) ph Till/no-till Crop rottion Plnts h 1 Row/plnt spcing (cm) Fertilizer (kg h 1 ) Ure P 2 O 5 K 2 O No-till-1 Sndy lom Not tilled Mize-Soyen-mize 79,500 TR BTR 55 BP 25 Conventionl-1 Sndy cly lom Tilled Mize-mize-Soyen-mize 72,300 BR BP 15 No-till-2 Sndy lom Not tilled Sme s no-till-1 80,400 Sme s no-till Conventionl-2 Lomy snd Tilled Sme s conventionl-1 72,200 Sme s conventionl The no-till experimentl site ws designted s no-till-1 nd no-till-2 in the 2012 nd 2013 crop sesons, respectively. Conventionl-1 nd conventionl-2 represent the conventionl experimentl sites in the yers 2012 nd 2013, respectively. Pioneer Hi-Bred P0216 AM-R* mize vriety ws grown in ll experimentl sites. *AM-R geneticlly modified Pioneer Hi-Bred mize hyrid resistnt to rootworm, hericide, nd Europen stem orer SOM soil orgnic mtter, TR twin rows, BTR etween twin rows, BP etween plnts

5 No-till strip row frming using yerly mize-soyen rottion 841 Tle 2 Anlysis of nutritionl vlues in soils nd stem/leves of mize from no-till nd conventionl fields Crop field Plnt ge (dys) A. Solule minerl nutrients in the root zone soil NO 3 -N P S Zn Mn B Cu Fe K (%) C (%) Mg (%) No-till Conventionl No-till Conventionl Optimum B. Nutrient levels in mize stem nd lef tissues N (%) P (%) S (%) Zn Mn B Cu Fe K (%) C (%) Mg (%) No-till Conventionl No-till Conventionl Optimum The nutritionl vlues were compred in the 2012 seson etween no-till-1 nd conventionl-1sites t 30, 60, nd 90 d of plnting. The experiment ws repeted in the following yer nd the sites were designted s no-till-2 nd conventionl-2 sites. The vlues re n verge of rndomly selected 20 plnt smples. The nutrients re mesured in μg ml 1 unless indicted otherwise Vlues elow the optimum levels of nutrients Optiml levels of nutrients in soil, mize stems, nd leves

6 842 R. Islm et l. progressed, except tht no-till-2 soil t 90 d contined higher NO 3 -N compred to tht t 60 d. Insufficient NO 3 -N ws found in no-till-1 soil t 60 d (5.7 μg ml 1 ) nd 90 d (5.1 μgml 1 ), no-till-2 t 60 d (7.7 μgml 1 ), nd conventionl-2 t 60 d (5.4 μgml 1 ) nd 90 d (3.3 μgml 1 ). In contrst, very high NO 3 -N ws found in conventionl-1 soils t ll three growth stges (66,61,30 μg ml 1,respectively),presumly due to high orgnic mtter content in the soil. Most minerl nutrients in no-till-1/ 2 sites soils were dequte or ove the optiml rnges (K, 2 5%;C,60 80 %; Mg, %; S, μg ml 1 ;Zn,3 5 μg ml 1 ;Mn,10 25 μg ml 1 ;Cu,1 1.5 μg ml 1 ), except B deficiency ws present in no-till-2 (optimum 1 3 μgml 1 ). Bicronte P nd Fe in ll soils were found to e higher thn were considered to e the optimum rnges (P, μgml 1 ;Fe,12 24 μgml 1 ). Conventionl- 1 site soil hd very high S (52 67 μg ml 1 ) nd slightly high Zn, Cu, nd C, ut norml rnges of Mn, B, K, nd Mg. Conventionl-2 site soil hd high S (23 25 μg ml 1 ) nd sufficient or ove the norml levels of Zn, Mn, Cu, nd C. This soil lso hd indequte K (0.7 1 %) nd Mg (7 %). The K nd Mg rtio in the no-till site ws , which ws either in optiml rnge or slightly ove ( ), nd the vlues were sttisticlly higher compred to conventionl-1/2 site soils ( ). Conversely, the ction exchnge cpcity of the conventionl soils ws remrkly higher (17 21 meq 100 g 1 ) thn soils from the no-till site (9 10 meq 100 g 1 ). The higher orgnic mtter in the conventionl field soils is likely ssocited with the incresed ction exchnge cpcity of these fields. Bsed on results of the chemicl nlysis, oth no-till-1/2 nd conventionl-1 field crops hd suffered from N deficiency, prticulrly t the lter growth stges. N deficiency symptoms were visile in plnts from oth field plnts. Interestingly, no-till site plnts quickly recovered nd vigorous