Seasonal development of above‐ and below‐ground organs of Trifolium pratense in grass–legume mixture on different soils

Abstract

Grass–legume mixtures are suitable for crop rotations in organic farming. However, seasonal development of below‐ground organs of Trifolium pratense in mixtures and on different soils was neglected. We asked (1) how the diameter of the root neck, the maximum order of branching as well as (2) the nodule traits are affected by locality and time, and (3) how above‐ground plant traits of red clover vary in space and time. Red clover was investigated in grass–legume mixtures in the first year of vegetation. Five sites in S Germany were sampled at the day of cut at the end of May, the beginning of July, and at the end of August, respectively. Under similar climatic conditions root traits (diameter of the root neck, order of root branching, size of nodules, and proportion of senescent nodules) differed with soil conditions and time within the season. Root diameter increased during the season. Higher sand content fostered root branching and branched roots developed more nodules. Thinner roots had more active nodules (pink). Root diameter and non‐active senescent (green) or moribund (brown) nodules increased at the end of season. Nodule activity differed more according to season than to soil conditions. The number of nodules per plant (12.5–19.5) decreased from May to August. Cylindrical nodules were found on 85–100% of the plants and branched nodules only on 0–25%. The height of plants was lowest in May and increased in July. The mean number of stems per plant (3.3–6.3) was highest in August. Understanding red clover traits and N2 fixation is interesting scientifically as well as agronomical. Organic and conventional farmers can both benefit of our findings.

Assessing the accuracy of current near infra-red reflectance spectroscopy analysis for fresh grass-clover mixture silages and development of new equations for this purpose

“…Roughly half the total number of samples obtained were below the minimum optimum clover inclusion rate of 300 g/kg DM suggested by Nyfeler et al (2011). This may be due to the sample set comprising a greater number of first cut silage samples than second, third or fourth cuts in which CC would have been greater due to warmer and drier conditions in the latter half of the year (Chmelikova et al, 2015).…”

A new emphasis on root traits for perennial grass and legume varieties with environmental and ecological benefits

“…Typical approaches, such as those described by Chmelikova et al. () for analysis of red clover roots, involve digging up a soil monolith beneath the plant and washing to extract the below‐ground organs of the plants from the soil. The root mass of the whole plant is then digitized using a scanner and the number and size of roots quantified.…”

“…Phenotyping of root traits presents technical challenges, particularly in relation to the number of plants that must be screened in a plant breeding program. Typical approaches, such as those described by Chmelikova et al (2015) for analysis of red clover roots, involve digging up a soil monolith beneath the plant and washing to extract the below-ground organs of the plants from the soil. The root mass of the whole plant is then digitized using a scanner and the number and size of roots quantified.…”