Response of Corn to Uneven Emergence

Abstract

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 after E (M), and 21 to 27 d after E (L) to produce various patterns of among‐row and within‐row unevenness. There was no consistent interaction of hybrid with emergence patten, and responses were quite consistent among environments. Across environments, uniform E, M, and L plantings produced 11.8, 11.1, and 10.4 Mg ha−l, respectively. Uniform E rows bordered by M rows [E(M)] produced 11.4 Mg ha−l, while the other among‐row treatments E(L), M(E), L(E), and M(L) produced 12.2, 10.5, 7.9, and 11.8 Mg ha−l, respectively. The within‐row, repeating patterns of 3E:1M, 1E:1M, 3E:3M, and 1E:3M produced yields of 11.0, 10.7, 10.9, and 10.9 Mg ha−l, respectively, while the 3E:1L, 1E:1L, 3E:3L, and 1E:3L treatments produced grain yields of 10.5, 9.2, 9.4, and 9.1 Mg ha−l, respectively. Comparison of uneven within‐row patterns with incomplete stands showed that in no case did the presence of late‐emerging plants cause yield loss. While uneven emergence decreased yields, these data do not show a yield benefit to replanting in order to attain uniformity, with the possible exception of cases where one‐half or more of the plants are delayed in their emergence by at least 3 wk.

Processo de semeadura e o rendimento do milho na região dos Campos Gerais do Paraná

“…Ao contrário do estudo de WEIRICH NETO (2004), as variáveis pressão de população e índice de pressão de população não se mostraram importantes. Vários trabalhos descreveram alguma forma de correlação entre o rendimento de milho e a heterogeneidade de emergência (NAFZIGER et al, 1991;FORD & HICKS, 1992). Problemas de vigor das plântulas, incidência de pragas e doenças na fase inicial e má polinização podem ser catalisados pela variabilidade temporal de emergência de plântulas.…”

JOURNAL of PLANT NUTRITION

“…Non-uniform plant stands can increase inter-plant competition and decrease yields (Nafziger et al, 1991). Boomsma et al (2011) noted that high plant densities result in reduced per-plant resource availability, increased plant competition, decreased productivity, developmental variability, and ultimately lower yields.…”

CORRELATION BETWEEN CLAY CONTENT AND SEED DEPTH IN NO-TILLAGE CORN (Zea mays L.)

“…Several studies describe some form of correlation between corn yield and heterogeneity of emergence (NAFZIGER et al, 1991;MEROTTO JUNIOR et al, 1998). The temporal dissimilarity of plantlet emergence may cause losses up to 3.0 Mg per hectare (MEROTTO JUNIOR et al, 1998).…”

“…Plants emerging at distinct speeds, in addition to the initial stress, are likely to face lower photosynthetic rates due to shading or having its pollination process affected (NAFZIGER et al, 1991).…”