Blue Panicgrass Research Articles

Influence of cutting time interval and season on productivity, nutrient partitioning, and forage quality of blue panicgrass (Panicum antidotale Retz.) under saline irrigation in Southern region of Morocco.

Salinity has become a major issue in various parts of the world negatively impacting agricultural activities and leading to diminished crop potential and lower yields. Such situation calls for urgent interventions such as adopting salt-tolerant crops to fill the gap in food and feed availability. Blue panicgrass (Panicum antidotale Retz.) is a promising salt-tolerant forage crop that has shown an appropriate adaptation and performance in the saline, arid, and desertic environments of southern Morocco. However, for obtaining a highest forage productivity with nutritional quality, optimization of the cutting interval is required. Thus, the objective of this study was to determine the optimal cutting time interval allowing high forage production and quality under high salinity conditions. This experiment was conducted over one entire year covering the summer and winter seasons. The effect of five cutting time intervals on selected agro-morphological traits, crop productivity, mineral nutrient accumulation, and forage quality of blue panicgrass in the region of Laayoune, southern Morocco. The finding of this study recommend that cutting blue panicgrass every 40 days maximized the annual fresh and dry forage yield as well as the protein yield, which reached 74, 22, and 2.9 t/ha, respectively. This study also revealed a significant effect of the season on both productivity and quality. However, forage yield declined during the winter and increased during the summer, while protein content increased during winter compared to summer. The mineral nutrient partitioning between shoots and roots, especially the K+/Na+ ratio, indicated that blue panicgrass has salt tolerance mechanism as it excluded sodium from the roots and compartmentalized it in the leaves. In conclusion, there is a potential of blue panicgrass on sustaining forage production under salt-affected drylands, as demonstrated by the response to two key questions: (a) a technical question to farmers for its adoption such as at which interval should blue panicgrass be harvested maximizing both forage yield and quality? And (b) a scientific question on how does blue panicgrass maintain high K+/Na+ ratio to cope with salinity stress?

Growth response of blue panic grass (Panicum antidotale) to saline water irrigation and compost applications

ABSTRACT A pot experiment was conducted to examine the ability of Blue Panic grass (Panicum antidotale) to grow in slightly saline soils (2.40 dS m–1) under different levels of saline irrigation water in the presence or absence of compost. Eight treatments were set up in a randomized block design with five replicates as follows: T1 (Freshwater), T2 (Freshwater + compost at 20%), T3 (Saline water 5000 mg L–1), T4 (T3 + compost at 20%), T5 (Saline water 10000 mg L–1), T6 (T5 + compost at 20%), T7 (Saline water 15000 mg L–1) and T8 (T7 + compost at 20%). Growth parameters of Blue Panic Grass were evaluated at the end of the experimental period as plant and root length, shoot, and root fresh and dry weights, total chlorophyll, and total carbohydrates. In general, tested Blue Panic Grass appeared to be tolerant to high salt concentrations in irrigation water, and slightly significant differences were found for all the measured parameters. A remarkable growth increase occurred in plants grown in compost-amended soils, with respect to the unamended soils. The results demonstrate the possibility to stabilize the yield of blue panic grass, an important feed crop in Egypt, irrigated with saline water, which can secure animal feed resources without reducing the already limited freshwater availability.

Comparison of growth of annual crops used for salinity bioremediation in the semi-arid irrigation area

