Evaluation of legumes and poultry manure for the early protection of burnt soils .

Organic amendments combined with the sowing of gramineous grasses are effective for the early protection of burnt soils (BS) but cannot restore soil N status to pre-fire level; this has led to interest in combining their use with N₂ fixer legumes. The effectiveness of applying poultry manure (PM; 2 Mg ha^-1) and sowing legumes (<em>Lotus corniculatus, Lupinus polyphyllus </em>and <em>Trifolium repens</em>) for the early protection of BS was compared with that of applying PM + <em>Lolium perenne</em> and growing these four species without PM in a 3-month pot experiment, which also included a control consisting of an unburnt soil (US). In US, the shoot and root biomass increased as follows: <em>Trifolium </em>~<em> Lotus </em>&lt;&lt; <em>Lolium </em>&lt; <em>Lupinus.</em> Compared with those grown in US, plants grown in BS were smaller and weaker in three species (<em>Lupinus, Lolium</em> and <em>Trifolium</em>). The reverse was true for the four species grown in BS+PM, which showed the benefits of PM addition. In all the treatments, plant N uptake, which prevents soil-N losses, increased as follows: <em>Trifolium </em>~ <em>Lotus</em> &lt; <em>Lupinus </em>&lt; <em>Lolium.</em> The lack of nodules observed suggested that none of the legumes fixed atmospheric-N₂.