AGRONOMY

Author: LOPEZ CARLOS RAUL.
Year: 2003.
University: POLITÉCNICA DE MADRID [www.upm.es].
Place of defense: ETSI MONTES.
Place of preparation: ETSI MONTES UPM.

Summary: Eucalyptus camaldulensis Dehnh contains genetic materials with characteristics silvicultural and technological properties of the wood potentially suitable for the cultivation of forests for industrial purposes in the Northwest Argentina. In Australia occupies a large area of scattered with a wide variety of environments that produced diferenciándose genetic nested in backgrounds, families and progeny individual trees that can be used in improving forest genetics. For checking on their capacity to adapt to different environments and improve their implantation characteristics of volume growth, density and survival by selecting among and within populations from different geographical origins were introduced families of open-pollinated progeny from Australia and South Africa . The trials were established at two sites in northwestern Argentina, according to a block design of compact families with four replications. The traits were ways to 1.30 m diameter, survival and penetration pilodyn. The evaluation of the interaction of the properties with the environment and the consistency of performance in diameter and survival through the environments were done using the model of additive main effects and interactions multiplicativas (AMMI). The results revealed highly significant interactions with the properties of the atmosphere in diameter and detected increased survival and stability of materials from Dimbulah, Petford, QLD and Gibb River, Kimberley, WA. To predict the genetic values of individuals, simultaneously with the adjustment of the records to the fixed effects and maximize earnings per unit time, we used mixed model of individual trees (BLUP) for their ability to separate genetic effects of environmental and compare on equal terms to trees that grow in different environments. The results at progeny detected significant additive genetic variation in traits analyzed and highly significant interaction with the environment in diameter. The estimated parameters showed genetic heritabilities in restricted sense of 0.07 and 0.34 in diameter and penetration depilodyn respectively. Gains in volume and density genetic background estimated with a selection index constructed with the values predicted for improvement are 13% and 4% respectively. The correlation between genetic traits is moderately low (0.4), however, its value enables positive improvements together.

Author: CABALLERO GARCÍA CRISTINA.
Year: 2003.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS BIOLÓGICAS.
Place of preparation: FACULTAD DE CIENCIAS BIOLÓGICAS DE LA UCM.

Summary: We have studied the effects of three groups of terpenoids and natural hemisintéticos (diterpenos, sesquiterpenos and limonoids) against insects Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidade) and Spodoptera exigua (HÃ ¼ bner) (Lepidoptera: Noctuidade), which are specialists and generalists respectively. To evaluate the action of these compounds in these two is pecies insect bioassays were conducted evaluating its mode of action by calculating indices antialimentarios, so that trials of preference was obtained Index Deterrence and testing no preference Index Antiapetitivo. Once obtained these indices were established some relationships between the structure and activity of the compound. In view of the results, we can say that the natural compounds are generally more activity antialimentaria that hemisintéticos, but it is interesting to explore the latter because through them you can find out what are the functional groups more involved in the activity antialimentaria. Moreover, the kind generalist (S.exigua) was less susceptible to these compounds that the specialist (L.decemlineata). Of all the compounds, we selected those who poseína increased activity for the two species, as to whether these compounds impacted post-ingestivos in the larvae of two species studied, and therefore teína a mode of toxic action, or whether it Otherwise the mode of action was deterrent. This evaluation of the mode of action took place on the one hand, by calculating nutritional indices which provide information about the rate of growth and eating larvae and on the other hand through the study of the activity of enzymes detoxification esterases monooxigenasas and glutathione S.transferasas. The diterpenos, teumasileninas A and C, were having a mode of action and toxic deterrent respectively vs. larvae L.decemlineata and scutecyprol In a deterrent for food versus larvae S.exigua. To study the activity of detoxification enzymes, came to the same conclusion as Ortego et al. (1999), since no significant change in enzyme activity when the larvae S.exigua were fed scutecyprol A (mode of action deterrent) and yet these activities are veina modified when they were fed a mixture of limonoids proved toxic effect.

Author: SAAVEDRA DE AVILA SUSANA DEL VALLE.
Year: 2004.
University: POLITÉCNICA DE MADRID [www.upm.es].
Place of defense: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS DE MONTES.
Place of preparation: DE MADRID.

