The stalk borer (SB), Papaipema nebris Gn. exhibited from 7 to 9 instars when reared on a meridic diet in a control-led environment. Both sexes went through variable numbers of instars before pupation. Head capsule width measurements did not form discrete sets, and overlap occurred between adjacent instars. In feeding preference tests with first instar larvae using either leaf disks or stem sections, higher numbers of larvae fed on grasses, such as orchardgrass, Dactylis glomerata L. or fescue, Festuca arundinacea Schreb., compared to numbers feeding on other plants. In no-choice laboratory and field tests, larvae tunnelled into plant stalks at the same frequency by which they would feed on foliage, showing a tendency to tunnel into plants they accept as hosts. Third or fourth instar larvae preferred to tunnel into orchardgrass and rye, Secale cereale Lover the other plants present in field cage tests. The SB prefers to oviposit on narrow leaved, perennial grasses, such as fescue and orchardgrass, over wide leaved annual grasses or broadleaf plants. Significantly higher numbers of eggs were laid on upright over prostrate plants in cage studies. The SB also preferred ovipositing on desiccating or dry plant material. Higher numbers of SB infested corn seedlings were found next to field margins compared to numbers found within fields. Contour and transect maps of SB infested fields showed considerable aggregation over three years, and this distribution was confirmed by high variance to mean ratios, and small k values. SB distribution in no-till corn can be adequately described by the negative binomial model. Field collections of SB in corn stalks showed 2, 3, or 4 instar larvae infesting the youngest seedlings. Variation existed in larval development from year to year. Linear regression covariance analysis showed that larval development was different between field collected larvae from year to year. / Ph. D. / incomplete_metadata

Thesis (MScAgric)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: The aim of this study was to determine the effect of a grass herbicide, a broadleaf herbicide with some grass control capabilities, method of tillage (tine and no-tillage) at planting of wheat as well as different medic cultivars on the regeneration, dry matter (OM) production and quality of a medic pasture. The trial was conducted at Langgewens experimental farm in the Swartland wheat producing area. Nine medic cultivars of three different species were evaluated after being sprayed with either haloxyfop-R-methyl (HAL) ester or imazamox (IMI) and subjected to either a tine tillage or a no tillage treatment at planting of wheat. Soil samples were taken during January 2000 to determine the size of the medic and weed seedbank as well as the degree of dormancy in the medic seeds, while OM samples were taken throughout the growing season to determine the OM production of the different medic cultivars and weed species. OM samples taken during October 1998 on the same pasture, were used to determine the crude protein (CP) and neutral detergent fibre (NOF) content of the pasture. The samples were subjected to in vitro digestion and the digestibility of pasture CP (OCP), NOF(ONOF) and DM (DOM)were determined. Results showed that seedling establishment differed between cultivars used, herbicide treatments applied as well as the crop stage in the rotation. The cultivars produced more seedlings where IMI was applied compared to HAL as well as where the area consisted of two year pasture compared to one year pasture (1998) and one year wheat (1999). After a year of pasture and a year of wheat, cultivars Sephi and Paraggio produced the most seedlings, while Caliph and Orion produced the least. Caliph however, showed a very high degree of seed dormancy while Orion's low seedling establishment was due to its sensitivity to the IMI herbicide used. Little difference was found between the nine cultivars early in the season (July - August) with regard to cumulative OM production, except for Orion, whose growth was severely damaged by the IMI treatment. At the end of the growing season (October), the cultivar Caliph's cumulative OM production (2010.1 kg/ha) was significantly higher than all the other cultivars, except for Parabinga (1053. 