Made available in DSpace on 2015-08-20T17:09:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-02-24. Added 1 bitstream(s) on 2015-08-20T17:26:26Z : No. of bitstreams: 1 000843763.pdf: 3771507 bytes, checksum: 95075b8d207831c0a64fbf7c2f3c81e0 (MD5) / No Brasil e no mundo, a cultura do milho é uma das mais importantes, por ser a base da alimentação animal e utilizado também na alimentação humana. Técnicas sustentáveis de manejo na cultura do milho são necessárias, visando aumento de produtividade, minimizando custos e impactos ambientais. O objetivo deste trabalho foi avaliar diferentes coberturas vegetais (milheto, crotalária, guandu, milheto + crotalária, milheto + guandu e pousio), doses de N (0, 40, 80 e 120 kg ha -1 ) com e sem a inoculação de sementes com Azospirillum brasilense na cultura do milho, cultivado em sistema plantio direto no crescimento e produtividade na região do Cerrado. Foi utilizado delineamento experimental em blocos casualizados em esquema fatorial 6x4x2, constituindo 48 tratamentos, com 4 repetições. O estudo foi realizado na Fazenda Experimental pertencente à Faculdade de Engenharia - UNESP - Campus de Ilha Solteira, localizada no município de Selvíria - MS. O solo do local é do tipo LATOSSOLO VERMELHO Distrófico típico argiloso. A precipitação média anual é de 1.330 mm, a temperatura média anual é de 25 oC e a umidade relativa do ar entre 70 e 80%. Durante a condução do experimento, foram realizadas as seguintes avaliações: massa seca, teores e quantidades acumuladas de N, P e K nas plantas de cobertura; no milho: população inicial e final de plantas, produção de massa seca da parte aérea das plantas, teor de N foliar, índice de clorofila foliar, teores e valores acumulados de N, P e K na planta, altura de plantas e de inserção de espiga, diâmetro de colmo, comprimento de espiga, diâmetro de espiga, massa de mil grãos e produtividade de grãos. As coberturas vegetais, exceto o guandu no primeiro ano e pousio no segundo, produziram quantidade adequada de resíduo para manter o sistema plantio direto na região de Cerrado de baixa altitude. O consórcio milheto + crotalária possibilita quantidades acumuladas de N e K.. / In Brazil and in the world, maize crop is one of the most important because it is the basis of animal feed and also used in human feed. Sustainable techniques of management in maize crop are needed, aiming at increasing yield, reducing costs and environmental impacts. The objective of this study was to evaluate different cover crops (millet, sunn hemp, pigeonpea, millet + sunn hemp, millet + pigeonpea and fallow), N rates (0, 40, 80 and 120 kg ha -1 ) with and without inoculation of seeds with Azospirillum brasilense in maize crop, cultivated in no- tillage system on growth and yield in the Cerrado region. The experimental design was complete randomized blocks in a factorial scheme 6x4x2, constituting 48 treatments, with 4 replications. The study was conducted at the Experimental Farm belonging to the Faculty of Engineering - UNESP (Ilha Solteira), located in Selviria - MS. The soil of the place is a Typical Dystrophic Red Latosol clayey texture. The average annual rainfall is 1.330 mm, the average annual temperature is 25°C and the relative humidity between 70 and 80%. During the experiment, the following evaluations were performed: dry matter, content and accumulated values of N, P and K in cover crops; in maize: initial and final population of plants, production of dry matter of the shoots, leaf nitrogen content, leaf chlorophyll index, content and accumulated values of N, P and K in the whole plant, plant height and of ear insertion, stem diameter, ear length, ear diameter, thousand grain weight and grain yield. The cover crops except the pigeonpea in 2012/13 and fallow in 2013/14 produced adequate amount of residue to keep the no-tillage system in the Cerrado region. The consortium of millet + sunn hemp provided the greater accumulated amount of N and K for both years of cultivation. The great yield of maize grains under pigeonpea residue was due to increase in ear diameter and thousand-grain weight. Thus, the great maize yield ...

