Orientador: Carlos Alexandre Costa Crusciol / Banca: Heitor Cantarella / Banca: Dirceu Maximino Fernandes / Resumo: No sistema plantio direto praticamente não há revolvimento do solo e o conseqüente acúmulo de resíduos vegetais e fertilizantes na superfície aceleram o processo de acidificação, contínuo e acentuado que ocorre naturalmente em solo de regiões úmidas, onde, geralmente, é observada baixa disponibilidade de nutrientes e elevados teores de H + Al. Assim, da mesma forma que no sistema de cultivo convencional, no sistema plantio direto também existe a necessidade de aplicação de insumos, especialmente, materiais corretivos de acidez. Dentro deste enfoque, o trabalho desenvolvido na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas - UNESP, localizada no município de Botucatu (SP), com o objetivo de avaliar a influência de diferentes sistemas de produção em plantio direto e da aplicação superficial de corretivos nas características físicas, na movimentação de bases, na correção da acidez do solo, bem como na nutrição e produtividade das culturas produtoras de grãos em região de inverno seco. O delineamento experimental foi em blocos casualizados em parcelas subdivididas, com 8 repetições. As parcelas serão constituídas por quatro sistemas de produção (I. Sistema "Safra consorciada com Forrageira"- soja + Braquiária / milho + Braquiária; II. Sistema "Safra - safrinha" - soja / aveia-branca / milho / feijão da Seca; III. Sistema "Safra - Pousio" - soja / Pousio / milho / Pousio; IV. Sistema "Safra - Adubo Verde/Planta de Cobertura" - soja / milheto / milho / Guandú) e as subparcelas foram constituídas por duas fontes de corretivos e uma testemunha (I - Correção com calcário dolomítico; II - Correção com silicato de cálcio e magnésio - Agrosilício®; III - Sem correção). Foram realizadas as seguintes avaliações: produção de massa de matéria seca e teores de macronutrientes... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In no tillage system the absence of soil mobilization consequently decreases plant residues accumulation and places fertilizers on surface, affecting the acidification process. Like in conventional system, in no tillage it is also necessary input application, especially materials for acidity correction. The experiment was carried out in an experimental area, in the city of Botucatu (SP, Brazil). The objective was to evaluate the influence of no-till crop systems and superficial application of products for acidity correction on soil physical properties, base movement, acidity correction, nutrition and yield of grain crops in a dry winter region. The experimental design was the completely randomized block with subdivided plots and eight replications. The main plots consisted of: "Season - Forage"- Soybean + Brachiaria / Maize + Brachiaria; "Season - Off season": Soybean / White oat / Maize / Field-grown bean; "Season - Fallow": Soybean / Fallow / Maize / Fallow; "Season - Green manure": Soybean / Millet / Maize / Pigeon pea. Subplots consisted of two correction sources (dolomitic limestone, calcium and magnesium silicate) and a control (no correction). The following evaluations were carried out: dry matter production and macronutrient level, silicon content and water-soluble cations; yield components and final yield for grain crops; routine soil testing for silicon (6, 12 and 18 months after acidity correction) and soil residual lime (18 months after acidity correction); and soil physical characteristics. Production costs were also calculated. Superficial application of products for acidity correction increased plant nutrition and yield. Among the systems, the "Season-Fallow" showed lower maize yield. Silicate application was more effective in correcting soil profile than liming. The "Season-Off season" system showed better economic response. / Mestre

Thesis (M. Sc. (Plant Protection)) -- University of Limpopo, 2021 / Worldwide, root-knot (Meloidogyne species) nematodes are considered to be the most important and damaging genus in crop husbandry. The existence of a wide host range, over 2000 plants, and several biological races, makes the management of this nematode genus difficult with nematode-resistant crop Hybrid Sorghum Sudan grass (Sorghum bicolor × Sorghum Sundanese) has been classified as being resistant to certain Meloidogyne species and races, with a wide range of uses in crop rotation intended to manage nematode population densities. However, due to the ability of nematodes to enter chemiobiosis when gradually exposed to chemicals, this hybrid might not be effective in managing nematode population densities for the subsequent highly susceptible sweet potato (Ipomoea batatas L.) cultivars. The objective of the study was to determine whether hybrid Sorghum-Sudan grass would suppress M. javanica (Trial 1), M. incognita race 2 (Trial 2) and M. incognita race 4 (Trial 3) population densities, allowing a nematode susceptible sweet potato cv. ′Beauregard′ as successor crop to be cultivated without suffering nematode damage. The hybrid Sorghum-Sudan grass study was conducted under greenhouse conditions, with seven inoculation levels, namely, 