Twin rows are being promoted as a means to increase maize yield through increased interception of photosynthetically active radiation (PAR) and plant morphology modification. The objective of this research was to explore the interactive effects of maize hybrid, plant population, and row configuration on grain yield and grain yield components, interception of PAR during vegetative growth, plant morphology, and percent lodging. Twin‐row irrigated maize produced the same grain yield as single‐row production. Small changes in plant morphology and grain yield components and 2.3 to 4.2% increased interception of PAR at the V9 (nine leaves with visible collars) stage were documented for twin rows, but the sum of these did not result in changes in grain yield. Twin‐row production increased lodging by 3.5%. Few interactions between row configuration and hybrid and target population were found, leading to the conclusion that twin‐row production of maize affords little opportunity to increase maize grain yields. Hybrid and plant population had a much larger effect on grain yield and lodging. Increasing the maize target population to 93,000 plants ha−1 maximized grain yield at 14.3 Mg ha−1, and led to small changes in plant morphology that increased lodging from 6.8 to 14.9%. Ear height had the highest direct effect on lodging in both the low (2009) and high (2010) percent lodging years. Based on these results, current promotion of twin rows is not justified for irrigated maize production in the western Maize Belt.

Organic agriculture aims to build soil quality and provide long-term benefits to people and the environment; however, organic practices may reduce crop yields. This long-term study near Mead, NE was conducted to determine differences in soil fertility and crop yields among conventional and organic cropping systems between 1996 and 2007. The conventional system (CR) consisted of corn (Zea mays L.) or sorghum (Sorghum bicolor (L.) Moench)-soybean (Glycine max (L.) Merr.)-sorghum or corn-soybean, whereas the diversified conventional system (DIR) consisted of corn or sorghumsorghum or corn-soybean-winter wheat (wheat, Triticum aestivum L.). The animal manure-based organic system (OAM) consisted of soybean-corn or sorghum-soybean-wheat, while the forage-based organic system (OFG) consisted of alfalfa (Medicago sativa L.)-alfalfa-corn or sorghum-wheat. Averaged across sampling years, soil organic matter content (OMC), P, pH, Ca, K, Mg and Zn in the top 15 cm of soil were greatest in the OAM system. However, by 2008 OMC was not different between the two organic systems despite almost two times greater carbon inputs in the OAM system. Corn, sorghum and soybean average annual yields were greatest in either of the two conventional systems (7.65, 6.36 and 2.60 Mg ha -1 , respectively), whereas wheat yields were greatest in the OAM system (3.07 Mg ha -1 ). Relative to the mean of the conventional systems, corn yields were reduced by 13 and 33% in the OAM and OFG systems, respectively. Similarly, sorghum yields in the OAM and OFG systems were reduced by 16 and 27%, respectively. Soybean yields were 20% greater in the conventional systems compared with the OAM system. However, wheat yields were 10% greater in the OAM system compared with the conventional DIR system and 23% greater than yield in the OFG system. Alfalfa in the OFG system yielded an average of 7.41 Mg ha -1 annually. Competitive yields of organic wheat and alfalfa along with the soil fertility benefits associated with animal manure and perennial forage suggest that aspects of the two organic systems be combined to maximize the productivity and sustainability of organic cropping systems.

In the United States, much grain sorghum [Sorghum bicolor (L.) Moench] production area has shifted to maize (Zea mays L.) during the last 25 yr, which has been partially due to grain yield differences between these crops. The objective of this study was to document the rate of grain yield increases for maize and sorghum hybrids from 1950 to 1999 in rainfed and irrigated environments in eastern Nebraska. Across all production environments and years, maize produced 1.7 to 4.3 Mg ha−1 greater yield than sorghum. The rate of yield increase was approximately three times faster for maize than sorghum but varied with production environments. The highest rate of yield increase (0.050 Mg ha−1 yr−1) was found for rainfed, high water‐holding capacity soil conditions; the second highest rate of increase was for irrigated maize (0.028 Mg ha−1 yr−1). The rate of sorghum yield increase under all environments and maize under rainfed, low water‐holding capacity soil conditions was low at 0.010 to 0.015 Mg ha−1 yr−1 Pearson correlations indicated that the number of ears (panicles) per square meter had the highest association with yield (r = 0.68 for maize and r = 0.59 for sorghum) while both the number of kernels per ear (per panicle) and kernel weight were significantly correlated to yield for both crops. Yield component analysis for maize shows that yield increases with introduction year resulted from increased number of ears per square meter and kernel weight, while sorghum saw no significant correlation between yield and yield components.

Few studies have examined grain quality of food‐grade sorghum hybrids. The objective of this study was to determine the effects of environment and hybrid on grain quality of commercially available food‐grade sorghums. A randomized complete block experiment with three replications was planted in 12 environments, which included the 2004 and 2005 growing seasons and irrigated and dryland water regimes in eastern, central, and west central Nebraska and a dryland low‐N environment in eastern Nebraska. Environment accounted for 5 to 140 times greater variation in measured parameters than hybrid, and the hybrid × environment interaction accounted for less than 2% of the total variation. Grain yield and kernel mass varied, with low yields of 1.4 Mg ha−1 and kernels weighing 9.5 g 1000 kernels−1 in the low‐N 2004 environment, high grain yields of 10.5 Mg ha−1 under irrigated conditions in central Nebraska in 2005, and kernels weighing 27.8 g 1000 kernels−1 in the eastern Nebraska dryland 2005 environment. Harder grain was produced in 2005 than in 2004, with the west central and central 2005 environments having the lowest tangential abrasive dehulling device (TADD) removals of 14%. Non‐food‐grade hybrids produced higher grain yields and kernel mass than food‐grade hybrids. Grain hardness was greater for non‐food‐grade and medium maturity hybrids when environmental means were lower (i.e., softer) but showed little or no difference in hardness when environmental means were high. Nebraska production environments have the capability to produce high quality food‐grade sorghums for specific food uses to benefit both the producer and the food processor.

Core Ideas Organic farming can contribute to water capture relative to conventional systems. Soil aggregates are more water stable under organic than conventional practices. Organic farming systems can improve soil physical properties in the long term. Organic farming is one environmentally viable approach to agriculture through its use of animal and green manures to provide nutrients and cultural practices to manage weeds, insects, and pathogens. The sustainability of organic agriculture, however, is less well understood, especially under long‐term management. A study was conducted near Mead, NE, to investigate the long‐ term impacts of organic management on soil physical properties including soil aggregate stability, bulk density, Proctor bulk density (parameter of soil’s susceptibility to compaction), water infiltration, saturated hydraulic conductivity, and soil‐water retention characteristics in conventional farming (CR1), conventional farming with diversified rotation (DIR), organic practices with green manure (OGM), and organic practices with animal manure (OAM). The OGM and OAM treatments increased cumulative water infiltration by about 10 times compared with the CR1 treatment, indicating that organic farming can increase water storage relative to conventional systems. Mean weight diameter of water‐stable soil aggregates increased by 50% with the OGM and by 30% with the OAM treatments in the upper 15‐cm depth, indicating that aggregates were larger and more stable under organic than conventional practices. At the same depth, the Proctor bulk density was 3% lower under organic practices than in the CR1 treatment, suggesting that organic farming reduces the soil’s susceptibility to compaction. The increase in aggregate stability and porosity increased water infiltration and saturated hydraulic conductivity. Overall, organic farming can improve soil physical properties in the long term and provide a strategy for farmers to enhance soil physical quality and agricultural sustainability.