H.D.J.vanHeemst2.2.1Introduction.PDF

2.2 Crop phenology and dry matter distribution H.D.J. vanHeemst 2.2.1 Introduction Figure 4 shows the time course of above ground dry matter accumulation of a summer wheat crop during its growth cycle. With respect to the growth rate, three growth stages can be distinguished (Section 2.1). However, a crop not only accumulates weight, it also passes through successive phenological devel- opment stages: after sowing or planting, a cereal crop first forms roots, leaves and stems during the pre-anthesi s phase, subsequently it flowers, and the seeds set and fill and the crop matures in the post - anthesis phase. These phenological stages are schematically illustrated for a rice crop in Figure Kh Recognizing the distinction between growth and development, growth is defined as the increase in weight or volume of the total plant or the various plant organs, and development is defined as the passing through consecutive phenological phases; it is characterized by the order and rate of appearance of vegetative and reproductive plant organs. The two processes, growth and development, are often strongly interrelated, which is probably the reason why the term development is used often when growth is meant . TRANSPLANTING i •rgenc e Seedling Yellow s Tillerin g Hssd Development H e a d i n g Grai n Fillin g + Ripenin g Yiel d Establishment ( 0 ) V e g e t a t i v e i ) Flowering f 2 ) Formatio n R i p e n i n g ( 4 ) N u f ( 3 ) ! » « f y + F.Sid Transplan t ,ng 2 5 - 35 day i 10 days 4 0 - e O d a y s 10-1S days 2S-3S day s 10-20 day s Figure 10