王瑞雪, 苏丽珍, 张连娅, 王思睿, 王景, 肖靖秀, 郑毅, 汤利. 玉米与大豆间作土壤生物学活性对磷有效性影响的定量解析[J]. 中国生态农业学报 (中英文), 2022, 30(7): 1155−1163. DOI: 10.12357/cjea.20210636
引用本文: 王瑞雪, 苏丽珍, 张连娅, 王思睿, 王景, 肖靖秀, 郑毅, 汤利. 玉米与大豆间作土壤生物学活性对磷有效性影响的定量解析[J]. 中国生态农业学报 (中英文), 2022, 30(7): 1155−1163. DOI: 10.12357/cjea.20210636
WANG R X, SU L Z, ZHANG L Y, WANG S R, WANG J, XIAO J X, ZHENG Y, TANG L. Quantitative mechanism analysis of the improved P availability in red soil during maize/soybean intercropping[J]. Chinese Journal of Eco-Agriculture, 2022, 30(7): 1155−1163. DOI: 10.12357/cjea.20210636
Citation: WANG R X, SU L Z, ZHANG L Y, WANG S R, WANG J, XIAO J X, ZHENG Y, TANG L. Quantitative mechanism analysis of the improved P availability in red soil during maize/soybean intercropping[J]. Chinese Journal of Eco-Agriculture, 2022, 30(7): 1155−1163. DOI: 10.12357/cjea.20210636

玉米与大豆间作土壤生物学活性对磷有效性影响的定量解析

Quantitative mechanism analysis of the improved P availability in red soil during maize/soybean intercropping

  • 摘要: 间作可提高红壤磷有效性, 但缺乏田间试验条件下土壤生物学活性与磷有效性之间关系的定量解析。通过4年的田间定位试验, 研究2017年和2020年玉米||大豆间作和玉米单作2种种植模式在4个施磷水平P0: 0 kg(P2O5)∙hm−2; P60: 60 kg(P2O5)∙hm−2; P90: 90 kg(P2O5)∙hm−2; P120: 120 kg(P2O5)∙hm−2下, 土壤磷有效性及其与主要土壤因素的关系, 通过回归分析、冗余分析与结构方程模型分析, 定量解析间作提高红壤磷有效性的机制。结果表明: 玉米干物质量土地当量比(LER)和磷吸收土地当量比(LERp)均大于1, 2020年LER随施磷水平的增加而降低, 但LERp不受磷水平影响。与单作相比, 间作显著提高了土壤速效磷含量, 且种植模式对土壤速效磷含量的影响由2017年的显著水平变化为2020年的极显著水平。回归分析表明, 单作条件下, 相比2017年, 2020年土壤有效磷(速效磷和微生物量磷)与作物磷吸收的线性关系斜率有所降低, 而间作条件下该斜率有所提高。冗余分析表明, 土壤速效磷和微生物量碳的增加对促进玉米磷吸收的解释量分别由单作中的37.6%和10.0%变化为间作中的33.3%和13.8%。通过结构方程模型分析发现, 碱性磷酸酶活性的提高能够直接提高土壤速效磷含量, 而酸性磷酸酶则通过提高微生物量磷含量进而提高土壤速效磷水平。因此, 在低磷条件下, 间作能够通过提高玉米根际土壤微生物量与磷酸酶活性而增强红壤磷有效性, 从而具有维持玉米干物质量及磷吸收量的能力。

     

    Abstract: Intercropping has been shown to improve P availability in red soil, but a quantitative mechanistic analysis of the relationships between soil biological activity and P availability has not been conducted in field experiments. The aim of this study was to determine the specific effect of soil biological activity on P availability in red soil. In this study, maize/soybean intercropping and maize monocropping with four P application levels 0 kg(P2O5)∙hm−2, 60 kg(P2O5)∙hm−2, 90 kg(P2O5)∙hm−2, and 120 kg(P2O5)∙hm−2, labeled as P0, P60, P90, and P120, respectively were used to analyze P availability and its relationship with major soil factors during a 4 year field experiment, which compared the values in the first and last years (2017 and 2020). Regression, redundancy, and structural equation model analyses were conducted to determine these relationships. The results showed that the land equivalent ratio of dry matter mass (LER) and land equivalent ratio of P uptake (LERp) were both greater than 1, indicating that intercropping increases biomass production and P uptake of crops. LER significantly (P<0.05) decreased with an increase in P application level in 2020, but LERp did not. This indicates that the advantage of P absorption in intercropping was not affected by P level, and low P levels still had the ability to maintain this advantage. Compared with monocropping, intercropping significantly (P<0.05) increased the soil available P content in maize rhizosphere; the increasing amplitude was from 24% to 103%, and the role of planting pattern changed from a significant level (P<0.05) in 2017 to an extremely significant level (P<0.01) in 2020. This indicates the effects of intercropping and P application on maize rhizosphere P availability in red soil with low fertility over multiple planting years. Regression analysis showed that the slope of the linear relationship between both Olsen-P and microbial biomass P (MBP) with maize P absorption in 2020 was lower than that in 2017 under monoculture (varied from 4.73 to 4.42 in Olsen-P and 19.68 to 7.16 in MBP), whereas the slope increased under intercropping (varied from 4.12 to 4.44 in Olsen-P and 13.72 to 17.78 in MBP). Redundancy analysis showed that the increase in soil available P and microbial biomass carbon (MBC) accounted for P absorption varied from 37.6% and 10.0% in monoculture to 33.3% and 13.8% in intercropping, respectively. This result shows that intercropping decreased the effect of available P on P uptake and increased the role of MBC. Through structural equation model analysis, increasing the activity of alkaline phosphatase was found to directly increase the content of soil available P, whereas acid phosphatase could increase soil available P by increasing MBP. These two enzymes are speculated to affect P availability in rhizosphere soil via different mechanisms. Therefore, under low P application levels, intercropping can enhance P availability in red soil by increasing soil microbial biomass and phosphatase activity in the maize rhizosphere, thus maintaining the dry matter mass and phosphorus uptake of maize. The quantitative contribution of microbial processes should be further studied.

     

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