种植牧草和增施生物质炭对松嫩平原退化盐碱草地土壤养分的影响

Effects of planting herbage and adding biochar on soil nutrients of degraded saline-alkali grassland in Songnen Plain

为了研究生物质炭对退化盐碱草地土壤养分的影响,试验在松嫩平原退化盐碱草地连续两年(2019年和2020年)施用不同水平的秸秆生物质炭,采用随机区组设计,共设6个处理,即空白对照(CK),未种植鹅头稗+未施加生物质炭;M0,种植鹅头稗+未施加生物质炭;M30,种植鹅头稗+施加生物质炭30 t/hm^(2);M60,种植鹅头稗+施加生物质炭60 t/hm^(2);M90,种植鹅头稗+施加生物质炭90 t/hm^(2);M120,种植鹅头稗+施加生物质炭120 t/hm^(2)。2019年9月份和2020年9月份采集土壤样品,测定其p H值、有机质、全氮、全磷和全钾含量,同时测定牧草的株高和鲜重。结果表明:与CK平均值相比,连续两年施用生物质炭可显著降低土壤pH值(P<0.05),在2020年,M120处理p H值的平均值虽降低,但没达到显著水平(P>0.05);与M0处理和CK相比,M30、M60、M90、M120处理可以显著提高土壤有机质、全氮、全磷、全钾含量(P<0.05);M90处理鹅头稗牧草株高及鲜重达到最高值,与M0处理相比,株高分别提高了54.49%(2019年)和52.56%(2020年),鲜重分别提高了10.95%(2019年)和11.20%(2020年)。从牧草株高、鲜重、土壤养分及经济投入角度综合分析,施用生物质炭90 kg/hm^(2)时,对pH值>10的退化盐碱草地的改良效果较好,适宜在齐齐哈尔地区退化盐碱草地大面积推广。

To investigate the effects of biochar on soil nutrients of degraded saline-alkali grassland, in the experiment, different levels of straw biochar were applied to degraded saline-alkali grassland in Songnen Plain for two consecutive years(from 2019 to 2020), and a randomized block design was used. A total of six treatments were set, namely blank control(CK), without growing Echinochloa crusagalli(L.) Beauv. and without applying biochar;M0, growing Echinochloa crusagalli(L.) Beauv. without biochar;M30, growing Echinochloa crusagalli(L.) Beauv. with biochar 30 t/hm^(2);M60, growing Echinochloa crusagalli(L.) Beauv. with biochar 60 t/hm^(2);M90, growing Echinochloa crusagalli(L.) Beauv. with biochar 90 t/hm^(2);M120, growing Echinochloa crusagalli(L.) Beauv. with biochar 120 t/hm^(2). Soil samples were collected in September 2019 and 2020 to determine the pH value, the contents of organic matter, total nitrogen, total phosphorus and total potassium, and the plant height and fresh weight of herbage. The results showed that compared with the average of CK, the application of biochar for two consecutive years significantly decreased the soil pH value(P<0.05). In 2020, the average pH value in the M120 treatment was decreased, but did not reach a significant level(P>0.05). Compared with the M0 treatment and CK, the contents of soil organic matter, total nitrogen, total phosphorus and total potassium in the M30, M60, M90 and M120 treatment were significantly increased(P<0.05). Compared with the M0 treatment, the plant height and fresh weight of paspalum in the M90 treatment reached the highest value. The plant height increased by 54.49%(2019) and 52.56%(2020), respectively, and the fresh weight increased by 10.95%(2019) and 11.20%(2020), respectively. With comprehensive analysis of forage plant height, fresh weight, soil nutrients and economic input, when the application of biochar was 90 kg/hm^(2), the improvement effect of degraded salinee-alkali grassland with pH value>10 was better. The results indicated that it was suitable to be widely used in degraded saline-alkali grassland in Qiqihar area.