Native Rangeland Research Articles

Texas GLCI: Growing Partnerships on Texas Grazing Lands

The Ogallala Aquifer region, located in the Great Plains of the central United States, is the largest freshwater aquifer in North America, supporting one of the most agriculturally productive regions in the world. In this paper, we discuss the history of settlement and water use in this region, from the Homestead Act and the Dust Bowl to modern irrigation systems. While many improvements to irrigation technology and water-efficient crops have helped to prolong the life of the Ogallala, continued use of this finite resource is leading to a tragedy of the commons, wherein difficult land management decisions will have to be made by this century's end. We posit that the art and science of rangeland management stands uniquely poised to tackle this challenge directly through creative integration, where appropriate, of native rangeland restoration, improved pasture management, integrated crop-livestock systems, and regenerative agricultural practices aimed at preserving soil and rangeland health, thereby providing continuity in the ability of the Ogallala region to continue to provide food, fiber, and other ecosystem services both locally and globally. Furthermore, we provide discussion on future research, extension, and educational needs to consider as the exploration for adaptive solutions are developed and evaluated in the coming decades.

Effects of sand sagebrush control in southern mixed-grass prairie rangeland on cattle performance and economic return

<h2>ABSTRACT</h2> To evaluate the effects of sand sagebrush (Artemisia filifolia Torr.) control in native rangelands on cattle performance, 15 pastures (10 to 21 ha each) were selected in northwest Oklahoma. Eleven pastures had been sprayed with 2,4-dichlorophenoxyacetic acid in 1984 or 2003 to establish differences in sagebrush cover. The pastures were categorized into 3 sagebrush cover levels: 1) high (27 ± 2.7% cover, n=4), 2) medium (10 ± 2.7% cover, n=6), and 3) low (5 ± 2.7% cover, n=5). From 2003 to 2008, steers (BW = 202 ± 6.1 kg) were stocked annually in late January and grazed until mid-August. The high, medium, and low pastures were stocked at 47, 69, and 69 animal-unit-d/ha, respectively. Cattle were supplemented with oilseed-based cubes (41% CP) from January through April at a rate of 0.68 kg/ steer daily. From January to April, ADG did not differ (P = 0.96) among treatments, but from April to August steers grazing the high pastures gained BW faster (P < 0.01; 1.03 kg) than did steers grazing medium pastures (0.96 kg) or low pastures (0.98 kg). Gain of BW and net return per hectare were greatest (P < 0.01) for low pastures (102 kg, $123.20) compared with high (67 kg, $88.71) or medium (81 kg, $97.74) pastures. These results suggest that increasing levels of sagebrush control coupled with appropriate adjustments in stocking rates may be most profitable for stocker cattle production, but this removal of sagebrush could limit the ecological services that rangeland provides because of loss of protective cover for wildlife.

Assessing the impacts of livestock production on biodiversity in rangeland ecosystems

Biodiversity in rangelands is decreasing, due to intense utilization for livestock production and conversion of rangeland into cropland; yet the outlook of rangeland biodiversity has not been considered in view of future global demand for food. Here we assess the impact of future livestock production on the global rangelands area and their biodiversity. First we formalized existing knowledge about livestock grazing impacts on biodiversity, expressed in mean species abundance (MSA) of the original rangeland native species assemblages, through metaanalysis of peer-reviewed literature. MSA values, ranging from 1 in natural rangelands to 0.3 in man-made grasslands, were entered in the IMAGE-GLOBIO model. This model was used to assess the impact of change in food demand and livestock production on future rangeland biodiversity. The model revealed remarkable regional variation in impact on rangeland area and MSA between two agricultural production scenarios. The area of used rangelands slightly increases globally between 2000 and 2050 in the baseline scenario and reduces under a scenario of enhanced uptake of resource-efficient production technologies increasing production [high levels of agricultural knowledge, science, and technology (high-AKST)], particularly in Africa. Both scenarios suggest a global decrease in MSA for rangelands until 2050. The contribution of livestock grazing to MSA loss is, however, expected to diminish after 2030, in particular in Africa under the high-AKST scenario. Policies fostering agricultural intensification can reduce the overall pressure on rangeland biodiversity, but additional measures, addressing factors such as climate change and infrastructural development, are necessary to totally halt biodiversity loss.