The decline of soil organic carbon (SOC) has aggravated salinity-related problems in semi-arid irrigation areas of the Awash river basin, Ethiopia. This study aimed at evaluating the performance of potential remediation crops on saline soil and their effectiveness for remediating soil salinity and improving pH, SOC, bulk density (BD) and hydraulic conductivity (HyCo). Rhodes grass (RHG), alfalfa (ALF), sudangrass (SUG) and blue panicgrass (Retz) (BPG) were grown in saline (3–13.9 dS/m) field plots. The crop biomass was incorporated into the soil immediately before flowering. The results show that at high soil salinity levels, BPG and SUG grew well, with the harvesting frequency of BPG being much higher than for SUG. Conversely, the growth of ALF and RHG was strongly inhibited by high soil salinity. Significant (P < 0.05) reduction of soil salinity levels (–3.2 dS/m) and related ionic concentrations, an increase of SOC (0.8% to 1.6%) and improvement of BD and HyCo were observed in BPG plots. The fast-growing nature of BPG in the hot climate of the experimental area resulted in harvests every three weeks and promoted the incorporation of high amounts of biomass to the soil and efficient soil salinity remediation. At moderately saline conditions, ALF also showed a great potential for salinity reclamation (–1.8 dS/m) and SOC accumulation. The cultivation of fast-growing annual crops proved an efficient and low-cost strategy for soil salinity mitigation and the reclamation of salinity-associated soil degradation in irrigation agriculture in Ethiopia.

FEED VALUE OF BLUE PANIC (Panicum antidotale retz.) GRASS AT DIFFERENT GROWTH STAGES AND UNDER VARYING LEVELS OF HUMIC ACID IN SALINE CONDITIONS

This study underscored an underexploited crop, blue panic grass as a potential crop for hot and saline regions. It investigated feed value of the crop at two growth stages, before flowering (BF) and after flowering (AF), and under different levels of humic acid application (HA, at 0, 15, 30, 45, 60, 75, and 90 kg ha−1 ). Significant (P < 0.05) effects of different growth stages, HA while non-significant effect of their interactions were observed for various parameters. Low dry matter (DM) was recorded for cutting at BF than that for AF, whereas the DM production increased with increasing HA levels. For plants at BF stage, low acid detergent fiber (ADF) and low neutral detergent fiber (NDF) levels were observed. In contrast, leaf/stem ratio, digestible dry matter (DDM), crude protein (CP) content, and the concentrations of macro and micro elements, were all high in plants at BF stage. A similar pattern for all the above mentioned parameters was observed for augmentation of HA. The study suggests the application of 75-90 kg ha-1 HA to the soil, whereas cutting of the crop at BF stage for enhancing both the yield and quality of the crop. Furthermore, findings of this study are expected to be a valuable reference for researchers and producers, because it broadly highlights the grass feed values

گزارش علمی کوتاه: اثر تنش شوری بر شاخصهای جوانهزنی و رشد گیاهچه ارزن پادزهری (Panicum antidotale L.)

شوری ناشی ازکلریدسدیمتعادلیونیووضعیتموادغذاییرادرگیاهتغییرمی‌دهد. لذا به منظور بررسی تاثیر سطوح مختلف شوری در مراحل جوانه‌زنی و گیاهچه‌ای آزمایشی در قالب طرح کاملا تصادفی در شرایط گلخانه‌ای انجام شد. اعمال شوری در مرحله جوانه‌زنی شامل پنج سطح 0، 2/5، 5، 7/5 و 10 دسی‌زیمنس بر متر با چهار تکرار انجام شد. شاخص‌های جوانه‌زنی با افزایش شوری کاهش یافت به طوری که در 2/5 دسی زیمنس‌بر متر افت شدید مشاهده شد (درصد جوانه‌زنی نسبت به شاهد 47 درصد کاهش یافت) و در غلظت شوری 10 دسی زیمنس بر متر به حداقل خود (89 درصد کاهش نسبت به شاهد) رسید. آزمایش در مرحله گیاهچه‌ای نیز در پنج سطح 0، 2/5، 5، 7/5 و 10 دسی‌زیمنس بر متر با سه تکرار انجام شد، که شامل سه بخش: 1- اعمال تیمارهای شوری تا قبل از سبز شدن 2- اعمال تیمارهای شوری پس از سبز شدن و 3- اعمال تیمارهای شوری از ابتدا تا پایان آزمایش (4 برگی) بود. در این مرحله از آزمایش سطح برگ، وزن خشک ریشه و ساقه و نسبت ریشه به ساقه تحت تاثیر شوری معنی‌دار شد. در بخش دوم آزمایش دوم در شوری 5 دسی زیمنس بر متر نسبت ریشه به ساقه افزایش نشان داد (یعنی 0/62 ولی در شاهد 0/44 بود). به طور کلی نتایج نشان داد که گیاه ارزن پادزهری در مرحله جوانه‌زنی به تنش شوری نسبت به مرحله گیاهچه‌ای حساستر است.

