Under good soil fertility conditions, Bromus wildenowii Kunth and Bromus parodii Covas et Itria are two high producing forage grasses. The objective of this study was to evaluate the effect of nitrogen fertilization or the association with alfalfa (Medicago sativa L) on yield and forage quality of mixtures of both grasses during the establishment year. Nitrogen fertilizer (300 kg ha-1) was broadcasted in three 100 kg N dosis. Nitrogen fertilization or alfalfa intercropping did not increase dry matter yield. Tiller density and crude protein content of grass forage were increased by nitrogen application. Intercropped alfalfa increased N content of grasses mixture. In vitro dry matter disappearance, neutral detergent fiber and lignin content were not affected by treatments

Abarza, S.

Brevedan, R. E.

Laborde, H.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings XIX International Grassland Congress Forage Quality of Mixtures of Bromus wildenowii and B. parodii Influenced by Nitrogen Fertilization or Alfalfa Interseeding S. Abarza Universidad Nacional de Jujuy, Argentina R. E. Brevedan Universidad Nacional del Sur, Argentina H. Laborde Universidad Nacional del Sur, Argentina Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/19/2/10 This collection is currently under construction. The XIX International Grassland Congress took place in São Pedro, São Paulo, Brazil from February 11 through February 21, 2001. Proceedings published by Fundacao de Estudos Agrarios Luiz de Queiroz This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. ID # 02-13FORAGE QUALITY OF MIXTURES OF BROMUS WILDENOWII AND B. PARODIIINFLUENCED BY NITROGEN  FERTILIZATION OR ALFALFA INTERSEEDING.S. Abarza1, R. Brevedan2 and H.Laborde21Facultad de Ciencias Agrarias , Universidad Nacional de Jujuy, Argentina.2Departmento de Agronomía and CERZOS, Universidad Nacional del Sur-CONICET, 8000.Bahía Blanca. Argentina.AbstractUnder good soil fertility conditions, Bromus wildenowii Kunth and Bromus parodii Covaset Itria are two high producing forage grasses. The objective of this study was to evaluate theeffect of nitrogen fertilization or the association with alfalfa (Medicago sativa L) on yield andforage quality of mixtures of both grasses during the establishment year. Nitrogen fertilizer (300kg ha-1) was broadcasted in three 100 kg N dosis. Nitrogen fertilization or alfalfa intercroppingdid not increase dry matter yield. Tiller density and crude protein content of grass forage wereincreased by nitrogen application. Intercropped alfalfa increased N content of grasses mixture. Invitro dry matter disappearance, neutral detergent fiber and lignin content were not affected bytreatments.Keywords: forage quality, nitrogen, alfalfa, cool season grasses.IntroductionBromus wildenowii is a native cool season grass with wide adaptation and highproductivity in Argentina. Its potential is better shown under high fertility conditions. Usually itis used in mixtures with others cool season grasses or alfalfa. High initial growth, forage qualityand seed production capacity under intense defoliation are some of its attributes (Batallanez andBertín, 1990).Bromus parodii is also a native forage plant cultivated in semiarid Argentina (Covas andItria, 1968). During the growing season, B. parodii shows a similar initial growth rate than B.wildenowii. However it reaches its maximum growth rate about one month later than B.wildenowii (Covas et al, 1996).The productivity and forage quality of both species grown in mixture with forage legumessuch as alfalfa in southern semiarid Argentina has not been fully explored. Our objective was toevaluate the effect of nitrogen fertilization and the association with alfalfa on yield and foragequality of B. wildenowii and B. parodii during the first year.Material