Comparing Morphological Development and Nutritive Value of Caucasian Old World Bluestem and Native Grasses

Caucasian old world bluestem (OWB) [Bothriochloa bladhii (Retz) S.T. Blake] has been introduced in the southern and central USA for conservation and forage production. It has escaped into some native rangelands, and observations indicate that it is usually avoided by grazing animals. Caucasian OWB matures at a greater rate than some native grasses, and maturity was speculated as being a factor for poor forage quality and avoidance by grazing animals when found in mixed stands with native grasses. This study was conducted to examine if forage quality and morphology of Caucasian OWB and native perennial warm-season grass species differs. Caucasian OWB, big bluestem (Andropogon gerardii Vitman), little bluestem [Schizachyrium scoparium (Michx.) Nash], and sideoats grama [Bouteloua curtipendula (Michx.) Torr] were hand clipped at approximately 3-week intervals each growing season in 2004 and 2005. Caucasian OWB morphologically developed at a greater rate than the native species. Caucasian OWB had equal or greater crude protein and in situ digestibility, and equal or lower neutral detergent fiber at each harvest compared to the native species, even though it was equal or more morphologically developed at each harvest. Avoidance of Caucasian OWB that has invaded native rangelands may be related to other factors that are not tested by standard forage quality analyses.

The perception and adaptation of herdsmen to climate change and climate variability in the desert steppe region of northern China

The herdsmen in the desert steppe region in Northern China live primarily on the native rangelands. The semiarid climate has a profound impact on the economy and the livelihood of rural communities. Adaptation to the highly variable climate is the norm in pastoral management in the region but the increasing aridity and variability projected by climate change models provides new challenges for sustainable living in the harsh environment. The study surveyed the herdsmen’s perception of climate change and variability in the desert steppe region of Inner Mongolia, and compared it with the observed climatic patterns and the recorded disastrous climatic events. The existing rangeland and livestock management strategies used by local herdsmen to cope with variable climate were also investigated in order to assist in the development of better management adaptation strategies. The herdsman perceived temperature changes over the past 30 years, which matched well with the meteorological observations, while their perceived change in precipitation (decrease) did not agree with the meteorological records (no change). The discrepancy between the observed and perceived precipitation changes may have arisen from the combination of large seasonal and inter-annual fluctuation of precipitation, more recent drought years and a herdsmen’s desire to have a ‘wet year’, and more forage demand from increased livestock numbers. Herdsmen also had a reasonably good perception of strong wind/dust storms and snow storms, and their sensitivity to these extreme disastrous climatic events appeared to be related to the perception of drought. The herdsmen had better perceptions of recent short-term climate change and possibly to use it to assess the long-term changes. The major adaptive management strategies to cope with disastrous climatic events included selling livestock, buying feed, seeking other grazing resources, housing livestock and looking for other alternative jobs to compensate for the economic loss. Grazing other resources, either the reserved winter rangelands in the growing season in current household farm systems or the common winter rangelands in a traditional nomadic system, played a vital role in buffering the effects of extreme climatic events. Setting appropriate stocking rates and growing forage crops in suitable land areas may contribute to increasing the resilience of rangeland systems. Raising the herdsmen’s awareness of long-term climate change and its effects on rangelands is needed to improve their preparedness to adapt to the future climate.

Spring burning of native tallgrass pastures influences diet composition of lactating and non-lactating beef cows (2012)

Introduction Diet selection is a dynamic process because of seasonal changes in animal and plant characteristics. Nutrient requirements of grazing animals are a function of physiological state; moreover, plant characteristics may be altered with prescribed spring burning of native rangelands. Prescribed spring burning is used to improve the average quality of pasture forage by removing old growth and making new plant growth more accessible to grazing cattle.

