Enhancing Botanical Composition and Wildlife Habitat of Pastures in South Central Iowa through Soil Disturbance by Mob-grazing of Beef Cattle

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1 Animl Industry Report AS 66 ASL R Enhncing Botnicl Composition nd Wildlife Hitt of Pstures in South Centrl Iow through Soil Disturnce y Mo-grzing of Beef Cttle Justin J. Bisinger Iow Stte University, equus146@istte.edu Jmes R. Russell Iow Stte University, jrussell@istte.edu Dougls Allen Ber Iow Stte University, morricl@istte.edu Joe Sellers Iow Stte University Helg Offenurger Iow Deprtment of Nturl Resources Recommended Cittion Bisinger, Justin J.; Russell, Jmes R.; Ber, Dougls Allen; Sellers, Joe; nd Offenurger, Helg (214) "Enhncing Botnicl Composition nd Wildlife Hitt of Pstures in South Centrl Iow through Soil Disturnce y Mo-grzing of Beef Cttle," Animl Industry Report: AS 66, ASL R2888. DOI: Aville t: This Environment is rought to you for free nd open ccess y the Animl Science Reserch Reports t Iow Stte University Digitl Repository. It hs een ccepted for inclusion in Animl Industry Report y n uthorized editor of Iow Stte University Digitl Repository. For more informtion, plese contct digirep@istte.edu.

2 Iow Stte University Animl Industry Report 214 Enhncing Botnicl Composition nd Wildlife Hitt of Pstures in South Centrl Iow through Soil Disturnce y Mo-grzing of Beef Cttle A.S. Leflet R2888 Justin Bisinger, Grdute Assistnt; Jim Russell, Professor, Deprtment of Animl Science; Dn Morricl, Professor, Deprtment of Animl Science; Joe Sellers, Livestock Specilist; Helg Offenurger, Iow DNR Summry nd Implictions South centrl Iow grsslnds re dominted y cool seson grss species with low productivity nd little plnt diversity which limits the forge yield nd qulity for grzing nimls nd hitt for ntive grsslnd wildlife. Strtegic spring mo-grzing my reduce competition from cool-seson grss species llowing erly successionl species, legumes, nd ntive plnts to estlish while improving soil chrcteristics. Two locks of three replicted pstures were divided into 5 equl-sized pddocks to determine the effects of erly spring mo-grzing on psture forge nd soil chrcteristics. In ech psture, one pddock ws not grzed (NG) nd 4 were strip- (S; moved once per dy with ck fence) or mo- (M; moved 4 times per dy with ck fence) grzed eginning in My of 211 (BL1) nd 212 (BL2) y 1 cows t live forge DM llownce of 2% BW/d. Susequently, one mo (MR) nd strip (SR) pddock in ech psture ws rottionlly stocked to remove 5% of the live forge with 35-d rest periods eginning 6 d fter spring grzing in yr 1 of ech lock. Mesurements included psture otnicl composition determined y the line trnsect method, soil penetrtion resistnce determined with penetrometer, wter infiltrtion determined with doule ring infiltrometers, soil ulk density, nd ground nesting ird hitt mesured s visul ostruction to 3.3x 3.3 ft ord y imge nlysis of digitl photos. In BL1 nd BL2 fter mo- or strip- grzing, the proportion of re ground ws greter (P<.5) in rottionlly grzed pddocks thn NG pddocks in most months. The proportion of nnul grsses ws greter (P<.5) in grzed thn NG pddocks in July 211 in BL1. In 212, the proportion of legumes ws greter (P<.5) thn NG pddocks in M, MR, nd SR pddocks in My, M nd SR pddocks in July, nd ll grzed pddocks in BL 1 in Octoer. But in 213, the proportion of legumes ws greter in MR nd S pddocks in My nd MR pddocks in Octoer thn NG pddocks. The proportion of wrm seson grsses in BL2 ws less (P<.5) in MR nd SR pddocks thn NG nd M pddocks in August 213. In BL1, penetrtion resistnce ws greter (P<.5) in rottionlly stocked pddocks compred to NG pddocks in My nd Octoer of 212 nd 213, however reductions (P<.5) in wter infiltrtion rtes occurred in rottionlly stocked pddocks only in Octoer 212 nd 213. In BL1, visul ostruction ws less (P<.5) in M pddocks thn S nd NG pddocks to 15.7 inches high in Octoer 211. However in BL2, no differences in visul ostruction occurred in Octoer 212. A single mo- or strip-grzing event of grsslnd in the spring my improve the nutritionl vlue of the forge for grzing livestock nd hitt for wildlife. However, the extent nd longevity of these