Orientador: Orivaldo Arf / Banca: Salatier Buzetti / Banca: Domingos Fornasieri Filho / Resumo: No Brasil e no mundo, a cultura do milho é uma das mais importantes, por ser a base da alimentação animal e utilizado também na alimentação humana. Técnicas sustentáveis de manejo na cultura do milho são necessárias, visando aumento de produtividade, minimizando custos e impactos ambientais. O objetivo deste trabalho foi avaliar diferentes coberturas vegetais (milheto, crotalária, guandu, milheto + crotalária, milheto + guandu e pousio), doses de N (0, 40, 80 e 120 kg ha -1 ) com e sem a inoculação de sementes com Azospirillum brasilense na cultura do milho, cultivado em sistema plantio direto no crescimento e produtividade na região do Cerrado. Foi utilizado delineamento experimental em blocos casualizados em esquema fatorial 6x4x2, constituindo 48 tratamentos, com 4 repetições. O estudo foi realizado na Fazenda Experimental pertencente à Faculdade de Engenharia - UNESP - Campus de Ilha Solteira, localizada no município de Selvíria - MS. O solo do local é do tipo LATOSSOLO VERMELHO Distrófico típico argiloso. A precipitação média anual é de 1.330 mm, a temperatura média anual é de 25 oC e a umidade relativa do ar entre 70 e 80%. Durante a condução do experimento, foram realizadas as seguintes avaliações: massa seca, teores e quantidades acumuladas de N, P e K nas plantas de cobertura; no milho: população inicial e final de plantas, produção de massa seca da parte aérea das plantas, teor de N foliar, índice de clorofila foliar, teores e valores acumulados de N, P e K na planta, altura de plantas e de inserção de espiga, diâmetro de colmo, comprimento de espiga, diâmetro de espiga, massa de mil grãos e produtividade de grãos. As coberturas vegetais, exceto o guandu no primeiro ano e pousio no segundo, produziram quantidade adequada de resíduo para manter o sistema plantio direto na região de Cerrado de baixa altitude. O consórcio milheto + crotalária possibilita quantidades acumuladas de N e K.. / Abstract: In Brazil and in the world, maize crop is one of the most important because it is the basis of animal feed and also used in human feed. Sustainable techniques of management in maize crop are needed, aiming at increasing yield, reducing costs and environmental impacts. The objective of this study was to evaluate different cover crops (millet, sunn hemp, pigeonpea, millet + sunn hemp, millet + pigeonpea and fallow), N rates (0, 40, 80 and 120 kg ha -1 ) with and without inoculation of seeds with Azospirillum brasilense in maize crop, cultivated in no- tillage system on growth and yield in the Cerrado region. The experimental design was complete randomized blocks in a factorial scheme 6x4x2, constituting 48 treatments, with 4 replications. The study was conducted at the Experimental Farm belonging to the Faculty of Engineering - UNESP (Ilha Solteira), located in Selviria - MS. The soil of the place is a Typical Dystrophic Red Latosol clayey texture. The average annual rainfall is 1.330 mm, the average annual temperature is 25°C and the relative humidity between 70 and 80%. During the experiment, the following evaluations were performed: dry matter, content and accumulated values of N, P and K in cover crops; in maize: initial and final population of plants, production of dry matter of the shoots, leaf nitrogen content, leaf chlorophyll index, content and accumulated values of N, P and K in the whole plant, plant height and of ear insertion, stem diameter, ear length, ear diameter, thousand grain weight and grain yield. The cover crops except the pigeonpea in 2012/13 and fallow in 2013/14 produced adequate amount of residue to keep the no-tillage system in the Cerrado region. The consortium of millet + sunn hemp provided the greater accumulated amount of N and K for both years of cultivation. The great yield of maize grains under pigeonpea residue was due to increase in ear diameter and thousand-grain weight. Thus, the great maize yield ... / Mestre

