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Highlights: [•] A one-year experiment was conducted in a field used to grow annual ryegrasses. [•] Manure was applied at a rate of 150m3 ha−1 (410kgNha−1) to all treatments. [•] We included a control and two biochar treatments (5.7tha−1 and 18.8tha−1). [•] Biochar did not impact GHG emission but temporarily decreased NO3 in leachate. [•] Biochar increased K in leachate and temporarily increased P and NH4 in leachate. [Copyright &y& Elsevier]

In California's Mediterranean type grasslands, native perennial grasses such as Nassella pulchra are surrounded by introduced annual species and these annuals are thought to have displaced natives through much of their range. Amongst other invaders, two grasses Lolium multiflorum and Bromus hordeaceus, commonly dominate portions of the grassland with potential for N. pulchra restoration. We hypothesized that competitor species differences and small-scale gaps (150 cm2) could be important determinants of N. pulchra survival and performance on these sites. Lolium multiflorum and B. hordeaceus were planted in 20 cm diameter circular plots at a constant rate of 1 seed per cm2 surrounding newly transplanted N. pulchra plants. Nassella pulchra showed no significant effect of the species of competitor or from the distribution of the competitors. Both interspersion of patches of bare ground and separation of competitors into patches did not increase N. pulchra pre-dawn water potential, basal area change, number of seeds produced, or average weight of seeds. The presence of L. multiflorum was associated with a decrease in N. pulchra survival compared with plots with only B. hordeaceus. Plants with increases in basal area of less than 0.75 cm2 during the growing season had 74% mortality compared with no mortality in plants with more growth. However, initial N. pulchra plant size was not a good predictor of mortality. Limiting competition from annuals may increase survival of N. pulchra plantings, but 60% of the plants survived for at least 1 year, despite being transplanted into soil containing substantial annual grass seed. [ABSTRACT FROM AUTHOR]

Focuses on a report by Lyons and Schwartz, which suggests that rare plant species contribute to the resistance of ecological communities to invasion. Series of experiments in a California grassland ecosystem; Susceptibility to successful invasion by an exotic ryegrass.