No abstract

Sand-based turfgrass root zones have limited nutrient retention and water-holding capacity. Peat moss oft en is used to off set these defi ciencies, but peat moss decomposes. Biochar is a co-product of several biofuel production processes used to produce bio-oil. Biochar is stable and could have similar water and nutrient retention impacts as peat moss when mixed in sand-based turfgrass root zones. Th e objective of this research was to evaluate the effi cacy of biochar as a sand-based root zone amendment. Water retention, water infi ltration, creeping bentgrass (Agrostis stolonifera L.) rooting depth, and nutrient evaluation experiments were conducted on six sand and biochar root zone mixtures. At fi eld capacity, sand-based media containing 25% (v/v) biochar retained 260 and 370% more water compared to media containing 5% biochar and a pure sand control, respectively. Saturated hydraulic conductivity (K sat ) of the root zones decreased as biochar concentrations increased. Th e rooting depth of bentgrass was reduced up to 46% at biochar concentrations >10%. Extracted pore water electrical conductivity and dissolved total organic carbon increased as biochar concentrations increased. Nitrogen leaching was reduced as biochar concentrations increased. According to the results, biochar may improve water storage, reduce overall water use, and decrease N fertilizer applications in sand-based turfgrass ecosystems.

Low‐input sustainable turf (LIST) management represents a resource‐efficient option in maintaining uniform, persistent turf. What species are best suited to such management needs to be established. To this end, 12 hardy species were evaluated for 3 yr in Illinois, Indiana, Iowa, Michigan, Missouri, Ohio, and Wisconsin: crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult. ‘Fairway’, ‘Ephraim’, and ‘Ruff’], streambank wheatgrass [Agropyron riparium Scribn. & Smith ‘Sodar’; syn. Elymus lanceolatus (Scribn. & J.G. Smith) Gould subsp. lanceolatus], Canada bluegrass (Poa compressa L. ‘Reubens’), hard fescue [Festuca ovina var. duriuscula (L.) Koch ‘Durar’; syn. F. lemanii T. Bastard], sheep fescue (F. ovina L. ‘Covar’ and common), tall fescue (F. arundinacea Schreb. ‘Alta’), bulbous bluegrass (P. bulbosa L.), alpine bluegrass (P. alpina L.), redtop (Agrostis alba L. ‘Reton’; Agrostis gigantea Roth), roughstalk bluegrass (P. trivialis L. ‘Colt’), colonial bentgrass (Agrostis tenuis Sibth. ‘Exeter’; syn. Agrostis capillaris L.), and buffalograss [Buchlöe dactyhides (Nutt.) Engelm. ‘Texoka’ and ‘NE‐315’]. AH were field‐established and compared at three mowing heights: 3.8 cm, 7.6 cm, and no mowing. Quality ratings were based on uniform persistence. Tall fescue and common sheep fescue were the best and most broadly adapted to LIST. In Iowa, hard fescue, Canada bluegrass, and crested wheatgrass also did well. Colonial bentgrass was best adapted in Missouri. Redtop and roughstalk bluegrass grew better in a north‐south area from Wisconsin through central Illinois to Missouri. The buffalograsses excelled in Ohio and southern Illinois. Over all species, the 7.6‐cm mowing height allowed the best turf quality. Specifically, tall fescue, colonial bentgrass, redtop, and common sheep fescue performed best at the 7.6‐cm mowing height. Covar sheep fescue, hard fescue, Canada bluegrass, and Fairway crested wheatgrass could not maintain persistent stands under the 3.8‐cm mowing height. No mowing resulted in intermediate levels of quality with all species. A 7.6‐cm mowing height would be appropriate for testing species in LIST within the seven‐state region used in this study.

The degradation and vertical movement of pendimethalin, chlorpyrifos, isazofos, and metalaxyl were monitored in Kentucky bluegrass (Poapratensis L.) turf managed as a golf course fairway. Intact turf‐soil cores from Mead, NE, on a Sharpsburg soil (fine montmorillonitic, mesic Typic Argiudoll) and Gilbert, IA, on a Nicollet loam (fine‐loamy, mixed, mesic Aqnic Hapludoll) planted to Kentucky bluegrass were periodically removed to 60‐cm depth through 113 d after pesticide application. Cores were sectioned into verdure, thatch, and multiple soil depths. While verdure contained high pesticide concentrations after application, precipitation, and clipping, and degradation reduced the amount in plant tissue with time. Thatch was highly retentive of the pesticides, generally containing the most residue throughout the monitoring period. Pesticide residues tended to be lower in soil at the Iowa site where more thatch was present. Little chlorpyrifos or pendimethalin moved through the thatch to the underlying soil. Isazofos was more mobile and metalaxyl moved through the entire soil column. Soil contained an average of 58% less pesticide than thatch over all sampling times, and concentrations in soil were highest at the 0‐ to 5‐ and 5‐ to 10‐cm depths. Average time for 50% dissipation in the turf‐soil profile (DT50) was 16, 12, 10, and 7 d for metalaxyl, pendimethalin, chlorpyrifos, and isazofos, respectively. The pesticides appeared to degrade more rapidly in the turfgrass environment than typically reported for other agronomic cropping systems. Variability in pesticide residue concentrations for each soil depth among the turf‐soil cores indicated non‐uniform dissipation in the field.