4 kg/ha). Oifferent pasture samples, of which the botanical composition was known, was analysed for CP, NOF, OOM, OCP and ONOF. There was no significant difference in pasture composition during 1998 but variation in the pasture composition did however cause the IMI treatment, compared to the HAL treatment, to have a lower ONOFand OOMcontent. A modelling procedure was used to predict the pasture quality parameters (CP, NOF, OOM,OCP and ONOF) from the pasture composition (medic hay, medic pods, grassy and broadleaf weeds). This prediction of CP, NOF, OOM, ONOF and OCP from the pasture components had a relative low accuracy (49 -74.1 %) and a further refinement of this model for possible use on farms in order to improve grazing management and animal production is advised. In conclusion it could be said that broadleaf weed control caused a definite increase in medic seed and OMproduction, but Orion should not be used with an IMI herbicide. All the cultivars, except for Orion, produced enough seedlings up to the second year to ensure sustainability of the medic pasture. All the cultivars, except for Orion, produced a sufficient amount of OM early in the growing season. Caliph however, produced by far the most OM later in the growing season. A reduction of broadleaf weeds and medic pods will increase the digestibility of NOFand OMand therefore increase the quality of the pasture. Pods however are an important part of summer forage and the aim should therefore rather be to reduce the number of broadleaf weeds in the pasture. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die effek van 'n gras en breëblaar onkruiddoder (wat sekere grasse beheer), metode van bewerking tydens die saai van koring asook nege verskillende medic kultivars op die regenerasie, droë materiaal produksie en kwaliteit van medic weidings te bepaal. Die proef is gedoen op Langgewens proefplaas wat geleë is in die Swartland koring produserende gebied. Nege medic kultivars is geëvalueer nadat die weiding met of haloxyfop-R-metiel ester (HAL) of imazamox (IMI) onkruiddoders gespuit is en onderwerp is aan of 'n vlak tand of geen bewerking tydens die saai van koring. Grondmonsters is geneem in Januarie 2000 om die grootte van die medic en onkruid saadbank asook om die graad van dormansie in die verskillende medic kultivars se sade te bepaal. Droë materiaal monsters is gedurende die 2000 groeiseisoen geneem om die droë materiaal produksie van die verskillende medic kultivars asook onkruid spesies te bepaal. Droë materiaal monsters is gedurende Oktober 1998 geneem en gebruik om die ruproteïn (CP) en neutraaloplosbare vesel (NDF) inhoud van die weiding te bepaal. Die monsters is in vitro verteer en die verteerbaarheid van CP (OCP), NDF (ONOF) en droë materiaal (DOM) is bepaal. Resultate wys dat saailing vestiging verskil tussen die verskillende kultivars wat gebruik is, verskillende onkruiddoder behandelings asook die stadium van die weidings/koring. Die kultivars het meer geproduseer waar die weiding met IMI behandel is in vergelyking met waar HAL toegedien is, asook waar koring nog nie gesaai is nie. Na 'n jaar van weiding en 'n jaar van koring, het die kultivars Sephi en Paraggio die meeste saailinge, en Caliph en Orion die minste saailinge gehad. Caliph het egter 'n hoë graad van dormansie in sy saad getoon, terwyl die swak vestiging van Orion die gevolg is van die kultivar se hoë sensitiwiteit teenoor IMI. Min verskil is gevind tussen die nege kultivars, vroeg in die groei seisoen (Julie - Augustus), wat kumulatiewe droë materiaal produksie betref, behalwe vir Orion wat erg beskadig is deur die IMI behandeling. Aan die einde van die groeiseisoen (Oktober 2000) was die kumulatiewe droë materiaal produksie van die kultivar Caliph (2010.1 kg/ha) betekenisvol hoër as al die ander kultivars behalwe vir Parabinga (1053.4 kg/ha). Weidingsmonsters, waarvan die botaniese samestelling bekend was, is ontleed vir CP, NDF, DDM, DCP en DNDF. Daar is geen betekenisvolle verskille gevind in die botaniese samestelling van die weidingmonsters geneem in 1998 nie,maar die variasie in botaniese samestelling het veroorsaak dat IMI in vergelyking met HAL 'n laer DNDF and DDM inhoud het. 'n Model is opgestel wat die weidingskomponente (medic hooi, medic peule, gras en breëblaar onkruide) gebruik om die kwaliteits parameters (CP, NDF, DDM, DCP en DNDF) van die weiding te skat. Hierdie skatting van CP, NDF, DDM, DCP en DNDF deur van die weidingskomponente gebruik te maak het 'n relatiewe lae akuraatheid gehad (49 -74.1 %) en verdere verfyning van hierdie model vir moontlike gebruik op plase, ten einde weidings bestuur en diere produksie te verbeter, word voorgestel. Die gevolgtrekking kan gemaak word dat breëblaar onkruidbeheer 'n definitiewe verbetering in die medic saailing en droë materiaal produksie van die medies te weeg gebring het, maar die kultivar Orion behoort nie saam met 'n IMI gebruik te word nie. AI die getoetste kultivars, behalwe Orion, het voldoende saad oorlewing vertoon tot en met die tweede jaar van die rotasie om lewensvatbaarheid van die sisteem te verseker en alle kultivars, behalwe Orion, het voldoende droë materiaal produseer vroeg in die groeiseisoen. Caliph het egter laat in die groeiseisoen by verre die meeste droë materiaal geproduseer. 'n Vermindering in die hoeveelheid breëblaar onkruide en peule in die weiding sal tot 'n verhoging in die verteerbaarheid van NDF en DM lei en dus 'n verhoging in die kwaliteit van die weiding tot gevolg hê. Peule is egter 'n belangrike bron van voedsel aan weidende diere gedurende droë somermaande en die verbetering van weidings moet eerder gedoen word deur te poog om breëblaar onkruide te beheer.

