Fall Mowing Research Articles

Annual bromes decrease with increasing fall defoliation intensity

Japanese brome (Bromus japonicus Thunb.) has been introduced to four continents from its Eurasian origins and has increased during recent decades, particularly in North America. Invasion of this C3 annual grass into rangelands diminishes native plant communities and hinders livestock performance. Control methods have been developed, but have proven short-lived. Japanese brome is positively correlated with plant litter and standing dead material, suggesting management of those components could be important. Objectives for this study were to isolate and quantify the effects of litter and standing dead on Japanese brome utilizing fall defoliation with four different mowing heights (10, 6, 4, or 1 cm) compared to a non-mowed control. Research was conducted on two ecological sites (silty and claypan) with each site consisting of 25 plots (5.5 × 1.6-m). This study was conducted over 4 yr (2013–2017) and fall mowing reduced old dead mass every year except 2016, which followed a severe drought. Spring soil water was not reduced by fall defoliation. Mowing to 1 cm reduced brome biomass by 40% compared to non-mowed plots and brome production was highly dependent on Sep-Oct precipitation. Brome biomass was least in 2015 during a drought and greatest in 2017 following double the median Sep-Oct precipitation. Non-brome biomass was similar across treatments. An 11% reduction in current-year biomass was observed for mowing heights of 10, 6, and 4 cm whereas a 22% reduction was measured for the 1 cm mowing height compared to non-mowed plots. Perennial grass basal cover was similar for 10, 6, and 4 cm mowing heights and greater than that for mowing at 1 cm whereas, no differences were detected between non-mowed plots and any mowing height. Increasing fall defoliation intensity reduced annual bromes while allowing perennial grasses to persist, indicating fall mowing and possibly grazing are viable options for annual brome management.

Land use alters relationships of grassland productivity with plant and arthropod diversity in Inner Mongolian grassland.

The threats of land-use intensification to biodiversity have motivated considerable research directed toward understanding the relationship between biodiversity and ecosystem functioning (BEF). Functional diversity is deemed a better indicator than species diversity to clarify the BEF relationships. However, most tests of the BEF relationship have been conducted in highly controlled plant communities, with terrestrial animal communities largely unexplored. Additionally, most BEF studies examined the effects of biodiversity on ecosystem functions, with the effects of ecosystem functioning strength on biodiversity hardly considered. Based on a 6-yr grassland experiment in the typical steppe region of Inner Mongolia, we examined the variation of taxonomic diversity (TD) and functional diversity (FD) of both plant and arthropod communities, and their relations with grassland productivity, across three land management types (moderate grazing, mowing, and enclosure). We aimed to clarify the interrelations among plant FD, arthropod FD, grassland productivity, and soil factors. We found the following: (1) Grassland under mowing performed best in terms of sustaining a high TD and FD of plants and arthropods compared to that under grazing and enclosure. (2) The relationships between plant and arthropod diversity and productivity varied with management types. Plant TD and FD were negatively related, whereas arthropod FD was positively related with productivity under enclosure; plant FD, but not arthropod FD, was positively related with productivity under grazing; arthropod FD, but not plant FD, was negatively related with productivity under mowing. (3) Grassland productivity was positively interrelated with plant FD, but not plant TD; and was negatively interrelated with arthropod TD, but not arthropod FD across different management types. The respective positive vs. negative bidirectional relationships of productivity with plant diversity vs. arthropod diversity, were majorly a consequence of divergent grazing/mowing effects on plant vs. arthropod diversity. The results indicate that grazing increases plant diversity, but decreases arthropod diversity, whereas fall mowing provides a management strategy for conservation of both trophic levels. These results also provide new insights into the effects of land-use changes on biodiversity and ecosystem processes, and indicate the importance of incorporating the functional interrelations among different trophic groups in sustainable grassland management.