0; 5; 25; 125; 625; 3 125 and 15 625 eggs and second-stage juveniles (J2) of each nematode species or race, arranged in randomised complete block design, with six replications and validated in time. Plant growth, foliar nutrient elements and nematodes were collected at 56 days after inoculation and prepared for analysis using standard methods. The reproductive factor (RF) at all levels was zero, whereas nematode inoculation at all levels did not have any effect on plant growth of the hybrid Sorghum-Sudan grass. However, the nematode levels affected the accumulation of nutrient elements and the quality of forage. After cultivating the susceptible sweet potato cultivar in pots xxx previously with hybrid Sorghum-Sudan grass at increasing levels of M. javanica alone, that is in Trial 1, similar results were observed with respect to RF and lack of nematode damage to plant growth. Consequently, the hybrid was suitable for use in crop rotation with sweet potato for the purpose of managing nematode population densities of thermophilic Meloidogyne species and/or races. / National Research Foundation of South Africa (NRF) and the Agricultural Research Council (ARC)

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Thesis (MScAgric)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: Protein and oilseed production in the winter rainfall region of South Africa (primarily the Southern and Western Cape) is well below the potential for the area. One possible method of increasing production is to convince producers that the inclusion of protein and oilseed rotational crops will enhance the sustainability of wheat production systems. A project to investigate, quantify and elucidate the effect of canola (Brassica napus), lupins (Lupinus angustifolius) and medics (Medicago spp.) on subsequent wheat (Triticum aestivum) production as well as their influence on soil fertility in respect to nitrogen was initiated in 1999. The long- term rotational crop system experiment on Langgewens experimental farm near Malmesbury, provided the infrastructure for the project. During the 1999 and 2000 wheat-growing seasons, 50m2 plots were demarcated in wheat fields where wheat, lupins, canola or medics were produced in 1998 and 1999 respectively. Each plot was cleared of all vegetation and received no fertilizer N. In these fallow plots, soil samples were collected at three to four week intervals and the available nitrate-N and ammonium-N content of the topsoil (0-15cm depth) and the subsoil (15-30cm depth) were determined. Additional soil samples were also taken from the topsoil on 09/03/2000 after a summer fallow period. These samples were taken on plots that were subjected to a wheat crop in 1999, but were preceded by either wheat, canola, lupins or medics in 1998. The soil samples were then subjected to a 60-day incubation period at 15°C while being maintained at 75% of their water holding capacity. Mineral N was determined after 0, 3, 7, 15, 30, 45 and 60 days of incubation. Large variation in the nitrogen contents observed made it difficult to always obtain significant differences. The results of the soil investigations however indicate that the inclusion of lupins and medics in wheat cropping systems in the Swartland could help to limit the decline of mineral N in the soil profile, experienced within a growing season. This will therefore enable farmers to reduce fertilizer inputs without facing soil mineral N depletion. Plant samples were also collected from wheat plots during the 1999 growing season on three occasions (23/06/99 (growth stage 5), 5/08/99 (growth stage 15), 14/09/99 (growth stage 23)). Plots were selected to represent the same treatments as in the soil sampling procedure during the growing season of 1999 as described above. Plant and tiller numbers of a 0.25m2 sub sample from each plot were counted and leaf area was determined, whereafter the dry material was weighed. The percentage nitrogen content in the leaves and stems were subsequently determined using Near Infra-Red Spectroscopy. In terms of vegetative growth, little difference was observed. A significant increase in nitrogen content of wheat plants growing in plots where wheat and canala were grown in 1998 was observed in the second plant sampling (growth stage 15) and this was attributed to higher nitrogen topdressing. However, on the third sampling date on 14/9/1999 (growth stage 23), the difference was no longer evident. The most important conclusion to make from this study, is that farmers can probably save on fertilizer inputs when including lupins and medics in their wheat production systems, without risking poorer wheat growth. At growth stage 28, a 0.25m2 sub sample of wheat plants was removed at a randomly chosen point in each of the plots described above. Ears and grains were subsequently counted. The wheat remaining on the plots were then harvested at the end of October 1999 using a plot combine. Subsequently the yield, hectolitre mass, thousand grain mass and % crude protein was determined from samples of harvested grain from each plot. The % flour and % bran extraction were then determined whereafter the % flour