Two grain sorghum (Sorghum bicolor L. Moench) studies were conducted in the Coastal Bend Region of Texas over a two-year period. In one study, sorghum growth and yield were compared when planted in a single row on beds or planted in twin rows on beds with different plant populations under dryland or irrigation. Above average rainfall occurred in May 2000 which resulted in twin rows at any plant population producing higher yields than the single row at lower plant population. In 2001, single-row plantings with either plant population (124,000–160,000 or 161,000–198,000 plants/ha) produced higher yield than twin rows planted at 161,000–198,000 plants/ha. Under irrigation, twin rows planted at 161,000–198,000 plants/ha produced higher yields than single row at the same population; however, no other yield differences were noted when row systems or plant populations were compared. In another study, 38 cm row spacings were compared with 76 cm row spacings under two plant populations. In 2000, when rains fell at an opportune time, no yield differences were noted; however, in 2001 with below average rainfall, the 76？cm plantings at 170,000–200,000 and 210,000–240,000 plants/ha produced higher yield than the 38？cm plantings at those same plant populations. 1. Introduction Row spacing and plant populations are variables that can have a significant impact on the net returns of sorghum producers. Grain sorghum along the Texas Gulf Coast is commonly cultivated in rows 76–102？cm apart [1]. Recent technological developments in farming equipment and improved herbicides open new doors for using rows narrower than 76？cm or twin rows on a single bed in grain sorghum production. The use of narrow rows in grain sorghum production is not new. A number of previous studies published in the late 1950s and 1960s showed yield increases when grain sorghum was planted in narrow rows [2, 3]. Though optimal plant densities for grain sorghum differ from region to another, previous research has indicated that grain yields generally increase as plant populations increase [4–6]. At lower than suggested plant densities, grain sorghum head number per plant or seed number per head increased when compared to the recommended plant density [7–10]. In other crops, Grichar [11] reported variable results of the effects of different seeding rates in soybean (Glycine max L.). He reported that the effect of seeding rate on soybean yields varied from year to another depending on variety and rainfall received during the growing season. Brown et al. [12] showed a 34% yield increase in corn (Zea mays
References
[1]
D. D. Fromme, C. J. Fernandez, W. J. Grichar, and R. L. Jahn, “Grain sorghum response to hybrid, row spacing, and plant populations along the upper Texas Gulf Coast,” International Journal of Agronomy, vol. 2012, Article ID 930630, 5 pages, 2012.
[2]
K. B. Porter, M. E. Johnson, and W. H. Stetten, “The effect of row spacing, fertilizer, and planting rates on yield and water use of irrigated grain sorghum,” Agronomy Journal, vol. 52, pp. 431–433, 1960.
[3]
F. C. Stickler and S. Wearden, “Yield and yield components of grain sorghum as affected by row width and stand density,” Agronomy Journal, vol. 57, pp. 564–567, 1965.
[4]
O. R. Jones and G. L. Johnson, “Row width and plant density effects on Texas High Plains sorghum,” Journal Production Agriculture, vol. 4, pp. 613–621, 1991.
[5]
S. P. Conley, W. G. Stevens, and D. D. Dunn, “Grain sorghum response to row spacing, plant density, and planter skips,” Crop Management, 2005.
[6]
S. A. Staggenborg, “Grain sorghum response to row spacings and seeding rates in Kansas,” Journal of Production Agriculture, vol. 12, no. 3, pp. 390–395, 1999.
[7]
T. J. Gerik and C. L. Neely, “Plant density effects on main culm and tiller development of grain sorghum,” Crop Science, vol. 27, pp. 1225–1230, 1987.
[8]
T. A. Lafarge and G. L. Hammer, “Predicting plant leaf area production: shoot assimilate accumulation and partitioning, and leaf area ratio, are stable for a wide range of sorghum population densities,” Field Crops Research, vol. 77, no. 2-3, pp. 137–151, 2002.
[9]
T. A. Lafarge and G. L. Hammer, “Tillering in grain sorghum over a wide range of population densities: modelling dynamics of tiller fertility,” Annals of Botany, vol. 90, no. 1, pp. 99–110, 2002.
[10]
Y. O. M’Khaitir and R. L. Vanderlip, “Grain sorghum and pearl millet response to date and rate of planting,” Agronomy Journal, vol. 84, pp. 579–582, 1992.
[11]
W. J. Grichar, “Planting date, cultivar, and seeding rate effects on soybean production along the Texas Gulf Coast,” Crop Management, 2007.
[12]
R. H. Brown, E. R. Beaty, W. J. Ethredge, and D. D. Hays. “, “Influence of row width and plant population on yield of two varieties of corn (Zea mays L.),” Agronomy Journal, vol. 62, pp. 767–770, 1970.
[13]
J. M. Fulton, “Relationships among soil moisture stress, plant populations, row spacing, and yield of corn,” Canadian Journal Plant Science, vol. 50, pp. 31–38, 1970.
[14]
B. A. Besler, W. J. Grichar, S. A. Senseman, R. G. Lemon, and T. A. Baughman, “Effects of row pattern configurations and reduced (1/2x) and full rates (1x) of imazapic and diclosulam for control of yellow nutsedge (Cyperus esculentus) in peanut,” Weed Technology, vol. 22, no. 3, pp. 558–562, 2008.