مطالعه کمی و کیفی تولید علوفه در کشت مخلوط کوشیا (Kochia scoparia L.) با ارزن پادزهری (Panicum antidotale Retz.) تحت شرایط آبیاری با آب شور

شوری خاک و آب آبیاری مشکلات عمده ای را برای تولید علوفه بوجود آورده است بنابراین این تحقیق با هدف بررسی کمی و کیفی تولید علوفه در کشت مخلوط کوشیا (Kochia scoparia L.) و ارزن پادزهری (Panicum antidotale Retz.) در شرایط آبیاری با آب شور به اجرا درآمد. هدایت الکتریکی آب آبیاری در طی دوره رشد 9/4 دسی زیمنس بر متر بود. این آزمایش در قالب طرح بلوک‌های کامل تصادفی با سه تکرار در سال زراعی 90-1389 در مزرعه تحقیقات شوری قطب علمی گیاهان زراعی ویژه دانشگاه فردوسی مشهد انجام شد. تیمارهای آزمایش متشکل از سه سطح مختلف (25، 50 و 75 درصد) از ترکیب نسبی دو گونه و دو تیمار تک کشتی بود. در بین تیمارهای مخلوط در مجموع دو چین، تیمار 50% ارزن و 50% کوشیا با میانگین 1408 گرم در مترمربع بیشترین عملکرد ماده خشک را داشت و پس از آن تیمار 25% ارزن و 75% کوشیا و تیمار 75% ارزن و 25% کوشیا به ترتیب با میانگین 1317 و 993 گرم در مترمربع قرار گرفتند. به علت رشد کمتر ارزن پادزهری (گیاهی چند ساله) در سال اول، سهم زیادی از عملکرد ماده خشک در هر تیمار، مربوط به کوشیا بود و در تمامی تیمارهای مخلوط، نسبت برابری زمین کمتر از یک بود. در چین اول و دوم، تفاوت معنی داری بین تیمارهای مخلوط از نظر درصد پروتئین خام، خاکستر، فیبر شوینده خنثی (NDF) و فیبر شوینده اسیدی (ADF) وجود نداشت. ولی با توجه به خصوصیات متفاوت کمی و کیفی علوفه این دو گیاه، تحقیقات بیشتر در این زمینه توصیه می شود.

The Mechanisms of Salinity Tolerance in the Xero-halophyte Blue Panicgrass (Panicum antidotale Retz)

Identifying the physiological traits associated with salt tolerance is important in optimal management of biosaline systems and optimum utilization of saline water resources in dry and saline areas. Therefore, some indices of photosynthetic activity, dry matter production and accumulation of sodium and potassium ions in Blue panicgrass (Panicum antidotale Retz) were evaluated in five levels of salinity treatment (0, 70, 140, 210 and 280 mM NaCl solution) under greenhouse conditions. The results showed that at 28 and 35 days after salt stress, plant leaf area reduced in the highest salinity treatment, 93 and 96% respectively, compared with control. Leaf stomatal conductance, CO2 fixation and quantum efficiency of photosystem II were decreased by increasing salinity. It caused also a reduction in chlorophyll content (Chl a, Chl b) in leaves of Blue panicgrass. Content of carotenoids showed binary patterns to different salinity levels, slightly increased in 70-140 mM NaCl and decreased again in 210-280 mM, respectively. Increasing levels of salinity, increased sodium content in both roots and shoots but the shoots potassium content decreased. Decline in photosynthesis indices caused the reduction of root and shoot dry weight. This decrease resulted from lower leaf area (r=0.91**), lower stomatal conductance (r=0.78**), lower CO2 fixed in photosynthesis (r=0.63**), lower quantum efficiency of photosystem II (r=0.54**) and lower Chl a (r=0.45**), respectively. Data analysis base on using stepwise regression introduced leaf area (?=0.560), chlorophyll a content (?=0.245) and shoot potassium content (?= 0.264) as main effective components of salinity tolerance in Blue panicgrass.

