Wang Zhi-Gang, Jin Xin, Bao Xing-Guo, Li Xiao-Fei, Zhao Jian-Hua, Sun Jian-Hao, Christie Peter, Li Long
Key Laboratory of Plant and Soil Interactions, Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Institute of Soils, Fertilizers and Water-Saving Agriculture, Gansu Academy of Agricultural Sciences, Lanzhou 730070, China.
PLoS One. 2014 Dec 8;9(12):e113984. doi: 10.1371/journal.pone.0113984. eCollection 2014.
Yield and nutrient acquisition advantages are frequently found in intercropping systems. However, there are few published reports on soil fertility in intercropping relative to monocultures. A field experiment was therefore established in 2009 in Gansu province, northwest China. The treatments comprised maize/faba bean, maize/soybean, maize/chickpea and maize/turnip intercropping, and their correspoding monocropping. In 2011 (the 3rd year) and 2012 (the 4th year) the yields and some soil chemical properties and enzyme activities were examined after all crop species were harvested or at later growth stages. Both grain yields and nutrient acquisition were significantly greater in all four intercropping systems than corresponding monocropping over two years. Generally, soil organic matter (OM) did not differ significantly from monocropping but did increase in maize/chickpea in 2012 and maize/turnip in both years. Soil total N (TN) did not differ between intercropping and monocropping in either year with the sole exception of maize/faba bean intercropping receiving 80 kg P ha-1 in 2011. Intercropping significantly reduced soil Olsen-P only in 2012, soil exchangeable K in both years, soil cation exchangeable capacity (CEC) in 2012, and soil pH in 2012. In the majority of cases soil enzyme activities did not differ across all the cropping systems at different P application rates compared to monocrops, with the exception of soil acid phosphatase activity which was higher in maize/legume intercropping than in the corresponding monocrops at 40 kg ha-1 P in 2011. P fertilization can alleviate the decline in soil Olsen-P and in soil CEC to some extent. In summary, intercropping enhanced productivity and maintained the majority of soil fertility properties for at least three to four years, especially at suitable P application rates. The results indicate that maize-based intercropping may be an efficient cropping system for sustainable agriculture with carefully managed fertilizer inputs.
间作系统中常常具有产量和养分获取优势。然而，关于间作相对于单作的土壤肥力，已发表的报告较少。因此，2009年在中国西北部的甘肃省开展了一项田间试验。试验处理包括玉米/蚕豆、玉米/大豆、玉米/鹰嘴豆和玉米/芜菁间作，以及它们相应的单作。2011年（第3年）和2012年（第4年），在所有作物收获后或在生长后期，对产量、一些土壤化学性质和酶活性进行了检测。在两年时间里，所有四种间作系统的谷物产量和养分获取均显著高于相应的单作。总体而言，土壤有机质（OM）与单作相比无显著差异，但在2012年玉米/鹰嘴豆间作以及两年的玉米/芜菁间作中有所增加。土壤全氮（TN）在间作和单作之间，除了2011年施磷量为80 kg P ha-1的玉米/蚕豆间作外，在任何一年均无差异。间作仅在2012年显著降低了土壤有效磷、两年均降低了土壤交换性钾、2012年降低了土壤阳离子交换量（CEC）以及2012年降低了土壤pH值。在大多数情况下，与单作相比，不同施磷水平下所有种植系统的土壤酶活性并无差异，但2011年施磷量为40 kg ha-1时，玉米/豆科植物间作的土壤酸性磷酸酶活性高于相应的单作。施磷可以在一定程度上缓解土壤有效磷和土壤阳离子交换量的下降。总之，间作提高了生产力，并在至少三到四年内维持了大部分土壤肥力特性，尤其是在合适的施磷水平下。结果表明，基于玉米的间作可能是一种高效的种植系统，通过精心管理肥料投入实现可持续农业。