protein was determined. Micro bread loafs were baked to estimate the loaf volume. Flour and dough properties were also tested using the Falling Number System, mixograph and alveograph. Wheat in cropping systems consisting of legume phases such as lupins and medics, required less nitrogen fertilizer application to achieve statistically the same yield, flour and dough properties. These crop rotations can therefore be considered as more ecologically sustainable and economically viable for the Swartland. This study was aimed at determining the effect of different crop rotations on soil fertility, and because clear soil fertility trends take time to form, this study was probably too short to obtain fully significant differences. / AFRIKAANSE OPSOMMING: Proteïen- en oliesaad produksie in die winter reënval streek van Suid Afrika (hoofsaaklik die Suid- en Weskaap) is ver benede die potensiaal vir die streek. Een moontlike manier om die produksie hiervan te verhoog is om produsente in hierdie streek te oortuig dat die insluiting van proteten en oliesaad gewasse die volhoubaarheid van koring verbouingstelsels sal verhoog. Na aanleiding hiervan, is In projek in 1999 van stapel gestuur om die effek van canola (Brassica napus), lupiene (Lupinus angustifolius) en medies (Medicago spp.) op daaropvolgende koring (Triticum aestivum) produksie, asook die invloed daarvan op grondvrugbaarheid in terme van stikstofinhoud, te ondersoek. Die langtermyn wisselbouproef op Langgewens proefplaas naby Malmesbury, het as infrastruktuur vir die ondersoek gedien. Gedurende die 1999 en 2000 koring groeiseisoene is 50m2 plotte in koringkampe gekies waarop koring, canola, lupiene en medies geproduseer is in onderskeidelik 1998 en 1999. Hierdie plotte is skoon gehou van plantegroei en het ook geen stikstof in kunsmisvorm gekry nie. Met drie tot vier week intervalle is grondmonsters op hierdie plotte versamel in die bogrond (0-15cm diep) en ondergrond (15-30cm diep), waarna die beskikbare nitraat-N en ammonium-N konsentrasie bepaal is. Adissionele grondmonsters van die bogrond is ook geneem op 9/03/2000 na In somer braak periode. Hierdie monsters was geneem op persele wat blootgestel was aan In koringproduksie in 1999, maar voorafgegaan is deur koring, canola, lupiene en medies in 1998. Hierdie monsters is dan vir 60 dae geïnkubeer teen 15°C en 75% van die grond se water houvermoeë. Minerale N inhoud bepalings is gedoen na 0, 3, 7, 15, 30, 45 en 60 dae van inkubasie. Groot variasie in die minerale stikstof inhoud, het die verkryging van herkenbare tendense en konstante statistiese verskille belemmer. Die resultate wat verkry is dui egter dat die insluiting van lupiene en medies in koring produksie stelsels in die Swartland, hoër minerale N vlakke in die grond handhaaf en dit kan boere gevolglik in staat stelom kunsmis insette te besnoei sonder dat grondvrugbaarheid verswak. Op 23/06/99 (groeistadium 5), 5/08/99 (groeistadium 15) en 14/09/99 (groeistadium 23) is plantmonsters versamel van koringpersele. Hierdie persele is gekies om die behandelings van die grondmonsterontledings soos hierbo beskryf, te verteenwoordig. Plante en halms van 'n 0.25m2 area uit die persele is getel en die blaaroppervlaktes is bepaal, waarna die droëmateriaal massa van die area bepaal is. Die persentasie stikstofinhoud van die blare en stingels was daarna bepaal. In terme van vegetatiewe groei was daar nie groot verskille te bespeur nie. Betekenisvolle hoër stikstof inhoud van koringblare in plotte waar daar in die vorige jaar canola en koring verbou was, is in die tweede planttrekking (groeistadium 15) gevind en dit is toegeskryf aan die hoër stikstof kopbemesting wat daardie behandelings ontvang het. Teen die derde monsterneming op 14/09l99 (groeistadium 23), was hierdie verskille nie meer in die ontledingsdata te sien nie. Die afleiding wat van hierdie studie gemaak is, is dat boere moontlik stikstofbemesting kan verminder as hulle lupiene en medies in hulle koring produksiestelsels inbring, sonder om die risiko van swakker groei te verhoog. Op 20/10/99 (groeistadium 28) is 0.25m2 plante van elke koringperseel verwyder waarna die are en die korrels getel is. Die koring wat nog op die persele was is teen die einde van Oktober 1999 met 'n perseelstropertjie geoes. Opbrengs, hektoliter massa, duidendkorrel massa en % ru-proteïene is daarna bepaal. Volgende is die % meel en % semel ekstraksie bepaal waarna die % meelproteïene bepaal is. Mikro broodjies is ook gebak om die broodvolume te bepaal. Meel en deeg eienskappe is ook getoets met die Falling Number System, mixogram en alveogram. Koring in produksiestelsels met peulplant fases (lupien en medies in hierdie geval), het minder N toediening nodig gehad om statisties dieselfde opbrengs, meel- en deeg eienskappe te verkry. Lupien en medic gebaseerde wisselbou praktyke in die Swartland kan gevolglik as meer ekologies volhoubaar en ekonomies haalbaar bestempelword. Hierdie studie het gepoog om die invloed van wisselbou op grondvrugbaarheid te ondersoek. Sodanige veranderings neem egter tyd en daarom is dit waarskynlik nog te gou om werklike grondvrugbaarheids verskille waar te neem.