Re-alimentation strategy to manoeuvre body condition and carcass characteristics in cull ewes

Improvement in body condition and carcass traits through nutritional intervention was studied in cull ewes. Sixty-eight adult non-productive Malpura ewes (average body weight 26.7 ± 0.33 kg) were randomly divided into four equal groups: G0 maintained on free grazing for 8 h on protected natural rangeland with ad libitum guar (Cyamopsis tetragonoloba) straw (GS) after grazing; G1, G2 and G3 fed with supplemental concentrate at the rate of 250 g, 2.5% of live weight (LW) and ad libitum, respectively. The experiment was continued for 90 days and daily feed intake, weekly LW and body condition score (BCS) were recorded. Intake and digestibility of nutrients were assessed by indicator method. Rumen fermentation attributes and blood biochemical profile were studied to assess the dietary effects and animals were slaughtered at the end of experiment for evaluation of carcass characteristics. Higher dry matter (DM) intake and improvement in plane of nutrition was observed in G2 and G3 with a higher LW gain (LWG) and improvement in BCS than in G0. The digestibility of DM, organic matter, CP, ADF and cellulose was higher (P < 0.05) in G2 and G3 than in G0. A lower ruminal pH and ammonia N but higher total N and trichloroacetic acid-precipitable N, an increase in holotrichs, spirotrichs and total protozoa population, increase in haemoglobin but decrease in serum total cholesterol and non-esterified fatty acids were observed in high-concentrate-fed groups. Carcass attributes revealed increase (P < 0.05) in empty LW, dressing yield, eye muscle area, subcutaneous and intramuscular fat, decrease in shear force value and higher (P < 0.05) protein content in Longissimus dorsi muscle in test groups than in the control. Above all, the G2 animals had better rumen environment and blood biochemical attributes and consumed more feed with enhanced digestibility that supported higher LWG at better feed conversion efficiency, improvement in BCS and carcass quality. Thus, re-alimentation of cull ewes with challenged feeding of concentrate at 2.5% of LW on a basal roughage diet for a period of 3 months may have promise for better economic return to the farmers with possibly meeting quality mutton for human consumption.

Land tax: towards a multifunctional institutional tool for land reform and rangeland conservation

This paper presents a bio-economic modelling technique which provides insight on the probable impacts on the management of natural resources of a land tax as an example of policy instrument. The paper is based on a case study carried out in arid natural rangelands of Namibia, where an agricultural land tax has been implemented in 2006. Responding to concerns regarding the impact of this institutional change on farming strategies’ sustainability, the objective of this paper was first to assess the impact of the current taxation scheme. Second, we propose alternative taxation schemes which have the potential to foster on-farm rangeland conservation. We found that the tax at its current level does not lead to changes in the farming strategy, but that if modulated into an incentive design, it has great potential to achieve both income generation for the state and ecological goals of conservation.

SURVEY OF EVALUATION TECHNIQUES FOR STUDYING RANGELAND GRASS SPECIES NUTRITIONAL VALUES

Studying the philosophy of animal grazing and diet selection in rangelands is crucial. There are vast activities regarding animal diet that have gradually been developed since the beginning of rangeland research studies. Survey of the investigation of the animal diets throughout the world can assist in gathering and categorizing the compiled information on this subject. The present study is done by utilizing databases (e. g. Science Direct, Elsevier, and J. Store) as library research method. About 700 articles have been examined in this investigation and the results showed that the study of animal diets started in 1950s and continued in 1980s as applied and comparative research. The early studies were carried out on cattle, sheep, and goats, and then progressed on wildlife including deer, rabbits, red elk, and wild goats. The survey of these investigations have also shown that there are eight methods to study animal diets, including direct vision, fistulation, stomach content, fecal analysis, utilization, and more recently, DNA analysis. The fecal analysis and fistulation method with 11.63% and 8.25%, respectively, as maximum, and the time method and the DNA analysis with 0.15% and 0.29%, respectively, as minimum were the study methods of animal diets in which grasses, forbs and shrubs were used in most of these methods for evaluating the animal diets. Furthermore, the results showed that North America has published about 24.73% of the research articles and Asia about 1.33% articles. Although different journals have published articles on animal diets, Journal of Range Management has published about 21.06% of all the articles. The survey has also indicated that Asia has published less research on animal diet, and the Range Society or the Range Bureau of Iran collected this information from the world as a database that can be used for proper management of the native rangelands in the country.