responses re relted to soil moisture t the time of grzing nd susequent mngement nd climtic conditions. Introduction Overgrzing from continuous stocking of southern Iow pstures llows cool seson grsses like tll fescue to dominte other forge species nd decrese persistence of legumes. Even with nitrogen inputs, production of these pstures re limited, resulting in reduced vegettive cover nd incresed soil erosion in precipittion runoff. Furthermore, the low productivity nd nutritionl vlue of overgrzed pstures provides little incentive to deter producers from converting psturelnd into croplnd or selling it for recretionl uses like hunting. Typiclly fter psturelnd is sold for recretionl uses such s hunting, cttle re removed. However, without the disturnce nd defolition provided y grzing of perennil grsslnds, tree cover increses nd cool seson grsses ecome dominnt resulting in poor hitt for some wildlife species including owhite quil. Reducing competition from cool seson grsses through disturnce y grzing llow legumes nd other plnt species to estlish which increse sesonl productivity, resilience to wether disruptions, nd wildlife hitt. The nitrogen-fixing cpilities nd high protein concentrtions of legumes improves productivity nd nutritionl qulity of forges for grzing livestock. Incresed plnt diversity increses root mss nd this long with forge incorported into the soil through disturnce increses soil orgnic mtter which my increse soil cron sequestrtion, nd wter infiltrtion rtes. These fctors will, in turn, increse resilience to environmentl stress nd decrese soil erosion in grsslnds. In ddition, incresed plnt species diversity in grsslnd ecosystems will increse feed sources nd hitt structure for wildlife. The improvement of wildlife hitt from grzing my crete llinces etween cow/clf producers needing more grzing lnd nd lndowners wnting to estlish or improve wildlife hitt.

3 Iow Stte University Animl Industry Report 214 Strtegic grzing t high stocking densities for short periods of time followed y long rest periods, known s mo-grzing, my reduce competition from cool seson grss species nd provide the soil disturnce necessry to estlish more diverse plnt communities while providing other ecosystem enefits in psture nd grsslnds. The ojective of this study ws to evlute the effectiveness of strtegic spring mo-grzing to improve otnicl composition of forge for grzing, wildlife hitt, nd soil qulity under the soil nd climtic conditions prevlent in south centrl Iow. Mterils nd Methods Two locks of three replicted pstures contining mixtures of cool seson grsses nd legumes without (BL1) or with (BL2) wrm seson grsses were divided into 5 equl-sized pddocks (BL1, 1 cre; BL2,.5 cre) to determine the effects of single erly spring mo-grzing event on susequent plnt species diversity nd soil chrcteristics in grsslnds. In ech psture, one pddock ws not grzed (NG) nd 4 were strip (S; moved once per dy with ck fence) or mo (M; moved 4 times per dy with ck fence) grzed eginning in My of 211 (BL1) nd 212 (BL2) y 1 August-clving cows (men ody weight; 1291[BL1] nd 1416 [BL2] l) t live forge llownce of 2% BW/d. Susequently, one mo (MR) nd strip (SR) pddock in ech psture ws rottionlly stocked with 35-d rest periods eginning 6 d fter spring mogrzing in the first yer of ech lock nd in erly My of ech susequent yer. When grzing y rottionl stocking, cttle were stocked to remove 5% of the live forge mesured with flling plte meter (8.8 l/yd 2 ). Dominnt vegettive cover or plnt species including re soil, ded plnt residue, perennil cool nd wrm seson grsses, nnul grsses, legumes, nd rodlef weeds were identified t 1 eqully spced sites on 5 ft string t 1 sites per pddock in spring, summer, nd fll of ech yer. The numer of sites with perennil cool or wrm seson grsses, nnul grsses, rodlef weeds, sedge, nd legumes were summed s the numer of sites with live forge nd the proportion of sites with ech plnt clss ws expressed s percentge of sites with live forge. Wter infiltrtion ws determined t three rndomly selected sites in ech pddock in My nd Octoer y dding wter to doule ring infiltrometers to mintin ponding depth etween 2 nd 1 inches over 9 minutes. Wter