Department of Environmental Engineering, Norwegian Geotechnical Institute (NGI), P.O. Box 3930, Ullevål Stadion, NO-0806 Oslo, Norway; Faculty of Environmental Science and Natural Resource Management (MINA), Norwegian University of Life Sciences (NMBU), P.O. Box 5003, NO-1432 Ås, Norway.
Indonesian Soil Research Institute (ISRI), Bogor, Indonesia.
Sci Total Environ. 2018 Sep 1;634:561-568. doi: 10.1016/j.scitotenv.2018.03.380. Epub 2018 Apr 7.
Low fertility limits crop production on acidic soils dominating much of the humid tropics. Biochar may be used as a soil enhancer, but little consensus exists on its effect on crop yield. Here we use a controlled, replicated and long-term field study in Sumatra, Indonesia, to investigate the longevity and mechanism of the effects of two contrasting biochars (produced from rice husk and cacao shell, and applied at dosages of 5 and 15tha) on maize production in a highly acidic Ultisol (pH3.6). Compared to rice husk biochar, cacao shell biochar exhibited a higher pH (9.8 vs. 8.4), CEC (197 vs. 20cmolkg) and acid neutralizing capacity (217 vs. 45cmolkg) and thus had a greater liming potential. Crop yield effects of cacao shell biochar (15tha) were also much stronger than those of rice husk biochar, and could be related to more favorable Ca/Al ratios in response to cacao shell biochar (1.0 to 1.5) compared to rice husk biochar (0.3 to 0.6) and nonamended plots (0.15 to 0.6). The maize yield obtained with the cacao shell biochar peaked in season 2, continued to have a good effect in seasons 3-4, and faded in season 5. The yield effect of the rice husk biochar was less pronounced and already faded from season 2 onwards. Crop yields were correlated with the pH-related parameters Ca/Al ratio, base saturation and exchangeable K. The positive effects of cocoa shell biochar on crop yield in this Ultisol were at least in part related to alleviation of soil acidity. The fading effectiveness after multiple growth seasons, possibly due to leaching of the biochar-associated alkalinity, indicates that 15tha of cocoa shell biochar needs to be applied approximately every third season in order to maintain positive effects on yield.
低生育率限制了主导潮湿热带地区大部分地区的酸性土壤上的作物生产。生物炭可用作土壤改良剂，但对于其对作物产量的影响尚未达成共识。在这里，我们使用印度尼西亚苏门答腊的一项对照、重复和长期田间研究来调查两种不同生物炭（由稻壳和可可壳制成，施用量为 5 和 15 吨/公顷）对高度酸性强风化淋溶土（pH3.6）上玉米生产的长期影响和作用机制。与稻壳生物炭相比，可可壳生物炭表现出更高的 pH（9.8 对 8.4）、CEC（197 对 20cmolkg）和酸中和能力（217 对 45cmolkg），因此具有更大的石灰化潜力。可可壳生物炭（15 吨/公顷）的作物产量效应也远强于稻壳生物炭，这可能与可可壳生物炭（1.0 至 1.5）相比稻壳生物炭（0.3 至 0.6）和未施肥样地（0.15 至 0.6）的更有利的 Ca/Al 比有关。与稻壳生物炭相比，可可壳生物炭的玉米产量在第 2 季达到峰值，在第 3-4 季继续产生良好的效果，在第 5 季逐渐减弱。稻壳生物炭的产量效应不那么明显，从第 2 季开始就已经减弱。作物产量与 pH 相关参数 Ca/Al 比、基础饱和度和可交换 K 相关。可可壳生物炭对该强风化淋溶土作物产量的积极影响至少部分归因于土壤酸度的缓解。在多个生长季节后，有效性逐渐减弱，可能是由于生物炭相关碱度的淋失，这表明需要每三个季节大约施加 15 吨/公顷的可可壳生物炭，以维持对产量的积极影响。
