Field and greenhouse studies were conducted to assess the effects of row-spacing on diseases, weed control, herbicide persistence and plant development in peanut. Tebuconazole, when averaged across cultivars and row spacing, effectively controlled white mold (57%) and rust (58%). Azoxystrobin also controlled white mold (58%) and controlling rust (44%). Both fungicides reduced leaf spot severity in the conventional and twin rows when compared to untreated plots. Twin rows showed a 10% yield increase compared to the conventional planting. Both diclosulam and imazapic, when applied to twin rows at the full and reduced rate, provided better yellow nutsedge control than when applied to the conventional row. Twin rows yielded higher than the conventional rows when averaged across herbicides in one year. All full rate herbicide treatments enhanced yield over the untreated check. Diclosulam and imazapic treated soil sampled 60 DAP adversely affected all four crops. The advantage of planting peanuts in twin rows to reduce diclosulam and imazapic residual concentrations was not apparent. Georgia Green and Tamrun 96 planted in twin rows at three of the four locations in 1999 and 2000 yielded higher than peanuts planted in conventional rows. Yields were comparable to twin-row spacings that had higher plant densities. Georgia Green and Tamrun 96 planted in conventional rows, in most cases, had higher yields than narrow-rows. Measurements for plant diameter, pod distribution, and main stem length were higher with Tamrun 96 at most row spacings and planting densities compared to the respective Georgia Green planting densities and row spacings. Both cultivars when planted in twin or narrow rows at all planting densities did not enhance maturity when sampled late season. Georgia Green and Tamrun 96 when planted in conventional rows had the most pods/plant compared to the narrow and twin row spacing. No clear evidence was found to suggest that peanuts grown in narrow or twin rows increased white mold disease incidence. Grades for Georgia Green were higher than Tamrun 96 when planted in twin rows at the standard planting density. Tamrun 96 in twin rows at the standard planting density had a higher grade than when planted in conventional rows at the low planting density.

Field and greenhouse studies were conducted to assess the effects of row-spacing on diseases, weed control, herbicide persistence and plant development in peanut. Tebuconazole, when averaged across cultivars and row spacing, effectively controlled white mold (57%) and rust (58%). Azoxystrobin also controlled white mold (58%) and controlling rust (44%). Both fungicides reduced leaf spot severity in the conventional and twin rows when compared to untreated plots. Twin rows showed a 10% yield increase compared to the conventional planting. Both diclosulam and imazapic, when applied to twin rows at the full and reduced rate, provided better yellow nutsedge control than when applied to the conventional row. Twin rows yielded higher than the conventional rows when averaged across herbicides in one year. All full rate herbicide treatments enhanced yield over the untreated check. Diclosulam and imazapic treated soil sampled 60 DAP adversely affected all four crops. The advantage of planting peanuts in twin rows to reduce diclosulam and imazapic residual concentrations was not apparent. Georgia Green and Tamrun 96 planted in twin rows at three of the four locations in 1999 and 2000 yielded higher than peanuts planted in conventional rows. Yields were comparable to twin-row spacings that had higher plant densities. Georgia Green and Tamrun 96 planted in conventional rows, in most cases, had higher yields than narrow-rows. Measurements for plant diameter, pod distribution, and main stem length were higher with Tamrun 96 at most row spacings and planting densities compared to the respective Georgia Green planting densities and row spacings. Both cultivars when planted in twin or narrow rows at all planting densities did not enhance maturity when sampled late season. Georgia Green and Tamrun 96 when planted in conventional rows had the most pods/plant compared to the narrow and twin row spacing. No clear evidence was found to suggest that peanuts grown in narrow or twin rows increased white mold disease incidence. Grades for Georgia Green were higher than Tamrun 96 when planted in twin rows at the standard planting density. Tamrun 96 in twin rows at the standard planting density had a higher grade than when planted in conventional rows at the low planting density.

10 pp. / Forage sorghum yields have been should to increase with narrow row spacing of 20 inches or less. The purpose of this research is to determine the effect of narrow row spacing on forage sorghum yield and quality in Arizona. Two row spacing (20 and 40 inch) and two forage sorghum hybrids (Great Scott and Silo 700D BMR) were evaluated in a study conducted at the University of Arizona Maricopa Agricultural Center in 2015. Row spacing had no effect on forage yield, moisture, plant height, or maturity even though light interception was greater for the closer row spacing. The only feed quality parameter affected by row spacing was lactic acid which increased with row spacing. Hybrid by row spacing interactions was detected for a few feed quality parameters. Decreasing forage sorghum row spacing from 40 to 20 inches does not appear to have an advantage based on the results of this study.

There is renewed interest in cotton performance grown using various row spacings and plantings patterns in the Midsouth. Cotton seed size has been reduced compared to sixty years ago. Planting smaller seeds is concerning due to having less energy for emergence as well as complicating the ginning process. Two row spacings, two planting patterns, and two cotton varieties were evaluated over eight site years from 2019-2020. The solid planting pattern produced a higher yield on a land area basis. In addition, two varieties, each with three seed counts, were planted at three seeding rates and evaluated over six site years from 2019-2020. Greater seedcotton yields were observed from larger seed sizes and higher seeding rates. Row spacing had no impact on yield but depending on input cost, a 2x1 skip pattern could be beneficial. Also, higher seeding rates and larger seeds maximized yields.