growth ws oserved during dys fter plnting. This oservtion rised the question of whether the tremendous growth of mize is ssocited with certin microorgnisms tht hve evolved in this long-term undistured soil. Although most soils hd sufficient levels of other essentil nutrients over the seson, no-till-2 hd indequte B nd conventionl-2 hd K nd Mg deficiencies. This likely hd some dverse effects on crop performnce t these fields (Ckmk et l. 1994). Plnts nutrient cquisition is ffected y gronomic prctices (Mlhi et l. 2006); therefore, the plnt tissues from the fields were nlyzed to confirm if plnts hd dequte nutrients for proper growth nd development Nutritionl sttus in mize plnt tissue Plnt tissues from no-till site hd optiml concentrtions of N ( %), P ( %), S ( %), Zn (25 70 μg ml 1 ), Mn ( μg ml 1 ), Cu (5 20 μg ml 1 ), Fe ( μg ml 1 ), K ( %), C ( %), nd Mg ( %) (Tle 2-B) (Mills nd Jones 1997). Although notill-2 site plnts suffered from B deficiency t 30 d (1.0 μg ml 1 ) nd 60 d (1.5 μg ml 1 ), the expected level (5 20 μgml 1 ) ws met t 90 d (8.6 μgml 1 ). With some exceptions, plnts from conventionl-1 nd -2 sites hd dequte nutrients t ll three growth stges. Plnt tissues from conventionl-1 field hd insufficient K (1.6 %) t 90 d, nd Mn (13 μg ml 1 ) t 30 d. In erly growth stges (30 d), conventionl-2 site plnt tissues were found to e deficient in N (2.7 %), nd Zn (20 μg ml 1 ), nd Mn deficiency ws determined t 90 d (14.4 μgml 1 ). With the ove exceptions, plnt tissues from ll sites hd dequte levels of N in ll growth stges, including the soils tht were found to e deficient in NO 3 -N. The chemicl nlyses indicte tht overll, plnts likely did not suffer from ny prolonged periods of nutrient deficiency during the seson nd thus soil fertility did not likely contriute considerly to yield differences etween fields. Tken together, these results imply tht other fctors, such s soil/endophytic microorgnisms, could e involved in the vigorous plnt growth nd incresed grin yield t no-till site (Ryn et l. 2008). 3.3 Lef chlorophyll content, shoot height, nd totl plnt iomss The lef chlorophyll content in ll fields incresed with plnt development when exmined t 30, 60, nd 90 d. The chlorophyll levels of plnts t the no-till site were 3 4 SPADunits higher thn those t conventionl sites t ll dtes smples (dt not shown). Shoot heights were identicl etween fields t 30 d, ut y 60 d, tller plnts were found t no-till site compred to plnts t the conventionl site. The differences were significnt t 90 d etween no-till site crops (verge of no-till-1/2 sites, 270/273 cm) nd conventionl-1/2 sites (237/ 241 cm) (p lower thn 1 %) (Fig. 2). Between 60 nd 90 d, the verge shoot growth t no-till-1/2 sites nd conventionl- 1/2 sites were clculted to e 3.3/3.2 nd 2.2/2.2 cm d 1, respectively. Similrly, the totl dry plnt iomsses of notill nd conventionl sites t 30 d were similr (no-till-1/2 sites, 2.1/2.5 g plnt 1 ; conventionl-1/2 sites, 2.4/2.3 g plnt 1 ) (Fig. 2). By 60 d, however, the plnt iomss t the no-till-1/2 sites (71.5/73.3 g) ws higher thn tht found t the conventionl-1/2 sites (66.9/68.4 g). The verge iomsses of no-till-1/2 plnts (274.8/276.6 g plnt 1 )t90d were lso significntly higher thn those t the conventionl- 1/2 sites (242.5/245.4 g plnt 1 )(p lower thn 1 %). The lef chlorophyll, plnt heights, nd totl iomsses were sttisticlly similr etween no-till-1 nd no-till-2, nd conventionl- 1 nd conventionl-2 field crops. The lef chlorophyll content results indicte tht plnts t the no-till site hd generlly higher photosynthetic cpcity nd lef N, which likely contriuted to the incresed growth, iomss production, nd seed yield (Gholizdeh et l. 2011).