infiltrtion ws clculted s the verge of the mount nd time of the lst three dditions of wter to the infiltrometers. Compction ws mesured to depth of 6 inches with field scout SC 9 penetrometer with.5 inch dimeter cone tip t 1 sites in ech pddock in My nd Octoer of ech yer. Soil ulk density nd totl cron were determined with soil smples to depth of 3 inches from 6 sites in ech pddock. Ground nesting ird hitt ws mesured s visul ostruction in digitl photos of 3.3x3.3 foot ord t distnce of 13.2 feet nd height of 3.3 feet in July nd Octoer of ech yer. Digitl photos were cropped nd visul ostruction determined with Sigm Scn Pro 5 t 3.8 inch intervls mrked on the visul ostruction ord. Dt were nlyzed y month with the MIXED procedure of SAS within BL1 nd BL2. Differences etween mens with significnt tretment effects were determined y the PDIFF procedure of SAS. Results nd Discussion Stocking densities for mo- nd strip-grzed pddocks during erly spring mo grzing were 53, nd 147, ls/cre in BL1 nd 47, nd 18, ls/cre in BL2, respectively. In BL1, re ground ws greter (P<.5) in S thn MR nd SR pddocks in July 211. Following July 211, the proportion of re ground ws (P<.5) greter in MR pddocks thn NG pddocks in ll smpling months, ut only greter in SR thn NG pddocks through My 212. Ded plnt residue ws greter (P<.8) in Octoer in pddocks grzed y either the M or S systems thn NG pddocks fter mo-grzing in 211.The proportion of coolseson grsses (fig. 1A) ws less (P <.5) in pddocks grzed y either the M, S, MR, or SR systems in July 211 nd My 212 thn NG pddocks. Following My 212, lower (P <.5) proportions of cool seson grsses were oserved in MR nd SR pddocks thn NG pddocks. Annul grsses s proportion of live forge were greter (P<.5) in July 211. The proportion of nnul grsses in the live species did not differ etween tretments in Octoer 211, 212, nd My 213. However, in August nd Octoer 213 the proportion of nnul grsses ws greter in MR nd SR thn NG, M, nd S pddocks. Conversely, in 212, legumes (fig. 1B) s proportion of live forge were greter (P<.5) in M, MR, nd S in My, M nd S in July, nd ll grzed pddocks in Octoer thn NG pddocks. Susequently, in 213, greter (P<.7) proportions of legumes still occurred in MR nd S in My, nd MR pddocks in Octoer thn NG pddocks. This result implies tht the increse in the proportion of legumes ws etter mintined in mo-grzed pddocks tht were susequently rottionlly stocked. The proportion of re ground ws greter (P <.5) in MR nd SR pddocks thn NG pddocks in ll smpling months fter My 212. While M or S grzing hd little effect on the proportions of cool seson grsses in the live forge immeditely fter grzing, the proportion of cool seson grsses (fig. 2A) ws less (P<.5) in M nd S thn NG pddocks in Octoer 212. In comprison to NG pddocks, the proportion of wrm seson grsses ws (P<.5) lower in MR nd SR pddocks in August 213, ut did not differ in other months. No differences in the proportion of nnul grsses etween tretments occurred in the yer tht pddocks in BL2 were mo- or strip-grzed (212). However, while there continued to e no difference in the proportion of nnul grsses in the NG, M, nd S pddocks in My 213, the proportion of nnul grsses in MR nd SR pddocks were greter (P <.5) thn M, S,

4 Iow Stte University Animl Industry Report 214 nd NG pddocks in July nd Octoer 213. Conversely, the proportions of legumes in the live forge were greter (P<.5) in S nd M pddocks thn NG pddocks in Octoer 212 nd My 213, respectively (fig. 2B). No differences in penetrtion resistnce t ny depth were oserved etween tretments fter tretments were pplied in BL1 in 211. However, compred to NG pddocks in BL1, penetrtion resistnce ws greter (P<.5) t depth of 2 inches in pddocks grzed y ny tretment in My 212 nd 213 nd in MR nd SR pddocks in Octoer 212 nd 213 (fig. 3A). In ddition, greter (P<.5) penetrtion resistnce in pddocks grzed y ny tretment thn NG pddocks occurred t depth of 5 nd 6 inches in Octoer 212 nd My 213. In BL2, penetrtion resistnce t depth of 2 inches ws greter (P <.5) in MR nd SR pddocks thn NG, M, nd S pddocks in Octoer 213 (fig. 3B). In 212 nd My 213 there were few significnt differences t other depths. However in