Black and Navy Bean Response to Row Spacing and Plant Population in Eastern North Dakota

Narrower row spacings and higher plant populations are trending in dry bean production. Data from a 2021 dry bean grower survey (Knodel et al., 2022) indicate 85% of black and 73% of navy bean were planted in North Dakota at rates of 110,000 seeds per acre or greater, with the likely goal of establishing at least 100,000 plants per acre. In addition, the survey for North Dakota indicates 74% of black and 75% of navy bean were planted in row widths ranging from 11 to 25 inches.

Based on historic North Dakota work, NDSU recommends an established stand of 90,000 plants per acre for black and navy bean. Research conducted in 1999 to 2000 indicated no seed yield response among black and navy bean planting rates of 90,000, 105,000 and 120,000 pure live seeds (PLS) per acre and a yield increase in one of two years with 7- versus 30-inch row spacings (Schatz et al., 2000).

This publication summarizes NDSU research trials conducted from 2014 to 2018 in eastern North Dakota to evaluate potential yield increase of black and navy bean with higher plant populations and narrower rows compared to the traditionally recommended plant density in wide rows.

Experimental design: Randomized complete block with four replications at all locations. Carrington: main plot of row spacing and sub- plot of plant populations; Park River and Prosper: factorial arrangement of market class and plant population.

Treatments: Eclipse black and Avalanche navy bean were planted in 14-, 21- and 28-inch rows at 100,000, 125,000 and 150,000 PLS per acre for a targeted population of 90,000, 110,000 and 130,000 plants per acre, respectively, at Carrington in 2014 to 2017. The research continued with black bean in 2018 with slightly lower planting rates. In addition, the two dry bean market classes were planted at the three planting rates at Park River in 2014 and Prosper in 2014 to 2017 in intermediate row spacing (either 14 or 18 inches).

General: The dryland trials were conducted with conventional tillage on Heimdal-Emrick loam soil at Carrington, Fairdale silt loam soil at Park River and Kindred-Bearden fine-silty loam soil at Prosper. Dry bean was planted generally during the last half of May. Plant populations were measured two to four weeks after planting at Carrington and prior to harvest at Park River and Prosper. After seed maturity, plants were hand- pulled and threshed with a plot combine during the first half of September. Best management practices were used for dry bean production. White mold was not present in trials.

Black bean seed yield was statistically different among means of the two factors averaged across four years at Carrington (Table 1). Among plant populations, which averaged 101,700, 126,200 and 148,500 plants per acre, yield increased 13% to 14% with 14-inch rows compared to 28-inch rows. However, among plant populations, 21-inch rows had similar yield as 28-inch rows. Within each row spacing, yield did not differ among plant populations.

Table 1. Black bean seed yield among row spacings and plant populations, Carrington, 2014 and 2016-18 (4 site-years). 

¹ Means with no similar letters are significantly different. 

Averaged across four years and plant populations at Carrington, black bean yield with 14-inch rows was 9% and 13% greater compared to yield with 21- and 28-inch rows, respectively (Figure 1). Plant emergence, flowering and physiological maturity dates generally were similar with row spacing each year of the study (data not shown). Canopy closure visually evaluated during late July to early August and averaged over three years was 85%, 76% and 64% with 14-, 21- and 28-inch rows, respectively. Test weight and seed size generally were similar among row spacings (data not shown).

Figure 1. Black bean seed yield among row spacings (inches), Carrington, 2014 and 2016-18 (4 site-years)1.

Averaged across eight site-years, black bean planted at the low, medium and high rates produced 99,100, 118,500 and 140,700 plants per acre, respectively (Figure 2). Yield was statistically similar among plant populations. Plant emergence, flowering and physiological maturity dates generally were similar with plant population (data not shown). Canopy closure, averaged across five site-years, generally was similar among plant populations. Also, test weight and seed size were similar with plant population at each of the eight site-years of the study.

Figure 2. Black bean seed yield among plant populations, Carrington, Park River and Prosper, 2014 and 2016-18 (8 site-years)1.

Averaged across row spacings.

Navy bean seed yield, averaged across three site-years at Carrington, was statistically different with the two-factor interaction (Table 2). Averaged across three years and rows, plant population was 92,600, 116,800 and 139,800 plants per acre with the low to high planting rates, respectively. Highest yield was achieved at 2,790 and 2,660 lb. per acre with 14-inch rows and the high and medium plant populations, respectively. The combination of 14-inch rows and plant populations of greater than 115,000 plants per acre increased yield 24% to 28% compared to 28-inch rows with slightly more than 90,000 plants per acre.

Among the three plant populations, navy bean seed yield increased 10% to 23% with 21-inch rows compared to 28-inch rows. Within 21- and 28-inch rows, yield did not increase with increasing plant populations.

Navy bean plant emergence, flowering date and physiological maturity generally were similar with row spacing and plant population each year of the study at Carrington (data not shown). Canopy closure, averaged over two years, was 91%, 76% and 70% with 14-, 21- and 28-inch rows, respectively. Also, canopy closure was similar among plant populations (data not shown). Test weight and seed size were similar with row spacing and plant population each year of study.

Table 2. Navy bean seed yield among row spacings and plant populations, Carrington, 2014 and 2016-17 (3 site-years). 

¹ Means with no similar letters are significantly different. 

Black bean seed yield was 13% to 14% greater with narrow (14-inch) row spacing compared to wide (28-inch) rows. Average plant population ranging from about 100,000 to 150,000 plants per acre provided similar yield.

Narrow rows with navy bean plant populations of greater than 115,000 plants per acre increased yield 24% to 28% compared to wide rows with slightly more than 90,000 plants per acre.

Knodel, J.J., P.B. Beauzay, M. Ebert, G.J. Endres, D.W. Franzen, J. T. Ikley, H.J. Kandel, S.G. Markell, and J.M. Osorno. 2022. 2021 Dry bean grower survey of production, pest problems and pesticide use in Minnesota and North Dakota. NDSU Extension publication E2052.

Schatz, B.G., S.F. Zwinger, and G.J. Endres. 2000. Dry edible bean performance as influenced by plant density. NDSU Carrington Research Extension Center. Crop and Livestock Review. Vol. 41, p. 9.

Northarvest Bean Growers Association provided financial support for this study.