Cette thèse visait à caractériser et à modéliser la dynamique des trois ressources principales que sont l'eau, l'azote et le rayonnement dans une association en relais maïs-plante de couverture en semis direct en région tropicale subhumide et ses conséquences sur la productivité de la culture principale et de l'ensemble du système et sur les flux d'eau et d'azote dans le sol. Le travail repose sur un dispositif expérimental mis en place dans les Cerrados, à Unaí (Minas Géras, Brésil) en 2007 pour deux années agricoles, d'une part en station expérimentale permettant un effort de mesure intense et d'autre part dans un réseau de parcelles d'agriculteurs offrant une large gamme de situations pédoclimatiques et de modalités de mise en œuvre des systèmes de culture étudiés. Dans ces derniers, la culture principale était un maïs, et la plante de couverture associée en relais était une culture fourragère tropicale, soit la légumineuse, Cajanus cajan soit la poacée, Brachiaria ruziziensis. Deux dates de semis, précoce et tardive étaient considérées pour le semis de la plante de couverture au sein du maïs, dans le cas de l'essai en station. Ce travail montre que rendement du maïs n'a pas été significativement affecté par la présence de la plante de couverture semée précocement au sein du maïs, en comparaison avec le rendement du maïs en culture pure. En revanche, la production en biomasse de la plante de couverture a été significativement réduite dans l'association. Le semis précoce de la plante de couverture au sein du maïs permet une production en biomasse significativement plus importante qu'un semis tardif (20 jours après floraison du maïs), et une production totale en biomasse de l'ensemble de l'association significativement plus importante par rapport aux cultures pures. Cette production totale a été plus du double comparée à celle de la culture pure de maïs dans le cas de l'association maïs-Cajanus. Les valeurs du Land Equivalent Ratio (LER) du rendement en grain de maïs et de la production de biomasse ont été supérieures à 1, atteignant jusqu'à 2.03 témoignant d'une meilleure valorisation des ressources par les espèces associées et l'avantage de tels systèmes pour produire à la fois du grain et du fourrage. La thèse montre aussi la forte variabilité du potentiel de production de ces systèmes en parcelles de producteurs et suggère que lorsque les ressources en eau et en azote sont moins disponibles que dans l'essai de station, des compétitions entre maïs et plantes de couverture peuvent réduire les performances agronomiques du maïs et/ou de la plante de couverture comparativement par rapport à la culture pure équivalente. La biomasse totale produite reste cependant supérieure à celle de la culture pure de maïs, sauf pour de rares exceptions où de plus faibles disponibilités en ressources, parfois accentué par des difficultés de gestion technique, le maïs semble souffrir de compétition plus forte et/ou la plante de couverture ne produit que très peu de biomasse. La thèse évalue la capacité d'un modèle de simulation de culture associées, STICS-CA, à fournir une analyse plus fine de la dynamique du partage des ressources dans ces systèmes et à en estimer les performances agronomiques et certains impacts environnementaux en fonction de conditions techniques et édapho-climatiques différentes de celles de notre dispositif. Des modifications mineures et le calage du modèle ont conduit à une simulation satisfaisante des cultures pures de maïs et Brachiaria et de l'association maïs-Brachiaria en semis direct sur mulch pailleux. En revanche il n'a pas été possible d'obtenir une simulation satisfaisante du maïs en semis conventionnel sur sol labouré, ni du Cajanus en culture pure et de l'association maïs-Cajanus en semis direct. . La thèse fournit des informations sur les imperfections du modèle et propose des améliorations aussi bien en termes de formalismes pour la prise en compte de la minéralisation du mulch, qu'en termes de dispo exp / This thesis dealt with characterizing and modeling the dynamics of the three principal resources which are water, nitrogen and radiation in a no-tillage relay intercropping maize-cover crop systems, under sub-humid tropical area climate. Moreover, productivity of the main crop and of the whole system and nitrogen and water flows in the soil are assessed.The study was based on an on-field approach/experimental design carried out during two crop growing seasons in Cerrados region, in Unaí (Minas Géras, Brazil) since 2007. Firstly, an experimental station was used allowing an intense effort of measurement and secondly, a whole of several farmer's fields offering a wide range of soil and climate conditions and modalities of implementation of the studied cropping systems. In the latter, main crop was maize, and intercropped cover crop was a tropical fodder crop, either leguminous, Cajanus cajan or gramineous, Brachiaria ruziziensis. Two dates of sowing, early and late were considered for the sowing of the cover crop in established maize, in the case of the experimental station. This study showed that maize yield was not significantly affected by the presence of the relay cover crops in comparison with maize as the sole crop, even when the cover crop was sown soon after maize emergence in comparison with maize sole crop. In contrast, the production of biomass by the cover crop was significantly lower when grown with maize than when it was grown as a sole crop. In the intercropped systems, when sown early, the cover crop produced higher total biomass than when sown late (20 days after maize flowering). Moreover, total aboveground biomass production of maize intercropped with a cover crop was much higher than that of any of the crops sown alone. Total biomass produced by maize and pigeon pea (Cajanus cajan) was more than double that maize grown alone. The Land Equivalent Ratio (LER) values of both maize grain yield and biomass production were higher than one, whatever the intercrop system, reaching up to 2.03 providing better available resources use efficiency by the intercropped plants. Thus, such systems permit to produce both maize grains and forage.The thesis shows also the strong variability of the production potential of these systems in farmer's fields and suggests that when water and nitrogen resources are less available than in the experimental station, competitions between maize and cover crops can reduce the agronomic performances of maize and/or the cover crop when compared to the equivalent pure sole crop. Total biomass produced by intercropping remained however higher than that of maize sole crop, except for rare exceptions where lower resources availability, sometimes accentuated by difficulties of technical practice, maize seems to suffer from stronger competition and/or the cover crop produced only very little biomass. The thesis evaluates the capacity of the STICS intercrop model, STICS-CA, to provide a finer analysis of the dynamics of the resource sharing in these systems and to estimate their agronomic performances and certain environmental impacts according to technical practices and soil and climate conditions that were different from those of our experimental station. Minor modifications and model calibration led to obtain satisfying simulations of the sole crops maize and Brachiaria and intercrop maize-Brachiaria in no-tillage under mulch. On the other hand, it was not possible to obtain satisfying simulations of sole crop maize in conventional tillage, nor of sole crop pigeon pea and intercrop maize-pigeon pea in no-tillage under mulch. The thesis provides information on the model imperfections and as well proposes improvements in terms of formalisms to take into account the mineralization of the mulch, as in terms of experimental design.

