Influence of microclimatic conditions in growth analysis of maize BR 106, cultivated under no-tillage

Abstract

Research was conducted in CNPMS (Embrapa), Sete Lagoas-MG, to quantify the influence of micrometeorological variables on growth and development in the canopy of a maize crop variety BR 106 under no-tillage in irrigated conditions. The flow of CO₂ was measured above the canopy using a system that comprises a three-dimensional sonic anemometer. The growth of BR 106 was affected by changing in the canopys microclimate, with extended periods of cloudiness, reducing the vapor potential in the atmosphere and higher content of energy, especially light and air temperature, contributing to the maximum values of the attributes of growth present in P2 (12 leaves to flowering). However, the senescence of lower leaves of canopy, in the transition from P2 to P3 (beginning of grain formation), increased the RLA (relation leaf area) and SLA (specific leaf area), and reduce the RLM (rate leaf matter), dependent on LAI (leaf area index) and NAR (net assimilation rate), which led to a decrease of 13% the assimilation of CO₂ over the reproductive period. This behavior did not affect the final yield of the variety that showed a value close to potential.