Summary: As the population grows increase pressure on the forests looking meet the basic needs of food production and energy sources. This assertion has become a reality in Latin America, particularly in the region Chaqueña, where progress of the forntera agriculture has led to the deforestation of large tracts and disappearance of vast masses of trees, leaving in some cases just a few bosquetes representative who was the original forest productive. At present the forest resources in the province of Santiago del Stereo, is in a state of alarmaente deterioration. In the present work seeks to expand knowledge about the productive capacity of quebrachales, specifically estudiandos the prámetros descriptive of mass quebracho blanco (Aspidosperma quebracho blanco Schelcht), one of the species of greatest importance today in the Park Chaqueño. In a manner similar to what happens in regular masses, the height of the dominant trees is directly related to the productivity of the site. The results show that there is a high correlation between the climatic summer precipitation and productivity in volume.

Author: ZAPATA COLL PEDRO JAVIER.
Year: 2004.
University: MIGUEL HERNÁNDEZ DE ELCHE [www.umh.es].
Place of defense: ESCUELA POLITECNICA SUPERIOR DE ORIHUELA.
Place of preparation: ESCUELA POLITECNICA SUPERIOR DE ORIHUELA.

Summary: At present, the salinity is the most important environmental factor that limits the development and productivity of plants. Specifically, the accumulation of salts in the soil of irrigated land in the arid and semiarid regions is one of the biggest global problems (Rhoades and Loveday, 1990). When plants grow in saline conditions, there are a series of changes in the levels of certain hormones and growth regulators some specifically appear to be of particular importance, among others, ethylene and polyamines. The overall objective of this thesis has been studying whether camvios occurring in the levels of ethylene and polyamines when plants are found in saline conditions relate to the tolerance or sensitivity to the salinity of different varieties or plant species, or responses are general of the plants to salt stress. By working with nine varieties of lettuce during germination and subsequent vegetative development, it was noted that during germination, ethylene could be a potential marker for tolerance to salinity, because there was a correlation invesa between production ethylene could provide greater tolerance to salinity, as it found an inverse correlation between the increase in ethylene production and the decrease in the fresh weight under saline conditions, so the ability to increase ethylene production, could provide greater tolerance to sallinidad at this stage of growth. The polyamines would not be appropriate as physiological markers, and found that changes in this parameter is not able to connect with different tolerance to salinity. During the vegetative growth phase, the different varieties analyzed presented some physiological responses to stress saline similar not explain the differences obtained in sensitivity to salinity. In the second part of the memory has worked with various plant species, also in the germination and during the subsequent vegetative development. During the germination, the implementation of salinity induced changes in the route of ethylene biosynthesis and in the levels of jpoliaminas, but these are not puedieron connect with different tolerance to salinity. During the vegetative development, salinity had an overall effect by increasing the synthesis of ethylene of the most sensitive species, while the tolerant declined. Furthermore, the saline stress induced changes in the levels of polyamines in the air that it could reelacionarse with different tolerance to salinity, as the most sensitive species (eg Pepper) increased more than in the tolerant polyamines (eg . Beet). At least one of the roles of polyamines could contribute to the osmorregulación of plants in saline conditions. In considering the immediate effect of salinity on different plant species, it became apparent that the application of sharp NaCI 100 mm caused an immediate increase in the concentration of Put, Spd and Spm, which was higher in the two most sensitive species, pepper and lettuce , in which the two species consideredas more tolerant: spinach and beet, both in the air and at the root. The polyamines could have a role osmorregulación of plants salinized, and that the plants in which the Na + accumulates in the air (the most tolerant) do not increase or decrease to a great extent, while in the most sensitive to accumulate little Na + partly aerial increase polyamines.

Author: RAMÍREZ ARISTIZABAL LUZ STELLA.
Year: 2004.
University: PABLO DE OLAVIDE [www.upo.es].
Place of defense: FACULTAD DE CIENCIAS EXPERIMENTALES.
Place of preparation: FACULTAD DE EXPERIMENTALES.