Animal and Vegetation Response to Modified Intensive–Early Stocking on Shortgrass Rangeland

Abstract A comparison of animal gains and vegetation trends was made from 2002–2008 between a continuous season-long stocking (SLS) system and a modified intensive–early stocking system (IES) with late-season grazing (IES 1.6× + 1; 1.6 times the number of animals of the SLS system from May 1 to July 15, and 1 times the number of animals of SLS from July 15 to October 1) on shortgrass native rangeland of western Kansas. The continuous season-long stocked system placed animals at a density of 1.37 ha · steer −1 from May through October, or 2.63 animal unit months (AUM) · ha −1 , whereas the intensive–early stocked system with late-season grazing (3.33 AUM · ha −1 ) stocked pastures at 0.85 ha · steer −1 from May through the middle of July, and then stocked pastures at 1.37 ha · steer −1 for the remainder of the grazing season by removing the heaviest animals mid-July each yr. Average daily gains (0.78 vs. 0.70 kg · d −1 , P = 0.039) and total animal gain (58 vs. 52 kg, P = 0.042) were different between the continuous season-long stocked and the intensive–early stocked animals during the first half of the grazing season. No difference was found between average daily gain (0.61 vs. 0.62 kg · d −1 , P = 0.726) and total animal gain (48 vs. 49 kg, P = 0.711) for the continuous season-long stocked and intensive–early stocked with late-season grazing animals during the last half of the season. Total individual animal gain (106 vs. 101 kg, P = 0.154) and average daily gain (0.70 vs. 0.66 kg · d −1 , P = 0.152) was not different between the continuous season-long stocked and the intensive–early stocked system animals that were on pasture the entire grazing season. Total beef gain on a land-area basis (96 vs. 77 kg · ha −1 , P = 0.008) was greater for the modified intensive–early stocked system with late-season grazing with greater animal densities. Changes in residual biomass and most key vegetation components at the end of the grazing season were not different between the two systems.

The effects of dietary consumption of plants secondary compounds on small ruminants’ products quality

Worldwide policies are encouraging the use of natural rangelands and low input feeding resources for livestock farming. Most of the low input feed contain secondary compounds (PSCs) – such as phenolic compounds (PhCs), saponins, and essential oils (EO) – which play a primary role on animal digestion and performances and also on product quality. Meat and milk fatty acid composition can be manipulated by dietary tannins as these PSCs modify ruminal biohydrogenation of dietary polyunsaturated fatty acids through changes in ruminal ecology. Dietary tannins improve products’ flavour by reducing the ruminal biosynthesis of skatole and its accumulation in meat and milk. The addition of garlic or juniper EO in lamb diets reduces the off-flavours perception while thyme or rosemary EO lowered the rancid-odour perception of meat under display. It is proved that dietary PhCs ameliorate meat oxidative stability and prevent meat from discoloration thus extending product shelf life. The dose–response effect of these PSCs as well as their mechanisms of action are not fully unravelled. Nevertheless, the use of plants rich in secondary compounds or the supplementation of purified PSCs in small ruminants diet seem to be a promising strategy for improving products quality.