A mowing strategy to convert red clover to annual crops in organic farming

AbstractOrganic producers are interested in no-till cropping systems. In this study, we found that perennial clover can be converted to corn without tillage. Conversion tactics involved fall mowing in the third year of red clover, followed by between-row mowing of weeds and volunteer red clover in corn grown during the fourth year. Corn yielded 85% of the weed-free control with mowing conversion. In contrast, weed interference in tillage-based conversion and between-row tillage reduced corn yield 53%. Weed emergence was sixfold greater in the tilled conversion. Weeds were present in the corn row with mowing, but recently developed implements could control these weeds and further support a no-till conversion method.

Converting perennial legumes to organic cropland without tillage

AbstractOrganic producers are interested in developing a no-till system for crop production. In this study, we examined management tactics to convert perennial legumes to annual crops without tillage. Our hypothesis was that reducing carbohydrate production in the fall by mowing would favor winterkill. Mowing treatments were imposed in the fall of the third year of alfalfa or red clover, and corn planted in year 4. The conventional practice of tillage to convert legumes to cropland was also included as a treatment. Mowing in autumn reduced red clover biomass 93% compared with alfalfa when measured 3 weeks after corn planting (WAP). Red clover biomass was still 75% less than alfalfa 6 WAP. Fall mowing suppressed red clover sufficiently to enable corn seedlings to establish, but corn seedlings did not survive in mowed alfalfa due to alfalfa competition. Corn grain yield following red clover was similar in the mowed and tilled treatments when weeds were present. Late season clover and weed growth reduced corn yields 46% compared with weed-free corn. Weed emergence in corn was three times higher after tillage compared with the mowed treatment. Converting red clover to annual crops with fall mowing will support a no-till system for organic farming.

Integrating a complex rotation with no-till improves weed management in organic farming. A review

No-till practices are restoring and protecting soil health and are considered critical for achieving sustainability of global agriculture. Organic producers in the USA would like to no-till, but are concerned about managing weeds without tillage. In conventional agriculture, no-till improves weed management in diverse rotations when crops are arranged in 2-year intervals of cool season and warm season crops. A similar approach with organic rotations may enable producers to also accrue the weed management benefit of no-till in organic farming along with restoring soil health. Here, we review the benefits gained for weed management when a complex rotation is integrated with continuous no-till. The complex rotation included 3 years of a perennial legume and 6 years of annual crops arranged in 2-year intervals of warm season or cool season crops. The no-till, complex rotation can (1) reduce weed emergence 3- to 4-fold in some annual crops; (2) delay weed emergence 2 to 4 weeks; (3) reduce yield loss due to weed interference; (4) suppress invasion of dandelion into cropland; and (5) enhance soil restoration, improve nutrient cycling, and increase soil porosity. Furthermore, perennial red clover can be converted to no-till cropland with fall mowing; thus, organic producers can include a perennial legume in a no-till rotation. The complex rotation increases the impact of no-till on weed seed decay in soil and provides numerous opportunities for cover crops to replace tillage for controlling weeds. These benefits suppress weed growth and interference such that organic producers may be able to continuously no-till in their farming systems, thus accruing restoration of soil health and long-term sustainability gained with no-till.

Restoring Invaded Pacific Northwest Prairies: Management Recommendations from a Region-Wide Experiment

Abstract We conducted a 5-year study at 10 sites from British Columbia to the Willamette Valley aimed at improving methods for restoring degraded prairies and oak savannas. Our manager-recommended treatment combinations were applied over 4 years and included the following components: spring and fall mowing, grass-specific and broad-spectrum herbicide, and fall burning. All treatment combinations were crossed with native seed addition. As expected, we found there was no ‘silver bullet’; while some treatment combinations led to large improvements in weed control and native diversity and abundance, the optimum combination and degree of success varied across sites. Where non-native grasses are the most pressing problem, we recommend the use of grass-specific herbicides as highly effective with minimal non-target effects on native forbs and some native grasses. Fire is a useful tool for preparing a site for seeding and can be followed closely with a broad spectrum herbicide to control rapidly resprouting weeds...

