CORRELATION BETWEEN CLAY CONTENT AND SEED DEPTH IN NO-TILLAGE CORN (Zea mays L.) / CORRELAÇÃO ENTRE O CONTEÚDO DE ARGILA E A PROFUNDIDADE DE DEPOSIÇÃO DAS SEMENTES MILHO (Zea mays L.) EM PLANTIO DIRETO
Abstract
The region of Campos Gerais, in the State of Paraná, is leader in grain yields and state-of-the-art no-tillage farming. The widely adopted no-tillage system tends to increment soil variability. There are several studies about spatial variability of soil characteristics affecting grain yield, but not enough attention has been given to the variability resulting of human actions. The objective of this study was to evaluate the correlation of soil clay content and the depth of placement of corn seeds on areas under no-till systems management. The four selected cornfields areas for the study are property of local farm cooperatives associates. The points for evaluation were defined considering the local mapping of soil texture. Clay content varied from 94 to 489 g kg-1 on Plot 1; from 222 to 414 g kg-1 on Plot 2; from 269 to 509 of rows to be considered for plant distribution and seed depth analyses. The coefficient of variation (CV) of plant distribution was between 23 and 56%. For seed depth, the CV was between 18 and 34%. The regression analysis showed high coefficients of determination (r2) for plots 1 and 2 (r2=0,85 and 0,83). The clay content was generally higher on plots 3 and 4. In this case, the analysis of variance was not significant, and the coefficients of determination were low (r2=0,22 and 0,01). Results indicate that clay content values may be used to delimit g kg-1 on plot 3; and from 368 to 698 g kg-1 on plot 4. The type of planter determined the number management zones on the field, where the depth of seed placing in the planting process can be regulated in different ways.
Keywords: Soil Texture, Planting Process, Management Zones
ResearchGate has not been able to resolve any citations for this publication.
Potential yield benefits from improving within‐row plant spacing variability and plant emergence variability in corn ( Zea mays L.) production are often questioned by growers. Research was conducted at two locations in south‐central Ontario during a 2‐yr period to quantify the effects and interactions of plant spacing variability and plant emergence variability on growth and grain yield of corn. Nine treatments were established by hand planting corn rows with repeating six‐plant sequences consisting of uniform and nonuniform spacing, even and uneven emergence, and their combinations. Spacing treatments consisted of (i) uniform within‐row plant spacing of 20 cm; (ii) one 40‐cm gap associated with a double; and (iii) one 60‐cm gap associated with a triple in each six‐plant sequence. Emergence treatments included uniform early emergence, a two‐leaf stage delay, and a four‐leaf stage delay for one plant in each six‐plant sequence. Only plant emergence variability significantly affected plant height, leaf area index (LAI), dry matter accumulation, and grain yield. Compared with the uniformly early emerged plants, one out of six plants with a two‐leaf stage delay in emergence reduced yield by 4%, and one out of six plants with a four‐leaf stage delay reduced yield by 8%. Whereas corn plants next to a gap demonstrated compensatory growth, plants adjacent to a late emerging corn plant did not exhibit compensatory growth. These results indicate that corn is more responsive to plant emergence variability than plant spacing variability. Variation in plant emergence reduced yield, whereas variation in within‐row spacing did not affect yield, and interactions between the two factors were not significant.
O nível de compressão no leito da semeadura e a profundidade podem interferir na velocidade de emergência das plântulas, conseqüentemente, no estabelecimento inicial de plantas de milho. O presente estudo objetivou analisar a influência da compressão do solo associado com a profundidade de semeadura sobre o índice de velocidade de emergência e a sua relação com o crescimento inicial da cultura do milho. Para isso instalou-se um experimento na Faculdade de Ciências Agrárias e Veterinárias da UNESP, Campus de Jaboticabal, no período de abril a junho de 1999, em um Latossolo Vermelho. O delineamento experimental utilizado foi o inteiramente casualizado, com três repetições. Os tratamentos constaram da compressão do solo nos níveis 0 (testemunha), 5, 10 e 15 kgf, atingindo em média uma resistência à penetração no solo de 1,91, 3,39, 3,93 e 4,43 Mpa, respectivamente, e a profundidade de semeadura nos níveis 3, 5 e 7 cm. Avaliou-se, semanalmente, o índice de velocidade de emergência e a altura da planta de milho até 60 dias após a semeadura. Os resultados mostraram que para o estabelecimento inicial das plantas de milho a resposta foi linear para o índice de velocidade de emergência e para a altura de plantas a compressão do solo variou de 5 a 15 kgf na roda compactadora de semeadura, sem restrições para profundidade de semeadura dentro da faixa de 3 a 7 cm.