Wildfire and Invasive Plants in American Deserts: A Special Feature

and over 2.7 M ha has burnedannually (NIFC 2011). These fires resulted in the death of morethan 18 people and the loss of over 3000 structures. In 2002,fires burned 2.9 M ha and firefighting cost exceeded $1.6billion with $100s of millions more spent on revegetationefforts and emergency watershed stabilization to preventcatastrophic flooding and permanent loss of ecosystem servicesacross the Nation (Miller and Narayanan 2008). In 2005, over205000 ha burned in the southern Nevada complex fire and in2007 over 400000 ha burned in the Murphy Complex fire inSouthern Idaho and the Milford Flat fire in Central Utah (NIFC2011).One of the greatest threats to ecosystems of the Great Basin isthe invasion of cheatgrass (Bromus tectorum L.). Cheatgrass isthe most dominant weed species in the Intermountain West,infesting more than 40 M ha, more than 10 M ha in the GreatBasin alone. Cheatgrass invasion has modified big sagebrushsites throughout the Great Basin by providing a fine-textured,early-maturing fuel that increases the chance of ignition, as wellas the frequency and season of wildfires. Adverse impactsinclude increased fire risk, reduced biodiversity and foragefor livestock and wildlife, degraded water quality, reducedrecreational and aesthetic values, and significant economiclosses. Historically, wildfire frequency was estimated at 60–100 yr in the sagebrush/bunchgrass vegetation type (Whisenant1990), 30–70 yr in pinyon/juniper types (Wright 1980), andvirtually absent from the salt desert shrub type and Mojavedeserts (due to lack of fine fuels; Billings 1994). Fire intervalshave decreased to as little as 5 yr in all of these vegetation typessince the invasion of cheatgrass, red brome (Bromus rubens L.),and other invasive plants (Whisenant 1990).The Society for Range Management (SRM) and 26 partnershosted a special conference in Reno, Nevada in December of2008 in response to the need to provide information for themanagement of native rangelands in the face of challengesposed by the interactions of invasive plants and wildfire. SRMhosted the Wildfires and Invasive Plants in American DesertsConference through its Center for Professional Education andDevelopment (CPED), and over 300 people representing 17states and over 70 different universities, state and federalagencies, tribal agencies, agricultural producers, and privatecompanies participated in this unique event. The purpose of theconference was to explore the interactions between invasiveplants, native plants, and wildfire intensity and frequencyacross the Intermountain west. The conference focused on theColorado Plateau and the Chihuahuan, Great Basin, Mojave,and Sonoran deserts of North America. The conference wasdesigned to engage both the scientific community and the landmanagers and producers who must address this issue on a dailybasis.A primary goal of the conference was to provide for theexchange of knowledge between the scientific community, landmanagers, and other stakeholders and synthesize what isknown about the impacts associated with the interactionsbetween invasive plants and wildfire so that land managers willhave state-of-the-art knowledge to address this critical issue.Six papers from the interactive workshops conducted duringthe conference were published in the June 2009 issue ofRangelands (31[3]: 2–35). These papers discussed science,management and policy recommendations, and training andoutreach coordination strategies essential to communicate theimpact that wildfire and invasive plants were having on westernrangelands to policy makers. The papers in this special featureprovide a detailed synthesis of the scientific literature of what isknown about the impacts of wildfire and invasive plants onIntermountain rangelands. It is timely that the SRM nowpublishes these five synthesis publications on what is knownabout the adverse impacts of wildfires and invasive plants whilehundreds of thousands of hectares are burning across thesouthwestern United States. We hope that this special featurewill provide the knowledge necessary to more effectively as-sess current impacts from wildfire and invasive plants andcontribute to management strategies that minimize pendingfuture impacts.

Effects of mineral-supplement delivery system on frequency, duration, and timing of supplement use by beef cows grazing topographically rugged, native rangeland in the Kansas Flint Hills1,2

