紫色丘陵区玉米/大豆套作系统土壤磷吸附-解吸动力学

利用田间小区试验研究了玉米/大豆套作(M/S)、玉米单作(M)、大豆单作(S)3种栽培模式下施磷对土壤磷吸附解吸特征的影响.结果表明： 在不施磷处理下，M/S系统产量较M、S分别提高9.8%、79.1%，土地当量比为1.58；在施磷处理下，M/S系统产量较M、S分别提高10.4%、80.3%，土地当量比为1.62.与不施磷处理相比，施磷使M/S、M、S 3种栽培模式下的系统总产量分别提高12.7%、12.2%、17.6%.无论施磷与否，3种栽培模式下土壤最大缓冲容量(SBC)值均表现为M/S>M>S；但与施磷处理相比，不施磷处理下M/S、M、S栽培模式下土壤SBC值分别降低19.6%、30.3%、12.0%.各栽培模式在施磷处理下土壤单位吸附量的解吸量b值大小为M/S>M>S；与不施磷处理相比，施磷使M/S、M、S模式下b值分别增加10.9%、39.1%、-9.6%.土壤最大吸磷量(Q_m)及土壤磷解吸率也表现出相同的趋势.

Dynamics of soil phosphorus adsorption-desorption in maize/soybean relay intercropping system in purple hilly area.

Field plot experiment was carried out to study the effect of phosphorus application on soil phosphorus adsorption desorption characteristics under three cropping patterns including maize/soybean relay intercropping (M/S), maize monoculture (M), and soybean monoculture (S). Results showed that without phosphorus fertilization, the system crop yield under M/S was increased by 9.8% and 79.1% compared with that of M and S, respectively, and the land equivalent ratio (LER) was 1.58. With phosphate fertilizer application, the system crop yield under M/S was increased by 10.4% and 80.3% compared with that of M and S, respectively, and theLER was 1.62. The system crop yields under M/S, M and S with phosphate fertilizer application were increased by 12.7%, 12.2% and 17.6%, respectively, compared with that without phosphorus fertilization. Among three cropping patterns, the soil buffer capacity (SBC) values were in the order of M/S>M>S regardless of phosphate fertilizer applied or not. The SBC values of M/S, M and S without phosphate fertilizer application were reduced by 19.6%, 30.3% and 12.0% compared with phosphate fertilizer application treatments, respectively. The soil desorption per absorption (b) values of the three cropping patterns with phosphate fertilizer application were in the order of M/S>M>S, and the b values increased by 10.9%, 39.1% and -9.6%, respectively, compared with non phosphate fertilizer application. The soil phosphorus maximum absorption (Q_m) and soil phosphorus desorption rate also showed the same trend.