Thesis (MScAgric)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The aim of this study was to investigate the influence of crop rotation and soil tillage on the soil water balance and water use efficiency of wheat, canola, lupin and medics in the Swartland sub region of the Western Cape. This trail was conducted as a component study within a long-term crop rotation/tillage trial during 2012 and 2013 at the Langgewens Research Farm (33016’42.33” S; 18042’11.62” E; 191m) of the Western Cape Department of Agriculture near Moorreesburg. The experiment was laid out as a randomized complete block, with a split-plot treatment design and replicated four times. Three crop rotation systems, continues wheat (WWWW), wheat/medic/wheat/medic (WMcWMc) and wheat/canola/wheat/lupin (WCWL) were allocated to main plots. . Each main plot was subdivided into four sub-plots allocated to four tillage treatments namely: zero-till (soil left undisturbed and planted with zero-till planter), no-till (soil left undisturbed until planting and then planted with a tined no-till planter), minimum-till (soil scarified March/April and then planted with a no-till planter) and conventional tillage (soil scarified late March/early April, then ploughed and planted with a no-till planter). All straw, chaff and stubble remained on the soil surface and no-grazing was allowed on all tillage treatments. Three replicates were included in this current study. Only the no-till (NT) and conventional till (CT) were included in this current study as main tillage treatments. The volumetric soil water content was monitored at weekly intervals during the active growing season (May-October) and once a month during the fallow period (November-April) using a Diviner 2000 soil moisture meter. The Diviner 2000 was used to record the soil water content at every 100 mm depth increment up to the maximum depth of the profile. At the end of the growing season the total biomass, grain yield and quality parameters were determined. The soil water balance data calculated from the 2012 season were found to be inconclusive due to too shallow installation of soil water monitoring tubes and big variations in the depth complicating any attempt in comparing data from treatments and cropping systems. Soil water monitoring tubes was installed to a depth of 900 mm in the 2013 season. Complications during planting in the 2013 season resulted in very poor emergence in the CT sites. Weed counts revealed that only 38 % of CT sites were covered by crop, 31 % with weeds and 31 % were completely bare. The NT sites had 40 % crop coverage, 50.5 % grass weed coverage and only 9.5% bare surface. As a consequences crop rotation had no effect on the soil water balance, while the tillage treatments showed a response. The effect that tillage had on the soil water balance was clearly shown in the 2013 season, in which 79 mm more rainfall occurred than the long-term average. NT retained more soil water in the profile in the drier first half of the season when only 30 % of the total rainfall in the 2013 season occurred. There was no real difference in the soil water retention in the second half of the season where 70 % of the total rainfall in the 2013 season occurred. Crop rotation did have a positive effect on grain yield. Wheat monoculture was out performed by legume based cropping systems. This trend was also observed in the biomass production. No significant difference between tillage treatments were recorded when comparing grain yield data. However wheat mono culture was again out-performed by the McWMcW, CWLW and LWCW systems producing on average significantly higher biomass. The data from both seasons suggest that in seasons where more rainfall than the long term average occurs, there is no difference in the RUE between cropping systems or tillage practices.. This study highlighted the major effect that the prevailing weather conditions have and that the expected advantages associated with NT most likely only come into play in dry conditions when plant water availability is limited. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die invloed van grondbewerking en gewasproduksiestelsels op die grondwaterbalans en doeltreffendheid van watergebruik te ondersoek in die koringproduserende gebied van Malmesbury. Hierdie eksperiment is uitgevoer as 'n komponentstudie binne 'n langtermyn grondbewerking/gewasrotasieproef gedurende 2012 en 2013 op die Langgewens Navorsingsplaas (33016'42 .33 'S; 18042'11 0,62' E, 191m) van die Wes-Kaapse Departement van Landbou naby Moorreesburg. Die eksperiment is uitgelê as 'n volledige ewekansige blok, met 'n gesplete perseel behandelingsontwerp met vier herhalings. Drie gewasproduksiestelsels naamlik, koring monokultuur (WWWW), koring/medic/koring/medic (WMcWMc) en koring/canola/ koring/lupiene (WKWL) is elk toegeken aan persele en vier keer herhaal. Elke hoofperseel is onderverdeel in vier subpersele en bewerkingsbehandelings is soos volg toegeken: Konvensionele bewerking (CT) - grond gebreek in Maart/April, en daarna geploeg en geplant met geen bewerkingsplanter. Minimum bewerking (MT) - grond gebreek in Maart/April en daarna geplant met 'n geen bewerkingsplanter. Geen bewerking (NT) - grond is heeltemal onversteur gelaat tot planttyd en daarna geplant met 'n geen bewerkingsplanter. Zero bewerking (ZT) - grond tot planttyd met rus gelaat en dan geplant met 'n sterwielplanter. Alle strooi, kaf en stoppels het op die grondoppervlak gebly en geen beweiding is toegelaat nie. Slegs drie herhalings is ingesluit in die huidige studie en slegs die geen bewerking (NT) en konvensionele bewerking (CT) is in die huidige studie as hoof bewerkingbehandelings ingesluit. Die volumetriese grondwaterinhoud is weekliks gemonitor tydens die aktiewe groeiseisoen (Mei - Oktober) en een keer 'n maand gedurende die braaktydperk (November - April) met behulp van 'n Diviner 2000 grondvogmeter. Die Diviner 2000 is gebruik om die grondwaterinhoud by elke 100 mm diepte tot die maksimum diepte van die profiel te bepaal. Aan die einde van die seisoen is die totale biomassa, graanopbrengs en kwaliteitparameters bepaal. Die data vir grondwaterbalans van die 2012-seisoen is buite rekening gelaat weens te vlak installering van moniteringsbuise en groot variasie in die dieptelesings wat enige poging om vergelykende data van rotasie en behandelings te verkry, bemoeilik het. Moniteringsbuise vir grondwater is geïnstalleer tot op 'n diepte van 900 mm in die 2013-seisoen. Komplikasies tydens die plantaksie in die 2013-seisoen het gelei tot 'n baie swak opkoms in die CT-persele. Slegs 38 % van die CT-persele was bedek deur die gewas en 31 % met onkruid, terwyl 31 % van die oppervlak onder CT-behandeling heeltemal kaal was. Die NT-persele het 40 % gewasbedekking, 50.5 % grasbedekking en slegs 9.5 % kaal oppervlak gehad. Dit het die poging, om die effek van wisselboustelsels op die grondwaterbalans, in die wiele gery. Alhoewel wisselbou skynbaar geen effek op die grondwaterbalans gehad het nie, het die tipe bewerking egter wel ‘n effek gehad. Die effek van grondbewerking op die grondwaterbalans het duidelik na vore gekom in die 2013-seisoen. In hierdie seisoen het 79 mm meer reën geval as die langtermyngemiddelde. Geen bewerking het meer grondwater in die droër eerste helfte van die seisoen in die profiel behou, toe slegs 30% van die totale reënval in die 2013 geval het. Daar was geen beduidende verskil in die grondwaterretensie in die tweede helfte van die seisoen toe 70% van die totale reënval in die 2013 geval het nie. Wisselbou het egter 'n positiewe uitwerking op die graanopbrengs gehad. Koring monokultuur is in opbrengsyfers geklop deur stelsels met peulplante as komponent. Hierdie tendens is ook waargeneem in die biomassaproduksie. Bewerkingsbehandelings het geen beduidende verskil in graanopbrengste tot gevolg gehad nie, hoewel die biomassaproduksie van koring monokultuur weer geklop is deur die McWMcW-, CWLW- en LWCW-stelsels. Die data van beide seisoene dui daarop dat in seisoene waar meer reën as die langtermyn gemiddelde voorkom, daar geen verskil in die RUE tussen verbouingstelsels of bewerkingspraktykes was nie. Hierdie studie beklemtoon die groot invloed wat die heersende klimaat speel en dat die verwagte voordele wat verband hou met NT waarskynlik slegs ‘n rol speel in droër jare.