Octoer 213, penetrtion resistnce in rottionlly stocked pddocks ws greter thn NG pddocks to depth of 4 inches. Unlike BL1, in BL2 there were no significnt differences in penetrtion resistnce elow 4 inches etween tretments. Soil ulk density in BL1 ws greter (P<.5) in MR nd S pddocks in Octoer 211 nd ll grzed pddocks in Octoer 212 thn NG pddocks. However, unlike penetrtion resistnce, there ws no difference in soil ulk density etween tretments in BL1 in Octoer 213. In BL2, soil ulk density ws greter (P<.5) in SR pddocks thn NG pddocks in Octoer 213. As result of the differences in soil compction, wter infiltrtion rte ws greter (P<.5) in NG, M, nd S pddocks in Octoer 212 nd NG pddocks in Octoer 213 thn MR nd SR pddocks in BL1. In BL2, infiltrtion rtes in pddocks grzed y ny of the systems were greter (P<.5) thn NG pddocks in Octoer 212. However, no differences in infiltrtion rtes etween tretments in BL2 occurred in ny other month. In BL1, M nd S pddocks provided less (P<.5) visul ostruction up to 39.4 inches thn forge in NG pddocks in July 211 which ws immeditely fter the tretments were pplied. In Octoer 211, visul ostruction to height of 15.7 inches in M pddocks ws less (P<.5) thn NG nd S pddocks (fig. 4A). In ddition, ove 15.7 inches, visul ostruction ws lower (P<.5) in M nd S pddocks thn NG pddocks. In July 212, no differences occurred in visul ostruction etween tretments. But in Octoer 212, there ws less (P<.5) visul ostruction t 3.9 to 7.9 inches in S thn M pddocks. In BL2, visul ostruction ws less (P<.5) up to 39.4 inches in M nd S pddocks thn NG pddocks in July 212 immeditely fter the tretments were pplied. In Octoer 212, there were no differences in visul ostruction in BL2 (fig. 4B). Becuse of the differences in the responses of plnt communities nd soil qulity to grzing tretments in BL1 nd BL2, this study indictes the effects of mo- nd stripgrzing on plnt species nd soil properties re likely influenced y more fctors thn stocking density. The species succession which occurred in BL1 with incresed levels of nnul grsses, did not occur in BL2. Furthermore increses in penetrtion resistnce which occurred in ll grzed pddocks in BL1 only occurred in pddocks tht were rottionlly grzed in BL2. Differences etween locks my hve een relted to rinfll during mo- nd strip-grzing which were.55 nd.5 inches in BL1 in 211 nd BL2 in 212, respectively. Results from BL1 indicte mo- or strip-grzing cn e used to reduce competition from cool seson grsses nd llow nnul grsses nd eventully legumes to estlish if rinfll mounts re enough to llow significnt soil disturnce. These effects my lso e ltered y greter stocking densities or lengths of the grzing period. The increse in nnul grsses nd legumes resulting from mo- nd stripgrzing in BL1 my e eneficil to ground nesting irds nd other wildlife. However within 2 yers, the plnt community egn to resemle pddocks with no grzing which lcked qulity wildlife hitt. In oth locks re ground incresed with rottionl grzing nd ws most persistent in MR pddocks. This effect could increse the risks of soil erosion in pstures, ut re ground is needed in grsslnds mnged for owhite quil hitt. Furthermore, the incresed legume popultions in rottionlly stocked pddocks in BL1 lsted longer in mogrzed thn strip-grzed pddocks possily resulting from more soil disturnce. Although soil penetrtion resistnce nd ulk density re sometimes relted to wter infiltrtion rtes, in this project correltion coefficients were not greter thn.25. Further nlysis on the impct of soil moisture on the chnge in plnt species nd soil chrcteristics following mo- nd strip-grzing is needed to determine environmentl conditions most likely to produce the desired chnge in plnt species while improving soil qulity chrcteristics. Acknowledgements The uthors would like to thnk Kevin Mher nd the other personnel t the McNy Reserch Frm for ssistnce with mngement of the cttle; grdute students Mrgret Dunn nd Lur Dniels; nd undergrdute students Dve Mstolek, Kelsey Mrtin, Brin Nyheim, nd Quinton Normn tht hve helped with the dt collection nd nlysis in this experiment. This mteril is sed upon work supported y the Leopold Center for Sustinle Agriculture.