7 No-till strip row frming using yerly mize-soyen rottion 843 A Shoot height (cm) No-till site 30 d 60 d 90 d PLANT AGE Conventionl 2 Conventionl-1 Fig. 2 Growth pttern of mize plnts produced in two differentilly mnged production prctices. Shoot height nd totl dry iomss of mize plnts collected from long-term no-till nd conventionl production sites, nd compred t 30, 60, nd 90 d fter plnting. The experiment ws conducted in 2012 (no-till-1 site nd conventionl-1 site) B Plnt iomss (g plnt -1 ) No-till-1 30 d 60 d 90 d PLANT AGE Conventionl-1 No-till-2 Conventionl-2 nd 2013 (no-till-2 site nd conventionl-2 site). No-till site represents the verge shoot length of two crop sesons (no-till-1 nd no-till-2). Different field dt re seprted y line or r colors. The vlues re the verge of 20 plnts. Significntly different vlues re indicted y different letters t p vlue lower thn 1 % ccording to Tukey s HSD test 3.4 Numer of nodl roots, longer roots, nd root iomss At 90 d, root systems of plnts from no-till sites were generlly lrger, thicker, longer, nd more rnched compred to those collected from the conventionl sites. The numers of nodl roots, considered to e crucil for supplying the mjority of wter nd minerl nutrients to plnts, ws lso greter t the no-till-1/2 sites: (53/54 plnt 1 )compredtoplntsfrom the conventionl-1/2 sites (48/50 plnt 1 )(Fig.3). More thn 75 % of no-till site plnts hd long roots (lrger thn 35 cm) tht penetrted the plough pn lyer (Brrclough nd Weir 1988)(Fig.3). This implies tht roots hd much esier time penetrting the porous soils t the no-till site. Conversely, significntly fewer plnts from conventionl-1/2 sites (4/5 %) hd roots lrger thn 35 cm (p lower thn 1 %), indicting the potentilly dverse effect of tillge nd compction on soil physicl properties. Although the root iomss from no-till nd conventionl site plnts ws comprle t 30 nd 60 d, y 90 d, no-till-1/2 crops hd significntly higher root iomss (50.7/51.3 g plnt 1 ) thn crops t the conventionl-1 (39.8 g plnt 1 ) nd conventionl-2 sites (41.0 g plnt 1 )(p lower thn 5 %) (Fig. 3). These results suggest tht the etter root growth nd rchitecture of no-till site crops incresed rte of nutrients nd wter uptke to the plnts, which might hve contriuted to higher plnt growth nd incresed grin yield. 3.5 Insect pest/diseses nd crop losses At 30 nd 60 d, occsionl scttered rown lesions nd root tip necrosis were found on roots from the no-till nd conventionl sites. At 90 d, the incidence nd severity of lesions were slightly higher on roots from the no-till site thn on roots from the conventionl sites. No-till prctice ppers to uild up specific soil-orne pthogens (Sturz et l. 1997), nd the yerly rottions with soyens do not pper to ddress this concern. The degree of root infection ws found to vry considerly mong the replicted plots within the sme fields. Interestingly, the level of root lesions did not lwys correlte with the grin yield loss or increse in ny of the experimentl Numer, percentge or weight (g) Nodl roots Longer roots Root iomss ROOT PARAMETERS Fig. 3 Comprisons of root growth of mize grown in no-till strip row nd conventionl production fields. The dt were otined from no-till-1 in 2012, nd no-till-2 in 2013 crop sesons. Conventionl-1 nd conventionl-2 sites represent the conventionl mize fields in the yer 2012 nd 2013, respectively. Numer of nodl roots per plnt, percentge of plnts hving longer roots (>35 cm), nd dry root iomss per plnt (g) from 20 replicte smples were nlyzed t 90 d fter plnting. The r colors represent dt from different fields. Vlues seprted y different letters within the sme prmeter re significntly different t p vlue lower thn 1 % (longer roots) or 5 % (root iomss) ccording to Tukey s HSD test No-till-1 Conventionl-1 No-till-2 Conventionl-2