Summary: We studied the activity of the ribulosa -1.5 - bisfosfato carboxylase / oxigenasa (Rubisco) and the photosynthetic activity of 23 genotypes between wild and cultivated Coffea. The total content of soluble protein showed values between 7.7 mg and 35.65 mg g-1 fresh weight of leaf. The content of Rubisco ranged from 8.9% in KFO3 (genotype Ethiopian), and 45.7%, Kent (genotype Indian). The activity of Rubisco, tested in 18 genotypes showed values of 0.2172 umol RuDP g-1 min-1 in Kent and 3.6813 umol RuDP g-1 min-1 in World Novo constants Michaelis-Menten (Kmco2 and KmRuDP) ranged from 10.2 uM CO2 World Novo (tetraploid) to 34.47 uM CO2 in BP358 (diploid genotype), while the KmRuDP showed values between 15.8 uM RuDP 118 uM RuDP. The net photosynthetic activity ranged from 31892.4 (umol (CO2) m -2 day -1) for varieties Dilla-Alghe and Ethiopian 167 respectively. We found high correlation between the specific activity of the enzyme and net photosynthetic assimilation. This result can be used as a parameter for the selection of genotypes photosynthetically more eficientes.Además were isolated and purified the holoenzima and subunits LyS of Rubisco in leaf tissue of Coffea arabica. Var Colombia. It secuenciaron 15 amino acids for subunit S. Cebadores designed based on the time frame allowed clone that encodes a fragment of this polypeptide (Gene Bank AY 601652)

Author: Pire Cordero Reinaldo.
Year: 2005.
University: VALLADOLID [www.uva.es].
Place of defense: Campus Palencia.
Place of preparation: Campus Palencia.

Summary: The viticulture in the state of Lara, Venezuela, has been developed on a single rootstock, known as' Black Creole. Most of the state is a semi-arid region, a condition in which the rootstock has been identified as drought tolerant: however, this potential has not been demonstrated tolerance. The objective of this study was to determine the ability of tolerance of rootstock 'Black Creole' (NC) and possible mechanisms that might be conditional, as well as determining the differences physiological and growth when compared with cvs. Chenin blanc (Ch) and Syrah (S), planted both direct and grafted to be subjected to water deficit in the town of Tarabana (10Â º 02 'N and 500 meters), Lara State .. A first test was carried out using plants grown in containers and assessed rootstock CN and cvs. Ch and Sy francs standing or grafted (Ch / CN and S / NC) to form five types of plant material. Irrigation was applied at three levels: heavy, moderate and low. The 15 treatments resulting from factorial arrangement were evaluated in a completely randomized design with 12 repetitions. In a second test was evaluated in field conditions, the growth of the roots of rootstock during a development cycle. The moisture deficit negatively affected the leaf water potential, stomatal conductance and photosynthesis rate of all materials vine. The rootstock outperformed the rest of the materials, except in conditions of poor irrigation when they had a similar behavior. There was a slight tendency for cultivars grafted to overcome the stand taken francs. In drought conditions the rootstock developed a moderate osmotic adjustment, which was associated with the high rate of growth of roots that held under such conditions. The hydraulic conductivity of the material vine decreased as a result of water shortage which was associated with a reduced thickness of xylem vessels but not with the presence of embolismos. No differences were detected between different cultivars vine or in the conditions of grafting. In general, the water shortage resulted in a slight decline of the mass of strong root system and reduction of the air. The mass radical rootstock far exceeded the rest of the material. In terms of irrigation, leaf area and dry mass of the root of Ch / CN and S / CN exceeded in many cases and Sy Ch. Under field conditions, the roots of rootstock had high activity growth at the beginning of the development cycle plant, which was declining over time until it reaches the minimum value in the period of rest. The highest density of roots occurred in the upper soil, presenting a progressive decrease with depth. There was uniform development in horizontal direction and is not detected a pattern of distribution of the thickness of the roots on the side depth or location. The rootstock proved to be very vigorous and partly tolerant to drought, and was able to convey part of its graft force capable of irrigation him tolerance but not in a position to water shortage. The most important characteristics that allow classified as very strong and can confer certain capacity for drought tolerance are the extensive development coupled with the dramatic high density longitudinal roots and high root / side air. Two of the mechanisms for drought tolerance of rootstock were the more efficient use of water and its ability to osmotic adjustment to the water shortage.

Author: BARRES BENLLOCH MARÍA TERESA.
Year: 2005.
University: POLITÉCNICA DE VALENCIA [www.upv.es].
Place of defense: Dep. Ecosistemas Agroforestales.
Place of preparation: Universidad Politécnica de Valencia.

