The projected population growth implies an increased food demand with a severe impact on Earth’s natural resources. Improving crops yield without compromising the environment will be one of the main challenges of the next decades. Among the practices that can promote sustainable agriculture, organic fertilizers, and seaweeds in particular, are receiving growing attention. The aim of the current study was to test two macroalgae (Chaetomorpha sp. and Cystoseira sp.), one microalga (Chlorella CH2) and Bioguano (a mixture of macroalgae, spirulina, and guano) as organic fertilizers for the growth of barley seedlings. Remarkable plant growth was obtained on Bioguano, with seedlings showing a comparable total biomass yield with respect to the positive control plants on mineral fertilizer. Plants growth on macroalgae was reduced, even if in Chaetomorpha sp. not significantly compared to the positive control. Plants growth on Chlorella CH2 was close to that of the negative control (only water). Plants on Bioguano attained high uptake efficiencies of N (60%) and K (41%). Plants on macroalgae showed high N, and especially P (about 30%) uptake efficiency. Our results suggest a high potential for Bioguano and, to a lesser extent, for macroalgae without any synthetic fertilizer application to be used as growing substrates for crops.

预计的人口增长意味着粮食需求增加，这将严重影响地球的自然资源。在不损害环境的情况下提高农作物产量将是未来几十年的主要挑战之一。在可以促进可持续农业发展的实践中，有机肥料尤其是海藻正受到越来越多的关注。本研究的目的是测试两种大型藻类（Chaetomorpha sp。和Cystoseira sp。），一种微藻类（Chlorella）CH2）和Bioguano（大型藻类，螺旋藻和鸟粪的混合物）作为大麦幼苗生长的有机肥料。在Bioguano上获得了显着的植物生长，幼苗显示出与矿物肥料上阳性对照植物相当的总生物量产量。即使在Chaetomorpha sp。中，大型藻类上的植物生长也会减少。与阳性对照相比没有显着差异。小球藻上的植物生长CH2接近阴性对照（仅水）。使用Bioguano的植物获得了较高的N（60％）和K（41％）吸收效率。大型藻类的植物表现出较高的氮素吸收效率，尤其是磷（约30％）。我们的结果表明，对于没有生物合成肥料用作农作物生长基质的大型生物来说，鸟粪有很大的潜力。