A permeabilidade ao ar (Ka) pode ser utilizada para avaliar alterações que ocorrem na estrutura do solo em virtude de diferentes sistemas de manejo. Este estudo testou a hipótese de que o menor revolvimento do solo sob sistema plantio direto resulta na formação de poros contínuos e melhor condição de aeração no solo. O objetivo do estudo foi avaliar, por meio da Ka, porosidade de aeração (a) e índices de continuidade de poros (K1 e N), a aeração em um Latossolo Vermelho submetido ao preparo do solo convencional (PC) e plantio direto (PD). Amostras de solo indeformadas foram coletadas em cada sistema nas profundidades de 0-0,10 e 0,10-0,20 m em área experimental do Instituto Agronômico do Paraná IAPAR, no município de Ponta Grossa, Paraná. A Ka foi medida pelo método da carga decrescente em seis potenciais mátricos, -2, -6, -10, -30, -70 e -100 kPa. A macroporosidade e a Ka foi maior no PC nas duas camadas avaliadas. A continuidade de poros avaliada pela razão entre Ka e a (K1) foi similar entre os sistemas na camada superficial e foi maior para o PC em subsuperfície. O índice de continuidade N, referente ao coeficiente angular da relação log-log entre Ka e a foi diferente quando determinado para cada amostra individualmente (n=6) e quando obtido com todas as observações (n=120). Os dois métodos revelaram poros mais contínuos no PC em superfície. Na camada de 0,10-0,20 m o primeiro (n=6) não indicou diferença de continuidade de poros entre os sistemas, enquanto o segundo (n=120) resultou em uma maior continuidade de poros nesta profundidade no PD. / Air permeability (Ka) can be used for assessing soil structure changes due tillage systems. This study tested the hypothesis that the less soil disturbance under no-tillage result in continuous pores and better soil aeration conditions. The objective of this study was to evaluate a Rhodic Hapludox aeration dynamics, by measuring Ka, air-filled porosity (ea) and pore continuity indices (K1 and N), under conventional tillage (CT) and no-tillage (NT). Undisturbed soil cores were collected in each systems at depths of 0-0,10 and 0,10-0,20 m in Parana Agronomic Institute research farm - IAPAR, in Ponta Grossa, Paraná. Ka was determined using falling pressure method in six soil water potentials, -2, -6, -10, -30, -70 e -100 kPa. The soil macroporosity and Ka was higher in CT in both depths. The pore continuity assessment by ratio between Ka and ea (K1) was similar between the systems in the top layer and was higher at CT at depth of 0,10-0,20 m. The continuity index N, relative to the slope from the log-log relationship between Ka and ea was different when calculated for each core individually (n=6) or obtained including all data for each tillage (n=120). The two methods revealed a more continuous pores in CT in the top layer. At depth of 0,10-0,20 m the first (n=6) did not indicate pore continuity difference between the systems, while the second resulted in better pore continuity in NT at this depth.

Tendo-se em conta a importância da lavoura tritícola para o país, e que o aumento da produtividade depende também da correta execução das operações de implantação e condução da cultura, este trabalho tem como objetivo avaliar a estabilidade dos processos de produção e ao atendimento aos padrões especificados de um sistema de plantio direto na cultura do trigo. Os dados foram coletados em um talhão da Fazenda Paiquerê, do Grupo Lúcio Miranda, no município de Piraí do Sul, Estado do Paraná. Foram consideradas seis operações do processo produtivo do trigo sob sistema plantio direto: colheita da cultura antecessora, pulverização pré-semeadura, semeadura, adubação de cobertura, pulverização para tratamento fitossanitário e colheita do trigo. Para a avaliação do sistema produtivo em questão, foram determinados, para cada operação considerada, indicadores de desempenho e limites de especificação para cada indicador. Foram utilizados para a avaliação dos resultados, ferramentas de análise estatística descritiva, de controle da qualidade e do SIG. Pode-se concluir que o sistema de plantio direto de trigo considerado neste estudo não atendeu aos padrões especificados, necessitando de melhorias em todas as operações envolvidas no processo. A utilização das cartas de controle, do histograma e do SIG identificou os pontos que apresentaram problemas e que não se encontravam dentro das especificações agronômicas em todas as operações avaliadas. O uso de técnicas geoestatísticas aliadas à tecnologia SIG permitiu o adequado zoneamento dos indicadores analisados, identificando áreas com diferentes quantidades. / Considering the relevance of wheat crop in Brazil, and that the yield increase depends also on the correct execution of implementation and management of the crop, this work aimed to evaluate how stable the production processes are and to the specified patterns attending of a no-tillage wheat crop. The data were collected at Paiquerê farm, belonged to Lúcio Miranda Group, in of Piraí do Sul city, Paraná state. Six operations of the production process of the no-tillage wheat were considered: harvesting of the former crop, spraying before drilling, drilling, fertilizer spreading, spraying and wheat harvesting. To evaluate the studied production system, it were determined to each considered operation, performance indicators and specification limits to each indicator. Tools of descriptive statistics analysis, of quality control and GIS were used. It was concluded that the evaluated system did not attend the specified patterns, needing improvements in all operations involved in the process. The utilization of control charts, histogram and GIS identified where there were problems and that were not in the agronomic specification range in all the evaluated operations. The use of geostatistical techniques together GIS technology allowed the adequate zoning of the studied indicators, identifying areas with distinct quantities.