Thesis (PhD(Agric) (Agronomy))--University of Stellenbosch, 2003. / 108 leaves printed on single pages, preliminary pages i-vi and numbered pages 1-1 to 1-5 to 9-1 to 9-3. Includes bibliography, list of abbreviations and 22 figures in color. Digitized at 300 dpi grayscale and 300 dpi 24-bit Color to pdf format (OCR), using an HP Scanjet 8250 Scanner. / ENGLISH ABSTRACT: A long term experiment was conducted at the Langgewens Experimental Farm, near Malmesbury in the Western Cape province of the Republic of South Africa. The effect of soil tillage, crop rotation and nitrogen fertiliser rates on mineral-N levels in the soil, nitrogen levels in plants, wheat growth and yield components, grain yield as well as quality parameters of spring wheat were determined. Although the tillage treatments tested were initiated in 1976, present crop rotations and nitrogen application rates were only applied since 1990. Most of the data that are discussed however was recorded during the 1997 to 2001 period. The trial was designed as a randomised complete block with a split-plot arrangement and four replicates. Main plots were tillage methods namely conventional tillage (CT), tine tillage (TT), minimum tillage (MT) and no tillage (NT). Crop rotations used were continuous wheat (WW) and wheatl lupin/wheat/canola (WLWC). Both soil and crop data were recorded. The results of this study showed the differences in total mineral-N content of the soil. N-contents of wheat, wheat growth and yield components as well as wheat quality parameters were found between tillage treatments, crop rotations used as well as N- fertiliser rates applied. Response however, varied largely between years due to annual variation in especially total precipitation and distribution of rainfall. The inclusion of a legume crop (lupin) and canola in the rotation with wheat was found to have only a small effect probably due to the fact that lupins were grown once in a four year cycle only. Application of different nitrogen rates did increase the mineral-N in the soil, but the effect did not last very long in most years due to either N-leaching or plant uptake. To ensure sufficient mineral-N levels, late application of N-fertiliser will therefore be needed. Minimum tillage or reduced tillage performs better than conventional tillage in low rainfall years. In general these tillage systems should be combined with crop rotation to ensure that yields are comparable to that obtained with conventional tillage. / AFRIKAANSE OPSOMMING: Die ontwikkeling, graanopbrengs en bakkwaliteit van koring (Tritium aestivum L.) in reaksie teenoor gewasratasie, metode van grondbewerking en N-bemestingspeil is in 'n lang tennyn sllldie op Langgewens Proefplaas, naby Malmesbury in die Weskaap provinsie van die Republiek van Suid-Afrika, bepaal. Hoewel die verskillende grand bewcrkingsmetodes sedert 1976, en gewasrotasies en slikstofpeile sedert 1990 toegepas is, is daar in hierdie studie gekonsentreer op data wal gcdurcnde die periode 1997-2001 ingesamel is. Die eksperiment is as 'n randomiseerde blok ontwerp met vier bewerkingsmetodes nl. konvcnsionele bewerking (CT), tand bewerking (TT). minimum bewerking (MT) en geen bewerking (NT), twee gewasratasies nl. monokuhuur koring (WW) en koring/lupienelkoringiCanola (WLWC) en drie N-peie (60 kg N ha- ', 100 kg N ha- 1 , 140 kg N ha- I uitgevoer. Aile stikstof is in die vorm van kalksteen-ammoniumnitraat toegedien. Die reaksie van beide grondfaktore soos die minerale N inhoud en gewaskomponente 5005 biomassa produksie, opbrengs en kwaliteit teenoor bogenoemde faktore het '0 goeie korrelasie getoon met die heersende klimaatstoestande. Lae reenval jare (gebiede) sal volgens hierdie stlldie die grootste voordeel verkry met minder intensiewe grand bewerkingstelsels. terwyl 'n frekwensie van meer as een peulgewas per siklus van 4 jaar nodig sal wees om grondvrllgbaarhcidsvlakke betekenisvol te verhoog. Stelsels van rninder intensiewe grondbewerking is ook tot 'n grater mate deur gewaswisseling bevoordeel as konvensionele melOdes van grondbewerking. Hocwel minerale-N vlakke in grond deur verskillende N-peile be'lnvloed is, was die efTektiwiteit van toedienings laag en het verdeelde tocdienings groat voordele ingehou.

