Influence of delayed emergence and canopy skips on the growth and development of maize plants: a plant scale approach with CERES-Maize

• Published in: European journal of agronomy 2002, Vol.16 (4), p.263-277
• Main Authors: Pommel, B, Mouraux, D, Cappellen, O, Ledent, J.F
• Format: Article
• Language: English
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agricultural and forest meteorology; Agricultural sciences; Agronomy. Soil science and plant productions; Biological and medical sciences; CERES-Maize; Crop climate. Energy and radiation balances; Delayed emergence; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Life Sciences; Light interception; Plant to plant competition; Variability of plant spacing; Zea mays L
• ISSN: 1161-0301; 1873-7331
• DOI: 10.1016/S1161-0301(01)00130-7

Our objective was to study by observation and simulation the effects of (1) three different dates of seedling emergence and (2) presence of short sequences of missing plants in rows of maize canopies which we refer to as skips. Trials were carried out in Belgium and France during two consecutive years. We had eight trials in total (i.e. two experimental designs in two locations for 2 years). In a field mechanically sown with a precision drill to give ‘normal plants’, ‘late 1 plants’ and ‘late 2 plants’ (respectively) were sown by hand when ‘normal plants’ had germinated or emerged. The radiation available at the top of the plants was measured for each cohort which allowed the calculation of a ‘coefficient of correction for light climate’ corresponding to the ratio of incident light at the top of each cohort relative to normal. Heterogeneity (skips) was created in maize canopies by removing three adjacent plants situated in the same row at 16 different locations across the field. The part of the canopy affected by the presence of these skips was considered to consist of the 12 plants bordering each skip. Radiation was measured near soil level on both sides of these plants: plants of the part of the canopy affected by skips received on average the same amount of radiation as a uniform stand with a population density equal to three quarters of the density of the parts of the stand without skips. To test if differences in radiation reaching the level of plants in each cohort could explain the effects on the plants the behaviour of each cohort of plants in each location x year was modelled separately with CERES-Maize after introducing into the model a ‘coefficient of correction for light climate’ corresponding to each cohort×location×year combination. Simulations generally reproduced correctly decreases in LAI, total biomass, grain number and total grain yield in the late 1 and late 2 cohorts, but not decrease in individual grain weight. The observed loss of grain yield per unit surface area in the parts of the canopy disturbed by skips was between 7 and 15%, whereas corresponding simulated values were between 6 and 11%. In the absence of compensation, values in the disturbed parts would have been 20%. Thus in our conditions amount of light reaching the different cohorts explained a large part of the treatments effects.