EVALUATION OF FACTORS AFFECTING YIELD REDUCTION IN MATURE ALFALFA (Medicago sativa L.)

1984 ◽  
Vol 64 (4) ◽  
pp. 901-907 ◽  
Author(s):  
E. R. JONES ◽  
R. H. SWAIN ◽  
K. W. BELL ◽  
R. B. CARROLL

Alfalfa (Medicago sativa L.) stand longevity continues to be a problem even though progressive management practices are followed. The following parameters were evaluated on mature alfalfa stands to determine what factors were responsible for stand thinning: forage production, stand density, foliar and crown-root diseases, root and crown tissue weights, and total nonstructural carbohydrate levels. Foliar diseases did not affect stand density; however, three of five anthracnose-resistant cultivars had denser stands than susceptible parents. Fusarium infection was quite high but did not appear to be related to stand density. Individual root weight, root mass, and total nonstructural carbohydrates were not good indicators of stand density.Key words: Alfalfa stand longevity, foliar diseases, crown and root rot, root and crown tissue weight, total nonstructural carbohydrates, forage production

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 550
Author(s):  
Panagiotis Kanatas ◽  
Ioannis Gazoulis ◽  
Ilias Travlos

Irrigation is an agronomic practice of major importance in alfalfa (Medicago sativa L), especially in the semiarid environments of Southern Europe. Field experimentation was conducted in Western Greece (2016–2018) to evaluate the effects of irrigation timing on weed presence, alfalfa yield performance, and forage quality. In a randomized complete block design (four replications), two cultivars (“Ypati 84” and “Hyliki”) were the main plots, while three irrigation timings were the subplots (split-plot). The irrigation timings were IT-1, IT-2, and IT-3, denoting irrigation 1 week before harvest, 1 week after harvest, and 2 weeks after harvest, respectively. IT-1 reduced Solanum nigrum L. density by 54% and 79% as compared to IT-3 and IT-2, respectively. Chenopodium album L. density was the highest under IT-2. IT-3 resulted in 41% lower Amaranthus retroflexus L. density in comparison to IT-2, while the lowest values were observed under IT-1. Stand density and stems·plant−1 varied between years (p ≤ 0.05). Mass·stem−1 and alfalfa forage yield were affected by the irrigation timings (p ≤ 0.001). Total weed density and forage yield were negatively correlated in both the second (R2 = 87.013%) and the fourth (R2 = 82.691%) harvests. IT-1 and IT-3 increased forage yield, leaf per stem ratio, and crude protein as compared to IT-2. Further research is required to utilize the use of cultural practices for weed management in perennial forages under different soil and climatic conditions.


1988 ◽  
Vol 68 (2) ◽  
pp. 427-438 ◽  
Author(s):  
J. S. McKENZIE ◽  
D. G. STOUT ◽  
L. P. LEFKOVITCH

A 3-yr field study was conducted to compare two common methods of estimating stored food reserves in crowns and roots of alfalfa (Medicago sativa L.) during autumn and winter. A chemical method to measure total nonstructural carbohydrates (TNC) was compared with a method that measured total etiolated growth (TEG). No significant correlation was observed between the two methods. TNC increased during autumn, attained a maximum in midwinter and then declined in the spring in association with rising soil temperatures. In contrast, TEG attained a maximum in the fall and declined or remained at a steady level throughout the winter and during rapid growth in the spring. This suggests that not all TNCs in crowns and roots are used for growth of shoots. A significant and approximately constant level of TNC remained in the crowns and roots following completion of etiolated growth. Cutting frequency and cultivars significantly affected TEG and TNC values, but the specific information provided by each measurement remains to be elucidated.Key words: Alfalfa, food reserves, TNC, etiolated growth, clipping, crown buds


2004 ◽  
Vol 84 (1) ◽  
pp. 217-221 ◽  
Author(s):  
D. Spaner and A. G. Todd

Oats (Avena sativa L.) or barley (Hordeum vulgare L.) sown at increasing seeding rates of 23, 45 and 68 kg ha-1 with a timothy (Phleum pratense L.)-alfalfa (Medicago sativa L.) mixture (harvested at cereal soft dough) resulted in increasing forage yields containing decreasing alfalfa, crude protein, P and Ca percentage in the planting year. Barley out-yielded oats by 11% in the planting year. Oats or barley sown at seeding rates up to 68 kg ha-1 do not impede underseeded forage establishment or forage production in the subsequent year in central Newfoundland. The implications of farmer-directed on-farm experimentation are discussed. Key words: Hordeum vulgare L., Avena sativa L., Phleum pratense L, Medicago sativa L., underseeding


2012 ◽  
Vol 63 (12) ◽  
pp. 1135 ◽  
Author(s):  
M. C. Raeside ◽  
Z. N. Nie ◽  
S. G. Clark ◽  
D. L. Partington ◽  
R. Behrendt ◽  
...  

Bituminaria bituminosa (L.) C.H. Stirton, commonly known as tedera, is a perennial legume of interest in Australia due to its adaptation to Mediterranean environments. Field experiments were conducted at two sites in Victoria, Australia, a high rainfall site at Hamilton and a low rainfall site at Bealiba, to evaluate tedera var. albomarginata lines against other forage species. At Hamilton, tedera achieved similar seedling densities to lucerne (Medicago sativa L.) following sowings in late spring 2009 and early winter 2010 (30–60 seedlings/m2). Forage production from the spring-sown tedera was between 1.0 and 2.3 t DM/ha at harvests in March and May 2010, but from May onwards the species failed to remain productive and its content in the swards decreased to become <10%. Forage production from all early winter-sown tedera swards was low (<0.5 t DM/ha). At Bealiba, some of the tedera lines outyielded lucerne. The tedera at Bealiba had a vigour rating of 8.3, on a scale of 1–10, in the summer of 2008–09, after surviving three summers. The tedera lines evaluated are unlikely to persist in cold wet winter environments but in drier zones tedera may persist and offer good DM yields of high nutritive value.


