Nitrogen Transfer Between Plants: A 15N Natural Abundance Study with Crop and Weed Species

Abstract

An increasing amount of evidence indicates that N can be transferred between plants. Nonetheless, a number of fundamental questions remain. A series of experiments was initiated in the field to examine N transfer between N 2 -fixing soybean (Glycine max [L.] Merr.) varieties and a non-nodulating soybean, and between N 2 -fixing peanut (Arachis hypogaea L.) or soybean and neighboring weed species. The experiments were conducted in soils with low N fertilities and used differences in N accumulation and/or 15 N natural abundance to estimate N transfer. Mixtures of N 2 -fixing and non-nod soybean indicated that substantial inter-plant N transfer occurred. Amounts were variable, ranging from negligible levels to 48% of the N found in the non-nod at maturity. Transfer did not appear to strongly penalize the N 2 -fixing donor plants. But, in cases where high amounts of N were transferred, N content of donors was noticeably lowered. Differences were evident in the amount of N transferred from different N 2 -fixing donor genotypes. Results of experiments with N 2 -fixing crops and the weed species prickly sida (Sida spinosa L.) and sicklepod (Senna obtusifolia [L.] Irwin & Barneby) also indicated substantial N transfer occurred over a 60-day period, with amounts accounting for 30-80% of the N present in the weeds. Transfer of N, however, was generally very low in weed species that are known to be non-hosts for arbuscular mycorrhizae (yellow nutsedge, Cyperus esculentus L. and Palmer amaranth, Amaranthus palmeri [S.] Watson). The results are consistent with the view that N transfer occurs primarily through mycorrhizal hyphal networks, and they reveal that N transfer may be a contributing factor to weed problems in N 2 -fixing crops in low N fertility conditions.

Nitrogen transfer from forage legumes to nine neighbouring plants in a multi-species grassland

“…This plant-derived belowground N can be taken up again by the plant that lost it or relocated to neighbouring plants over different pathways (Høgh-Jensen 2006;Paynel et al 2008). N can be relocated from plant to plant directly by rootroot contacts or arbuscular mycorrhizal fungi that often connect roots of different plant species (He et al 2003;Moyer-Henry et al 2006; van der Heijden and Horton 2009) or indirectly over immobilizationmineralization processes. Høgh-Jensen et al (2006) showed in a three-species grass-legume-herb mixture that towards the end of the growing season approximately 6% of N in chicory and almost three times as much in perennial ryegrass derived from lucerne while the exchange of N between the two non-leguminous plant species, chicory and perennial ryegrass, was small.…”

Aspectos fitossociológicos e manejo de plantas espontâneas utilizando espécies de cobertura em cafeeiro Conilon orgânico

“…Entretanto, podem competir com outras espécies vegetais por recursos escassos (água, luz e nutrientes), por meio da competição direta, ou por liberação de substâncias alelopáticas (MOYER-HENRY et al, 2006;KONG;WANG;XU, 2007), prejudicando o desenvolvimento das culturas (DIAS; ALVES; SOUZA., 2004;RONCHI;.…”

Root penetration through a high bulk density soil layer: differential response of a crop and weed species

“…But, a key question has been 'how are soil resources acquired to drive shoot growth processes when the larger soybean plants dominate the root zone?' One answer was provided in recent experiments by our group, where it was found that large amounts of N can be transferred from the N 2 -fixing soybean plants to sicklepod through mycorrhizal interconnections (Moyer-Henry et al 2006). From the current experiments, it also seems that sicklepod roots may have access to resources deeper in the soil horizon that are unavailable to soybean, especially if compaction zones exist.…”