8 844 R. Islm et l. Tle 3 Comprisons of yield prmeters, mize yield, production expenses, nd net return Crop fields Prmeters/fctors No-till-1 Conventionl-1 No-till-2 Conventionl-2 Er prmeter Er length (cm)* Er dimeter (cm)* No. kernel co 1 ** Grin yield Ech kernel weight (g)* Grin weight plnt 1 (g)** Totl yield (ton h 1 )** Yield increses t no-till site Plnt 1 (%) Totl h 1 (%) Fctors reduced yield t conventionl site Lte plnting (%) Er dmges y the pest (%) Fctorsincresedyieldtno-tillsite Higher plnt popultion (%)* Lrger ers (%) Cost enefit per hectre (CDN $) Totl expense Gross return Net income** The components were compred etween no-till-1 nd conventionl-1 fields in the 2012 seson, nd no-till-2 nd conventionl-2 sites in Vlues in one row with different letters re sttisticlly different ccording to Tukey shsdtesttp vlues less thn 5 % (*) or 1 % (**). Totl yield = yield plnt 1 X no. plnts h 1. + nd ++ Differences etween no-till-1 nd conventionl-1, nd no-till-2 nd conventionl-2, respectively. +++ Lrger ers = totl yield increses t the no-till site (fctors tht reduced yield t conventionl site + incresed plnt popultion dded to higher yield t no-till site). CDN $ = Cndin dollr plots. We re currently exmining how to minimize the incresed popultions of root pthogens t the no-till site nd perhps generte yield increses ove 20 t h 1. Both incidence nd severity of er diseses (hed light) were significntly higher in crops grown t the conventionl-1 nd 2 sites compred to those found t the no-till site (plower thn 5 %), lthough none of the fields were spryed with fungicides. At the conventionl-1 site, 5.2, 10.75, nd 35 % of ers were infected severely (20 30 % er infection from the tip of the co), modertely ( % infection), or mildly (5 9.9 % infection), respectively. In contrst, t the no-till-1 site, 0.5, 0.75, nd 34 % ers were found to e dmged severely, modertely, or mildly, respectively. The cumultive grin yield losses t no-till-1 nd conventionl-1 sites were estimted to e 1.8 nd 5.2 %, respectively. Crop losses in no-till-2 nd conventionl-2 sites were estimted to e 1.7 nd 5.0 %, respectively. Due to hed light disese, the grin yield losses t conventionl-1 nd -2 sites were estimted to e 3.4 nd 3.3 % higher compred to those t no-till-1 nd -2 sites, respectively (p lower thn 5 %) (Tle 3). 3.6 Grin yield, nutritionl vlues in grins, cost of crop production, nd net return Mesurements of ll yield prmeters of the no-till site were found to e significntly higher thn tht of the conventionl site. The verge co sizes of no-till-1/2 sites (length, 20.8/ 20.6 cm; dimeter, 5.4/5.5 cm) were significntly greter thn similr mesurements of cos from the conventionl-1/2 (length, 17.7/19.4 cm; dimeter, 4.9/4.7 cm) (p lower thn 5%)(Tle 3). Significntly higher numers of kernels per co were found with no-till-1/2 crops (642/645) thn from the conventionl-1/2 cos (501/490) (p lower thn 1 %). Ech notill-1/2 plnt yielded 55.4/61.7 % more grin on verge compred to conventionl-1/2, respectively (p lower thn 1 %). Regrdless of seson, yield vrition etween replicte plots of no-till site ws indistinguishle; for instnce, no-till-2 site produced 21.22, 22.54, 21.63, nd kg grins per 100 plnts in plots 1, 2, 3, nd 4, respectively. In contrst, vrition of yields etween replictions ws oserved in the conventionl sites. For exmple, (plot 1), (plot 2), 16.39

