Department of Soil Science, Universidade de São Paulo, Escola Superior de Agricultura "Luiz de Queiroz", Avenida Pádua Dias 11, 13418-900, Piracicaba, São Paulo, Brazil.
Shell Westhollow Technology Center, 3333 Highway 6 South, Houston, TX, 77082, USA.
J Environ Manage. 2019 Dec 15;252:109638. doi: 10.1016/j.jenvman.2019.109638. Epub 2019 Oct 3.
The application of biochar to soil combined with synthetic fertilizers has been proposed for enhancing N availability to plants and crop yields while reducing nitrous oxide (NO) emissions. However, little is known about those interactions for tropical soils. Thus, this study evaluated the effects of sugarcane straw biochar on tropical soil attributes, crop productivity, NO emissions and N use efficiency. It was conducted a greenhouse pot experiment with wheat cultivation using aN-labelled source (NHNO). The treatments evaluated were: Soil, with N, no biochar; Soil, with N and biochar at rates equivalent to 0.4%, 0.8% and 1.9% (w/w); and a control (soil only). Increasing biochar amendments decreased cumulative NO emissions by 71% compared to the fertilized, no-biochar soil. Moreover, increasing biochar rates to soil increased available P up to 30% and led to 8-fold higher exchangeable K concentrations. Grain yield and shoot biomass increased by 27 and 16%, respectively, with the rate of 1.9% biochar to soil, which also resulted in higher tillering and number of heads compared to fertilized, no-biochar soil. The amount of N in grains was 28% higher with 0.8 and 1.9% of biochar compared to no-biochar soil, which correspond to 25% of the total N-labelled fertilizer applied to soil. The N loss by volatilization did not differ between treatments. Nevertheless, the biochar amended soils produced less NO than the no-biochar treatment, indicating that biochar amendment to tropical soil led to gaseous N losses in forms other than NO. The application of biochar to soil improved N utilization and the efficiency with which N is acquired by the plants and converted to grain yield, thereby enhancing crop performance, while simultaneously reducing NO emissions from N fertilization, thus mitigating GHG emissions to the atmosphere under tropical conditions.
生物炭应用于土壤与合成肥料相结合，被提议用于提高植物对氮的利用率和作物产量，同时减少一氧化二氮（NO）排放。然而，对于热带土壤，人们对此知之甚少。因此，本研究评估了甘蔗秸秆生物炭对热带土壤特性、作物生产力、NO 排放和氮利用效率的影响。采用温室盆栽试验，用 15N 标记源（NH4NO3）进行小麦种植。评估的处理方法如下：土壤，含氮，无生物炭；土壤，含氮和生物炭，添加量分别相当于 0.4%、0.8%和 1.9%（w/w）；以及一个对照（仅土壤）。与施肥、无生物炭土壤相比，增加生物炭添加量可使累积 NO 排放减少 71%。此外，增加生物炭添加到土壤中可使有效磷增加 30%，并导致可交换钾浓度增加 8 倍。土壤中添加 1.9%生物炭可使籽粒产量和地上生物量分别增加 27%和 16%，与施肥、无生物炭土壤相比，分蘖数和穗数也有所增加。与无生物炭土壤相比，0.8%和 1.9%生物炭的籽粒氮含量分别增加了 28%，相当于施用于土壤的总 15N 标记肥料的 25%。氮挥发损失在不同处理之间没有差异。然而，与无生物炭处理相比，添加生物炭的土壤产生的 NO 较少，这表明生物炭添加到热带土壤中导致了除 NO 以外的气态氮损失形式。将生物炭应用于土壤可以提高氮的利用效率和植物对氮的获取效率，并将其转化为籽粒产量，从而提高作物的性能，同时减少氮施肥引起的 NO 排放，从而在热带条件下减轻大气温室气体排放。