Tallgrass prairie restoration in the midwestern and eastern United States: a hands-on guide

Tallgrass prairie restoration in the midwestern and eastern United States: a hands-on guide

Integrated Management of Perennial Pepperweed (Lepidium latifolium)

AbstractPerennial pepperweed is invasive throughout California. It thrives in a wide range of environments and is a common weed in floodplains, pastures, wetlands, and roadsides. In disturbed areas, perennial pepperweed rapidly forms monotypic stands with a thick litter layer. These infestations not only out-compete other vegetation, but prevent re-establishment of desirable species even after perennial pepperweed control. This experiment examined integrated management strategies with the goal of maximizing perennial pepperweed control and establishment of desirable native vegetation. The experiment was conducted at two sites in Lassen County, CA. Both sites were heavily infested with perennial pepperweed and lacked competing vegetation. The experimental design was a split-split-randomized block with four replications. Site preparation treatments included winter burning, summer and fall mowing, winter grazing, and fall disking. These treatments were designed to remove thatch to facilitate herbicide application and reseeding of desirable perennial grasses. Herbicide treatments included chlorsulfuron, 2,4-D, or glyphosate applied at the flower bud stage. Revegetation treatments included no seeding and no-till seeding of native perennial grasses. Most site preparation plus herbicide combinations reduced perennial pepperweed cover > 85% compared to the untreated control, although treatment efficacy was variable between sites and years. Burning, grazing, mowing, or disking in combination with herbicide treatment and no-till seeding was necessary for successful native perennial grass establishment. Burning or mowing with yearly 2,4-D applications for 3 yr gave the best combination of perennial pepperweed control and native grass establishment. Chlorsulfuron caused chlorosis and stunting to western wheatgrass, basin wildrye, and beardless wildrye at both sites when applied the spring before seeding. No treatment offered complete weed control, suggesting follow-up spot herbicide applications are needed for long-term perennial pepperweed suppression. These results provide several successful integrated strategies for control of perennial pepperweed and revegetation to a desired native perennial grass community.

Fall cattle grazing versus mowing to increase big-game forage

The effects of 3 levels of mowing and cattle (Bos taurus) grazing were examined on rough fescue (Festuca scabrella) range on the Blackfoot Clearwater Wildlife Management Area in west-central Montana. Treatments were implemented in enclosures during the fall of 1997 and 1998 at 50%, 70%, and 90% removal of herbaceous standing crop. Elk (Cervus elaphus) and mule deer (Odocoileus hemionus) forage measurements were obtained in spring and summer on standing dead vegetation, green grass and forb biomass, total biomass, and percent live vegetation, and compared between mowing and prescribed cattle grazing at the same removal level. At the 50% mowing level, there was increased (P<0.05) availability of grass and biomass in the spring, with increased standing dead and decreased percent live vegetation in the summer. At the 70% mowing level, there was increased standing dead and grass and decreased percent live vegetation available to elk and mule deer in the spring when compared with the same level of grazing (P<0.05). At the 90% mowing level, there was decreased availability of grass and total biomass during spring and summer (P<0.05). Results indicated that at moderate (50%) levels of vegetation removal, fall mowing might be adequate to increase grass and total biomass availability in the spring, but fall grazing by cattle might remove more standing dead material, leaving more nutritious plants available to wildlife in the summer. Fall mowing at 70% removal might provide more grass for wildlife in the spring, but reduces percent live vegetation and leaves more standing dead when compared to fall cattle grazing. This would make it more difficult for wildlife to select preferred forage in the spring, when nutrition is needed for calf and fawn production. Fall cattle grazing might be a better tool to use at the 90% level, since mowing removes more grass and total biomass, leaving reduced vegetation for elk and mule deer.