Summary: It discusses the problems caused by soil pathogens, weed problems and replanting of perennial crops. We found that microorganisms with the greatest difficulties in controlling nematodes are endoparasites trainers nodule gender Meloidogyne, mainly M. Javanica, M. Incognita, M. Arenaria and M. Hapla and fungal pathogens that cause marchiteces vascular podredumbres roots, stem and base it, "seedling blights" (singeing seedlings) and "damping-off" (marras of nascencia and fall of seedlings) of the genus Fusarium and Phythophthora, without excluding other as Rhizoctonia and Verticillium. Other problems, doubtful control WB levels deep soil, relate to controlling viruses and their delivery systems, soil bacteria and micro-organisms that live in plants and plant material remnants of propagation, whose control for the prevention and plant health is essential , but not sufficient in all cases. Weeds control with the greatest difficulties are the gender Cyperus. There seem to be defined the causes of unrest replanting in perennial crops, which should be for studying the feasibility of crop rotation. Purpose of the study should be the control of diseases caused by organisms and opportunistic factors influencing the performance of monocultures (strawberries, peppers), associated phenomena of "fatigue" in the soil, which has been among the preventive benefits of soil treatment with mountain biking. Actions are proposed to facilitate the compatibility of the alternatives presented to the World Bank with the duty of environmental eliminate the use of fumigant and fine chemicals alternative (blended 1,3-dicloropropeno (1,3-D) and chloropicrin, stream 1.3 - D metam-sodio, treatment with low-dose WB), whose use in the European Union could be limited by the rules of reviewing pesticides. Recommended use of organic matter for the purpose of crop protection, it is concluded the desirability of developing quality standards on the application of it in fresh and in a greater degree of transformation to the ground and its environmental burdens. It is proposed to design protocols on the use of such inputs of the minimum negative effects of waste, emissions, discharges and harmful effects on the biota. It cocluye the need to regulate, studied the life cycles of materials for cultivation in substrate, the management of these products at the end of its first life, as well as the nutritional solutions and PPPs in these forms of production.

Author: CARRION JIMENEZ MARIA ENGRACIA.
Year: 2005.
University: CASTILLA-LA MANCHA [www.uclm.es].
Place of defense: E.T.S. DE ING. AGRO. DE ALBACETE.
Place of preparation: E.T.S. DE INGENIEROS AGRONOMOS.

Summary: The wine sector in Castilla-La Mancha is in the midst of a process of restructuring and conversion, which has led to improvements in the technology used to process wine production, varietal improvement and modernization of plantations by acting as a transforming driving systems and the transformation of a dry irrigation, among others. These changes in the production system could alter the morphology and morphometry in Vitis vinifera L., as they are highly influenced by the development of the plant. Therefore, through this study attempts to analyze the impact of the cropping system (rainfed or irrigated) and driving (glass or trellis) on the morphology of different bodies in different varieties of Vitis vinifera L. (Cencibel, Airén and Cabernet Sauvignon). This work falls within the Ampelografía studying various methods used to characterize, classifying and identifying grape varieties. We analyzed the respective advantages and limitations, and became an integrated analysis of the complementarity of the same. Moreover, it addresses an important issue of cultural adaptation of the grape varieties and their influence on morphological characteristics. The selected parcels are located in the area of the OJ "Ribera del Júcar" (Cuenca, Spain). During the period of 2002-2004 has been carried out on selected varieties exploring characters ampelográficos and ampelométricos (OIV, 1984), the histological study of leaves and pámpanos (Gattuso and Gattuso, 2002; Curtis, 1986), have isoenzimáticos analyzed three systems (catechol oxidase (CO), glutamate oxalacetato transaminase (GOT) and superoxide dismutase (SOD)) and nine microsatellite (Ibanez et al., 2003), using as reference material wine from IVICAM. The results verify that the characters ampelográficos, ampelométricos and relations between them that have been studied, are strongly influenced by environmental conditions that influence being different depending on the year. Moreover, these differences are specific to each variety and depend on the particular conditions of each cropping system and driving. The same goes for histological characters. The characterization ampelográfica does not allow discrimination of all varieties of the study, unlike the ampelometría, which allows separation through discriminant analysis. This methodology was also possible to separate the three varieties of the study using only five measures undertaken in mature leaf. This methodology is verified the influence of the production system on the leaf surface but not on the perimeter, because within the same range, where the leaf grows becomes more whole. The histological methods are not helpful for the identification of varieties, but can complement other methods. The isoenzymes and microsatellites are reproducible regardless of the production system and are useful for identification varietal. These methodologies also allow confirm the presence of a plant Cencibel in the plot of Cabernet Sauvignon grown in espaldera-regadío, which had a strange location in the scatter diagrams in the field of characterization ampelométrica.

