scholarly journals EFEITO DO ESTRESSE HÍDRICO E DOSES DE POTÁSSIO NA PRODUTIVIDADE DA ALFAFA (Medicago sativa L.)

Irriga ◽  
2000 ◽  
Vol 5 (2) ◽  
pp. 110-118
Author(s):  
Hatiro Tashima ◽  
Antonio Evaldo Klar

EFEITO DO ESTRESSE HÍDRICO E DOSES DE POTÁSSIO NA PRODUTIVIDADE DA ALFAFA (Medicago sativa L.)  Hatiro TashimaFundação Faculdade de Agronomia “Luiz Meneghel”, DEER,  Cx. Postal 261, CEP 86.350 -000, Bandeirantes - Pr - Fone: (0xx43) 543 8046 - E'mail: [email protected] Evaldo Klar2Dep. de Eng. Rural -FCA -UNESP - Cx. Postal 237 - CEP 18603-970 - Botucatu - SPFone: (0xx14) 6820 - 7165; Fax: 6820 - 7194 -E'mail: [email protected]  1 RESUMO Foi estudada, em condições de campo, a produtividade da alfafa (Medicago sativa L.) submetida  a cinco níveis de água e quatro doses de potássio. O delineamento experimental foi inteiramente ao acaso em um esquema fatorial 5x4 com 3 repetições.  Os níveis de água foram definidos como A1, A2, A3, A4 e A5, os quatro primeiros  corresponderam às tensões mínimas de -0,01; -0,05; -0,1; -1,5 MPa, respectivamente, e o nível A5 recebeu apenas água da chuva. As doses de potássio foram definidas como: K1 correspondeu o teor natural de potássio no solo (2,5 mmolc dm-3), K2, K3 e K4 corresponderam as aplicações de 117,3; 351,9 e 821,1 g de K / parcela de 6 m2, respectivamente.O experimento foi avaliado do terceiro até o oitavo corte. Pelos resultados obtidos, pode-se concluir que: as combinações entre níveis de água A2 e A3 com doses de potássio K3 e K4 produziram maior quantidade de massa seca no  total de seis cortes; os níveis de água não afetaram a concentração do nitrogênio (N) na parte aérea, exceto no 6º corte em que o tratamento A5 foi significativamente superior  e no 7º o tratamento A4 foi significativamente inferior em relação a outros tratamentos; as maiores doses de potássio aplicadas no solo propiciaram maiores teores do elemento na parte aérea da  planta, no entanto verificou que a concentração do nitrogênio diminuiu.   UNITERMOS: Alfafa, estresse hídrico, potássio.  TASHIMA, H., KLAR, A. E. Effect of water stress and potassium doses on alfalfa (Medicago sativa L .) yield.  2 ABSTRACT             This study was developed to evaluated the effect on alfalfa (Medicago sativa L) of four minimum soil water potentials (MPa): - 0.01 (A1); - 0.05 (A2); 0.1 (A3); 1.5 (A4) and A5, without any irrigation and four doses of potassium (mmol/dm3 ): K1 – 2.5 natural soil content; K2 – 117.3;  K3 – 351.9; K4 – 821.1 of K per plot of 6 m2. The harvest was divided in 8 cuts, but only 6 of them were evaluated, from the third to eight.            The combinations among A2 and A3 with K3 and K4 resulted on higher dry material of plants; water levels did not affected nitrogen concentration of plants, except the 6th cut, when A5 showed significantly higher and A4, at the 7th cut,lower values in relation to the other treatments. The highest potassium doses showed highest potassium doses in aerial parts of plants, but decreased the nitrogen contents. KEYWORDS: alfalfa, water stress, potassium.

1988 ◽  
Vol 39 (3) ◽  
pp. 447 ◽  
Author(s):  
JM Scott ◽  
GJ Blair

The relative efficiency of phosphorus (P) seed coatings and drilled and broadcast applications of P was investigated in a glasshouse experiment conducted with phalaris (Phalaris aquatica L.) and lucerne (Medicago sativa L.) in P-deficient soil. Two P sources (monocalcium phosphate [MCP] and dicalcium phosphate [DCP]) were used at three rates in seed coatings (0, 5 and 10 kg P ha-1) or at six rates each of drilled or broadcast applications (0, 2.5, 5, 10, 20 and 40 kg P ha-1). MCP coatings severely reduced lucerne emergence and hence yield, but had little effect on phalaris emergence. No other fertilizer treatment affected emergence. The height of phalaris plants at 27 days after sowing (d.a.s.) was increased as much by seed coatings containing MCP at 5 kg P ha-1 as by drill or broadcast applications of MCP at 20 kg P ha-1. Plant height of the MCP seed coating treatments was also less variable than the other application methods, suggesting that the coatings provided more uniform access to P. Seed coatings containing DCP at 10 kg P ha-1 increased phalaris plant height more than did drilled or broadcast applications at 40 kg P ha-1, but there was no effect of any DCP treatment on lucerne growth at 27 d.a.s. The relatively large differences observed in plant height between different application methods at 27 d.a.s. diminished over time until, at 57 d.a.s., only small differences were evident. The dry matter yield and P content of both species were increased by increasing rates of MCP, but DCP had little effect at any rate. The reduced differences between the seed coating treatments and the other application methods at harvest may have been due to the limited soil volume of the pots used; further work is necessary in larger soil volumes to determine the significance of the early growth advantage conferred on phalaris by the phosphorus seed coatings, and to find ways of protecting lucerne from soluble P sources during germination.