Spotted knapweed response to season and frequency of mowing

Spotted knapweed (Centaurea maculosa Lam.) is a non-indigenous weed that has invaded millions of hectares of rangeland in the United States. Mowing may be useful for reducing this weed. Our objective was to investigate the response of spotted knapweed and grasses to season and frequency of mowing. Response of grass and spotted knapweed to 16 mowing treatments applied annually for 3 years was studied at 2 sites. Treatments consisted of combinations of spring, summer, and fall mowing. Treatments were arranged in a randomized-complete-block design with 4 replications (16 treatments; 4 replications; 2 sites = 128 plots). After repeating mowing treatments for 3 years, a single fall mowing when spotted knapweed was in the flowering or seed producing stage reduced its cover and adult density as much as any treatment consisting of repeated mowing. Fall mowing decreased adult density 85 and 83% below that of the control at Sites 1 and 2, respectively. Treatments reduced seedling density at Site 2, but the response was not consistent between years or among treatments. Spotted knapweed cover was decreased by several mowing treatments at each site (10-36%), while grass cover was only decreased by 3 mowing treatments (18-23%) at Site 1 in 1998. We recommend a single annual mowing, applied at the flowering or seed producing stage, for the partial control of spotted knapweed.

Spotted Knapweed Response to Season and Frequency of Mowing

Spotted knapweed (Centaurea maculosa Lam.) is a non-indigenous weed that has invaded millions of hectares of rangeland in the United States. Mowing may be useful for reducing this weed. Our objective was to investigate the response of spotted knapweed and grasses to season and frequency of mowing. Response of grass and spotted knapweed to 16 mowing treatments applied annually for 3 years was studied at 2 sites. Treatments consisted of combinations of spring, summer, and fall mowing. Treatments were arranged in a randomized-complete-block design with 4 replications (16 treatments; 4 replications; 2 sites = 128 plots). After repeating mowing treatments for 3 years, a single fall mowing when spotted knapweed was in the flowering or seed producing stage reduced its cover and adult density as much as any treatment consisting of repeated mowing. Fall mowing decreased adult density 85 and 83% below that of the control at Sites 1 and 2, respectively. Treatments reduced seedling density at Site 2, but the response was not consistent between years or among treatments. Spotted knapweed cover was decreased by several mowing treatments at each site (10-36%), while grass cover was only decreased by 3 mowing treatments (18-23%) at Site 1 in 1998. We recommend a single annual mowing, applied at the flowering or seed producing stage, for the partial control of spotted knapweed. DOI:10.2458/azu_jrm_v54i1_rinella

Shoot Growth and Development of Alamo Switchgrass as Influenced by Mowing and Fertilization

The response of shoot development and forage yield of a 2-year old 'Alamo' switchgrass stand to mowing and fertilization was evaluated to provide information needed for effective management of this variety. Mowing to a 20-cm stubble height in mid-spring removed only a few apical me&ems and had little impact on shoot development. Late spring and early summer mowing were done when apical meristems of primary compound shoots were elevated to near the 20-cm cutting height in May and over 20 cm in June. Secondary nonrooted shoot and aerial shoot numbers were increased and plant vigor, measured by spring growth in 1980, was decreased slightly the following spring. Mowing in mid-summer removed apical meristems from essentially all primary compound shoots and many secondary compound shoots. Regrowth was slight during the remainder of the summer, but the number of secondary and tertiary nonroqted shoots and aerial shoots in- creased. The number of proaxis buds decreased, and plant vigor was severely decreased the following spring. Mowing twice includ- ing early fall, removed apical me&ems from secondary com- pound shoots and some primary and secondary nonrooted shoots. Numbers of secondary, tertiary, and quarternary nonrooted shoots increased, but proaxis bud numbers were reduced. Plant vigor was very low the following spring, possibly due to exposure of mowed plants to cold winter temperatures. Fertilization increas- ed the rate of development of compound and nonrooted shoots, the number of secondary and compound shoots in spring, the number of proaxis buds in fall and the weight of primary and secondary compound shoots. Fertilized stands mowed during summer and early fall were more productive than all other mowed stands. Fertilized plants mowed in mid-summer were vigorous and productive the following spring. However, fertilization did not overcome the loss of vigor caused by fall mowing.