2 pp. / Self seeding, planting equipment, planting into stubble, row spacing, bed vs flat planting, planting into moisture vs. irrigation up, and planting direction are discussed.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

No description available.

Master of Science / Department of Agronomy / J. A. Dille / Weed control in grain sorghum has always presented a challenge to producers in the semi-arid Great Plains. Cultural control tactics such as narrowing of row spacings and increasing seeding rates can be effective control methods. The objective of this research was to determine the row spacing and seeding rates that maximizes yield while suppressing weeds. Grain sorghum row spacings of 25, 51, and 76-cm and seeding rates of 75,000, 100,000, 125,000, and 150,000 seeds ha[superscript]-1 were evaluated in Kansas at Beloit and Manhattan in 2013 and Beloit, Manhattan, and Hays in 2014. Grain sorghum growth and yield response were measured in response to natural weed communities. After evaluation, Beloit was considered a low weed pressure site while Manhattan and Hays were considered to be moderate and high weed pressure sites, respectively. Grain sorghum biomass was different while weed biomass was consistent across row spacings. Yield loss equations and profit functions were derived to determine the amount of grain yield and $ ha[superscript]-1 loss from each of the three locations. Yield and profit lost was greatest amongst weedy observations. Results indicated that grain sorghum grown on wide row spacings and seeding rates of 125,000 seeds ha[superscript]-1 out yielded all other treatments under a low weed pressure site (Beloit) and narrow row spacings out yielded wider spacings in moderate and high weed pressure sites (Manhattan and Hays). These results imply that a Kansas grain sorghum producer should evaluate potential weed pressure before determining a final row spacing and seeding rate.

Planting date (PD), seeding rate (SR), genotype, and row spacing (RS) influence hard red spring wheat (HRSW, Triticum aestivum L. emend. Thell.) and soybean [Glycine max (L.) Merr.] yield. Evaluating HRSW economic optimum seeding rates (EOSR) is needed as modern hybrids may improve performance and have different SR requirements than cultivars. Two cultivars and five hybrids were evaluated in five North Dakota environments at two PDs and five SRs ranging from 2.22-5.19 million live seeds ha-1 in 2019-2020. Planting date, SR, and genotypes have unique yield responses across environments. Hybrid yield was the most associated with kernels spike-1 (r=0.17 to 0.43). The best hybrid yielded greater than cultivars in three environments. The EOSR ranged from 4.08-4.15 and 3.67-3.85 million seeds ha-1 for cultivars and hybrids, respectively. Hybrids are economical if seed prices are within $0.18 kg-1 of cultivars. In soybean, individual and synergistic effects of PD, SR, genotype relative maturity (RM), and RS on seed yield and agronomic characteristics, and how well canopy measurements can predict seed yield in North Dakota were investigated. Early and late PD, early and late RM, and two SRs (457 000 and 408 000 seed ha-1) were evaluated in 14 environments and two RS (30.5 and 61 cm) were included in four environments in 2019-2020. Individual factors resulted in 245 and 189 kg ha-1 more yield for early PD and late RM, respectively. The improved treatment of early PD, late RM, and high SR factors had 16% yield and $140 ha-1 more partial profit greater than the control. When including RS, 30.5 cm RS had 7% more yield than 61 cm RS. Adding 30.5 cm RS to the improved treatment in four environments resulted in 26% yield and $291 ha-1 more partial net profit compared to the control. A normalized difference vegetative index (NDVI) at R5 was the single best yield predictor, and stepwise regression using canopy measurements explained 69% of yield variation. North Dakota farmers are recommended to combine early PDs, late RM cultivars, 457 000 seed ha-1 SR, and 30.5 cm RS to improve soybean yield and profit compared to current management trends.

Row patterns affected irrigated corn productivity when grown in the Mid-South region of the United States. Narrow (76 cm) row spacing increased grain yield 8% when compared to traditional wide (96-102 cm) row spacing. Twin rows (20-25 cm spacing) in a wide (96-102 cm) row pattern, produced similar grain yield as a traditional wide single row. At a normal plant density of 79,040 ha-1, traditional wide rows yielded 10.51 Mg ha-1, twin wide rows yielded 10.34 Mg ha-1, and the narrow rows yielded 11.33 Mg ha-1. Growing corn at various plant densities did not affect corn grain yield response to various row patterns. As a comparison the traditional wide rows and twin rows were similar in their yield, and the narrow rows performed better. Corn grain yields for the traditional 96-102 cm wide single rows were 11.20 Mg ha-1, wide 96-102 cm twin rows yielded 11.22 Mg ha-1, and narrow 76 cm rows produced 12.07 Mg ha-1. Row pattern had no effect on corn plant height, photosynthetically active radiation (PAR), leaf area index (LAI), SPAD, stalk diameter, and plant lodging in either study.