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Individual sand lovegrass [Erugrostis trichodes (Nutt.) Wood.] plants on a choppy sands range site in Nebraska’s Sandhills were clipped with 7 different harvest regimes for 3 years to determine critical defoliation times. After 3 years unclipped plants had the greatest survival rate and phnts harvested only once a year on June 10 or July 10 survived better than those with other harvest regimes. Top and root yields, new tiller counts, and total non-structural carbohydrate (TNC) levels were all reduced severely with multiple harvests within one year. Sand lovegrass plants cannot tolerate close defoliation at anytime of the year although a single June defoliation appeared to be less detrimental than August defoliation. Sand lovegrass is difficult to manage when it makes up a small component of a pasture. Sand lovegrass will probably persist and yield best in a rotational grazing program where it is defoliated only once a year and some leaf area remains at the close of the grazing period. Plants are normally short lived so they should be managed to allow seed production periodically. A grazing management program necessary to maintain small amounts of sand lovegrass in a mixture may not be practical. Sand lovegrass [Erugrostis trichodes (Nutt.)Wood.] is a warmseason perennial bunchgrass that is native to sandy soils in the central Great Plains. It is best adapted to north and east-facing slopes and in some instances can be prevalent on sands and choppy sands range sites (Vallentine 1967). Sand lovegrass is very palatable and highly preferred by livestock. Yearling steer gains per acre in Oklahoma were improved with sand lovegrass compared to other grasses (Smith 1947). Adding sand lovegrass to either big bluestem (Andropogon gerardii Vitman), switchgrass (Panicum virgatum L.) or sideoats grama [Bouteloua curtipendula (Michx.) Torr.] at Lincoln, Nebraska increased the average daily gain and beef production per acre although dry matter yield was generally not increased. In several seasons a relatively small amount of sand lovegrass in switchgrass pastures helped maintain animal performance’ late in the summer (Conard personal communication). Due to its palatability and bunchgrass growth habit it is often overgrazed by cattle. Sand lovegrass is difficult to maintain in stand even with good management and generally acts as a short-lived perennial. Recently, Vogel and Kindler (1980) have shown that a subterranean aphid (Geoicu urticularia Passerini) reduced yields of sand lovegrass. Severe clipping treatments reduced yield of range grasses (Owensby et al. 1974, Branson 1956, Stout et al. 1980, Perry and Chapman 1976). Tiller numbers are reduced with intensive clipping even though removal of the shoot apex should remove apical dominance and increase tillering if environmental conditions are favorable. Carbohydrate level is important in tiller initiation and continued development (Jameson 1963). Root production was more adversely affected than top production by The senior author is a professor and the ju@or avthor was an as$ate pr+SSOr ~gw$ceased), Department of Agronomy, Umvers~ty of Nebraska-Lmcoln, Ltncoln This report is published as Paper Number 6216, Journal Series. Nebraska Agricultural Experiment Station. 236; severe clipping treatments (Branson 1956, Crider 1955, Biswell and Weaver 1933). Adequate carbohydrate reserve is important in initial regrowth (White 1973). Close defoliation treatments, especially at critical stages in plant development, often deplete carbohydrate reserves in range grasses to a level that is not replenished readily (Kinsinger 1961, Perry and Chapman 1974, White 1973) and as a result future tiller production, yield, and plant persistence are adversely affected. A critical time to defoliate grasses was during shoot apex elevation (Branson 1953, Booysen et al. 1963, Pearson 1964, Vogel and Bjugstad 1968). Sand lovegrass begins growth earlier in the spring than most warm-season grasses (Vallentine 1967, Smith 1947) and elevates its shoot apex later than many other warmseason range grasses (Gilbert et al. 1979). Consequently, sand lovegrass should have a long vegetative period where it would be somewhat resistant to grazing. Once tillers of sand lovegrass begin elevation, the process is more rapid than wijh other grasses(Gilbert et al. 1979). The experimental objective was to determine if there was a time during the growing season when relative close defoliation was not especially detrimental to vigor and persistence of sand lovegrass. Materials and Methods A southeast facing slope with abundant sand lovegrass on a chdppy sands range site was selected for the study near Halsey, in Nebraska’s sandhills, in an area protected from grazing. The data from the Halsey, Nebr., weather station, which is approximately 6 km from the plots, indicated normal to above normal rainfall for all 3 years of the study. Precipitation averaged 95 mm, 20 mm, and 289 mm above the normal of 528 mm for 1975, 1976, and 1977 respectively. The plants were fairly widely spaced and there was little other vegetation for competition. In March 1975, 7 replications were marked out and 3 sets of individual uniform plants were selected within each replication for the 3-year study. Seven harvesting treatments were imposed on the plants. The harvesting dates were as follows: (A) unclipped; (B) June 10; (C) July IO; (D) August 10; (E) June 10 and July 10; (F) June 10 and August 10; and (G) June 10, July 10, and August 10. At the end of the growing season, around November 1, all plants were clipped again and the unclipped treatment was harvested. Plants were clipped at S-cm height, which represented a fairly close harvest especially on a southeast facing slope. Tillers were counted at first harvest and the new tillers, which would represent many of those that would be producing the following year, were counted on November 1. In the fall of 1975 1 set of plants were carefully dug to a depth of 18 cm and removed from the site in order to measure root yields and the carbohydrate level. The remaining 2 sets were subjected to the same harvest treatments in 1976 and one set of them was removed in the fall of 1976. In 1977 the last set was subjected to the harvest treatments for the third year and then removed in the fall. Yield and tiller data from 1975 were averaged JOURNAL OF RANGE MANAGEMENT 36(2). March 1993 T&b 1. Vigor and wrvivoi of nnd lovegram pia& with various huventfng tre~lrncdr at H&y, Nebr. V&WI are averages of 7.piants per treatment. Harvest dates First harvest date 1976 First harvest date 1977 November 1977 % alive % vigorous’ % alive %J vigorous % alive % vigorous Unclipped 86 86 86 43 June 10 71 71 57 43 57 43 July 10 86 86 86 71 57 29 August 10 71 43 43 43 43 43 June 10, July IO 57 43 43 I4 43 0 June IO, August IO 57 0 29 0 29 0 June IO, July IO, August IO 71 ‘Plants were considered vigorous if they had 5 or more tillers per plant. across ail 3 sets of plants and in 1976 data were averaged over the 2 remaining sets. Total nonstructural carbohydrates (TNC) were measured using a takadiastase enzyme and a copper iodimetric method (Smith 1969). The stem base material was used for TNC analysis (Perry and Moser 1974). The experiment was designed as a randomized complete block and Duncan’s new multiple range test was used to separate treatment means. only once, generally had more tillers than those plants clipped more than once. Significantly w.05) more tillers developed in the fall of 1976 on unclipped plants and those clipped once on June 10 than on the other treatments. At the conclusion of the study the same trend was evident except all of the plants were generally less

Yield, Vigor, and Persistence of Sand Lovegrass [Eragrostis trichodes (Nutt.) Wood] following Clipping Treatments