O presente trabalho teve por objetivo: a) avaliar os processos do balanço de água no solo com culturas de milho sob sistema plantio direto e, adubada com diferentes doses de nitrogênio, em sucessão a plantas de cobertura do solo, e b) verificar possíveis alterações de algumas propriedades físico-hídricas do solo neste tipo de prática de manejo. O experimento foi conduzido em uma área experimental da ESALQ-USP, município de Piracicaba-SP. Segundo a classificação internacional de Köppen, o clima da região é do tipo Cwa, denominado "tropical de altitude". O solo do local é do tipo Latossolo Vermelho Amarelo. O delineamento experimental foi o de blocos casualizados com 4 repetições. Os tratamentos constaram de uma testemunha e de três doses de nitrogênio (60, 120 e 180 kg ha-1) na forma de sulfato de amônio, sendo que 30 kg ha-1 de N foram aplicados na semeadura e o restante em cobertura. A área da parcela experimental foi de 36 m2 (5,0 x 7,2 m), observando-se a declividade do terreno. A aveia preta foi semeada manualmente em julho de 2004 e o tremoço branco em junho de 2005, o milho em dezembro de 2004 e novembro de 2005, após manejo das plantas de cobertura do solo. No que diz respeito ao balanço de água o solo foram medidos a precipitação pluvial (P), o deflúvio superficial (R), a drenagem interna (D) (ou ascensão capilar) na profundidade de 0,8 m e a variação da armazenagem (Δh) na camada de solo de 0,0-0,80 m; a evapotranspiração real (ET) foi estimada como a incógnita na equação do balanço. Ainda foi avaliada a eficiência do uso da água (EUA) pela cultura do milho, bem como suas características agronômicas e produção de matéria seca (MS) das plantas de cobertura do solo. As propriedades físico-hídricas do solo avaliadas para atender o segundo objetivo do trabalho foram: porosidade total, macro e microporosidade do solo e densidade do solo. Os resultados obtidos mostraram que: quanto aos parâmetros do balanço de água, de forma geral, verificou-se que as doses de N os alteraram, uma vez que nos tratamentos com aplicação de N, o solo se encontrou com uma Δh relativamente menor que o tratamento sem N, refletindo em menor valor de D nesses tratamentos, sendo traduzido em maior absorção de água pelas plantas, bem como maior EUA e maior rendimento de grãos. Quanto às propriedades físico-hídricas do solo, percebeu-se tendências de mudança, principalmente no que se refere à macro e microporosidade do solo, condicionadas pela alteração estrutural do solo. Entretanto, estas mudanças ocorrem paulatinamente, com o tempo e com a aplicação de N, sendo interessante um estudo em longo prazo no SPD, para se obter resultados mais significativos e conclusivos quanto a essa prática de manejo na região. / The objective of this work was: a) to evaluate the processes of the water balance in the soil with maize plants, under no tillage system (NTS) and different nitrogen levels, in succession to cover crops; b) to verify possible alterations of some soil physico-hydric properties due to the no tillage system practice. The experiment was carried out in Piracicaba, SP, Brazil on a Typic Hapludox, locally called Yellow Red Latosol. According to Köppen's classification, the region climate is of Cwa type, tropical highland. The experimental design was of randomized blocks with four replicates. The treatments consisted of one control and three nitrogen levels (60, 120 and 180 kg ha-1 of N) as ammonium sulphate, 30 kg ha-1 of N being applied in the sowing and the remain in covering. The area of experimental plot was 36 m2 (5.0 x 7.2 m), observing the land slope. Avena strigosa was sown manually in July 2004 and Luppinus albus in June 2005, the maize in November 2004 and 2005, after handling of the cover crops. In relation to the soil water balance, it was evaluated the precipitation (P), the runoff (R), the internal drainage (D) (or capillary rise) at the 0.80 m of depth, soil water storage variation (Δh) at the 0.0-0.80 m layer and the evapotranspiration (ET). The latter, was considered as unknown in the water balance equation. The maize WUE was also calculated, as well as yield components and dry matter cover crops. The soil physico-hydric properties evaluated were: total porosity, macroporosity, microporosity and dry bulk density. The results showed that: for the soil water balance, generally, the N levels changed the equation parameters. As a result, the treatments with N application had lower Δh than the treatment without N, implying in a lower D in these treatments and leading to a higherwater absortion by plants, as well as WUE and yield grain. The soil physico-hydric properties have showed trends of changing, mainly for macro and microporosity, due to the soil structural change. However, these alterations, occur slowly, with the time and the N application. Therefore, it is necessary to study the long-term NTS to have significant and conclusive results for this soil management in this region.