Soil salinity as a selection pressure is a key determinant for the evolution of salt tolerance in Blue Panicgrass ( Panicum antidotale Retz.)

To assess the role of selection pressure in plant adaptation to saline environment, a hydroponic experiment was conducted on six Panicum antidotale Retz. populations collected from a wide range of habitats with varying selection pressure in the form of soil salinity. The soil electrical conductivity of six different habitats ranged from 3.39 to 19.23 dS m −1 and pH from 5.86 to 7.65. Plants of all populations collected from varying habitats were established in pots containing normal soil and allowed to grow for 6 months. Newly grown tillers from each plant were separated and 10 of them each formed a composite sample for a particular population. They were then transplanted in plastic containers each containing 10 l of half strength Hoagland's nutrient solution alone or with 150 mol m −3 NaCl. After 42 days growth in salt treatment, the populations collected form highly saline habitats proved to be more salt-tolerant compared with those from mild or non-saline habitats in terms of growth performance. The populations adapted to high salinity showed less decrease in leaf K +/Na + and Ca 2+/Na + ratios under salinity stress. Moreover, under stress the salt-tolerant populations showed less reduction in photosynthetic capacity than the salt-sensitive populations. In addition, hyper-accumulation of organic solutes such as glycinebetaine and proline and thereby higher osmotic adjustment seemed to be associated with the higher degree of adaptability of the salt-tolerant populations to salt stress. From the data presented, it is plausible to conclude that selection pressure (soil salinity) must have been one of the important determinants bringing about the evolution of salt-tolerance trait in Blue Panic grass.

Involvement of polyamines, abscisic acid and anti-oxidative enzymes in adaptation of Blue Panicgrass ( Panicum antidotale Retz.) to saline environments

A hydroponic experiment was conducted to assess the possible involvement of polyamines (PAs), abscisic acid (ABA) and anti-oxidative enzymes such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in adaptation of six populations of Panicum antidotale Retz. to selection pressure (soil salinity) of a wide range of habitats. Plants of six populations were collected from six different habitats with ECe ranging from 3.39 to 19.23 dS m −1 and pH from 7.65 to 5.86. Young tillers from 6-month-old plants were transplanted in plastic containers each containing 10 l of half strength Hoagland's nutrient solution alone or with 150 mol m −3 NaCl. After 42 days growth, contents of polyamines (Put, Spd and Spm) and ABA, and the activities of anti-oxidative enzymes (SOD, POD and CAT) of all populations generally increased under salt stress. The populations collected from highly saline habitats showed a greater accumulation of polyamines and ABA and the activities of anti-oxidative enzymes as compared to those from mild or non-saline habitats. Moreover, Spm/Spd and Put/(Spd + Spm) ratios generally increased under salt stress. However, the populations from highly saline environments had significantly higher Spm/Spd and Put/(Spd + Spm) ratios as compared to those from mild or non-saline environments. Similarly, the populations adapted to high salinity accumulated less Na + and Cl − in culm and leaves, and showed less decrease in leaf K + and Ca 2+ under salinity stress. Higher activities of anti-oxidative enzymes and accumulation of polyamines and ABA, and increased Spm/Spd and Put/(Spm + Spd) ratios were found to be highly correlated with the degree of adaptability of Panicum to saline environment.

Effect of Irrigation Water Salinity, Irrigation Interval and Sulphur Fertilizer Rates on Forage Yield,Yield Components and Quality of Blue Panic Grass (Panicum antictotale L.)