Field and greenhouse studies on the use of a byproduct of the corn (Zea mays L.) wet-milling process, corn gluten meal, have shown that this high-protein fraction of corn grain contains an organic compound that inhibits root formation of a variety of monocotyledonous and dicotyledonous species. Seeds that germinate in a soil media to which corn gluten meal has been added form normal shoots, but no roots. The seedling quickly dies as the media drys. This inhibition of root formation can be timed to prevent the establishment of weeds in turf areas and other plant systems. Corn gluten meal also contains approximately 10% nitrogen and can be used as a natural fertilizer material. Repeated field trials have shown no detrimental effect of the corn gluten meal on mature grass plants. This combination of a natural fertilizer with a natural weed inhibiting compound may result in a `weed and feed' product for those who do not wish to use synthetic fertilizers and pesticides. A patent on the use of corn gluten meal as a weed control was issued in 1991.

Corn (Zea mays L.) gluten meal (CGM) was evaluated under greenhouse conditions for efficacy on 22 selected monocotyledonous and dicotyledonous weed species. Corn gluten meal was applied at 0, 324, 649, and 973 g·m–2 and as a soil-surface preemergence (PRE) and preplant-incorporated (PPI) weed control product. CGM reduced plant survival, shoot length, and root development of all tested species. Black nightshade (Solanum nigrum L.), common lambsquarters (Chenopodium album L.), creeping bentgrass (Agrostis palustris Huds.), curly dock (Rumex crispus L.), purslane (Portulaca oleracea L.), and redroot pigweed (Amaranthus retroflexus L.) were the most susceptible species. Plant survival and root development for these species were reduced by ≥75%, and shoot length was decreased by >50% when treated PRE and PPI with 324 g CGM/m2. Catchweed bedstraw (Galium aparine L.), dandelion (Taraxacum officinale Weber), giant foxtail (Setaria faberi Herrm.), and smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl] exhibited survival and shoot length reductions >50% and an 80% reduction in root development when treated with PPI CGM at 324 g·m–2. Barnyardgrass [Echinochloa crus-galli (L.) Beauv.] and velvetleaf (Abutilon theophrasti Medic.) were the least susceptible species showing survival reductions ≤31% when treated with 324 g CGM/m2.

Weeds are considered the most important pest group for farmers interested in lowering external inputs and avoiding synthetic chemical use. Corn gluten meal (CGM) is a natural preemergence weed control used in turfgrass, which reduces germination of many broadleaf and grass weeds. The objective of this study was to investigate weed cover and vegetable seedling survival in field plots when CGM is incorporated before planting. Three studies were conducted, with three replications for each study. Five rates of powdered CGM (0,100, 200, 300, and 400 g m–2) were weighed and incorporated into the top 5–8 cm of soil in recently disked 1.5-m by 2.7-m plots. Seeds of eight vegetables were each planted in rows 1.4 m long and 0.3 m apart. Seedling survival and percentage of weed cover were recorded for each plot. Corn gluten meal at rates of 100, 200, 300, and 400 g m–2reduced mean weed cover by 50, 74, 84, and 82%, respectively, compared with the control. Seedling survival at 100 g CGM per m2was reduced by 67% for ‘Comanche’ onion, 35% for ‘Ruby Queen’ beet, 41% for ‘Red Baron’ radish, 71% for ‘Provider’ bean, 73% for ‘Scarlet Nantes’ carrot, 59% for ‘Maestro’ pea, and 68% for ‘Black Seeded Simpson’ lettuce, compared with the control. Seedling survival for ‘Daybreak’ sweet corn was not reduced by rates of 100 or 200 g CGM per m2, but was reduced by 26% at a rate of 300 g CGM per m2compared with the control. Because of the reduction in seedling survival at even the lowest rate of CGM (100 g m–2), direct seeding of these vegetables into soil into which CGM has been incorporated is not advisable. Using transplants may be an alternative that takes advantage of the herbicidal effects of CGM and the nitrogen it provides.

Development of a remote sensing system that can reliably identify nutrient deficiencies may reduce time spent sampling turfgrass areas and allow for site‐specific applications of fertilizers. The objectives of this research were to evaluate the use of a ground‐based remote sensing system and partial least‐squares (PLS) regression to predict the N concentration, biomass production, chlorophyll content, and visual quality of creeping bentgrass (Agrostis stolonifera L. ‘Penncross’) growing under varying N rates, and to compare PLS regression to other vegetative indices. The study consisted of three N treatments (0.0, 12.2, and 24.4 kg ha−1 15 d−1) arranged in a randomized complete block design. Spectral radiance measurements were obtained from plots using a fiber‐optic spectrometer to calculate vegetative indices. The PLS regression analysis yielded a strong relationship between actual and predicted N concentration of creeping bentgrass plant tissue during 2002 and 2003 (r2 = 0.95 and 0.71 respectively). However, PLS regression failed to produce a prediction for the chlorophyll concentration. Regressing the normalized vegetation index (NDVI), Stress1 (R706/R760), and Stress2 (R706/R813) ratios against N concentration yielded better results in 2003 when there were distinct differences in N concentration between the N rates. These results indicate that the traditional vegetation indices like NDVI might be better suited for determining the relative N status of turfgrass plants when compared against a well‐fertilized control. More research will be required to determine if the PLS regression analysis produces prediction models that are able to specifically identify a particular nutrient deficiency or plant stress, and how the results will vary between grass species.