EFFECTS OF TEMPERATURE ON PRIMARY GROWTH OF ALFALFA

1972 ◽  
Vol 52 (6) ◽  
pp. 1007-1015 ◽  
Author(s):  
C. J. PEARSON ◽  
L. A. HUNT

Effects of temperature on the cumulative gain and distribution of dry matter are described for the primary growth of alfalfa (Medicago sativa L.) cults Vernal and Moapa at an irradiance (400–700 nm) of 25 nE cm−2 s−1. Whole plant dry weights and leaf areas increased curvilinearly with time. Weight and area increments were faster, root-top weight increments were higher, and canopies were more erect, at 15/10 C and 20/15 C day/night temperatures than under warmer conditions. In contrast, rates of leaf, node, and flower production were slower at low temperatures. Differences between low and high temperatures were similar to those recorded in the field between first and third harvests in the cool humid zone of North America.

1972 ◽  
Vol 52 (6) ◽  
pp. 1017-1027 ◽  
Author(s):  
C. J. PEARSON ◽  
L. A. HUNT

The cumulative gain and distribution of dry matter are described for both primary growth and three subsequent regrowths of alfalfa (Medicago sativa L.) cults Vernal and Moapa at an irradiance (400–700 nm) of 25 nE cm−2 s−1 and day/night temperatures of 20/15 C and 30/25 C. Whole plant dry weight and leaf areas increased curvilinearly with time in primary growth and linearly in regrowth. Root plus stubble weight after cutting, increased from first to third regrowth. Rates of leaf area expansion increased with time in primary growth but were constant in regrowth; they were higher in regrowth than in primary growth, and higher at 20/15 C than at 30/25 C. Individual leaf area was greater at 20/15 C than at 30/25 C, whereas average specific leaf weight was less at 20/15 C than at 30/25 C. This latter finding probably reflected longer leaf life at 20/15 C. Number of days to 50% flowering was greater at 20/15 C than at 30/25 C. Growth responses to temperature were similar during primary growth and regrowths.


Author(s):  
Galina Stepanova

The article describes the main morphological and biological features of alfalfa varieties included in the State register of breeding achievements approved for use in the Central Chernozem zone of Russia. A total of 32 alfalfa varieties are included in the State register. This is 9 varieties of blue alfalfa (Medicago sativa L. subsp. Sativa) of domestic selection and 8 foreign, 11 varieties of variable alfalfa (Medicago sativa L. nothosubsp. varia (Martyn) Arcang.) domestic selection and 1 variety of foreign and 3 varieties of yellow alfalfa (Medicago sativa L. subsp. falcata (L.) Arcang.). It shows the average and maximum yield of varieties determined in the process of state variety testing, as well as independent evaluation in research institutions in the region. Varieties of blue alfalfa of domestic selection Kevsala, Elena, Satellite, Vavilovskaya Yubileynaya were the most productive. The average yield of dry matter of these varieties reaches 8.4–9.2 t/ha, the maximum — 15.3–17.7 t/ha. Alfalfa varieties Timbale and Galaxy were the most productive among foreign varieties: the average yield of dry matter was 8.1 and 8.3 t/ha, the maximum – 15.5 and 17.2 t/ha. Varieties of alfalfa variable Vitalina and Vela provided an average yield of dry matter of 7.6 and 9.0 t/ha, the maximum yield reached 15.4 and 18.1 t/ha.