This study was carried out at the Agricultural Experiment station, KAU, Hada Al– Sham during 2007 and 2008 seasons, to study the effects of three irrigation water salinity levels (1000, 5000 and 10,000 mg/l), three irrigation intervals and three sulphur rates on forage yield and quality of blue panic grass. The results revealed that decreasing water salinity or irrigation interval or increasing sulphur rate ceased increasing forage yield and yield components of dry forage yield /ha were 12.6, 10.3 and 8.07 t/ha under the effect of 1000, 5000 and 10,000 mg/l. As irrigation interval increased from 4 to 6 to 8 days dry forage yield decreased from 11.4 to 10.3 to 9.27 t/ha, respectively. Increasing sulphur rates from 0.0 to 7.5 to 15 t/ ha, increased dry forage yield from 8.68 to 10.59 to 11.69 t/ha, respectively. Leaf protein content increased as irrigation water salinity increased, where protein contents were 18.94% and 20.63% under 1000 mg/l and 10.000 mg/l, respectively. As sulphur rates increased, protein content of stems and leaves increased. Also, the interaction between the water salinity and sulphur rates had significant effects on fresh and dry forage yield. Also, the interaction between irrigation intervals and sulphur rates had significant effects on dry forage yield.

Competition for pulsed resources: an experimental study of establishment and coexistence for an arid-land grass

In arid environments, episodically-pulsed resources are important components of annual water and nutrient supply for plants. This study set out to test whether seedlings have an increased capacity for using pulsed resources, which might then improve establishment when in competition with older individuals. A second aim was to determine whether there is a trade-off in competitive strategies when resources are supplied continuously at low concentrations, or as pulses with pronounced inter-pulse periods. A glasshouse experiment used a target-neighbour design of size-asymmetric competition, with juveniles of Panicum antidotale (blue panicgrass) introduced into contrasting densities of adult plants. Stable isotopes of nitrogen were used for measuring plant resource uptake from pulses, and tolerance to inter-pulse conditions was assessed as the mean residence time (MRT) of nitrogen. A higher root/shoot ratio and finer root system enhanced the capacity of juveniles to use resources when pulsed, rather than when continuously supplied. Higher resource uptake during pulses improved the establishment of juvenile Panicum in mixed cultures with older individuals. However, a trade-off was observed in plant strategies, with juveniles showing a lower MRT for nitrogen, which suggested reduced tolerance to resource deficit during inter-pulse periods. Under field conditions, higher utilization of pulsed resources would lead to the improved seedling establishment of Panicum adjacent to "nurse" plants, whereas mature plants with well-developed roots, exploiting a greater soil volume, maintain more constant resource uptake and retention during inter-pulse periods.

Relationships between leaf gas exchange characteristics and growth of differently adapted populations of Blue panicgrass ( Panicum antidotale Retz.) under salinity or waterlogging

A greenhouse experiment was conducted to draw relationships between leaf gas exchange characteristics and growth of differently adapted populations (normal population collected from non-saline non-waterlogged soil, a population from waterlogged soil, and a population from salt affected soil) of Blue panicgrass ( Panicum antidotale Retz.) under waterlogging or salt stress. Imposition of salt stress and waterlogging for 46 days caused a significant reduction in growth of all three different populations of P. antidotale. However, the population from waterlogged conditions showed markedly higher growth under waterlogged conditions and that from saline conditions under salt stress as compared to the normal population. A positive association between growth and net CO 2 assimilation was observed in all three populations under these conditions. The net CO 2 assimilation and stomatal conductance of all three populations were positively associated and the former variable also had a strong positive relationship with transpiration. Relative intercellular CO 2 concentration ( C i/ C a) in waterlogging tolerant population reduced under saline or waterlogged conditions, and in the salt tolerant population no such reduction in C i/ C a was found. Water use efficiency was higher in the salt tolerant population under saline conditions as compared to other populations, but the pattern of increase or decrease in intrinsic water use efficiency was not consistent among the different populations. Although chlorophylls a and b were reduced in all three populations under salinity or flooding, they had no positive association with net CO 2 assimilation or the growth of different populations under varying stress conditions. No clear relationship between data for leaf water potential and that of turgor pressure of the three populations under varying stress conditions was found. Growth of the three populations of P. antidotale adapted to saline or waterlogged habitats was associated with net CO 2 assimilation and stomatal conductance, but not with any of the water relation parameters measured.