Orientador: Kuniko Iwamoto Haga / Banca: Elizabeth Orika Ono / Banca: Leandro Ferreira de Aguiar / Resumo: A assimilação do nitrogênio é um processo vital que controla o crescimento e o desenvolvimento das plantas e tem efeitos marcantes sobre a fitomassa e a produtividade final das culturas. A rota de assimilação do nitrato em plantas superiores envolve dois estágios seqüenciais, conversão do nitrato a nitrito pela redutase do nitrato (NR) e nitrito a amônio, mediada pela enzima redutase do nitrito (NiR). O presente trabalho teve o objetivo de verificar a atividade da enzima NR em arroz cv. IAC 202 conduzido sob solo proveniente de áreas de sistema de plantio direto e plantio em solo escarificado, aliado a doses crescentes de nitrogênio (0, 25, 50, 75, 100 e 125 kg.ha -1 ) em dois regimes hídricos. As plantas foram cultivadas em vasos a céu aberto e as análises foram realizadas de acordo com método clássico in vivo. O delineamento experimental foi blocos casualizados, com quatro repetições. Foram feitas três análises com intervalo de sete dias entre uma e outra e estas se iniciaram sete dias após a aplicação do N em cobertura. Com base nos resultados obtidos pode-se concluir que a maior atividade da enzima está relacionada com a disponibilidade de água e ao tipo de manejo do solo (plantio direto). / Abstract: The assimilation of the nitrogen is a vital process that it controls the growth and the development of the plants and it has outstanding effects on the biomass and the final productivity of the crops. The pathway of assimilation of the nitrate in plants involves two sequential stage, one is reduction the nitrate to nitrite mediated by the nitrate reductase (NR) and reduction the nitrite to ammonium mediated by the enzyme nitrite reductase (NiR). In the present work objetivated to verify the enzyme NR activity in rice cv. IAC 202 plants cultivated in two conditions of handling of the soil, no-tillage and minimum tillage, and doses of Nitrogen (0, 25, 50, 75, 100 and 125 kg.ha -1 ) on irrigation and without irrigation. The plants were cultivated in vases to open sky and the analyses were accomplished in agreement with method classic alive in. The experimental design was randomized blocks, with four repetitions. It was made three evaluations in the interval of seven days; the analysis began seven days after the N application on covering. The largest activity of the enzyme is related with readiness of water and to the soil cultivation with the better performance was observed in no-tillage system. / Mestre

Com o objetivo de avaliar os efeitos da adubação antecipada sobre a produção de matéria seca da cultura de Eleusine coracana, os caracteres produtivos, a qualidade fisiológica das sementes e a produtividade da cultura da soja em sucessão, sustentando-se a hipótese de que a produtividade da soja não é reduzida devido à antecipação da adubação de base para a cultura do capim-pé-de-galinha, foi conduzido o presente experimento na Estação Experimental Anhembi, Escola Superior de Agricultura Luiz de Queiroz (USP/ESALQ), no município de Piracicaba-SP, durante os anos agrícolas de 2001/2002, 2002/2003 e 2003/2004, em Latossolo Amarelo distrófico. A adubação consistiu da aplicação de 90 kg de P2O5 ha-1, 50 kg de K2O ha-1 e de micronutrientes (Co, Cu, Fe, Mn, Mo e Zn). O experimento adotou delineamento em blocos completos ao acaso com três repetições e 12 tratamentos que consistiram em diferentes níveis de antecipação da adubação da soja para a cultura do capim-pé-degalinha: T1= nenhuma adubação; T2= adubação convencional na soja; T3= antecipação de 50% de K, no capim-pé-de-galinha; T4= antecipação de 100% de K, no capim-pé-de-galinha; T5= antecipação de 50% de P, no capim-pé-de-galinha; T6= antecipação de 50% de P e K, no capim-pé-de-galinha; T7= antecipação de 50% de P e 100 % de K, no capim-pé-de-galinha; T8= antecipação de 100% de P, no capim-pé-degalinha; T9= antecipação de 100% de P e 50% de K, no capim-pé-de-galinha; T10= antecipação de 100% de P e K, no capim-pé-de-galinha; T11= antecipação de 100% de P e K + micronutrientes, no capim-pé-de-galinha; T12= antecipação da adubação foliar com micronutrientes, no capim-pé-de-galinha. As características avaliadas foram: a) capim pé-de-galinha: produtividade de matéria seca da parte aérea; b) soja: estande final, altura final de planta, grau de acamamento, número de ramificações por planta, número de vagens chochas por planta, número de vagens de 3 cavidades com 3, 2 e 1 semente, número de vagens de 2 cavidades com 2 e 1 semente, número de vagens de 1 cavidade com 1 semente, número total de vagens e de sementes por planta, peso de sementes por planta, peso de mil sementes e produtividade agrícola. As sementes de soja foram submetidas aos testes de germinação, de envelhecimento acelerado e de emergência em areia. Conclui-se: a) A antecipação das adubações fosfatada e potássica da soja para a semeadura do Eleusine coracana, incrementa a produtividade de matéria seca deste; b) A ausência de adubação do sistema de produção envolvendo a semeadura direta da soja em sucessão à cultura de cobertura com o capim-pé-degalinha conduz, ao longo das sucessivas safras, a perdas de produtividades agrícolas de matéria seca do capim-pé-de-galinha e de sementes de soja; c) A antecipação da adubação de base da cultura da soja para o capim-pé-de-galinha não interfere com a quantidade total de vagens formadas pelas plantas de soja; e, d) A antecipação da adubação de semeadura com fósforo e potássio da cultura da soja para a semeadura do capim-pé-de-galinha não interfere com a massa de mil sementes e nem com a produtividade agrícola da soja. / A research was carried out with the aim of evaluating the effects of anticipated fertilization on the production of Eleusine