9 No-till strip row frming using yerly mize-soyen rottion 845 (plot 3), nd (plot 4) kg grins per 100 plnts were recorded t conventionl-2 site. The finl grin yields of notill-1, conventionl-1, no-till-2, nd conventionl-2 sites were sttisticlly different (p vlue lower thn 1 %) nd the productions were determined to e 18.3, 10.7, 18.4, nd 10.2 t h 1, respectively. The yields were comprle to the verge yields hrvested y the frmers, nmely 18.1 (no-till-1), 10.5 (conventionl-1), 18.0 (no-till-2), nd 10.2 (conventionl-2) t h 1. No-till-1 nd -2 sites yielded 71.0 nd 80.4 % higher yields thn conventionl-1 nd -2 sites, respectively (p lower thn 1%). Liu et l.(2014) recently reported yield increses nd improvements of soil qulity nd fertility of cerel crops fter 17 yers of no-tillge mngement. Further, we determined the comprle quntities of nutritionl vlues, nmely strch (63 65 %), crude protein ( %), totl digestile nutrient (87 88 μg g 1 ), nd minerls in the kernels from no-till nd conventionl sites. In this study, the yield contriuting nd reducing fctors in no-till nd conventionl sites were determined. In conventionl-1/2 sites, 7 % yield loss ws ttriuted to 7 d lte plnting, t 1 % yield reduction per dy (Bgg et l. 2009), nd 3.4 nd 3.3 % losses were due to er diseses in conventionl-1 nd -2 sites, respectively (Tle 3). Since no-till-1 nd -2 sites hd plnt density of 10 nd 11 % greter thn conventionl-1 nd - 2 sites, they were estimted to yield 10 nd 11 % more grin conventionl sites, respectively (p vlues lower thn 5 %). Tken together, out of the 75 % (verge of no-till-1 nd -2) yield increse t no-till sites, 21 % (verge of no-till-1 nd -2) ws due to sowing seeds t the optiml time, higher plnt popultions, nd helthy ers/seeds, while 54 % ws due to igger ers nd more seeds. We re focusing our future studies on elucidting fctors tht contriute to the vigorous plnt growth nd formtion of the lrger ers found t the no-till site. The cost of production etween no-till-1/2 nd conventionl-1/2 per hectre ws the sme, CDN $1500 h 1 (Tle 3), since the extr tillge cost t the conventionl sites ws minimized y the dditionl seed cost of the no-till site. However, the verge net revenue ws CDN $2000 h 1 from no-till-1/2 site, nd CDN $500 h 1 from the conventionl-1/2 sites; therefore, the no-till sites were four times more profitle thn the conventionl sites (p less thn 1 %). Long-term no-tillge mngement hs een demonstrted to e n effective nd sustinle cerel production prctice, generting 30 % yield increses in whet fter 17 yers of the prctice (Liu et l. 2014). In Ontrio, Cnd, oth no-tillge nd conventionl prctices follow similr row/plnt spcing nd crop rottion nd produced comprle mize yields in the yers (9.2 t h 1 )(Bggetl.2009; Anonymous ). We show here tht chnges in the gronomics of no-tillge system which include leving cropping rows undistured, integrting yerly crop rottion with n pproprite crop, growing plnts exctly on the sme rows every yer, nd mximizing plnt popultion cn improve the yields of mize y 75 % in corse texture soil locted in southern Ontrio, Cnd. Fifty-four percent of the 75 % yield increse is ttriuted to the lrger ers, ut the underlying mechnisms for producing igger ers in the notill site crop hs yet to e determined. We hypothesize tht the enhnced plnt growth nd protection of ers from pests re due to the ctivity of soil nd/or endophytic microil communities (de Mtos Nogueir et l. 2001), nd we will present dt elsewhere showing tht the microorgnism communities nd their functions in soil nd inside plnt tissues t the two loctions re vstly different. It is very likely tht leving the soil undistured long with repeted plnting of prticulr crops enhnces the evolution of microil communities. This would llow for the estlishment of criticl iomss of eneficil gents tht