Recovery and germination of gelatin-encapsulated seeds fed to cattle

Artificial reseeding of marginal farmlands, wildlands, or rangelands by mechanical means is expensive and often unsuccessful. This study was conducted to determine the recovery and germinability of seeds of south-western U.S.A. rangeland forages fed to cattle. Seed of fourwing saltbush (Atriplex canescens), alkali sacaton (Sporobolus airoides), blue panicgrass (Panicum antidotale), and sideoats grama (Bouteloua curtipendula) were administered in gelatin capsules to steers maintained on a moderate-quality alfalfa (Medicago sativa) diet. Approximately 95% of the recovered seed passed through the steers within 72 h after dosing, but recovery varied among species. Total recovery was 9·5, 46·4, 61·8, and 0% for fourwing saltbush, alkali sacaton, blue panicgrass and sideoats grama, respectively. Fourwing saltbush, blue panicgrass, and alkali sacaton retained viability and germinated in the fecal material. Germination of seeds recovered 48h post ingestion was 14·8, 50·1, and 41·4% for fourwing saltbush, alkali sacaton, and blue panicgrass, respectively, and was similar to germinability of noningested seeds. The use of gelatin capsules would be an effective method for easily feeding known quantities of seeds to livestock in small herds and could be incorporated with other common and necessary livestock handling practices.

The Effect of Polyacrylamide on Grass Emergence in Southcentral New Mexico

Seeding rangeland is a challenge for rangeland scientists, especially on those soils with tendency to crusting. Although some information is available on how soil conditioners affect emergence of certain comestible crops, little is known about the effect of synthetic organic matter on grass emergence. We examined the effect of polyacrylamide, a soil conditioner, on seedling emergence of blue panicgrass (Panicum antidotale Retz.), King Ranch bluestem (Bothriochloa ischaemum [L.] Keng), sideoats grama (Bouteloua curtipendula [Michx.] Torr.), plains bristlegrass (Setaria macrostachya H.B.K.), and 'salado' alkali sacaton (Sporobolus airoides [Torr.] Torr.) under field conditions. Emergence of blue panicgrass and sideoats grama was increased with polyacrylamide applications, even at the lowest concentration (10 kg ha-1) during summer 1987. No emergence response to polyacrylamide applications was found for King Ranch bluestem, and plains bristlegrass did not emerge in any experimental plots during summer 1987. During summer 1988, blue panicgrass and sideoats grama emergence was again increased with polyacrylamide applications. Emergence of 'salado' alkali sacaton and King Ranch bluestem was unaffected by polyacrylamide applications. Soil conditioners may be a feasible alternative for seeding some rangeland in areas where crusting is a problem.

Seedling emergence and root elongation of four grass species and evaporation from bare soil as affected by polyacrylamide

Seedling establishment is particularly difficult on range soils with a tendency to crust. Although application of organic matter can correct this problem, it is usually scarce on rangeland and, in general, in arid areas. Therefore, synthetic soil conditioners have become important in replacing the effect of natural organic matter. The objectives of this study were to determine the effects of polyacrylamide (PAM) on seedling emergence and root elongation of blue panicgrass (panicum antidotale), King Ranch bluestem (Bothriochloa ischaemum), plains bristlegrass (Setaria macrostachya) and sideoats grama (Bouteloua curtipendula), as well as on evaporation, infiltration and strength of soil with a tendency to crusting. Three trials were performed, with PAM doses of 0, 10, 20 and 40 kg ha−1. Polyacrylamide markedly improved emergence of sideoats grama, even at the lowest PAM application level, while blue panicgrass and King Ranch bluestem were unaffected. Plains bristlegrass had no emergence in any of the test plots and so statistical analysis was not performed. Roots of blue panicgrass and sideoats grama that grew in tubes treated with PAM were larger than untreated ones. Measurements of shear strength showed PAM reduced the crust on the soil surface. In general, as PAM concentration increased, shear strength values decreased. PAM reduced evaporation in the short and long term. Infiltration measurements were inconsistent. Results of this study suggest PAM may become important in rangeland areas because it can improve emergence as well as the root system of some grasses, reduce shear strength that is directly correlated with crust formation, and reduce evaporation.