Author: CARRION JIMENEZ MARIA ENGRACIA.
Year: 2005.
University: CASTILLA-LA MANCHA [www.uclm.es].
Place of defense: E.T.S. DE ING. AGRO. DE ALBACETE.
Place of preparation: E.T.S. DE INGENIEROS AGRONOMOS.

Summary: The wine sector in Castilla-La Mancha is in the midst of a process of restructuring and conversion, which has led to improvements in the technology used to process wine production, varietal improvement and modernization of plantations by acting as a transforming driving systems and the transformation of a dry irrigation, among others. These changes in the production system could alter the morphology and morphometry in Vitis vinifera L., as they are highly influenced by the development of the plant. Therefore, through this study attempts to analyze the impact of the cropping system (rainfed or irrigated) and driving (glass or trellis) on the morphology of different bodies in different varieties of Vitis vinifera L. (Cencibel, Airén and Cabernet Sauvignon). This work falls within the Ampelografía studying various methods used to characterize, classifying and identifying grape varieties. We analyzed the respective advantages and limitations, and became an integrated analysis of the complementarity of the same. Moreover, it addresses an important issue of cultural adaptation of the grape varieties and their influence on morphological characteristics. The selected parcels are located in the area of the OJ "Ribera del Júcar" (Cuenca, Spain). During the period of 2002-2004 has been carried out on selected varieties exploring characters ampelográficos and ampelométricos (OIV, 1984), the histological study of leaves and pámpanos (Gattuso and Gattuso, 2002; Curtis, 1986), have isoenzimáticos analyzed three systems (catechol oxidase (CO), glutamate oxalacetato transaminase (GOT) and superoxide dismutase (SOD)) and nine microsatellite (Ibanez et al., 2003), using as reference material wine from IVICAM. The results verify that the characters ampelográficos, ampelométricos and relations between them that have been studied, are strongly influenced by environmental conditions that influence being different depending on the year. Moreover, these differences are specific to each variety and depend on the particular conditions of each cropping system and driving. The same goes for histological characters. The characterization ampelográfica does not allow discrimination of all varieties of the study, unlike the ampelometría, which allows separation through discriminant analysis. This methodology was also possible to separate the three varieties of the study using only five measures undertaken in mature leaf. This methodology is verified the influence of the production system on the leaf surface but not on the perimeter, because within the same range, where the leaf grows becomes more whole. The histological methods are not helpful for the identification of varieties, but can complement other methods. The isoenzymes and microsatellites are reproducible regardless of the production system and are useful for identification varietal. These methodologies also allow confirm the presence of a plant Cencibel in the plot of Cabernet Sauvignon grown in espaldera-regadío, which had a strange location in the scatter diagrams in the field of characterization ampelométrica.

Author: Bernat López Pasqual.
Year: 2005.
University: AUTÓNOMA DE BARCELONA [www.uab.es].
Place of defense: Facultad de Veterinaria.
Place of preparation: Centre d'Estudis d'Història de la Ciència.

Summary: This thesis explores the movement agronomic illustrated in Catalonia. From the context Spanish and European discusses the process of institutionalization of agronomical and proposals for improving agricultural launched by agronomists Catalans of the time. Without abandoning the social, political and economic development, the emphasis is on the scientific and technical aspects of the activity agronomic studied. It discusses in detail the activities and history of the Department of Agriculture of the Academy of Sciences of Barcelona and the School of Agriculture and Botany of the Board of Trade of Barcelona.

Author: MERTÍNEZ MORA CELIA.
Year: 2005.
University: POLITÉCNICA DE CARTAGENA [www.upct.es].
Place of defense: ESCUELA TÉCNICA SUPERIOR DE INGENIERÍA AGRONÓMICA.
Place of preparation: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS AGRÓNOMOS.

