2010 Tineweeding Trials

Transcription

1 21 Tineweeding Trils Figure 1. Erly seson crop tineweeding. Dr. Hether Drby UVM Extension Agronomic Specilist Roslie Mdden, Eric Cummings, Amnd Gervis, nd Philip Hltemn Visit us on the web! Mrch 211, University of Vermont Extension

2 21 Vermont Tineweeding Trils Hether Drby, University of Vermont Extension hether.drby[t]uvm.edu In 21, the University of Vermont Extension Crops nd Soils Tem conducted n evlution of tineweeding s weed mngement strtegy in corn nd sunflowers in Alburgh, VT. Tineweeding is type of mechnicl cultivtion tht is implemented erly on in the field seson (Figure 1). A tineweeder is low cost nd simple piece of equipment designed to disturb the root zones of weed seedlings while they re in the very delicte white thred root stge (Figure 2). This disturbnce often results in weed seedling desicction nd deth. Success of this prctice is highly dependent on wether conditions t the time of weeding. Wet soils cn prohibit the use of tineweeders when weeds re t the criticl white Figure 2. White thred root stge of growth. thred stge. Wether Dt Sesonl precipittion nd tempertures recorded t wether sttion in close proximity to the 21 reserch site re shown in Tble 1. This yer presented growing seson tht ws bove verge in tempertures, nd while we hd drier spring, overll, we ended up with bove verge rinfll. This yer we ccumulted 26.4 more Growing Degree Dys (GDD) thn usul. GDDs re reported for corn (bse 5 86 F) nd sunflowers (bse F) in Tble 1. Tble 1. Temperture, precipittion, nd GDD summry 21. My June July August September October Averge Temperture ( F) Deprture from Norml Precipittion (inches) * Deprture from Norml Corn (Bse 5 86 F) Growing Degree Dys Deprture from Norml Sunflower (Bse F) Growing Degree Dys Deprture from Norml *Missing dt Bsed on Ntionl Wether Service dt from South Hero, VT. Historicl verges re for 3 yers of dt (1971-2). The effectiveness of tineweeder s weed control tool in corn nd sunflowers ws evluted with replicted plots t Borderview Frm in Alburgh, VT. The soil type ws silt lom nd the

3 previous crop ws cerel rye. For ech experiment, the design ws rndomized complete block with four replictions. Corn ws plnted on My 19, 21. Sunflowers were originlly plnted on My 26 th, but due to poor germintion, they were replnted on June 9, 21. Five weed control strtegies were evluted in sunflowers: tineweeding 6 dys fter plnting (DAP), tineweeding 12 DAP, tineweeding 6 & 12 DAP, pre-plnt herbicide, nd no weed control. Corn ws only tineweeded once, t 6 DAP, due to wet conditions, tineweeding t 12 DAP ws not possible. The pre-emergence herbicide nd no weed control tretments were lso evluted in the corn plots. The seedbed for ll plots ws prepred with moldbord plow, disked, nd then finished with spike tooth hrrow. Corn Corn (Seedwy vriety 39L) ws seeded with John Deere 175 four row plnter t 34, seeds/cre in 3 inch rows. A strter fertilizer (1-2-2) ws pplied t rte of 2 lbs/cre. The plot size ws 1 x 25. On My 3 th Lumx (S-metolchlor, trzine, nd mesotrione) ws spryed on the plots tht hd n herbicide tretment t 2 qts/cre. Weed nd crop popultions were mesured t 6 DAP. Weeds were identified pre- nd post-tineweeding (Tble 2). On July 9 th, the corn ws sidedressed with 92 lbs N/cre. Weed biomss ws mesured on September 21, 21, prior to hrvest. The plots were hnd hrvested with mchetes. Two 1 row sections were hrvested nd weighed with smll pltform scle on September 29, 21. Popultions were counted on two 17.5 row sections. A 5 plnt subsmple ws chopped with Troy-Built chipper shredder. After mixing, one pound subsmple of chopped corn ws dried, ground, nd nlyzed for forge qulity by the Cumberlnd Vlley Forge Lbortory in Mrylnd. Anlysis determined crude protein (CP), cid detergent fiber (ADF), neutrl detergent fiber (NDF), nd 3 hour digestible NDF (dndf). Pertinent forge qulity informtion is summrized in Tble 3. All dt ws nlyzed using mixed model nlysis where replictes were considered rndom effects. The LSD procedure ws used to seprte tretment mens when the F-test ws significnt (P<.1). Tble 2. Impct of weed control strtegies on corn. Tretment Hrvest popultion Weed biomss Hrvest moisture Yield 35% DM plnts/c lbs/c % tons/c 6 Dy * 18.1* Control 347* Herbicide 34* 13* 43.7* 23.* LSD (.1) Mens * Tretments tht re not significntly different thn the top performer in prticulr column re indicted with n sterisk. At 6 DAP, corn hd not emerged, nd ws not visully ffected by tineweeding. However, lower hrvest popultions in the 6 DAP tineweed indicte tht corn seed my hve been disturbed through the weeding ction. At 12 DAP, corn ws still germinting or in the spike stge, but hevy rins mde tineweeding impossible until the proper window hd pssed, resulting in weeds tht were too well estblished to be ffected by tineweeding. Mustrds (Brssic spp.), redroot pigweed (Amrnthus retroflexus L.), dndelion (Trxcum officinle Weber), yellow woodsorrel (Oxlis strict L.), common lmbsqurters (Chenopodium lbum L.), hiry glinsog

4 Yield t 35% DM (tons/c) Weeds (lbs DM/c) (Glinsog cilite (Rf.) Blke), foxtils (Setri spp.), nd quckgrss (Elymus repens (L.) Nevski) were ll erdicted by tineweeding mesures. While the herbicide weed control method hd the lest number of weeds (Figure 3), it did not hve significnt effect on yield when compred with tineweeding 6 DAP (Tble 2). The control plots hd the highest weed biomss tht resulted in the corn tking longer to dry down nd lower silge yields (Figure 4) c b Herbicide 6 Dy Control Figure 3. Effect of corn weed control on weed biomss in pounds of dry mtter per cre b 5 Herbicide 6 Dy Control Figure 4. Effect of weed control method on corn silge yield (tons/cre).