1934 ◽  
Vol 24 (4) ◽  
pp. 532-539 ◽  
Author(s):  
H. G. Thornton ◽  
Hugh Nicol

V. Summary and abstract1. Inoculated lucerne was grown in pots of sand and watered with nitrogen-free food solution. In some of the pots the lucerne was clipped once, in some twice and in some it was left unclipped. Pots were harvested on four dates at intervals of about three weeks. Counts and measurements of nodules were made and dry weights and nitrogen contents of tops and roots were obtained.2. Clipping did not significantly alter the nodule numbers, their mean size, or the total nitrogen contents of the plants, i.e. in tops, including clippings, plus roots.3. Clipping, however, resulted in a decrease in the nitrogen content of the roots of about 40 per cent, as compared with undipped plants. This nitrogen was transferred to the tops where it was removed in the clippings.


2007 ◽  
Vol 87 (2) ◽  
pp. 267-272 ◽  
Author(s):  
J. Diane Knight

Because of its small seed size, alfalfa (Medicago sativa L.) typically is seeded at a shallow depth, putting Rhizobium inoculated onto the seed coat at a high risk of desiccation. Granular inoculants may provide a superior delivery formulation for Rhizobium because the inoculant can be placed deeper in the soil than the seed, where it is protected from desiccation. Sinorhizobium meliloti cv. Beaver delivered as (1) pre-inoculated alfalfa seed from the inoculant manufacturer, (2) commercial peat-based, self-sticking inoculant applied on-site, and (3) granular inoculant placed with the seed or (4) banded below and to the side of the seed was evaluated against uninoculated alfalfa controls at three field sites in Saskatchewan. Overall, alfalfa inoculated with the granular formulation placed below and to the side of the alfalfa seed was among the highest biomass producer in the establishment year, although it did not exhibit superior nodulation or biological N fixation compared with the other treatments. Any advantage conferred by the granular inoculant in the establishment year did not persist through the first and second production years. Under the conditions of this study, the delivery formulation had no long-term affect on alfalfa productivity, nodulation and biological N fixation. Furthermore, none of the inoculant treatments were consistently superior to the uninoculated controls. Key words: Alfalfa, granular inoculant, peat inoculant, pre-inoculated seed, Medicago sativa L., Sinorhizobium meliloti


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.


1992 ◽  
Vol 40 (2) ◽  
pp. 191-196 ◽  
Author(s):  
Wieslaw. Oleszek ◽  
Marian. Jurzysta ◽  
Michal. Ploszynski ◽  
Ian J. Colquhoun ◽  
Keith R. Price ◽  
...  

1986 ◽  
Vol 66 (3) ◽  
pp. 585-589
Author(s):  
J. H. ELGIN Jr. ◽  
C. M. RINCKER

Thirty-one seedlots of Arc alfalfa (Medicago sativa L.), produced between 1971 and 1974 at Prosser, Wash.; Stanfield, Oreg.; and Shafter and Tehachapi, Calif., were evaluated for shifts in field growth habits (regrowth after cutting, winter injury, and date of flowering) and greenhouse anthracnose resistance. Seedlots represented one (Syn 2), two (Syn 3), and three (Syn 4) generations of increase beyond the original Syn 1 lot, grown under four diverse environments. Results indicated a tendency for shift in regrowth rate among the Syn 3 and Syn 4 generation seedlots produced at Shafter, Calif. No shift in regrowth rate was observed for the other locations and no significant trends away from the original lot were observed for winter injury, date of flowering or anthracnose resistance.Key words: Medicago sativa L., seed production, genetic shifts, anthracnose resistance, fall growth, regrowth


1994 ◽  
Vol 74 (3) ◽  
pp. 451-456 ◽  
Author(s):  
J. W. Hall ◽  
W. Majak ◽  
D. G. Stout ◽  
K.-J. Cheng ◽  
B. P. Goplen ◽  
...  