Early Root and Shoot Elongation of Selected Warm-Season Perennial Grasses

Early Root and Shoot Elongation of Selected Warm-Season Perennial Grasses

The Use of Near‐Infrared Reflectance Spectroscopy to Predict Species Composition of Forage Mixtures1

Assessment of species composition of hay, pasture, and range samples is an important but laborious factor in forage quality evaluation. Near‐infrared reflectance spectroscopy (NIRS) was evaluated as a rapid technique for prediction of the species composition of hay and pasture forages and weeds. In Exp. 1, 97 mixtures were formed using eight species. Each species varied from 0 to 100% in each mixture. Each mixture of dried, ground material was scanned with monochromatic light from 1100 to 2500 nm at 2‐nm intervals, and the reflected energy was recorded. Percentage of each species was then regressed on the spectra using a modified stepwise regression procedure. Calibration equations with coefficients of determination (R2) from 0.94 to 0.99 and standard errors of difference (SED) from 1.9 to 6.8% were obtained using five to seven equation terms. Johnsongrass [Sorghum halepense (L.) Pers.] could not be predicted (SED = 6.8%) as precisely as the others, whereas blue panicgrass (Panicum antidotale Retz.) and sunflower (Helianthus annuus L.) were precisely predicted (SED &lt; 2%). One to three harvest dates of seven species of hay were used in a second experiment to determine if variability within a species resulted in additional imprecision. In general, SED were higher; however, all but ‘Midland’ bermudagrass [Cynodon dactylon (L.) Pers.] gave SED of 10 or less, and the R2 of the calibration data set ranged from 0.84 to 0.98. Bermudagrass predictions were more precise if samples containing eastern gamagrass [Tripsacum dactyloides (L.) L.] cut at boot were removed from the data set. With proper calibration, NIRS could save much time normally used to separate species in hand‐clipped samples. The number of samples that can be analyzed in an experiment could be increased, and hence the accuracy of determination of species composition in a given pasture should be improved.

Effects of Selected Seed Treatment on Germination Rates of Five Range Plants

Effects of various treatments on germination rates were determined for Lebmann lovegrass (Eragrostis lehmunniuna Nees), ‘Cochise’ lovegrass (Eragrostis lehmanniana Nees X Eragrostis tricophoru Coss & Dur), Boer lovegrass (Erugrostis curvulu var. conferta Nees), blue panicgrass (Panicurn untidotule Retz.) and four-wing saltbush (A triplex canescens (Pursh) Nutt.) seeds. Rates were approximations of time to 50% germination, and seed treatments included applications of potassium nitrate, ammonium nitrate, gibberellic acid, and heat desiccation. Germination rates could be increased, but treatment effects were not uniform between seed lots within a species or among species. Desiccation at 70” C for 24 hours was particularly effective in increasing germination rates of Boer and Lehmann lovegrass seeds. Increased rates of germination of certain species might aid in establishment of range seedings made under limited moisture conditions of the Southwest. A relatively high rate of germination is believed to be a key characteristic of various plants adapted for seeding semiarid environments, promoting germination during ephemeral moisture periods (Jordan 1981). Germination rates have not been relevant or of major concern in most germination research and generally not considered as a measure of seed quality for semiarid seedings. Consequently, quantitative data are scarce, and standard proce

Soil Properties in Creosotebush Communities and their Relative Effects on the Growth of Seeded Range Grasses