and MethodsA field experiment was conducted at the Argerich Experimental Farm of the UniversidadNacional del Sur, near Bahía Blanca, (38º 46´S, 62º 36´W).On 7 April 1998, the experiment was seeded in a silty soil, using a man-operated one- rowseeder (Almaco, IA). The plots were established on a tilled seed bed (plowed, disked andharrowed). Plots (1,5 by 6 m) containing six rows 0.25 m apart were replicated six times in arandomized complete block design. A binary mixture (60% - 40% by weight) of Bromuswildenowii Kunth. cv. Martin Fierro and Bromus parodii. Covas et Itria., cv. Don Lorenzo,respectively was seeded on twelve plots at 15 kg seed ha-1. The same mixture of B. wildenowiiand B. parodii (7 kg seed ha-1) mixed with alfalfa (Medicago sativa L. cv Armona, 10 kg ha-1)was sown on the six remaining plots. Weeds were controlled manually during the experiment.Treatments were 1) Control 2) N300  (300 kg ha –1 of N as urea) and 3) Mix/alf (mixture,grasses-alfalfa). Nitrogen fertilizer was broadcasted in three 100 kg ha-1 applications (late June1998; early October 1998 and late April 1999). After establishment, one permanent quadrat (0.04m2) was randomly assigned to each plot. Total grass tiller counts were performed in fouroccasions in every plot: Winter (2 August 1998), Spring (5 October 1998); Summer (7 January1999) and Fall (6 April 1999).No insecticide or herbicide was used after plots were sown. Plots were hand harvestedinitially on 9 November 1998 and regrowths were harvested on 14 January 1998; 29 March 1999and 4 June 1999. Herbage yield was determined by harvesting a 1.00- by 5.00-m area from eachplot at a cutting height of 0.07 m. Herbage weight from each plot was recorded and subsampledfor moisture and chemical analysis. Subsamples were dried for 72 h in a forced-air oven a 70º Cand grounded to pass a 2 mm screen. In the Mix/alf treatment, legume and grasses forage werehand separated before drying. Crude protein concentrations were determined by macroKjeldahlprocedure (AOAC, 1984).In vitro dry matter digestibility (IVDMD) was assessed according to the two-stageprocedure of Tilley and Terry (1963). Neutral detergent fiber (NDF) and lignin (L) weredetermined according to Goering and Van Soest (1970). Statistical analysis of data wasperformed with analysis of variance. Means comparisons were made with a Duncan´s multiplerange test (Steel and Torrie, 1980).Results and DiscussionHerbage yield was not affected by treatments (Table 1). In spite of the heavy applicationof nitrogen, fertilized plots did not produce more forage than the mixture of grasses with alfalfa.Nitrogen fertilization tended to increase forage production (23%) early in spring, whileMix/alf treatment yielded 14% more forage than the Control at the end of the growing season.Tiller density was increased by nitrogen fertilization. Mean tiller number on N-fertilizedplots was 76% higher than on Control though the nitrogen effects usually is more noticeable inless dense swards (Whitehead, 1995). Also nitrogen fertilization augmented grass tiller numberabout 114% over Mix/alf treatment. Nitrogen was applied around 40 days before first tillercounting. This could account for the initial higher tiller density observed in fertilized swardscompared to the other treatments.Nitrogen fertilization or association with alfalfa did not affect IVDMD, NDF and Lcontent (Table 2). Instead, the crude protein content of grass herbage is strongly influenced byavailable soil N level (Follett and Wilkinson, 1995). In this study nitrogen fertilization increasedCP content. It is interesting to observe the increase of CP content of both grasses associated withalfalfa (Mix/alf.) compared to the Control treatment. Maximum protein content was obtained latein the growing season (data not-shown).Nitrogen