coracana dry matter as well as it productive features. In addition to it, the physiological quality of the seeds and the culture yield were also evaluated, taking into account the hypothesis that soybean yield is not reduced due to the anticipated base fertilization of the finger millet culture. The experiment was conducted at the Estação Experimental Anhembi, Escola Superior de Agricultura Luiz de Queiroz (USP/ESALQ), in Piracicaba/SP, during the growing seasons of 2001/2002, 2002/2003 and 2003/2004, in an Oxisol. The fertilization consisted on the application of 90 kg of P2O5 ha-1, 50 kg of K2O ha-1 and micronutrients (Co, Cu, Fe, Mn, Mo and Zn). The experiment adopted a completely randomized blocks design with three repetitions and twelve treatments, which comprehended different levels of anticipated soybean fertilization for the culture of finger millet, as it follows: T1= without fertilization ; T2= traditional soybean fertilization; T3= anticipation of 50% of K on finger millet; T4= anticipation of 100% of K, on finger millet; T5= anticipation of 50% of P on finger millet; T6= anticipation of 50% of K and P on finger millet; T7= anticipation of 50% of P and 100% of K on finger millet; T8= anticipation of 100% of P on finger millet; T9= anticipation of 100% of P and 50% of K on finger millet; T10 = anticipation of 100% of P and K on finger millet; T11 = anticipation of 50% of K on finger millet; T11 = anticipation of 100% of P and K + micronutrients on finger millet; T12 = anticipation of foliar fertilization with micronutrients on finger millet. The evaluated characteristics were: a) finger millet: dry matter production; b) soybean: final stand, final plant height, lodging, number of branches per plant, number of empty pods per plant, number of pods with 3 cavities with 3, 2 and 1 seed, number of pods with 2 cavities with 2 and 1 seed, number of pods with 1 cavity and 1 seed, total number of pods per plant, seed weight per plant, mass of 1,000 seeds and total yield. Soybean seeds were submitted to germination tests, accelerated ageing tests and well as tests of sand emergency. It was concluded that: a) Phosphorus and potassium anticipated fertilization on soybean applied to the Eleusine coracana (L.) Gaertn. crop can increase the finger millet dry matter yield; b) The absence of fertilization on the soybean no-tillage yield system succeeding the finger millet cover culture can cause the decrease of total yield of finger millet dry matter and soybean seeds; c) The anticipation of base fertilization of soybean culture for finger millet does not interfere with the total amount of pods generated by soybean plants; and d) Phosphorus and potassium anticipated fertilization on soybean culture for finger millet crop do not interfere with the mass of 1,000 seeds and total soybean yield.

Tendo-se em conta a importância da lavoura tritícola para o país, e que o aumento da produtividade depende também da correta execução das operações de implantação e condução da cultura, este trabalho tem como objetivo avaliar a estabilidade dos processos de produção e ao atendimento aos padrões especificados de um sistema de plantio direto na cultura do trigo. Os dados foram coletados em um talhão da Fazenda Paiquerê, do Grupo Lúcio Miranda, no município de Piraí do Sul, Estado do Paraná. Foram consideradas seis operações do processo produtivo do trigo sob sistema plantio direto: colheita da cultura antecessora, pulverização pré-semeadura, semeadura, adubação de cobertura, pulverização para tratamento fitossanitário e colheita do trigo. Para a avaliação do sistema produtivo em questão, foram determinados, para cada operação considerada, indicadores de desempenho e limites de especificação para cada indicador. Foram utilizados para a avaliação dos resultados, ferramentas de análise estatística descritiva, de controle da qualidade e do SIG. Pode-se concluir que o sistema de plantio direto de trigo considerado neste estudo não atendeu aos padrões especificados, necessitando de melhorias em todas as operações envolvidas no processo. A utilização das cartas de controle, do histograma e do SIG identificou os pontos que apresentaram problemas e que não se encontravam dentro das especificações agronômicas em todas as operações avaliadas. O uso de técnicas geoestatísticas aliadas à tecnologia SIG permitiu o adequado zoneamento dos indicadores analisados, identificando áreas com diferentes quantidades. / Considering the relevance of wheat crop in Brazil, and that the yield increase depends also on the correct execution of implementation and management of the crop, this work aimed to evaluate how stable the production processes are and to the specified patterns attending of a no-tillage wheat crop. The data were collected at Paiquerê farm, belonged to Lúcio Miranda Group, in of Piraí do Sul city, Paraná state. Six operations of the production process of the no-tillage wheat were considered: harvesting of the former crop, spraying before drilling, drilling, fertilizer spreading, spraying and wheat harvesting. To evaluate the studied production system, it were determined to each considered operation, performance indicators and specification limits to each indicator. Tools of descriptive statistics analysis, of quality control and GIS were used. It was concluded that the evaluated system did not attend the specified patterns, needing improvements in all operations involved in the process. The utilization of control charts, histogram and GIS identified where there were problems and that were not in the agronomic specification range in all the evaluated operations. The use of geostatistical techniques together GIS technology allowed the adequate zoning of the studied indicators, identifying areas with distinct quantities.