AbstractSoils were collected to 15 cm along the four cardinal directions at three locations around 10 creosotebush [Larrea tridentata (DC.) Cov.] plants at five sites in the southwestern United States. The sampling locations were: (i) at the canopy center, (ii) along the outer canopy edge, and (iii) in open areas between plant canopies. A portion of the soil from each sampling location was analyzed for particle size distribution, pH, EC, CaCO3, Ca, K, Na, Mg, NO‐3‐N, organic C, available P, and Mn. The remaining soil from each sampling location was seeded with either Lehmann lovegrass (Eragrostis lehmanniana Nees) or blue panicgrass (Panicum antidotale Retz.). Grass seeds were germinated and grown for 42 d in a greenhouse. Nitrate was significantly (∝ = 0.05) lower in open areas between creosotebush canopies than near the shrub canopy center at all sites. Grass seedling growth decreased as the distance from the canopy center increased and seedling growth was highly correlated with nitrate concentrations. Spatial distribution patterns for the other measured soil properties did not occur in a consistent fashion across all sampled sites. The action of mechanical tillage to limit creosotebush competition, and corresponding dilution of NO‐3‐N in the soil volume, may reduce the probability of establishing perennial grasses.

Clipping Frequency and Fertilization Influence Herbage Yields and Crude Protein Content of 4 Grasses in South Texas

Crude protein content of herbage produced by buffelgrass, blue panicgrass, and Bell rhodesgrass was improved with nitrogen and phosphorus fertilization and clipping every 4 orJ weeks, compared to harvests only at the end of the growing season. Within a fertilization level, the 8-week clipping frequency generally increased dry matter production of the grasses over the 4-week clipping frequency or the end-of-season single harvest. Kleberg bluestem herbage generally contained less protein at all phenological stages than that of buffelgrass, blue panicgrass, or Bell rhodesgrass, and dry matter production was not increased by fertilization. Crude protein content of Kleberg bluestenm herbage was only slightly increased with the highest level of fertilization, regardless of clipping frequency. The South Texas Plains occupies nearly 9 million hectares of level to rolling terrain with elevations ranging from sea level to 95 m. Annual rainfall ranges from 45 to 75 cm with peaks occurring in May and September. Because of the long growing season and rainfall patterns, this area has a high potential for forage production. However, primarily as a result of continued excessive grazing of domestic livestock and cessation of fires, undesirable woody species have increase to the detriment of naturally occurring desirable vegetation (Scifres 1980). Brush management as a part of overall sound range management has proven its merit in restoring forage production (Scifres et al. 1976, 1980; Polk et al. 1976). Generally, natural revegetation through secondary succession is too slow for economical returns following high-cost mechanical control of undesirable woody species. Artificial revegetation with commercially available, adapted species is often considered the most feasible alternative for rapid restoration of these grazing lands. Major species that have been seeded successfully include buffelgrass (Cenchrus ciliaris), Bell rhodesgrass (Chloris gayana), Kleberg bluestem (Dicanthium annulatum), and blue panicgrass (Panicum antidotale). Although these grasses have been utilized in the overall range improvement program in south Texas for the past 4 decades, little is known about specific post-seeding management practices which could improve forage yield and quality. Brief descriptions, planting dates, seeding rates, and responses to irrigation and fertilization are found in experiment station leaflets (Novosad and Pratt n.d., Lancaster n.d., Lancaster 1949, and Anon. 1968). Since most of the livestock in this area are raised in yearlong cow-calf operations, high protein forage is required throughout the year to meet demands of growing calves and lactating cows. Waite At the time of this research, authors were graduate research assistant and associate professor, College of Agriculture,Texas Al and April 15 and 582 JOURNAL OF RANGE MANAGEMENT 36(5), September 1983 This content downloaded from 157.55.39.127 on Mon, 27 Jun 2016 05:36:06 UTC All use subject to http://about.jstor.org/terms Table 1. Fertility levels and pH of the soil of the study area where clipping frequency and fertilization was evaluated relatived to crude protein constants and herbage production of 4 grass species near Kingsville, Texas, during 1972-1973.' Nutrient availability