1972 ◽  
Vol 52 (6) ◽  
pp. 941-948 ◽  
Author(s):  
L. B. MacLEOD ◽  
H. T. KUNELIUS ◽  
F. W. CALDER

The effects of early summer and fall cutting managements on two alfalfa (Medicago sativa L.) cultivars were studied over a 3-year period. Removal of the first crop of Saranac and Narrangansett alfalfas at prebud stage, followed by two cuts at the early bloom stage before early September, and a late fall harvest on October 25, produced seasonal dry matter (DM) yields of 7.5–8.6 metric T/ha in the 1st year. Stand deterioration, however, was severe and by the 3rd year, practically all alfalfa had disappeared. Average percent crude protein (CP) in cut 1 was 17.7–21.9 and percent in vitro dry matter digestibility (IVD) 67.4–73.8. Removal of the first cut at bud stage with two subsequent harvests at the early bloom stage also allowed a total of three harvests before early September and resulted in seasonal DM yields of 8.6–8.8 in the 1st year. Although the survival of alfalfa was increased over the managements where cut 1 was at prebud stage, a considerable decrease of alfalfa was still observed in the 3rd year. Under this management, average CP in cut 1 was 15.8–16.3 and IVD 64.1–68.4. Harvesting the first crop at early to midbloom stage and the second crop at early bloom in early to mid-August, followed by third harvest in late October, resulted in good survival with seasonal DM yields of 6.1–10.6. Lower CP and IVD were recorded in cut 1 than in the more intensive managements. Under all managements, average CP in cuts 2 and 3 was 14.9–17.3 and 13.3–19.4, respectively. IVD was 54.5–60.7 in cut 2 and 56.0–64.4 in cut 3.


1999 ◽  
Vol 79 (4) ◽  
pp. 509-517 ◽  
Author(s):  
Suwarno Suwarno ◽  
K. M. Wittenberg ◽  
W. P. McCaughey

A study was conducted to monitor nutrient and microbial count changes during wilting of alfalfa (Medicago sativa L.) in response to varying degrees of maceration at mowing. Early bloom alfalfa was mowed with either a roller-conditioner (CONV) or a macerator set to deliver four degrees of maceration during alfalfa mowing: LIGHT, LIGHT+, SEVERE, and SEVERE+. Macerated alfalfa reached 80% dry matter in 9–11 h compared with alfalfa mowed by roller-conditioner, which required 54 h. The most rapid wilting rates were associated with LIGHT+, SEVERE, and SEVERE+ maceration treatments when alfalfa was not exposed to precipitation. The wilting coefficient in the first 24 h was increased by more than 100% for the SEVERE treatment compared with alfalfa mowed using a conventional roller-conditioner in alfalfa that was not exposed to precipitation. Precipitation at 1.5 h post-mowing increased wilting time by 8.3 h to achieve 45% DM, and by 17.5 to achieve 80% DM in the SEVERE+ maceration treatment relative to alfalfa from the same conditioning treatment that was not exposed to precipitation. Precipitation at 24 h post-mowing increased wilting time to reach 80% DM by 11 h and 21 h for the LIGHT and LIGHT+ maceration treatments relative to alfalfa of the same mowing treatments not exposed to precipitation. Maceration of alfalfa resulted in a 24.2 to 26.8 h shorter wilting time relative to the conventional roller-conditioner treatment when alfalfa was exposed to precipitation at 24 h post-mowing. SEVERE and SEVERE+ maceration treatments at mowing resulted in higher (P < 0.05) neutral detergent fibre and acid detergent fibre levels post-wilting. Lactic acid bacteria populations on alfalfa tended to be higher with maceration within 1 h post-mowing (P < 0.10) and post-wilting (P < 0.08). Key words: Alfalfa, maceration, precipitation, wilting time, bacteria, nutrient profile, compressibility


Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1438
Author(s):  
Gazali Issah ◽  
Jeff J. Schoenau ◽  
Herbert A. Lardner ◽  
J. Diane Knight