O presente trabalho teve por objetivo: a) avaliar os processos do balanço de água no solo com culturas de milho sob sistema plantio direto e, adubada com diferentes doses de nitrogênio, em sucessão a plantas de cobertura do solo, e b) verificar possíveis alterações de algumas propriedades físico-hídricas do solo neste tipo de prática de manejo. O experimento foi conduzido em uma área experimental da ESALQ-USP, município de Piracicaba-SP. Segundo a classificação internacional de Köppen, o clima da região é do tipo Cwa, denominado "tropical de altitude". O solo do local é do tipo Latossolo Vermelho Amarelo. O delineamento experimental foi o de blocos casualizados com 4 repetições. Os tratamentos constaram de uma testemunha e de três doses de nitrogênio (60, 120 e 180 kg ha-1) na forma de sulfato de amônio, sendo que 30 kg ha-1 de N foram aplicados na semeadura e o restante em cobertura. A área da parcela experimental foi de 36 m2 (5,0 x 7,2 m), observando-se a declividade do terreno. A aveia preta foi semeada manualmente em julho de 2004 e o tremoço branco em junho de 2005, o milho em dezembro de 2004 e novembro de 2005, após manejo das plantas de cobertura do solo. No que diz respeito ao balanço de água o solo foram medidos a precipitação pluvial (P), o deflúvio superficial (R), a drenagem interna (D) (ou ascensão capilar) na profundidade de 0,8 m e a variação da armazenagem (Δh) na camada de solo de 0,0-0,80 m; a evapotranspiração real (ET) foi estimada como a incógnita na equação do balanço. Ainda foi avaliada a eficiência do uso da água (EUA) pela cultura do milho, bem como suas características agronômicas e produção de matéria seca (MS) das plantas de cobertura do solo. As propriedades físico-hídricas do solo avaliadas para atender o segundo objetivo do trabalho foram: porosidade total, macro e microporosidade do solo e densidade do solo. Os resultados obtidos mostraram que: quanto aos parâmetros do balanço de água, de forma geral, verificou-se que as doses de N os alteraram, uma vez que nos tratamentos com aplicação de N, o solo se encontrou com uma Δh relativamente menor que o tratamento sem N, refletindo em menor valor de D nesses tratamentos, sendo traduzido em maior absorção de água pelas plantas, bem como maior EUA e maior rendimento de grãos. Quanto às propriedades físico-hídricas do solo, percebeu-se tendências de mudança, principalmente no que se refere à macro e microporosidade do solo, condicionadas pela alteração estrutural do solo. Entretanto, estas mudanças ocorrem paulatinamente, com o tempo e com a aplicação de N, sendo interessante um estudo em longo prazo no SPD, para se obter resultados mais significativos e conclusivos quanto a essa prática de manejo na região. / The objective of this work was: a) to evaluate the processes of the water balance in the soil with maize plants, under no tillage system (NTS) and different nitrogen levels, in succession to cover crops; b) to verify possible alterations of some soil physico-hydric properties due to the no tillage system practice. The experiment was carried out in Piracicaba, SP, Brazil on a Typic Hapludox, locally called Yellow Red Latosol. According to Köppen's classification, the region climate is of Cwa type, tropical highland. The experimental design was of randomized blocks with four replicates. The treatments consisted of one control and three nitrogen levels (60, 120 and 180 kg ha-1 of N) as ammonium sulphate, 30 kg ha-1 of N being applied in the sowing and the remain in covering. The area of experimental plot was 36 m2 (5.0 x 7.2 m), observing the land slope. Avena strigosa was sown manually in July 2004 and Luppinus albus in June 2005, the maize in November 2004 and 2005, after handling of the cover crops. In relation to the soil water balance, it was evaluated the precipitation (P), the runoff (R), the internal drainage (D) (or capillary rise) at the 0.80 m of depth, soil water storage variation (Δh) at the 0.0-0.80 m layer and the evapotranspiration (ET). The latter, was considered as unknown in the water balance equation. The maize WUE was also calculated, as well as yield components and dry matter cover crops. The soil physico-hydric properties evaluated were: total porosity, macroporosity, microporosity and dry bulk density. The results showed that: for the soil water balance, generally, the N levels changed the equation parameters. As a result, the treatments with N application had lower Δh than the treatment without N, implying in a lower D in these treatments and leading to a higherwater absortion by plants, as well as WUE and yield grain. The soil physico-hydric properties have showed trends of changing, mainly for macro and microporosity, due to the soil structural change. However, these alterations, occur slowly, with the time and the N application. Therefore, it is necessary to study the long-term NTS to have significant and conclusive results for this soil management in this region.