Cultural Practices Inhibiting Overwintering Survival of Brachycolus asparagi Mordvilko (Homoptera: Aphididae)1

Fall burning, mowing, or careful removal of dormant asparagus fern with or without subsequent spring tillage inhibited overwintering survival of an asparagus aphid, Brachycolus asparagi Mordvilko. Spring tillage alone reduced populations by 84% and the number of spears infested by 44%. Destruction of ferns in the fall alone reduced aphid numbers by 65 to 76% and the number of spears infested by 13to 56%. The best combination of treatments was fall mowing followed by spring tillage. This reduced the number of fundatrices by 98% and the percentage of spears infested by 85%. Mowing was 2-fold more effective than burning. There was no apparent relationship between numbers of eggs in the fall and the percentage of spears infested, the total number of fundatrices, or the number of fundatrices infesting each spear the following year in the untreated plots.

Highway Right-of-Way: Mowing versus Succession as Related to Duck Nesting

Alternate 1.6-km blocks of a 37-km section of a grass-forb community along Interstate 94 right-of-way in Stutsman County, North Dakota, were maintained in an early successional stage by annual fall mowing; the remaining 1.6-km blocks, representing later successional stages, were left unmowed. The preference for unmowed vegetation by nesting ducks did not vary over a 4-year period as the vegetation aged (P > 0.10). However, patterns of nest success were different in the 2 habitats (P 0.10) but declined continually in unmowed areas (P < 0.001). Nest location and success are discussed in relation to changes in the vegetation, and specific management recommendations are given.

Effects of Fall Mowing on Winter Survival of Lovegrass Strains1

Evaluating winterhardiness of perennial forages is difficult because of the irregularity of severe winters adequate for testing relatively hardy materials. The objective of this experiment was to examine fall mowing as a tool to increase differential winter injury among lovegrass (Eragrostis sp.) strains. Seventeen lovegrasses were mowed in early October, late October, and mid‐November, during each of 4 years at Woodward, Okla. Control treatments, late winter mowed or unmowed, were included. After mild to moderately severe winters, fall mowing increased winter survival discrimination among lovegrass strains. After one severe winter, discrimination was decreased.Most correlations between survival of strains in the control treatment after a severe winter and survival after fall‐mowing treatments during milder winters were relatively high. After mild winters, strain survival was strongly correlated with limited late fall regrowth. After the severe winter, survival was closely associated with the presence of live, green leaves in late fall. Late fall regrowth and leaf color accounted for 84% of the variation in control survival after that winter. Survival after fall‐mowing stress, and the associated late fall regrowth and leaf color scores, appear to be important predictors of winter survival ability in Eragrostis.

RESULTS OF AUTUMN TOP CUTTING OF FESTULOLIUM GRASS STAND WITH RYEGRASS MORPHOTYPE

Novel crop. Festulolium. is a hybrid of Festucа spp. and Lolium spp. Hybrids combine traits of both parents. Different varieties resemble morphologically either ryegrass or fescue. Compared to original parental forms - meadow and tall fescues and pe­rennial and Australian ryegrasses — festulolium hybrids show new biological and economically important traits, requiring de­velopment of specific technique for seed production. In the first year of life, plants of Festulolium and bushes grow vigorously during the entire summer period, forming a continuous closed sward height of 30 cm and density of shoots of more than 3.6 thousand pieces/m2. The accumulation of excessive vegetative mass leads to a deterioration of wintering conditions and the death of 37-39 % of the shoots. Autumn mowing of crops improves the conditions of overwintering and enhance the safety of sprouts at 14-17 %. The choice of duration of this application depends on the method of sowing of Festulolium. The optimum term of removal of the vegetative mass in the first year of life in the soil cultivating sowing method, and in the second year of life is the second week of September. When uncoated ranelate method of sowing of Festulolium best time of rejection of the vegetative mass is between 15 to 30 September. The fall mowing of the grass at the optimal time increases the number of generative shoots from 8-11% to 44% and seed yield of Festulolium of the first year of use of 9-11 to 24-27 %, second year by 17-25 %.