fertilization or the mixture with alfalfa had no significant effect on dry matteryield. Tiller number and crude protein increased with the appliction of nitrogen. Interseeding withalfalfa improve the crude protein of the grasses but the result was not significant.AcknowledgmentThe authors would like to thank Mr. A. Ferro for his help to carry out the experiment. Oneof the authors (Silvia Abarza) was in receipt of a scholarship from the FOMEC-Argentina that isgratefully acknowledged.ReferencesAssociation of Official Analytical Chemist. (1984). Official methods of analysis. 14th ed.AOAC, Washington, DC.Batallanez, E.E. and Bertin O.D. (1990). Características y evaluación de cultivares forrajerosde la Estación Experimental Agropecuaria Pergamino. INTA-EEA Pergamino. Boletín deDivulgación Técnica. 81:12-14.Covas, G.F. and Itria C.D. (1968). Nueva especie de Bromus de la flora argentina. Boletín de laSociedad Argentina de Botánica. 11:113-116.Covas, G.F., Sáenz A.M., Ferri C.M. and Babinec F.J. (1996). Patrones de distribución de laproducción de forraje de Bromus catharticus Vahl y B. parodii Covas et Itria. Revista de laFacultad de Agronomía – Universidad Nacional de La Pampa 9:25-31.Follett, R.F. and Wilkinson S.R. (1995). Nutrient management of forages. In: Barnes, R.F.;D.A. Miller and C.J. Nelson. Forages. The science of grassland agriculture. Vol. II Iowa StateUniv. Press. Ames. IA.Goering, H.K. and Van Soest P.J. (1970). Forage fiber analyses (apparatus, reagents,procedures, and some applications). Agriculture Handbook 379. U.S. Gov. Print. Office,Washington, DC.Steel, R.G.D. and Torrie J.H. (1980). Principles and procedures of statistics. McGraw-Hill,New York.Tilley, J.M.A. and Terry R.A. (1963). A two-stage technique for the in vitro digestion of foragecrops. Journal of the British Grassland Society 18:104-109.Whitehead, D.C. (1995). Grassland Nitrogen. CAB International. Wallingford, UK.Table 1 - Mean yield and mean tiller number of a binary mixture of  Bromus wildenowii and B. parodii (Control),the same binary mixture plus nitrogen (N300) and the same binary mixture interseeded with alfalfa (Mix/alf).Harvest Counting timeTreatments 1 2 3 4 Total Winter’98Spring’98Sumer’98Fall’99 Mean-----------kg dry matter ha-1------------ ---------------------Number of tillers m-2----------------Control 1103* a 1036 a 1077 a 686 a 3902 a 1125 bc 1266 b 2000 b 1283 b 1418 bN300 1356 a 1081 a 983 a 658 a 4078 a 2191 a 2308 a 3270 a 2250 a 2504 aMix/alf. 1186 a 1199 a 1285 a 788 a 4450 a 806 c 1260 b 1654 b 960 c 1170 b*Values within a column followed by the same letter are not significantly different at the 0.05 level using Duncan´smultiple range test.Table 2. Mean in vitro dry matter disappearance (IVDMD), neutral detergent fiber (NDF), lignin(L) and crude protein (CP) content of a binary mixture of Bromus wildenowii and B. parodii(Control), the same binary mixture plus nitrogen (N300) and the same binary mixture interseededwith alfalfa (Mix/alf).IVDMD NDF L CPTreatments------------------------------------- % -------------------------------------Control 59.1* a 42.7 a 6.29 a 7.62 bN300 56.6  a 46.2 a 6.47 a 11.83 aMix/alf. 61.7  c 48.9 a 6.99 a 10.41 ab*Values within any column followed by the same letter are not significantly different at the0.05 level using Duncan´s multiple range test.

Forage Quality of Mixtures of \u3ci\u3eBromus wildenowii\u3c/i\u3e and \u3ci\u3eB. parodii\u3c/i\u3e Influenced by Nitrogen Fertilization or Alfalfa Interseeding

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=3971&amp;context=igc

Forage Quality of Mixtures of \u3ci\u3eBromus wildenowii\u3c/i\u3e and \u3ci\u3eB. parodii\u3c/i\u3e Influenced by Nitrogen Fertilization or Alfalfa Interseeding

Abstract

Similar works

Full text

Available Versions

University of Kentucky