5 Iow Stte University Animl Industry Report 214 Figure 1. The Effects of Strip or Mo-grzing with or without Susequent Rottionl Grzing on the Proportion of Cool Seson Grsses (A) nd Legumes (B) s Percentge of Totl Psture Are in BL1 pddocks not grzed (NG), Mo-grzed (M), Mo-grzed with 6 Dys Rest Followed y Rottionl Grzing (MR), Strip-grzed (S), Stripgrzed with 6 Dys Rest Followed y Rottionl Grzing (SR). %, live forge (A; Cool Seson Grsses) c c c c %, live forge (B; Legumes) My, 211 July, 211 Octoer, 211 My, 212 July, 212 Octoer, 212 NG M MR S SR c c My, 213 August, 213 Octoer, 213 -c Differences etween tretment (NG, M, MR, S, SR) mens within month with different superscripts re significnt (P<.5) Figure 2. The Effects of Strip or Mo-grzing with or without Susequent Rottionl Grzing on the Proportion of Cool Seson Grsses (A) nd Legumes (B) s Percentge of Totl Live Forge in BL2 pddocks not grzed (NG), Mo-grzed (M), Mo-grzed with 6 Dys Rest Followed y Rottionl Grzing (MR), Strip-grzed (S), Stripgrzed with 6 Dys Rest Followed y Rottionl Grzing (SR). %, live forge (A; Cool Seson Grsses) c c %, live forge (B; Legumes) My, 212 July, 212 Octoer, 212 My, 213 August, 213 Octoer, 213 NG M MR S SR -c Differences etween tretment (NG, M, MR, S, SR) mens within month with different superscripts re significnt (P<.5)

6 Iow Stte University Animl Industry Report 214 Figure 3. The Effects of Strip or Mo-grzing with or without Susequent Rottionl Grzing on penetrtion resistnce t depth of 2 inches in BL1 (A) nd BL2 (B) pddocks not grzed (NG), Mo-grzed (M), Mo-grzed with 6 Dys Rest Followed y Rottionl Grzing (MR), Strip-grzed (S), Strip-grzed with 6 Dys Rest Followed y Rottionl Grzing (SR). KP KP (A; BL1) c c c My, 211 Octoer, 211 My, 212 Octoer, 212 My, 213 Octoer, 213 (B; BL2) My, 212 Octoer, 212 My, 213 Octoer, 213 -c Differences etween tretment (NG, M, MR, S, SR) mens within month with different superscripts re significnt (P<.5) c c NG M MR S SR NG M MR S SR Figure 4. The Effects of Strip or Mo-grzing with or without Susequent Rottionl Grzing on Visul Ostruction in Octoer 211 in BL1(A) nd Octoer 212 in BL2 (B) t Height Increments of , , , nd inches t Distnce of 13.2 feet in pddocks not grzed (NG), Mo-grzed (M), nd Strip-grzed (S). Visul ostruction, % (A; BL1) Height, inches NG M S Visul ostruction, % (B; BL2) Height, inches NG M S - Differences etween tretment (NG, M, MR, S, SR) mens within month with different superscripts re significnt (P<.5)