Investigations of legume species which do and do not cause bloat suggested that a bloat-safe alfalfa (Medicago sativa L.) might be produced by reducing its initial rate of digestion. This study compared a third cycle alfalfa synthetic selected for a low initial rate of digestion (LIRD) with a control cultivar (Beaver). The occurrence of bloat was not significantly lower when cattle were fed cycle 3 LIRD than when fed Beaver in three grazing trials or in two of three feedlot trials. The deviation of the results in the third trial could not be explained by differences in dry matter or protein content. When grown under irrigation, the 4 h dry matter disappearance (DMD) of cycle 3 LIRD was 89% to 96% of that for Beaver. This reduction was much less than has been hypothesized to prevent bloat. Without irrigation the 4 h DMD of both cultivars were reduced by 1–3% while cycle 3 LIRD continued to have a lower DMD than Beaver. LIRD may provide some protection against bloat on dry rangelands though the response may be variable in years when moisture is well supplied. Studies with a fourth cycle LIRD selection will investigate this further. Key words: Legumes, Medicago sativa L., nylon bag, digestion


1992 ◽  
Vol 72 (3) ◽  
pp. 793-799 ◽  
Author(s):  
G. Bélanger ◽  
J. E. Richards ◽  
R. E. McQueen

The number of annual harvests and the interval between harvests affect DM yield, persistence, and nutritive value of alfalfa (Medicago sativa L.). The effects of harvesting alfalfa three times annually, with the intervals between harvests varied and with the third harvest taken prior to, during, or after the critical fall rest period, were investigated from 1985 to 1988 on a field of alfalfa established in 1984. Seven harvesting systems, comprising three harvests with varied regrowth intervals and a two-harvest system, were studied along with two rates of potassium fertilization. Harvesting alfalfa three times a year, with the third harvest taken during or after the critical fall rest period, produced the largest yields of DM, digestible DM, and crude protein. Dry matter yield was not reduced in three-harvest systems when the third harvest was taken during the critical fall rest period, provided there was an interval of approximately 500 growing degree-days between second and third harvests. Taking the first harvest at the early bud stage of development instead of the early bloom stage reduced annual DM yields. Increasing annual potassium fertilization from 200 to 400 kg K ha−1 did not affect DM yield or persistence under any harvesting system. Harvesting management of alfalfa in the fall should be based on the duration of the growth period between the second and third harvests instead of a critical fall rest period based on calendar dates.Key words: Medicago sativa L., yield, nutritive value, persistence, harvest management, K fertilization


1997 ◽  
Vol 11 (3) ◽  
pp. 556-560 ◽  
Author(s):  
Eric Spandl ◽  
James J. Kells ◽  
Oran B. Hesterman

Component yields and forage quality were evaluated in established stands of alfalfa seeded alone and in binary mixtures with smooth bromegrass, orchardgrass, or timothy. Forage yields and quality were determined at three annual harvests in the third and fourth years after seeding. Weed yields in alfalfa seeded alone were significantly greater than those in the alfalfa–orchardgrass mixture. Average weed content was 24, 17, 2, and 15% for the alfalfa seeded alone, alfalfa–bromegrass, alfalfa–orchardgrass, and alfalfa–timothy, respectively. Seeding alfalfa with orchardgrass increased first harvest and annual forage yields while reducing alfalfa yield. Yields of orchardgrass often exceeded those of bromegrass or timothy. In the first harvest each year, crude protein was reduced and acid detergent fiber and neutral detergent fiber increased by including orchardgrass. Neutral detergent fiber was greater in alfalfa–orchardgrass than in the alfalfa seeded alone at most harvests. There were no consistent differences among the alfalfa seeded alone and the other mixtures in yield or quality.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
M. Raeeszadeh ◽  
P. Mortazavi ◽  
R. Atashin-Sadafi

Nicotine is one of the most important compounds in cigarette which can cause changes in the concentration of neurotransmitters and damage to the nervous system. The aim of this study was to investigate the effect of the hydroalcoholic extract of Medicago Sativa L. (alfalfa) on controlling nicotine-induced brain damage and anxiety behaviour in rats. Forty-two male Wistar rats were randomly divided into six equal groups and treated daily as follows: a control group, T1 and T2 groups where animals were subcutaneously injected 250 and 500 mg/kg alfalfa extract, respectively, T3 and T4 groups where animals were injected subcutaneously 0.2 mg/kg nicotine and 250 and 500 mg/kg alfalfa extract, and T5 group in which only nicotine at the dose of 0.2 mg/kg was injected. At the end of the period after weighing, the elevated plus-maze test was taken from the animals. Serum assay was conducted to measure TCA, IL-1, and TNFα, and half of the brain tissue was used to measure oxidative stress parameters (GPx, SOD, TAC, and MDA) and the other parts were used for histopathological studies. Body weight in the T5 group was significantly different from that of the other groups. The time and number of open arms reduced in the T5 group. The duration and number of times in the open arm significantly decreased in the treated groups in a dose-depended manner. Malondialdehyde concentration was the highest in the nicotine group and the lowest in T2. The concentration of GPx and SOD was significantly increased in the presence of alfalfa extract in nicotine groups. TNFα and IL-1 in the T5 group showed a significant increase compared to the other groups. Moreover, the number of neurons and the level of necrotic neurons and gliosis significantly decreased and increased in the nicotine group, respectively, while these histopathological damages improved by treatment with alfalfa extract in T3 and T4 groups. Alfalfa extract can have a significant dose-dependent therapeutic effect on inducing oxidative damage and inflammatory responses of nicotine in the brain and reducing anxiety behaviours.


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