The effects of mineral-supplement delivery system on patterns of supplement use by grazing beef cows were measured in 2 studies. Study 1 was conducted on 4 pastures grazed by pregnant, mature beef cows (BW = 562 ± 38 kg) from February to May. Study 2 was conducted on 4 pastures grazed by lactating beef cows (BW = 579 ± 54 kg) and their calves from May to September. Treatments were mineral delivered in salt-based, granular form (salty) or mineral provided in a low-protein, cooked, molasses-based block (sweet); both were fed ad libitum. The salty supplement was supplied to cattle via a covered mineral feeder; the sweet supplement was supplied via an open-topped barrel. Both salty and sweet supplements were deployed in each pasture. No additional salt was supplied to cattle. Forage use in the vicinity of each supplement-deployment site and the frequency and duration of herd visits to each supplement-deployment site were measured during four 14-d periods during study 1 and seven 14-d periods during study 2. Supplements were moved to new locations within pastures at the beginning of each period. Consumption of the sweet supplement was greater than salty during each data-collection period in study 1; however, relative differences in consumption diminished over time (treatment × time, P = 0.03). In study 2, sweet consumption was greater than salty in periods 1, 6, and 7 but was not different from salty during periods 2, 3, 4, and 5 (treatment × time, P < 0.01). Increased consumption of the sweet supplement in study 1 translated to greater frequency of herd visits to supplement-deployment sites compared with the salty sites (2.82 vs. 2.47 herd visits/d; P = 0.02) and longer herd visits to supplement-deployment sites compared with the salty sites (125.7 vs. 54.9 min/herd visit; P < 0.01). The frequency of herd visits to mineral feeding sites in study 2 was similar (P > 0.10) between treatments for periods 1 through 6; however, herds visited the sweet sites more often than salty during period 7 (P < 0.01). Herd visits to the sweet sites were longer than those to the salty sites in study 2 (83.8 vs. 51.4 min/herd visit; P < 0.01). Forage disappearance within 100 m of supplement-deployment sites was not influenced (P ≥ 0.54) by treatment in either study. Results were interpreted to suggest that the sweet supplement influenced the location of grazing cattle more strongly than the salty supplement and may be more effective for luring cattle into specific areas of pasture during the winter, spring, and early fall but not during summer.

Diversity of soil cellulase isoenzymes is associated with soil cellulase kinetic and thermodynamic parameters

This study was conducted to determine how land management in three ecosystems including forest, rangeland, and saline desert soils affects the activity and diversity of isoenzymes, and the kinetic and thermodynamic parameters of soil cellulase. Cellulase was chosen because it hydrolyzes cellulose, a major plant substance entering the soils. Soil samples were collected in October 2009 from a native forest, a native rangeland, and a native saline desert as well as adjacent cultivated fields in central Iran. Land use changes of the native forest, rangeland, and saline desert soils resulted in 79%, 47%, and 73% reductions in cellulase activity, respectively. The Michaelis constant ( K m) increased but the maximum catalytic velocity ( V max) decreased for soil cellulase as a result of cultivation in the study areas. The thermodynamic parameters ( E a and Q 10) of soil cellulase were also affected by cultivation. Higher E a and Q 10 values were obtained for the native soils, but the lower values belonged to the cultivated soils. The cellulase zymographic pattern revealed different cellulase isoenzymes in the soils. The prevailing cellulase isoenzymes in the soils were found to have molecular weights of 62 and 74 kDa in the native forest, 86 kDa in the cultivated forest, 55 and 65 kDa in the native rangeland, and 72 kDa in the reclaimed saline areas. Evidence reveals that the sensitivity of soil cellulase kinetic and thermodynamic parameters to land management seems to be due to differences in the cellulase isoenzymes present in soils.

Use of environmental predictors for vegetation mapping in semi-arid mountain rangelands and the determination of conservation hotspots

