Corn Root System Research Articles

Plant age and the phosphorus uptake characteristics of trimmed and untrimmed corn root systems

The influx of P per meter of corn (Zea mays L.) root for corn grown in nutrient culture was measured by following the rate of loss of P from solution over a 4 to 6 hour period. Experiments were conducted on corn grown for 12, 14, 28, 35, 43, 52, and 80 days. The maximum P influx, Km(the Michaelis constant), P efflux, and the minimum concentration to which the plants reduced the solution P level were measured on plants with untrimmed and trimmed roots. Reducing root length by trimming did not alter P uptake characteristics of corn roots. Trimming was done one or two days prior to the measurement of P flux.

Functions to Predict Optimal Irrigation Programs

Davis, Calif., programming dates and depths of irrigations are based on comparison of the estimated sequence of maximum evapotranspiration rates (ET m a x rates) throughout the season with the sequence of actual ET rates expected if no irrigation is given. The difference constitutes an expected sequence of ET deficits which carefully programmed irrigations may alleviate fully or in part. ET m a x depend on the sequence of leaf canopy development and on evaporative conditions at the site being planned for. ET actual rates (unirrigated) depend on the sequence of root system development, available soil water in storage at planting time, and growing season rainfall. Time relationships of corn leaf canopy and root system development researched at Davis, Calif., are combined with irrigation planning site measurements of climate, soil, and soil water content to estimate the sequence of ET deficits. Measurement of actual irrigation operational efficiency completes the needed information.

Development and Distribution of the Corn Root System Under Field Conditions1

AbstractThe rate of corn (Zea mays L.) root growth in the field and root distribution in the soil as related to stage of plant growth has not been studied in detail. To obtain more information we measured the length, fresh weight, and distribution of corn roots at time intervals between planting and harvest in 1970 and 1971. The study was made on corn growing on Chalmers silt loam soil at Lafayette, Indiana. Grain yields were 6,160 kg/ ha in 1970 and 11,700 kg/ha in 1971.Root length and fresh weight increased rapidly for 80 days following planting, remained relatively constant for 14 days, and then decreased rapidly when the plants were in the reproductive stage. A maximum root density of 4.1 cm/cm3 occurred in the 0 to 15 cm zone at 79 days. The lower soil zones reached maximum root density 1 to 2 weeks later than in the 0 to 15 cm zone. Root density in the 0 to 15 cm zone was greater in cores taken midway between plants in the row than at other locations. Maximum root length was 153 cm/cm2 of surface area at 86 days.

Corn root‐Configuration Response to Soil Temperature and Matric Suction1

Soil temperature and water variables imposed on the roots of corn (Zea mays L.) in field plots influenced root development. Responses were measured in separate portions of the root system where adventitious roots initiate and subsequent root elongation and branching occurs. These portions of the corn root system are separated far enough to permit specific field management for each portion. Temperature and water variables were produced by combinations of straw‐mulch strips and interrow tillage.Initiation of adventitious roots in the 0‐ to 10‐cm soil depth was dominantly influenced by soil temperature in the row.In soil depths below 10 cm, a functional relation between root configuration and the interrow‐minus‐row soil temperature, and matric suction described the elongation and branching responses subsequent to root initiation. In the year of lower soil temperature and higher moisture (measurements were made in two growing seasons), higher interrow temperatures stimulated branching and elongation, but in the year of higher soil temperature and moderate moisture conditions, responses to temperature were negligible. Higher interrow moisture stimulated branching and elongation in both years as long as the average matric suction was greater than about 85 mb.These explicit descriptions of corn‐root‐configuration response show the importance of soil temperature management in the row and water management in the interrow. This approach permits more extensive use of the row‐interrow concept for design of minimum tillage and residue management systems.

Effects of Subsurface Asphalt Layers on Corn and Tomato Root Systems1

AbstractIn recent years several reports have indicated an improved crop production on droughty sands treated with a subsurface asphalt layer at depths of about 60 cm. Root growth in these modified soil profiles has not been investigated. This study was initiated to determine the nature and reason of any influence of a subsurface asphalt layer on root growth and distribution in the soil profile.Observations of root distributions of sweet corn (Zea mays L. var. ‘Rugosa’) and tomato (Lycopersicon esculentum Mill. var. ‘Commune’) were made in freshly dug pits. Root sections in and out of the asphalt layer were photographed and examined microscopically for morphological effects. The “line‐intercept” method was used to obtain quantitative measurements of root concentration (cm root/cc soil) of field corn (Zea mays L).Tomato roots in the asphalt layer were larger in diameter and showed damage to cells in the cortex. Rooting of all crops was less extensive in soil below the asphalt layer than in soil at the same depth without the asphalt. Concentration of corn roots in the top 60 cm of soil averaged 1.6, 1.7, 2.0, and 2.2 cm/cc for the following respective treatments: control, control with irrigation, asphalt layer, and asphalt layer with irrigation. This compensation effect would limit any reduction in value of the root‐resistant asphalt layer to situations of low rainfall without irrigation.

Structure and conductivity of the corn root system

When comparing conductivity in 5 mm long segments from the basis of the primary seminal root with that in segments from adventitious roots of the first to fifth node it was revealed that the conductivity is not a general function of the transection area. The conductivity determined experimentally is minimal in the primary seminal root and gradually increases in the adventitious roots. However, when calculating per area unit, roots of the first coleoptile node appear the most efficient, with roots of the second and third node the values gradually decrease, and conductivity in roots of the fourth and fifth node approximately equals that of the primary seminal roots. The conductivity is not a function of the conducting area. The conducting capacity of tissues which do not function directly as conductors is substantially lower; however, they cannot be neglected in evaluating the conductivity because of their high percentual occurence. The total conductivity in the individual root types is influenced by the ratio of the participation of water-conducting and non-conducting tissues.

Excavation and Permanent Mounting of Corn Root Systems1

AbstractPermanent mounting of corn (Zea mays L.) root systems obtained by a pinboard technique can be achieved by placing the root system on a sheet of foamed polystyrene resin and spraying the roots and associated resin with an aerosol polyvinylchloride plastic. The polyvinylchloride forms a protective coating around the roots. The organic solvents present in the aerosol dissolve the surface of the adjacent resin and this, on drying, cements the root systems to the resin sheet.

THE LITHIUM METHOD OF MEASURING THE EXTENT OF CORN ROOT SYSTEMS

THE LITHIUM METHOD OF MEASURING THE EXTENT OF CORN ROOT SYSTEMS

Some Results of Differential Feeding by Corn Root Systems

Some Results of Differential Feeding by Corn Root Systems