Cover crops not only improve soil conditions, but can also suppress weed growth. In a field experiment the influence of two cover crops, Secale cereale (stooling rye), and Lolium multiflorum (annual ryegrass), on the growth of Zea mays (maize) and C. esculentus (yellow nutsedge) was compared to the latter crop and weed’s growth at three control treatments which involved weed residues left on the soil surface, application of herbicides and weed control by hoeing. Maize emergence and growth were delayed in the presence of residues of both cover crop species, especially in annual ryegrass residues. C. esculentus growth was significantly inhibited in the area between the maize planting rows by the cover crops for the first 14 days after maize emergence, but this growth suppressing effect diminished after 28 days. In a controlled environment study, the influence of the same cover crops, together with Avena sativa (oats) and three cultivars of annual ryegrass were evaluated. Maize and C. esculentus growth were suppressed, especially by the root residues of the cover crops with the annual ryegrass cultivar ‘Midmar’ being the most suppressive. Chemical analysis of the leachate of root residues indicated the presence of phenolic acids and benzoxazolin-2(3 H)-one (BOA). It is suggested that weed growth could be reduced by the allelochemicals leached from cover crop residues but in order to achieve prolonged, effective weed control the combination of mulch retained on the soil surface and the application of herbicides will required. In an integrated weed management approach a possible reduction in the type and number of herbicide applications required for effective weed control, could be implemented. / Thesis (PhD)--University of Pretoria, 2012. / Plant Production and Soil Science / unrestricted

Limited photosynthetically active radiation (PAR) can reduce interseeded cover crop growth in corn (Zea mays L.). Two experiments in North Dakota evaluated the effect that hybrid relative maturity (RM), row width, and cover crop planting date have on cereal rye (Secale cereale L.) and winter camelina [Camelina sativa (L.) Crantz.] establishment when interseeded into 80 and 89 RM hybrids at V7 and R4 growth stages in 56- and 76 cm corn row widths. Cover crop biomass was typically less than 100 kg ha-1. In the following spring larger amounts of PAR beneath the 80 RM hybrid increased cover crop biomass by 20.8 kg ha-1. Cover crop biomass tended to be greater in the 76 cm row width but was not significantly different from the 56 cm width. Cover crops decreased residual soil nitrate by 6.0 kg ha-1 in the fall and by 15.6 kg ha-1 in the spring.

The occurrence of herbicide resistance weeds across the southern United States has been increasing. Research is needed to develop alternative control measures, while supporting sound agronomic practices. Greenhouse and field studies were conducted to evaluate cereal cover cropping techniques along with novel herbicides to determine their value for Mississippi growers. Field studies were performed to determine which combination of cereal cover crops (cereal rye, wheat and oats) and residual herbicides (S-metolachlor + metribuzin, S-metolachlor + fomesafen, pendimethalin, flumioxazin, sulfentrazone + metribuzin and pyroxasulfone + flumioxazin) would maximize soybean yield in the presence of weeds. Cereal cover crop termination methods were evaluated and a partial budget was generated to examine the total costs of growing soybeans utilizing cereal cover crops and residual herbicides. Residual herbicide applications averaged across all cereal cover crops controlled Amaranthus spp. greater than 89% by 28 DAT. Control by the cover crops alone was 67% for of Amaranthus spp. In all cereal species tested, cutting the cover crops 10 cm above the soil and leaving the residue reduced weed numbers compared to other termination methods. However, high production and implementation costs may prevent widespread adoption of cereal cover crops and residual herbicides in Mississippi. Aminocyclopyrachlor (AMCP) is a synthetic auxin herbicide currently labeled for non-crop use, but has characteristics which may make it useful as a preplant burndown (PPB) herbicide. The application of AMCP prior to planting of corn and cotton were evaluated and carryover effects to soybean were also evaluated. Tank mix combinations of AMCP with residual herbicides (rimsulfuron, flumioxazin, pyroxasulfone, pyroxasulfone+ flumioxazin and atrazine) were also evaluated. A rate titration of AMCP and its impacts on crop species were evaluated in the greenhouse. Corn showed tolerance to AMCP except at 0.28 kg ai ha-1 applied prior to planting. Cotton was sensitive to AMCP as rate increased closer to the planting date, but response depended upon soil texture. AMCP impacts on soybean showed greater sensitivity (90% injury) then all other species evaluated. Due to potential impacts on soybean and cotton, AMCP is not a potential PPB for use in Mississippi.