Question: Can we predict the spatial distribution of plant communities in semi-arid rangelands based on a limited set of environmental variables? Where are priority areas for conservation located? Location: Al Jabal al Akhdar, Sultanate of Oman. Methods: A Classification Tree Analysis (CTA) was used to model the presence/absence of seven rangeland communities and agricultural areas based on seven selected environmental predictor variables. The latter were either obtained from existing digital datasets or derived from a digital elevation model and satellite images, whereas the grazing intensity was spatially modelled with the kernel density estimation technique. The resulting decision rules of a CTA were applied for predictive mapping within the study area (400 km2, resolution of 5 m) by means of ENVI's decision tree classifier. Plant communities of natural rangelands were subsequently evaluated to determine priority areas for nature conservation. Results: Altitude, grazing intensity and landform revealed the highest predictive power. Most of the rangelands were predicted as Sideroxylon–Oleetum. The overall classification accuracy was 89%, whereby agricultural areas and the Ziziphus spina-christi-Nerium oleander community at wadi sites had no misclassification. Inaccuracies occurred mainly because of low sample numbers and errors in available maps of predictor variables. The highest rank for nature conservation was observed for the Teucrio-Juniperetum occupying 20% of the study area. Conclusions: Vegetation mapping using CTA is a valuable tool for rangeland monitoring and identification of key representative areas for nature conservation. An extrapolation of the model used might be feasible to regions adjacent to the central Hajar Mountains.

Biomass production and water use efficiency of grassland in KwaZulu-Natal, South Africa

Using the results from a long-term grazing trial in the Dry Highland Sourveld of the KwaZulu-Natal province, we prepared a water use efficiency value (the ratio of the increment in annual biomass to total annual evapotranspiration) for this rangeland type. Using seasonal biomass measurements recorded between March 2000 and March 2007, we developed a model for predicting the increment in annual biomass using a regression relationship between fPAR (fraction of photosynthetically active radiation intercepted by the vegetation canopy) and measured standing biomass. This regression model was used to estimate the growth rates from fPAR for the period 2001–2006. During the period 2004–2007, when complete meteorological records were available, we calculated reference or potential evapotranspiration (ET0) using the Penman-Monteith equation. To approximate actual evapotranspiration (ET), we used the MODIS leaf area index to approximate canopy conductance component (G) of the Penman-Monteith equation. Using the adjusted fPAR curves as a surrogate for plant growth, and ET, we calculated a water use efficiency value for these grasslands of 7.5 ± 0.48 kg DM mm−1 ha−1 y−1. This value relates well to other published water use efficiencies for natural rangeland.

Does cultivation influence the content and pattern of soil proteins?

Proteins comprise one of the largest N inputs to soils. There is, therefore, a need to investigate the factors involved in the inputs and fate of proteins in soil. While land use management is expected to influence the amount and diversity of soil proteins, the responses of protein as a source of mineralizable N to land use changes have not yet been studied. We hypothesized that extractable soil protein could be a sensitive indicator in evaluating the effect of stress in ecosystem. Soil samples were collected in October of 2009 from a native forest (Typic Calcixerolls) and a native rangeland (Typic Calcixerepts) as well as adjacent cultivated fields in Zagros area, central Iran. Tris–HCl buffer (pH 6.8) containing 1% (w/v) SDS was used for soil protein extraction. The results showed that soil protein content decreased by 64% and 55% in cultivated sites, as compared with their corresponding native forest and native rangeland sites, respectively. To determine the effects of land use changes on soil protein pattern, SDS-PAGE was carried out. Electrophoretic patterns of soil proteins from agricultural soils were clearly different from those of native lands. Protein bands ranged from 17 to 90kDa and from 20 to 62kDa in native forest and in the adjacent cultivated soils, respectively. Protein bands were detected in the range of 17–57kDa for the native rangeland soil but in the range of 17–198kDa for the adjacent cultivated soil. Land use changes were found not only to decrease significantly the amount of soil proteins but also to influence the protein pattern. We achieved the objective of this paper which was to show the potential of the quantity and diversity of soil proteins as indicators of land use changes. The presented soil protein extraction method as well as soil protein content and pattern determination require further validation in a variety of soils types, climates and land use systems.