1991 ◽  
Vol 71 (2) ◽  
pp. 445-452 ◽  
Author(s):  
Michio Suzuki

Iroquois alfalfa (Medicago sativa L.) was seeded every spring from 1978 to 1988, and the established stands were maintained until the fall of 1988. Agronomic, morphological and chemical characteristics of the stands were compared among different age groups. A drastic reduction of alfalfa population occurred in the seeding year and during the first winter. There were about 40 plants m−2 in the 2nd yr which gradually decreased to 25 plants m−2 in the 8th yr, and between 12 and 24 plants m−2 in the 10th yr. There were more grass weeds in older stands. Total dry matter yield of forage, including weeds, did not decrease significantly with age of alfalfa stand Alfalfa yield, however, decreased with age, and the reduction in older stands was more evident in cut 1 than cut 2. There was little or no difference in cold hardiness among different stand ages in postseeding years. Root development pattern changed from vertical extension in the seeding year to lateral development of branched roots in postseeding years. Shoot number, crown diameter, crown decay taproot diameter, root depth, and number and spread of branched roots were associated with aging. Concentrations of total nonstructural carbohydrates (TNC) in the crown and roots decreased slightly with age. In the root, concentrations of K, Ca, B, and Fe increased, and Ca was most closely associated with age. No significant association of P, Mg, S, Mn, Cu, or Zn with age was found. Concentrations of minerals in the crown did not change with age, except B which increased slightly. Key words: Medicago sativa L., persistence, longevity, plant density, yield, minerals


Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2343
Author(s):  
John H. Grabber ◽  
Damon L. Smith ◽  
William R. Osterholz ◽  
Mark J. Renz

Interseeding alfalfa (Medicago sativa L.) into a silage corn (Zea mays L.) companion crop can increase the yield and profitability of forage production and reduce the risk of nutrient and soil loss from cropland, but unreliable establishment of alfalfa hampers the adoption of this practice on dairy farms. This study evaluated plant survival, foliar health, and dry matter yields of two alfalfa varieties when established in corn sown at populations ranging from about 47,500 to 100,000 plants per ha−1 and when treated with prohexadione (PHD), PHD followed by fungicide and insecticide (PHD-FI), or not treated with agrichemicals. The plant density of alfalfa during establishment was adversely impacted by above average precipitation and high corn populations, but substantially improved by PHD-FI treatment, which limited alfalfa etiolation, disease, and defoliation. First-cut dry-matter yields of interseeded alfalfa after corn were maximized at a stand density of approximately 200 plants m−2 or 850 stems m−2 and total first year yield exceeded conventionally spring-seeded alfalfa by 59 to 75%. Overall, our results indicated that PHD-FI treatment promoted good establishment and subsequent forage production of interseeded alfalfa. Applications of PHD-FI must, however, be fine-tuned, and additional management practices must be developed to ensure both good yields of corn silage and reliable establishment of interseeded alfalfa, especially during wet growing conditions.


2005 ◽  
Vol 32 (4) ◽  
pp. 321 ◽  
Author(s):  
Frédéric Meuriot ◽  
Marie-Laure Decau ◽  
Annette Morvan-Bertrand ◽  
Marie-Pascal Prud'Homme ◽  
François Gastal ◽  
...  

We studied the effects of stubble carbon / nitrogen (C / N) reserves or residual leaf area (RLA) on the contribution of taproot C / N reserves to shoot regrowth of Medicago sativa L. after cutting. The study assessed the effects of two cutting heights (6 and 15 cm), two RLAs (0 or 100%), and two initial C / N reserve levels (high N or low N) on forage production, nitrogen (N) distribution, and C / N reserve dynamics within stubble and taproot. Alfalfa forage production was mainly affected by the initial taproot C / N reserve levels. However, stubble initial organic reserves (and to a lesser extent the RLA) were also of particular importance during early regrowth. The increase of cutting height led to increased stubble C / N supply to regrowing shoots, which partly offset the negative effect on forage production and on taproot C / N reserve depletion. Unlike taproot reserves, the positive contribution of stubble organic reserves to shoot C / N supply was effective for a single defoliation–regrowth cycle. Alfalfa management strategies that increase cutting height (and RLA) during the penultimate harvest in autumn should be considered in cold regions with significant winter stress in order to improve alfalfa winter survival and persistence, as well as spring herbage regrowth.


1997 ◽  
Vol 77 (3) ◽  
pp. 381-384 ◽  
Author(s):  
John Waddington

To examine the possible benefits of crosslinked polyacrylamide gel when establishing forages in a semiarid environment, applications of dry gel in fine, medium and coarse granular forms were made at rates from 0.25 to 4.00 g m−1 of row with seed of alfalfa (Medicago sativa L.) and Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski] in each year 1992–1994 at Swift Current, Saskatchewan. The gel had no effect on seedling year establishment or first year forage production on a sandy-loam soil. On a nearby sandy-clay loam soil, in one of 3 yr with alfalfa, and 2 of 3 yr with Russian wildrye, the lowest gel rate decreased establishment compared with the check, with a further reduction as the rate of gel increased. Alfalfa forage yields were not affected. Gel application decreased Russian wildrye forage yield in 1 of 3 yr. Key words: Medicago sativa, Psathyrostachys juncea, forage yield, soil texture


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