Plant‐to‐Plant Variability in Corn Production

Abstract

resulting in an estimated 1066 kg ha Ϫ1 (17 bu ac Ϫ1 ) yield loss over 354 commercial fields. Lauer and Rankin Corn (Zea mays L.) grain yields are known to vary from plant to (2004) and Liu et al. (2004) had differing results, noting plant, but the extent of this variability across a range of environments has not been evaluated. This study was initiated to evaluate by-plant that PSV did not significantly alter grain yields in Wiscorn grain yield variability over a range of production environments consin and Ontario, Canada, respectively. Nafziger et and to establish the relationships among mean grain yield, standard al. (1991) noted that uneven emergence of corn can deviation, coefficient of variation, and yield range. A total of fortyoccur when soils are dry at the time of planting and six 8-to 30-m corn transects were harvested by plant in Argentina, could lead to decreased grain yields. It is generally ac-Mexico, Iowa, Nebraska, Ohio, Virginia, and Oklahoma from 2002 cepted that when adjacent plants differ by more than to 2004. By-plant corn grain yields were determined, and the average two leaf stages, the younger plant may not develop to individual plant yields were calculated. Over all sites in all countries its fullest potential. A two leaf stage difference can result and states, plant-to-plant variation in corn grain yield averaged 2765 from delayed emergence ranging from 5 to 10 d, which kg ha Ϫ1 (44.1 bu ac Ϫ1 ). At the sites with the highest average corn can cause a 1% yield loss for each 1-d delay (Robert grain yield (11 478 and 14 383 kg ha Ϫ1 , Parana Argentina, and Phillips, NE), average plant-to-plant variation in yield was 4211 kg ha Ϫ1 (67 bu L. Nielsen, Purdue University, personal communication, ac Ϫ1 ) and 2926 kg ha Ϫ1 (47 bu ac Ϫ1 ), respectively. As average grain 2004). Tollenaar and Wu (1999) found increased stress yields increased, so did the standard deviation of the yields obtained tolerance in corn when plant-to-plant variability was within each row. Furthermore, the yield range (maximum corn grain lower. In general, these statistics identify a twofold probyield minus the minimum corn grain yield per row) was found to lem: first, the need to homogenize plant spacing and increase with increasing yield level. Regardless of yield level, plantemergence and second, the need to recognize differto-plant variability in corn grain yield can be expected and averaged ences in yield potential that clearly exist by plant. more than 2765 kg ha Ϫ1 over sites and years. Averaging yield over Some technologies in precision agriculture have been distances Ͼ0.5 m removed the extreme by-plant variability, and thus, driven commercially. The most notable has been comthe scale for treating other factors affecting yield should be less than bine yield monitors. Depending on combine speed, 0.5 m. Methods that homogenize corn plant stands and emergence may decrease plant-to-plant variation and could lead to increased Published in Agron.

Effect of Delayed Emergence on Corn Grain Yields

“…Nielsen (2001) reported that plants that are next to a gap produced larger ears. Martin et al (2005) found an average difference equivalent to 2765 kg ha -1 plant to plant difference in corn yield. They further noted that production methods that homogenize plant stands and emergence, should decrease plantto-plant variation and will likely lead to increased yields.…”

Using NDVI and soil quality analysis to assess influence of agronomic management on within-plot spatial variability and factors limiting production

“…Apart from that, the general soil quality degradation under zero tillage with residue removal caused stressful conditions. Stressful conditions increase plant-to-plant competition for resources and this competition results in greater plant variability (Martin et al 2005). The zero tillage practice with residue removal caused a non-uniform distribution of crop performance within the field, indicating the inefficient use of available resources with consequent yield losses, since in some parts of the field a higher yield was achieved than in others within the specific conditions of climate and germplasm.…”

By-Plant Prediction of Corn Grain Yield Using Optical Sensor Readings and Measured Plant Height

“…Data collected by Martin et al (2005) from locations in Argentina, Mexico, Iowa, Nebraska, Ohio, Virginia, and Oklahoma showed that regardless of location, plant-to-plant variability in corn grain yield averaged more than 2765 kg ha −1 over sites and years. They further noted that plant-to-plant variability in corn grain yield can be expected in virtually all production environments.…”