Summary: The objective of this thesis was to analyze the genetic variability of germplasm traditional native of Spanish peach and apricot tough meat, collected and maintained in the IMIDA (Murcia) and belonging to the National Bank of Germplasm. This analysis was performed using microsatellite markers in 17 loci of a collection of 106 entries peaches, 32 varieties of apricot and five rootstock hybrid melocotonero-almendro. Inflows of peach were in turn subdivided into 7 groups according to their geographical origin: Murcia, Lerida, Gorga (Alicante), Periana (Malaga), Castillejar (Grenada), La Nava (Huelva) and the Canary Islands. The results indicated that with regard to material Murcia, Maruja varietal types and Jerome are genetically very close to the point that there are two types of tickets indistinguishable by 17 markers. In some distance are the types Calabaceros and Campillos, and even more distant the entries for Maruja Porvenir. As for the analysis of the plant material of the various indigenous populations, it was found that in all of them, are genetically related entries in varying degrees with plant material from Murcia or Lerida / Zaragoza, which appear as two outbreaks of expansion and distribution germplasm peach. This situation reaches its highest expression give the populations of Canary Castillejar and Nava, where almost all entries submitted that origin, while the populations of Gorga Periana and presented the highest proportion of indigenous materials themselves. As for the germplasm of apricot, analysis of microsatellite allowed to separate the 32 traditional varieties into two main groups, one of them composed of varieties of origin and another with Valencia varieties of origin Murcia. This time as u appeared subdividas into two groups. One group included traditional varieties of Murcia and the other included varieties known as "class", resulting in varying degrees of the variety Moniquí. Lastly, the five rootstocks could be identified by the use of only two markers, which is interesting for the protection of rights of plant breeders.

Author: RUIZ VICENTE DAVID.
Year: 2005.
University: AUTÓNOMA DE MADRID [www.uam.es].
Place of defense: AUTÓNOMA DE MADRID.
Place of preparation: CENTRO DE CIENCIAS MEDIOAMBIENTALES - CSIC.

Summary: The species is the subject of this thesis is Avena sterilis L., one of the most important weeds in cereal crops in areas with a Mediterranean climate. In Spain, it is particularly problematic in crops of wheat and barley, which occupies an area of more than 5.5 million ha, which can cause considerable loss in yields. The main objective was to determine the patterns of distribution of this weed in the fields of grain and causes that originated with the main purpose of optimizing the control treatments, especially considering applying techniques Precision Agriculture. The potential benefits are both economic and environmental therefore would reduce the amount of herbicides applied in the fields. The study will be addressed at four levels: first analyzed the soil preferences of the kind in four plots of the Madrid related the presence of the weeds with soil properties. Secondly, a study was conducted to scale microparcela for two years where he analyzed the combined influence of soil type and competition from a crop of barley on development and fertility artificially established populations of Avena sterilis. Finally expanded the scale of the study, both geographically (throughout the country) and in number of fields. This was made possible by the use of innovative techniques of Precision Agriculture (DGPS eg, GIS, harvesters equipped with sensors yield and grain moisture). Thus incorporate variables topographical and competition in the cultivation, and were able to obtain an accurate picture of the problem posed by this kind in our fields at the present time, both in size and habit of distribution. For the analysis of large volumes of data were used innovative programs and tools to escla International, which was merit in itself. Arguably, Avena sterilis was presented as a kind generalist who is able to grow and at almost all areas of a plot. The events with high is tocasticidad could largely explain their presence. However, in the long term, some areas of the camps tend to have a greater abundance than others, which makes this kind likely to receive treatments. The specific conclusions were as follows: 1-edaphic variables by themselves are not able to explain the presence of this species in the fields. 2 - The combined effect of soil and growing competition it can predict what areas will be a greater abundance of this species: wheat fields in the greater abundance will be given in areas most favorable soil, while in barley fields will be given in the most unfavorable. 3 - Soil texture is the most decisive variable soil, within a semi-arid climate. 4-A crop of barley controls more effective development and fertility of a population of Avena sterilis as soil conditions are best, because of their increased competitiveness. 5 - The topography is the main variable that explains the presence of this kind: the higher densities occur in low-lying areas and concave profile of the fields. 6-Areas with low crop yields and north directions also higher levels of infestation. 7-It is possible to define simple decision rules areas with higher risk of infestation than others, finding differences of more than six times. 8 - The levels of infestation are generally low and are distributed in a geometric progression from highest to lowest infestation. 9 - The estimated yield losses due to weeds that are 7%. 10-Most of the infestation is concentrated in a small number of stands of large and irregularly shaped, while a large number of smaller stands and regular constitute a small percentage of infestation. 11-In areas with low yields (higher 3.5 ton / ha) not to apply the herbicide is the most cost-effective option. In areas of greatest rend 8 dures 297 it is advisable to apply herbicides but in low doses or treatments. In these cases, the losses that are avoided in yield losses and saving the herbicide itself technological offset the increased costs of these treatments.