[15]
A. Limon-Ortega, S. C. Mason, and A. R. Martin, “Production practices improve grain sorghum and pearl millet competitiveness with weeds,” Agronomy Journal, vol. 90, no. 2, pp. 227–232, 1998.
[16]
H. H. Bryant, J. T. Touchton, and D. P. Moore, “Narrow rows and early planting produce top grain sorghum yields,” Highlights Agriculture Research Alabama Agricultural Experiment Station, vol. 33, article 5, 1986.
[17]
A. P. Everaarts, “Effects of competition with weeds on the growth, development and yield of sorghum,” Journal of Agricultural Science, vol. 120, no. 2, pp. 187–196, 1993.
[18]
R. H. Walker and G. A. Buchanan, “Crop manipulation in integrated weed management systems,” Weed Science, vol. 30, pp. 17–24, 1982.
[19]
W. J. Grichar, “Row spacing, plant populations, and cultivar effects on soybean production along the Texas Gulf Coast,” Crop Management, 2007.
[20]
B. E. Tharp and J. T. Kells, “Effect of glufosinate-resistant corn (Zea mays) population and row spacing on light interception, corn yield, and common lambsquarters (Chenopodium album) growth,” Weed Technology, vol. 15, pp. 413–418, 2001.
[21]
K. D. Thelen, “Interaction between row spacing and yield: why it works,” Crop Management, 2006.
[22]
F. H. Andrade, P. Calvi？o, A. Cirilo, and P. Barbieri, “Yield responses to narrow rows depend on increased radiation interception,” Agronomy Journal, vol. 94, no. 5, pp. 975–980, 2002.
[23]
W. C. Johnson, E. P. Prostko, and B. G. Mullinix, “Improving the management of dicot weeds in peanut with narrow row spacings and residual herbicides,” Agronomy Journal, vol. 97, no. 1, pp. 85–88, 2005.
[24]
J. R. Teasdale, “Influence of narrow row/high population corn (Zea mays) on weed control and light transmittance,” Weed Technology, vol. 9, no. 1, pp. 113–118, 1995.
[25]
C. J. Fernandez, T. Foutz, and R. Schawe, “Increasing irrigated grain sorghum yield through double-row planting,” in 4th Australian Sorghum Conference, A. K. Borrell and R. G. Hensell, Eds., Department of Primary Industries-Queensland Government, Grains and Research Development Corporation, Queensland, Australia, 2001.
[26]
M. J. Kasperbauer and D. L. Karlen, “Plant spacing and reflected far-red light effects on phytochrome-regulated photosynthate allocation in corn seedlings,” Crop Science, vol. 34, no. 6, pp. 1564–1569, 1994.
[27]
D. G. Bullock, R. L. Nielsen, and W. E. Nyquist, “A growth analysis comparison of corn growth in conventional and equidistant plant spacing,” Crop Science, vol. 28, pp. 254–258, 1988.
[28]
H. C. Dethloff and G. L. Nall, “AGRICULTURE,” Handbook of Texas Online, Texas State Historical Association, 2012http://www.tshaonline.org/handbook/online/articles/ama01.
[29]
P. L. Brown and W. D. Shrader, “Grain yields, evapotranspiration and water use efficiency of grain sorghum under different cultural practices,” Agronomy Journal, vol. 51, pp. 339–343, 1959.
[30]
C. Stichler, M. McFarland, and C. Coffman, “Irrigated and dryland grain sorghum production,” 2012, http://publications.tamu.edu/CORN_SORGHUM/PUB_Irrigated%20and%20Dryland%20Grain%20Sorghum%20Production.pdf.
[31]
H. J. Mascagni and B. Bell, “Plant patterns for different grain sorghum hybrids,” Louisiana Agriculture Magazine, 2005, http://www.Isuagcenter.com/en/communications/publications/agmag/Archive/2005/Winter/Plant+Patterns+for+Different+Grain+Sorghum+Hybrids.htm.
[32]
Z. Karchi and Y. Rudich, “Effects of row width and seedling spacing on yield and its components in grain sorghum grown under dryland conditions,” Agronomy Journal, vol. 58, pp. 602–604, 1966.
[33]
J. Kelley, “Chapter 1: growth and development,” Grain Sorghum Handbook, MP 297, http://www.uaex.edu/Other_areas/publications/PDF/MP297/MP297.PDF.
[34]
N. H. Welch, E. Burnett, and H. V. Eck, “Effect of row spacing, plant population, and nitrogen fertilization on dryland grain sorghum production,” Agronomy Journal, vol. 58, pp. 160–163, 1966.
[35]
M. M. Jones and H. M. Rawson, “Influence of rate of development of leaf water deficits upon photosynthesis, leaf conductance, water use efficiency, and osmotic potential in sorghum,” Physiologia Plantarum, vol. 45, no. 1, pp. 103–111, 1979.
[36]
J. L. Steiner, “Dryland grain sorghum water use, light interception, and growth responses to planting geometry,” Agronomy Journal, vol. 78, pp. 720–726, 1986.
[37]
J. R. Sanabria, J. F. Stone, and D. L. Weeks, “Stomatal response to high evaporative demand in irrigated grain sorghum in narrow and wide row spacing,” Agronomy Journal, vol. 87, no. 5, pp. 1010–1017, 1995.