Precision farming application requires better understanding of variability in yield patterns in order to determine the cause-effect relationships. This field study was conducted to investigate the relationship between soil attributes and corn (Zea mays L.)-soybean (Glycine max L.) yield variability using four years (1995-98) yield data from a 22-ha field located in central Iowa. Corn was grown in this field during 1995, 1996, and 1998, and soybean was grown in 1997. Yield data were collected on nine east-west transects, consisting of 25-yield blocks per transect. To compare yield variability among crops and years, yield data were normalized based on N-fertilizer treatments. The soil attributes of bulk density, cone index, organic matter, aggregate uniformity coefficient, and plasticity index were determined from data collected at 42 soil sampling sites in the field. Correlation and stepwise regression analyses over all soil types in the field revealed that Tilth Index, based upon soil attributes, did not show a significant relationship with the yield data for any year and may need modifications. The regression analysis showed a significant relationship of soil attributes to yield data for areas of the field with Harps and Ottosen soils. From a geographic information system (GIS) analysis performed with ARC/INFO, it was concluded that yield may be influenced partly by management practices and partly by topography for Okoboji and Ottosen soils. Map overlay analysis showed that areas of lower yield for corn, at higher elevation, in the vicinity of Ottosen and Okoboji soils were consistent from year to year; whereas, areas of higher yield were variable. From GIS and statistical analyses, it was concluded that interaction of soil type and topography influenced yield variability of this field. These results suggest that map overlay analysis of yield data and soil attributes over longer duration can be a useful approach to delineate subareas within a field for site specific agricultural inputs by defining the appropriate yield classes.
A região dos Campos Gerais, no Paraná, é pioneira na utilização de novas tecnologias e apresenta desempenho superior em rendimento de grãos. O sistema Plantio Direto é uma realidade, em que acurácia e precisão no processo de semeadura são de grande importância. Sendo assim, estudou-se o processo de semeadura de milho sob o sistema Plantio Direto na região dos Campos Gerais, avaliando-se a pressão populacional de plantas em 48 propriedades agrícolas. A área experimental era formada por 4 ou 5 linhas de semeadura, onde foram avaliados 3m por linha, medindo-se espaçamentos entre plantas e entre linhas. Não foram observadas diferenças significativas entre as linhas de semeadura em 42 áreas, sendo que o coeficiente de variação médio ficou em torno de 33%. Não se encontrou nenhuma área com média menor do que 50.000 plantas ha-1, valor mínimo para os híbridos avaliados. Pôde-se concluir que o processo de semeadura da região é eficiente quanto ao número de plantas por área. Já a grande variabilidade encontrada na distribuição de plantas na linha de semeadura sugere a necessidade de ações de pesquisa e extensão junto aos produtores.
O sistema de plantio direto atingiu, no Estado do Paraná, cerca de dois milhões de hectares, nos últimos anos, e um dos seus principais entraves é a falta de semeadoras-adubadoras apropriadas para operação em solos argilosos e de origem basáltica. Portanto, estudou-se a MAGNUM 2850 PD quanto à demanda energética e desempenho operacional, com a finalidade de oferecer subsídios ao seu aperfeiçoamento, de acordo com a realidade paranaense. Observou-se que o esforço de tração variou em função da umidade e características mecânicas do solo, atingiu valores elevados, e exigiu, em situações extremas, potência de até 79,5 kW do trator. Os componentes de ataque ao solo mostraram um bom desempenho no corte da vegetação e na uniformidade da profundidade de trabalho, porém apresentaram grande área mobilizada no sulco. Obteve-se boa qualidade de semeadura, avaliada pela porcentagem e velocidade de emergência das sementes no campo. Foram identificados erros de dosagem do fertilizante e deposição das sementes, e principalmente na velocidade de deslocamento de 8,0 km/h; porém, foi boa a uniformidade transversal das sementes e plantas no campo.
Four depth control designs were empirically evaluated with grain sorghum and corn crops in two different field conditions. An experimental no-tillage planter opener was used with each depth control. Dual rear presswheels malfunctioned by sinking into loosened soil and produced deeper and the most variable planting depths. Dual front depth control wheels gave significantly more variable planting depths than the side wheels and linked wheels at the highest applied downpressure. The best choice for depth control remains undecided between traditional wide dual side wheels and narrow experimental linked front-rear wheels. These results generally agree with simulation results from Part I of this series of papers.
Simulation models are needed to estimate crop yield responses to climate and soil water storage. Measured corn yields (Zea Mays L. ) from a tillage-residue management study on the Univ. of Wisconsin Lancaster Exp. Stn. were compared to simulated yields determined using the Nitrogen-Tillage-Residue Management (NTRM) simulation model. Data collected at the site from 1982 to 1985 on crop, soil, climate, and management characteristics were utilized in the model. A significant interaction effect on corn yield was observed between climate and soil-water-holding capacity of individual plots.
Deep planting (75 mm) delayed emergence from 2.8 to 18 d as the soil temperatures decreased from ranges of 15 to 25°C and 5 to 15°C. Seed zone growing degree days (GDD) needed to achieve 75% emergence increased with an increase in planting depth and a decrease in soil matric potential. Relationships of corn emergence vs. seed zone GDD needed to achieve 75% corn emergence at various planting depths were tested in the field for three planting depths, three tillage and three surface residue conditions during 1984 and 1985. Simulation studies were conducted to predict the effects of tillage, planting depth, and planting date on the probability of obtaining 75% corn emergence within 14 d of planting. Study results are discussed.
Uneven emergence of corn (Zea mays L.) may occur when soils are dry at the time of planting. This research was conducted in seven environments in Illinois and Wisconsin during a 2-yr period to measure the effect of uneven emergence on grain yield. Two hybrids (Pioneer Brand 3732 and 3615), chosen to represent differing responses to plant density, were hand planted in early May (E), 10 to 12 d after E (M), and 21 to 27 d after E (L) to produce various patterns of among-row and within-row uneveness. There was no consistent interaction of hybrid with emergence patten, and responses were quite consistent among environments (...)