cn then colonize different plnt orgns (Peters et l. 2003; Chi et l. 2005;Kir2005). The reduced disese on the ers of no-till site mize could e due to microil popultions resident within the plnt tissues nd/or vi induction of systemic plnt resistnce y the root-ssocited microorgnisms (Pozo nd Azcon-Aguilr 2007). There re other fctors tht could e implicted to the yield increses t the no-till site such s improvements in soil texture, soil qulity, fertility, nd yerly rottion of mize with legume (Mlhi et l. 2006; Riedell et l. 2009; Liu et l. 2014). It tkes some yers to estlish such highly productive ecosystem for mize (Rhoton 2000), nd there re dded costs ssocited with dpting frming equipment. However, over time, the enefits re enormous in terms of net return, sustinility, iodiversity, nd environment impct. 4 Conclusion This study demonstrted tht it is possile to develop growing conditions for mize tht generte significntly higher grin yields. Edgerton (2009) indictes tht increses in mize yield will e derived primrily from introductions of novel genetic trits nd will rise verge mize yields of from 10 to 20 t h 1 y In his predictions, only 1 t h 1 of dditionl increse will come from chnges in gronomics over the next 15 yers. We clerly show in this study tht mize hyrids currently ville cn lredy produce 20 t h 1,utdo so only on soil where gronomic prctices hs een drmticlly ltered from prctices currently used in North Americ. Our results provide very cler dt tht the yield potentil of current mize vrieties is not eing relized. We hypothesize tht under optiml production technologies, current mize vrieties will yield over 30 t h 1. We need mjor chnge in ttitude towrd gronomic technology to chieve this. Current efforts imed t chnging the mounts of chemicl inputs nd their plcement re likely to hve miniml enefits to yield. However, focusing on creting groecosystems nd productive soils, s illustrted in this study, cn provide the wy

10 846 R. Islm et l. forwrd for mjor rekthroughs in crop productivity. It is highly possile tht y further tweking this system, we cn rise production to 25 t h 1 in the next 5 yers without hving to pour enormous mounts of resources into creting more new hyrids. There is need, however, to demonstrte tht this technology will hve equl enefits t other sites nd whether the mgnitude of yield responses will e of similr levels. If this production system cn e reproduced, growers will find the technology less costly nd more sustinle economiclly nd environmentlly. Acknowledgements We cknowledge the ssistnce of Mr. Clrence Hessels for llowing us to perform this reserch on his frms. We re extremely thnkful to the Grin Frmers of Ontrio nd Agriculture nd Agri-Food Cnd through the Cndin Agriculturl Adpttion Progrm for their finncil support to this project. We pprecite the dvice nd contriutions of Mr. Greg Ptterson, nd the work Clire Joun, Dve Rodriguez, Atheer Zrir, Lucs Alno, Jonthn Mhoney, nd Christopher Chisson did to collect smples nd dt. We would lso like to thnk Joshu Iscson for his ssistnce proofreding nd editing the mnuscript nd the A&L Cnd Lortories Inc. stff for their help with this project. References Anonymous (2001) Agronomy hndook: A&L Lortories-Soil nd Plnt Anlysis. A&L Cnd Lortories Inc. lcnd.com/index_htm_files/soil_anlysis_guide.pdf. Accessed 20 My 2014 Anonymous ( ) Provincil field crop production nd prices estimtes. Ontrio Ministry of Agriculture nd Food. omfr.gov.on.c/english/stts/crops/index.html. Accessed20My 2014 Bgg J et l (2009) Agronomy guide for field crop: Ministry of Agriculture, Food nd Rurl Affirs. 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