Root growth dynamics and biomass input by Nordic annual field crops

• Published in: Agriculture, ecosystems & environment Vol. 108; no. 2; pp. 135 - 144
• Main Authors: Pietola, Liisa, Alakukku, Laura
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-06-2005; Elsevier Science
• Subjects: Agronomy. Soil science and plant productions; assimilation (physiology); Avena sativa; barley; Biological and medical sciences; biomass; Brassica rapa; carbon; Fundamental and applied biological sciences. Psychology; General agroecology; General agroecology. Agricultural and farming systems. Agricultural development. Rural area planning. Landscaping; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; Hordeum vulgare; Lolium multiflorum; Minirhizotron; oats; rapeseed; Root biomass; root growth; Root length density; Root surface area; Root width; roots; Shoot:root; shoots; Finland; Europe; Avena sativa; Root biomass; Root surface area; Brassica rapa; Minirhizotron; Hordeum vulgare; Lolium multiflorum; Shoot:root; Root width; Root length density; Monocotyledones; Brassica napus var. oleifera; Growth; Water supply; Sandy soil; Biomass; Cruciferae; Gramineae; Dicotyledones; Angiospermae; Cultivated plant; Root; Source sink relationship; Agroecosystem; Carbon cycle; Nutrient; Spermatophyta
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/j.agee.2005.01.009

Roots are an important sink for photoassimilates and carbon input to soil. Here the root growth and biomass of different spring sown annuals was determined to estimate the shoot:root (S:R) ratios and carbon inputs in the typical Nordic agroecosystem. The data, collected in southern Finland, present evidence for large difference in root growth dynamics and biomass input between spring oilseed rape (
Brassica rapa L.) and annual ryegrass (
Lolium multiflorum Lam. var
. italicum) whereas the rooting of spring sown barley (
Hordeum vulgare) and oats (
Avena sativa) was related. The four crops were sown at the same time in a field with a fine sand soil (Eutric Cambisol) with good nutrient and water supply. During one growing season, root growth was determined 12 times to a soil depth of 50
cm by using a minirhizotron-micro-video camera technology. At anthesis, root biomass and morphological parameters were measured to 60
cm soil depth at 5
cm intervals, with destructive soil sampling and image analysis of washed roots. The root growth rate of oilseed rape was clearly faster and that of rye grass slower compared with the other crops. At anthesis, the average total root dry biomass (0–60
cm) was160
g for barley, 260
g for oats, 340
g for ryegrass, and 110
g
m
−3 for oilseed rape. Also, the root length density and surface area of oilseed rape was less than that of other crops. Most of the biomass (59–80%) was accumulated the upper 20
cm of the soil. Shoot to root ratios (at anthesis for the seed crops) of 7.1, 4.4, 4.2 and 2.5 for barley, oats, oilseed rape, and ryegrass respectively, could be used for an approximation to estimate the amount of root biomass left in the 0–60
cm soil layer under Nordic long day conditions. In contrast to the seed crops, the root growth rate and density of ryegrass was high in the late season. Thus, ryegrass would be an efficient catch crop after harvest of cereals.