Availability of nitrogen (N) limits pasture production. Inclusion of legumes into grass pastures can provide an alternative N source through biological N2 fixation (BNF), and enhance retention and cycling of soil C and N. Despite the use of alfalfa (Medicago sativa L.), cicer milkvetch (Astragalus cicer L.) and sainfoin (Onobrychis viciifolia Scop.) in grass-legume pastures to improve forage quality, relative BNF potentials and resource partitioning are unknown. We quantified BNF using 15N isotope dilution and estimated resource partitioning in alfalfa, two cultivars of cicer milkvetch and two cultivars of sainfoin under controlled conditions. Percentage of nitrogen derived from atmosphere followed the order alfalfa (92%) > cicer milkvetch (87%) > sainfoin (81%); corresponding to estimated N contributions of 200, 128 and 65 kg N ha−1 yr−1, respectively, based on total herbage. Root dry matter was 24% to 36% greater than shoot dry matter in all of the legumes, providing substantial below-ground C and N. Cultivars of the same species did not differ in any measured parameter (p > 0.05). Despite the lower BNF in cicer milkvetch and sainfoin compared to alfalfa, their use may not negatively affect stand productivity and C storage.


1970 ◽  
Vol 21 (4) ◽  
pp. 583 ◽  
Author(s):  
GJ Leach

Lucerne (Medicago sativa L.) plants grown to two stages of maturity were cut at 2, 5, or 10 cm above the crown. In addition, the leaf on the stubble and on basal shoots was either removed or retained. The change in the number and size of the regrowth shoots growing from different heights above the crown, and the total yield of dry matter, were observed for 4 weeks after cutting. Nearly all the regrowth shoots arose from very near to the crown, either on the crown itself or from within the first 2 cm above it, so that cutting at higher levels increased shoot numbers only slightly. Also most of the shoots arising from near the crown resumed extension growth earlier, and therefore grew larger, than the shoots arising from higher positions. In general the growth of shoots from one stubble segment was not influenced by whether segments were still present above. Increasing the cutting height above 2 cm consequently produced little effect on the yield of dry matter 2 and 4 weeks after cutting. Retaining stubble leaf and basal shoot leaf increased the shoot yield 2 and 4 weeks later, because the basal shoots resuming growth first grew larger than those on plants from which leaves were removed. The effect of retaining leaves was independent of the stage of maturity when the plants were cut and of the cutting height.


1965 ◽  
Vol 45 (2) ◽  
pp. 162-168 ◽  
Author(s):  
D. A. Cooke ◽  
S. E. Beacom ◽  
W. K. Dawley

Two grass–alfalfa mixtures were compared for seven consecutive years when continuously and when rotationally grazed by yearling Hereford steers. The productivity of rotationally grazed pastures as affected by annual application of fertilizers was also determined. Intermediate wheatgrass (Agropyron intermedium L.) and alfalfa (Medicago sativa L.) compared favorably with the standard mixture of bromegrass (Bromus inermis L.) and alfalfa for pasture purposes. Production of dry matter ranged from approximately 2.5 to 0.5 tons per acre in the first and seventh year respectively. Precipitation in these two years was 20.7 and 7.7 in. respectively. Rotational grazing did not increase beef production. Fertilization of bromegrass–alfalfa with 20 lb of N per acre and with 20 lb of N + 40 lb of P2O5 per acre resulted in average yearly increase of 18 and 32 lb of beef per acre respectively. Fertilization of intermediate wheatgrass– alfalfa resulted in comparable increase of 1 and 26 lb of beef per acre respectively.


1973 ◽  
Vol 53 (4) ◽  
pp. 773-777 ◽  
Author(s):  
D. H. HEINRICHS

Winter injury occurring at Swift Current, Saskatchewan, was recorded in 17 tests during the period 1962–72. Cultivars developed in the Northern Great Plains Region of the USA and in Canada were generally more winter-hardy than cultivars developed in other regions of North America or in Europe. Cultivars classified as Medicago media Pers. were more winter-hardy than those classified as Medicago sativa L. Very few USA cultivars were more winter-hardy than Vernal, but most Canadian cultivars were. In nonhardy cultivars winter injury never occurred during the first winter, but it often occurred in the second winter and frequently in the third winter. There was considerably more winter injury among alfalfa cultivars on irrigated land than on dry land. Based on results from these tests, 50 cultivars and strains have been classified for relative winterhardiness under climatic conditions in southern Saskatchewan, Canada.


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