Impacto del manejo y ambiente sobre el rendimiento de maíces de diferente fecha de siembra
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Date
2022
Journal Title
Journal ISSN
Volume Title
Publisher
Facultad de Ciencias Agrarias-UNR
Abstract
El maíz es el segundo cultivo con mayor superficie y producción en la República
Argentina, donde actualmente los productores están sembrando en fechas de siembras
contrastantes (temprana y tardía) y exponiendo a los cultivos a diferentes condiciones
ambientales. En la presente tesis se estudió el efecto de las decisiones de manejo y las
variables ambientales sobre el rendimiento de cultivos sembrados en fechas de siembra
temprana y tardía. Además, se evaluó el incremento del rendimiento gracias a la optimización
del manejo. Se utilizaron ensayos comparativos de rendimiento en lotes de producción. Se
concluyó que las decisiones de manejo y el efecto de las variables ambientales más
importantes difieren con la fecha de siembra. Las decisiones de manejo más importantes para
fechas de siembras tempranas son la densidad, la disponibilidad de nitrógeno, la
disponibilidad de azufre y el fósforo aplicado. En contraste, para fechas de siembras tardías
fueron el uso de fungicidas foliares, el fósforo del suelo y la disponibilidad de nitrógeno. La
elección del genotipo presentó similar importancia y efecto para ambas fechas de siembra.
Las variables ambientales más importantes para ambas fechas de siembra fueron la presencia
de una napa cercana y las precipitaciones durante el ciclo. El efecto en el rendimiento de una
napa cercana fue positivo para fechas de siembra tempranas, mientras que el efecto fue
negativo en fechas de siembra tardías. La presencia de una napa cercana en un lote
condiciona la fecha de siembra, ubicando a la fecha de siembra temprana como la mejor
opción ante lotes con presencia de napa. A partir de estos resultados, se logró optimizar en el
manejo para aumentar el rendimiento en ambas fechas de siembra. La presente tesis
demuestra que los productores deben ajustar el genotipo, la densidad, el nitrógeno y el azufre
en fechas tempranas, mientras que en fechas tardías deben mejorar el manejo del genotipo,
el fungicida, el fósforo del suelo y el nitrógeno. De esta manera, se lograrían aumentos del
rendimiento de 3.053 kg ha-1 para fechas tempranas, y de 1.459 kg ha-1 para fechas tardías.
En cambio, las variables ambientales más importantes son las relacionadas al agua disponible
sin distinción de la fecha de siembra.
Maize is the second crop with the largest sown area and production in the Argentina, where farmers are currently sowing at contrasting sowing dates (early and late) and exposing the crops to different growing conditions. In the present thesis, the effect on yield of management decisions and environmental variables was studied at early and late sowing dates. In addition, the increase on yield by optimizing management decisions at each sowing date was evaluated. Genotype yield comparison trials were used throughout the thesis. It was concluded that the most relevant management decisions and environmental variables differed with sowing date. Stand density, nitrogen availability, sulphur availability and phosphorus applied were the most important management decisions at early sowing date. In contrast, for late sowing dates, fungicide use, soil phosphorus, and nitrogen availability were the most important management decisions. Genotype selection showed similar importance and effect for both sowing dates. The most important environmental variables for both sowing dates were the presence of a closed water table and rainfall during the cycle. The effect of a closed water table was positive for early sowing date, while, on late sowing date the effect was negative. The presence of a closed water table conditions the sowing date, making early sowing date as the best option for fields with a closer water table. Based on these results, optimizing through management decisions could increase yield on both sowing dates. In summary, the present thesis shows that farmers should adjust stand density, nitrogen and sulfur availability at early sowing dates, while at late sowing dates they should improve the management of fungicide, soil phosphorus and nitrogen availability. This would result, on yield increases of 3.053 kg ha 1 for early sowing dates and 1.459 kg ha-1 for late sowing dates would be achieved. Instead, the most important environmental variables are those related to available water at both sowing dates.
Maize is the second crop with the largest sown area and production in the Argentina, where farmers are currently sowing at contrasting sowing dates (early and late) and exposing the crops to different growing conditions. In the present thesis, the effect on yield of management decisions and environmental variables was studied at early and late sowing dates. In addition, the increase on yield by optimizing management decisions at each sowing date was evaluated. Genotype yield comparison trials were used throughout the thesis. It was concluded that the most relevant management decisions and environmental variables differed with sowing date. Stand density, nitrogen availability, sulphur availability and phosphorus applied were the most important management decisions at early sowing date. In contrast, for late sowing dates, fungicide use, soil phosphorus, and nitrogen availability were the most important management decisions. Genotype selection showed similar importance and effect for both sowing dates. The most important environmental variables for both sowing dates were the presence of a closed water table and rainfall during the cycle. The effect of a closed water table was positive for early sowing date, while, on late sowing date the effect was negative. The presence of a closed water table conditions the sowing date, making early sowing date as the best option for fields with a closer water table. Based on these results, optimizing through management decisions could increase yield on both sowing dates. In summary, the present thesis shows that farmers should adjust stand density, nitrogen and sulfur availability at early sowing dates, while at late sowing dates they should improve the management of fungicide, soil phosphorus and nitrogen availability. This would result, on yield increases of 3.053 kg ha 1 for early sowing dates and 1.459 kg ha-1 for late sowing dates would be achieved. Instead, the most important environmental variables are those related to available water at both sowing dates.
Description
Keywords
Fecha de siembra, Maíz, Zea mays, Napa, Genotipos, Rendimiento de cultivos