5 Milk per cre Tble 3. Impct of weed control on corn forge qulity. Tretment Forge qulity chrcteristics Milk per CP ADF NDF dndf NEL % % % % Mcl/lb ton cre 6 Dy * Control Herbicide * LSD (.1) NS NS NS NS NS NS 52 Mens * Tretments tht re not significntly different thn the top tretment in prticulr column re indicted with n sterisk. NS - None of the tretments were significntly different from one nother. Tretments did not differ significntly in CP, ADF, NDF, dndf, NEL, nd the performnce indices milk per ton. Significnce ws detected t the.1 level for milk per cre becuse of the higher yields found in the 6 DAP nd herbicide tretments (Tble 3; Figure 5) b 5 Herbicide 6 Dy Control Figure 5. Effect of weed control on milk per cre in corn.

6 Sunflowers Sunflower plots (Seeds 2 vriety Viper) were seeded with John Deere 175 plnter equipped with sunflower fingers t rte of 29, seeds per cre, with 3 inch spcing between rows. The plots size ws 1 x 25. Strter fertilizer (1-2-2) ws pplied t rte of 2 lbs/cre. An dditionl 7 lbs of N were topdressed in erly July. A pre-plnt ppliction of Trust (triflurlin) ws pplied to the herbicide plots t 1.5 pints per cre. Weed nd crop popultions were mesured t 6 nd 12 DAP. Weed identifiction ws performed t ech intervl. Weed biomss ws mesured on September 21 st, 21. To prevent bird predtion, ll plots were covered with bird netting nd scry eye bird deternts were errected in close proximity to the reserch trils. Plots were hrvested with n Almco SP5 plot combine on November 2, 21. Yield ws mesured by weighing the hrvested seeds on pltform scle. At hrvest, moisture, nd test weight were mesured. All dt ws nlyzed using mixed model nlysis where replictes were considered rndom effects. The LSD procedure ws used to seprte tretment mens when the F-test ws significnt (P<.1). No significnce difference ws observed mong tineweeding tretments for hrvest moisture, test weight, or yield (Tble 4). At 6 DAP, sunflowers hd not emerged, nd so were not visully ffected by tineweeding. Very few weeds were present t tht time, nd those tht were present were in white thred stge. Mustrds (Brssic spp.), redroot pigweed (Amrnthus retroflexus L.), common lmbsqurters (Chenopodium lbum L.), prickly lettuce (Lctuc serriol L.), dndelion (Trxcum officinle Weber), yellow woodsorrel (Oxlis strict L.), foxtils (Setri spp.), nd quckgrss (Elymus repens (L.) Nevski) were ll erdicted when tineweeded t 6 DAP. At 12 DAP, sunflowers were still germinting or t the cotyledon stge. Some seedlings were pulled out by the tineweeding, nd some were covered up. An verge of 21% of the crop ws either pulled up or covered up when the crop ws tineweeded 12 DAP. By hrvest, ll tineweeded stnds hd recovered to such n extent tht those few tht were buried or uprooted cused no significnt difference in yield (Tble 4). Tble 4. Impct of weed control strtegies on sunflower chrcteristics. Tretment Weed biomss Hrvest moisture Test Weight Yield t 13% moisture lbs/c % lbs/bu lbs/c 12 Dy 1528* & 12 Dy 136* Dy Control Herbicide 259* LSD (.1) 1325 NS NS NS Men * Tretments tht were not significntly different thn the top tretment in prticulr column re indicted with n sterisk. NS - None of the tretments were significntly different from one nother. hd significnt impct on finl weed biomss recorded ner hrvest (Figure 8), but weed pressure ws not significnt enough to impct yield (Figure 6).

7 Weeds (DM lbs/c) Tineweeding t 6 & 12 DAP resulted in significntly less weed biomss thn only tineweeding once or no weed control. The 6 & 12 DAP, 12 DAP, nd herbicide weed control methods were eqully effective t reducing weed biomss. Bsed on this seson s dt it is obvious tht tineweeding cn be n effective weed control tool in sunflowers. The best control seems to be chieved with multiple tineweeding events. The multiple tineweeding could result in reduced plnt popultions nd therefore higher seeding rtes my be wrrnted. Overll, sunflowers pper to be extremely competitive with weeds s the sunflower yields were not reduced even under high weed pressure c bc b b 6 & 12 Dy 12 Dy Herbicide Control 6 Dy Figure 6. Effect of weed control on weed yield in pounds of dry mtter per cre. The University of Vermont Extension would like to thnk Borderview Frm for their generous help with the trils. Support for this project provided by the Northest USDA SARE progrm. This informtion is presented with the understnding tht no product discrimintion is intended nd no endorsement of ny product mentioned or criticism of unnmed products is implied. University of Vermont Extension nd U.S. Deprtment of Agriculture, cooperting, offer eduction nd employment to everyone without regrd to rce, color, ntionl origin, gender, religion, ge, disbility, politicl beliefs, sexul orienttion, nd mritl or fmilil sttus.