O aparecimento de plantas daninhas resistentes ao glifosato tem colocado em risco a utilização de culturas que têm a tecnologia RR. A fim de verificar o desenvolvimento de plantas daninhas resistentes ao glifosato, um experimento de campo foi realizado na estação experimental AgroMarochi localizada em Ponta Grossa, estado do Paraná, de 2009 a 2012, com o objetivo de avaliar diferentes sistemas de produção, incluindo a rotação de culturas, culturas de cobertura e aplicação de herbicidas com diferentes mecanismos de ação. O delineamento experimental foi em blocos casualizados, com dezesseis tratamentos e três repetições. Em função dos resultados, conclui-se que: (i) a rotação de culturas e de ingredientes ativos de herbicidas proporcionam melhor desempenho agronômico e econômico (menor risco de aparecimento de plantas daninhas resistentes e maiores produtividades), (ii) os sistemas 3 (soja/ trigo/ soja/ aveia /milho /trigo) e 4 (soja/ azevém/ soja/ azevém/ milho/ aveia), com 33% da área com rotação de cultura com milho na safra de verão, são os mais rentáveis independentemente dos cenários 1 e 2 do VPL (Valor Presente Líquido), (iii) os tratamentos com manejo padrão de herbicidas contribuíram no aumento da população das plantas daninhas (leiteiro, guanxuma, erva-quente, azevém - resistente e não resistente ao Glifosato e buva - resistente e não resistente ao Glifosato), e apresentaram menor rentabilidade, (iv) os manejos com rotação de herbicidas propiciaram a redução da população de plantas daninhas, (v) a cultura de aveia contribui para a redução de plantas daninhas, como azevém e buva resistentes e não resistentes ao glifosato, principalmente, (vi) área em pousio contribui para o aumento da população de plantas daninhas, como azevém e buva resistentes e não resistentes ao glifosato, principalmente, e (vii) a aplicação de Glifosato associado a Atrazina em pós emergência (tratamentos 6, 7, 11 e 14: sistemas de rotação de culturas 2, 3, 4 e 5, respectivamente) não diferiu da aplicação de Tembotrione associado a Atrazina (tratamentos 8, 9, 12 e 15: sistemas de rotação de culturas 2, 3, 4 e 5, respectivamente) na cultura de Milho RR sobre a população de azevém e buva resistente e não resistente ao glifosato. / The emergence of weeds resistant to Glyphosate has been putting at risk the use of crops that have the RR technology. In order to check the development of weeds resistant to Glyphosate, a field experiment was carried out at AgroMarochi experimental station located in \'Ponta Grossa\', State of Paraná, from 2009 to 2012, with the purpose of evaluating different agricultural production systems, including crop rotation, cover crops and application of herbicides with different mechanisms of action. The experimental design was a randomized blocks, with sixteen treatments and three replications. In light of the results, it is concluded that: (i) rotation of crops and of active ingredients of herbicide provides better agronomic and economic performance (lower risk of emergence of resistant weeds and higher yields), (ii) the systems 3 (soybean/ wheat/ soybean/ oat/ maize/ wheat) and 4 (Soybean/ ryegrass/ soybean/ ryegrass/ maize/ oat), with 33% of the area with crop rotation with maize in the summer season, are the most profitable regardless of the scenarios 1 and 2 of the NPV (Net Present Value), (iii) treatment with standard management of herbicides contributed in increasing the population of weeds (Euphorbia heterophylla, Sida sp., Spermacoce latifolia, Lolium multiflorum - resistant and not resistant to Glyphosate, Conyza spp. - resistant and not resistant to Glyphosate), and had lower profitability, (iv) the management with rotation of herbicides favored reducing weed populations, (v) the oat crop helps in reducing weeds, as ryegrass (Lolium multiflorum) and Conyza spp. resistant and not resistant to Glyphosate, mainly, (vi) fallow area contributes to the increasing population of weeds, as ryegrass and Conyza spp. resistant and not resistant to Glyphosate, mainly, and (vii) the application of Glyphosate associate to atrazine in post emergency (treatments 6, 7, 11 and 14: crop rotation systems 2, 3, 4 and 5, respectively) not differ from application of Tembotrione associate to Atrazine (treatments 8, 9, 12 and 15: crop rotation systems 2, 3, 4 and 5, respectively) in RR maize crop over weed population of ryegrass and Conyza spp. resistant and not resistant to Glyphosate.