Mid-southern USA soybean [Glycine max (L.) Merr.] producers are being pushed to increase adoption of conservation tillage systems as a means of increasing the application efficiency of gravity flow irrigation systems. This research was conducted to determine whether the efficiency of furrow-irrigation systems could be manipulated through conservation tillage systems while maintaining soybean productivity and profitability. Three experiments were conducted near Stoneville, MS on a Dubbs silt loam (Fine-silty, mixed, active, thermic Typic Hapludalfs) to determine the effects of reducing tillage and increasing ground cover residues on irrigation application efficiency, irrigation water use efficiency, soybean grain yield, and net returns above specified costs. In experiment 1, transitioning from conventional tillage to a conservation tillage system had no adverse effect on irrigation application efficiency, irrigation water use efficiency, soybean grain yield, or net returns above specified costs when subsoiling was included. For experiment 2, replacing subsoiling with a cereal rye or tillage radish cover crop in a conservation tillage system either had no effect or reduced irrigation application efficiency, irrigation water use efficiency, soybean grain yield, and net returns above specified costs up to 41%. In experiment 3, independent of cover crop, reducing tillage to only furrow creation had no adverse effect on irrigation application efficiency, irrigation water use efficiency, soybean grain yield, and net returns above specified costs relative to a conservation tillage system with subsoiling. Conservation tillage systems that include subsoiling maximize irrigation application efficiency and irrigation water use efficiency while minimizing adverse effects on yield and net returns relative to conservation tillage systems that further reduce tillage and/or increase ground coverage with cover crops. Our data indicate that soybean producers in the mid-southern USA maximize furrow-irrigation functionality, yield, and profitability while minimizing risk by transitioning from a conventional tillage system to a conservation tillage system with subsoiling.

Cover crops and composted broiler litter (CBL) are two organic methods used to improve soils and organic vegetable production. The objectives of this study included determining the extent summer cover crops and CBL alter nutrient availability in soil, determining how summer cover crops and CBL influence fall vegetable crops in organic production systems and identifying which cover crops/ CBL combinations improve fall vegetable crop production best. Four cover crops were tested: sunn hemp (Crotalaria juncea), sesame (Sesamum indicum), sorghum sudan grass (Sorghum X drummondii) and a sunn hemp + sesame blend, in combination with four composted broiler litter rates: 0, 2,800, 5,600, 11,200 kg.ha-1 for two years. Few differences were seen among cover crop treatments except for the sorghum sudan grass treatment, which had negative effects on fall broccoli production unless combined with CBL. The CBL increased nutrient availability, percent organic matter, pH and broccoli yield as the rate increased.

No description available.

Cover crops (CC) can contribute to production in pastures, but the diversity of CC mixtures and defoliation frequency (DF) may alter productivity. A 2-yr experiment conducted at Raymond, MS, quantified CC × DF effects on forage mass (FM) and nutritive value of winter CC and subsequent summer hay production. Treatments were factorial combinations of 10 CC (using several species of grasses, legumes, and brassicas) and three DF (harvested every 4 or 8-wk or cut and left as mulch) in a split-plot arrangement of a randomized complete block design experiment with three replications. Generally, mixtures with legumes had greater FM and better nutritive value. Summer hay production did not respond to difference in CC composition, however, harvesting of CC reduced summer hay but increased year-long FM. These results suggest that CC when harvested can contribute to forage production with improved nutritive value and can increase year-long FM, but summer hay production can benefit when the CC is left as mulch.