Rate and Timing of Glyphosate Application to Control Caucasian Old World Bluestem (Bothriochloa bladhii)

AbstractCaucasian Old World bluestem (OWB) has escaped into native rangelands and could have unknown effects on distribution, utilization, growth, and reproduction of native plant and animal species. This trial was established to determine the rate and timing of glyphosate application that will provide the greatest OWB suppression. Treatments included glyphosate applied early at the five-leaf stage of growth with 1.12, 2.24, or 3.36 kg glyphosate ai ha−1(1, 2, or 3 lb ai ac−1), sequential application with an early glyphosate application of 1.12, 2.24, or 3.36 kg ha−1followed by a second application 8 wk later of either 1.12 or 2.24 kg ha−1, and a late-only application of 1.12, 2.24, or 3.36 kg ha−1. Sequential glyphosate applications with at least one of the early or late applications being 2.24 kg ha−1or more reduced OWB frequencies from over 87% to below 30% each year. During a moist year, all sequential application treatments reduced OWB frequency to 12% or less. Frequency of OWB the year after application was directly related (r2= 0.91) to the total amount of glyphosate applied during dry conditions. Seed heads were absent or nearly absent in all sequential application treatments, with the exception of glyphosate at 1.12 kg ha−1applied early and late during the dry season. Sequential application of glyphosate that includes one treatment either early or late of 2.24 or 3.36 kg ha−1appears to be the most effective treatment to reduce established OWB during dry years. During years of adequate moisture, a single late application of 2.24 or 3.36 kg ha−1or sequential applications with 1.12 kg ha−1at each application is as adequate as sequential applications with greater rates for reducing OWB frequency and achieving OWB control.

Notice of release of Maverick Germplasm pink pappusgrass: selected class of natural germplasm

A selected germplasm of pink pappusgrass (<i>Pappophorum bicolor</i> Fourn. [Poaceae]) has been released for rangeland seeding, highway rights-of-way revegetation, and wildlife habitat restoration plantings in south Texas. Maverick Germplasm pink pappusgrass is a blend of 7 accessions selected from an evaluation at multiple sites in the intended area of use. Selections were made based on multi-year evaluation of plant characteristics and germination tests of seed collected from each location. Following selection, components of the germplasm were increased in isolation and blended following harvest to ensure seed was included from each of the selected accessions. Accessions included in the blend originate from 7 different counties and distinct soil types. This germplasm represents the first commercial release of pink pappusgrass, an important component of native rangeland plant communities in south Texas.

Improved modeling of soil organic carbon in a semiarid region of Central East Kazakhstan using EPIC

Inappropriate land use and soil mismanagement produced wide-scale soil and environmental degradation to the short-grass steppe ecosystem in the semiarid region of central east Kazakhstan. A limitation for determining the impacts of land use changes on soil organic carbon (SOC) is the dearth of information on SOC stocks under the predominant land uses in the region. Here we used the Environmental Policy Integrated Climate (EPIC) model to study long-term impacts of land use changes and soil management on SOC to a depth of 50 cm during 1955–2030, in degraded agricultural lands of central east Kazakhstan. Simulated land uses were: native rangeland vegetation, wheat (Triticum aestivum L.), wheatgrass (Agropyron cristatum L.), and abandoned croplands. The EPIC model was initialized with soil properties obtained from a soil map of the study area. Data on crop management, fertilizer application and tillage practices were gathered from local expert knowledge. Simulations were performed for each polygon on a land use classification map, resulting in 4661 simulations. Our results showed that simulated SOC explained 50% of the variation in measured SOC. Of the 1.38 million hectares in the study area, 78% were under native vegetation, 3% cultivated to wheat, 8% on wheatgrass, and 11% were abandoned croplands in 2005. If land use remained constant, total stock of SOC would decrease at an annual rate of 723 kg C ha−1. However, if best management practices are implemented, resulting in reallocation of land use according to the land capability with abandoned croplands being converted to reduced-tillage wheat or wheatgrass, total stock of SOC would increase to an equivalent of 4700 kg C ha−1 yr−1. Combining land use classification and soil maps with EPIC, proved valid for studying impacts of land use changes and management practices on SOC; an important aspect of this approach is the ability to scale up site-specific SOC to the region. With the available data, EPIC produced relatively accurate results but more data on spatial and temporal variation in SOC are needed to improve model calibration and validation.