O objetivo do experimento foi avaliar o desempenho e a qualidade da carcaça de novilhos superprecoces submetidos a alturas de manejo de pastos de aveia preta e azevém anual (10, 20, 30 e 40 cm) e uma testemunha sem pastejo, bem como avaliar os efeitos dessas alturas de manejo sobre o estabelecimento e o rendimento da cultura de soja subseqüente. O experimento foi realizado na Fazenda do Espinilho, município de Tupanciretã, entre julho de 2004 e maio de 2005. Animais jovens com idade média de dez meses e peso inicial de 190 kg foram distribuídos num delineamento experimental de blocos ao acaso, com três repetições. As ofertas diárias de forragem para os tratamentos 10, 20, 30 e 40 cm foram, respectivamente, 8,8, 14,7, 29,0 e 48,9 kg de matéria seca/100 kg de peso vivo (PV). O ganho de peso por hectare foi superior nos tratamentos com menor altura de manejo, em decorrência da maior carga animal empregada, sendo 529,7, 489,5, 320,9 e 201,6 kg de PV/ha, para os respectivos tratamentos. O ganho médio diário e peso ao abate apresentaram resposta quadrática (P<0,05) conforme o incremento na altura do pasto. A deposição de gordura apresentou média de 3,8 mm e o rendimento médio de carcaça fria foi de 53,3% (P<0,05). As alturas reais do pasto ficaram próximas daquelas pretendidas, havendo um aumento linear da massa de forragem com o aumento das alturas de manejo do pasto. A taxa de acúmulo não foi afetada pelos tratamentos. A taxa de lotação apresentou resposta linear decrescente com o aumento da altura do pasto. A massa de forragem remanescente aumentou na medida em que houve incremento na altura de manejo do pasto. Foi observada diferença entre os tratamentos para palhada residual e estande inicial de plantas de soja, porém, essas diferenças não afetaram o rendimento de grãos da cultura. Concluiu-se que novilhos superprecoces atingem peso de abate e grau de acabamento adequados quando terminados em pastagem de inverno e suplementados no terço final do ciclo de pastejo. O melhor ganho médio diário foi obtido em altura entre 25 a 30 cm e a maior produção por área em 10 cm de altura. A utilização de pastos durante o inverno não prejudica o rendimento de grãos na cultura de soja subseqüente, possibilitando aumento da renda do produtor pela oportunidade de gerar receitas durante a entressafra da soja. / This trial aimed to evaluate the performance and carcass quality of “superprecoce” steers grazing oat and annual ryegrass pastures managed at 10, 20, 30 and 40 cm with a no grazing reference, as well as sward height management effects on soybean establishment and grain yield. The experiment was carried at Fazenda do Espinilho, Tupanciretã municipality, from July 2004 until May 2005. Young animals with 10 months on average and initial live weight of 190 kg were distributed in a randomized block design with three replicates. The daily herbage allowances were 8.8, 14.7, 29.0 and 48.9 kg of dry matter/100kg of live weight, respectively treatments. The live weight gain per hectare was superior in treatments with lower management heights, due to the greater stocking rate employed, being 529.7, 489.5, 320.9 and 201.6 kg of LW, respectively for the treatments 10, 20, 30 and 40cm height. The average daily gain and slaughter weight increased with pasture height being fitted by a quadratic model (P<0.05). The fat deposition and the medium dressing of cold carcass averaged 3.8mm and 53.3%, respectively (P<0.05). The actual sward heights were very similar to those previously intended. There was a linear increase in herbage mass with the increase of sward height. The pasture accumulation rate was not influenced by treatments. The stocking rate showed a decreased linear response with increasing sward height. Post grazing herbage mass increased with increasing sward height. Treatments had effect on initial soybean stand, but not in soybean yield. It was concluded that “superprecoce” steers can reache slaughter weight and adequately finishing degree when finished in winter cultivated pasture supplemented in final third of the grazing cycle. Better individual animal performance is obtained when pasture height ranges from 25 to 30 cm and animal production per hectare when the pasture was managed at 10 cm height. Results suggest grazing animals do not damage succeeding soybean crop, allowing farmers profitability enhancement during soybean intercropping.