While cover crops are actively growing, they compete with winter annual weeds. Studies were conducted to determine the ability of early planted cover crop monocultures and mixtures and a fall applied residual herbicide to compete with winter annual weeds. Cereal rye containing cover crops provided the greatest control of winter weeds in May. Flumioxazin, as a fall applied herbicide, controlled winter weeds in December, but control did not persist until May. Once cover crops are terminated, their residue suppresses summer annual weeds. A greenhouse experiment studying the effects of cereal rye biomass on common ragweed and Palmer amaranth control and light penetration and two field experiments to determine the effects of cereal rye and wheat cover crop biomass terminated with a roller crimper or left standing on summer weed control and light penetration were conducted. For summer weed control, as cover crop biomass increased, weed control increased, light penetration decreased, soil temperature decreased, and soil moisture increased. Standing cover crop residue provided greater control of common ragweed compared to rolled residue until 8400 kg ha⁻¹ of cover crop biomass. As cover crop biomass increased, rolled cover crop residue reduced light penetration compared to standing residue. Wheat cover crop residue increased soil moisture more compared to cereal rye residue. Cover crops must become established to produce adequate biomass to compete with weeds. Herbicide carryover has the potential to reduce cover crop establishment. A study was conducted to evaluate the potential for 30 different residual herbicides applied in the cash crop growing season to carryover to 10 different cover crops. While visible injury was observed, cover crop biomass was similar to the nontreated check in all cases, indicating that herbicide carryover to cover crops is of little concern. Herbicide carryover has few biological effects on establishment of cover crops, under the conditions and herbicides evaluated, that are effective at competing with winter annual weeds and suppressing summer annual weeds. / Master of Science in Life Sciences / Cover crops are grown after the cash crop has been harvested and terminated before another is planted. They are grown for environmental and agronomic benefits and not harvested. Cover crops improve soil health, reduce erosion, prevent nutrient loss, and control weeds. Cover crops can compete with weeds while they are actively growing. Their residue can create a mulch layer to reduce weed establishment and limit the amount of light reaching weed seed to reduce germination and establishment. As winter cover crops are growing, they compete with winter weeds for sunlight, nutrients, and water. Fall applied herbicides that remain active in the soil are also utilized to control winter weeds in between cash crop growing seasons. Experiments evaluated the ability of cover crop monocultures and cover crop mixtures compared to a fall applied herbicide to compete with winter annual weeds. Monocultures and mixtures of cereal rye, crimson clover, hairy vetch, and forage radish were utilized. Cereal rye containing treatments provided the greatest control of winter weeds in the spring. The fall applied herbicide provided adequate control of winter weeds in December, but control did not persist until the May, indicating that a fall applied herbicide will not provide control of winter weeds from cash crop harvest to the next cash crop planting. As cover crop biomass increases, summer annual weed control increases. Cover crops are usually terminated with herbicide and left standing in Virginia, but the use of a roller crimper lays down residue and creates a mulch layer. Experiments compared the effects of cereal rye and wheat cover crops at different biomass rates terminated with herbicide only (left standing) or a roller crimper and herbicide on summer weed control, light penetrating the cover crop canopy and reaching the soil surface, soil moisture, and soil temperature. As cover crop biomass increased, weed control increased, light reaching the soil surface decreased, soil temperature decreased, and soil moisture increased. Standing cover crop residue provided greater weed control until 8400 kg ha⁻¹ of cover crop biomass was reached. After 8400 kg ha⁻¹ rolled cover crop residue provided greater control, but control from standing and rolled were both greater than 80% compared to the no cover control. Cereal rye intercepted more light than wheat cover crop residue at less than 6000 kg ha⁻¹ of cover crop biomass was achieved. Rolled cover crop residue intercepted more light than standing residue. Established cover crops most produce adequate biomass to effectively control weeds. Herbicides applied during the cash crop growing season to control weeds can remain active in the soil and reduce the establishment of subsequently planted cover crops. Experiments evaluated the potential for different herbicides applied during the cash crop, such as corn, cotton, or soybeans, to remain in the soil at high enough concentrations to injure cover crops commonly utilized in the Mid-Atlantic region. Cover crops utilized were wheat, barley, cereal rye, oats, annual ryegrass, forage radish, Austrian winter pea, crimson clover, hairy vetch, and rapeseed. Results suggest that little potential exists for the herbicides utilized to persist in the soil to injure the five grass cover crop species utilized. There is the potential for some herbicides to injure forage radish, crimson clover, and rapeseed, but no reduction in cover crop biomass was observed, indicating there is little concern for herbicide carryover to cover crops. Residual herbicide carryover has little effect on establishment of cover crops and does not reduce cover crop biomass, under the conditions and herbicides tested in this study. Cover crops can effectively compete with winter weeds, and as cover crop biomass increases, summer annual weed control increases.