Data from: How does soil organic matter affect potato productivity on sandy soil?

While many studies note the positive effects of soil organic matter (SOM)
on crop yields, there is limited quantitative information on the influence
of increased SOM on potato productivity in sandy soil. This study
estimated the impact of varying SOM on potato productivity in sandy soils
and explored whether nitrogen (N) mineralization served as a primary
mediator. Soil from nine fields in Wisconsin (SOM range of 1.1 to 3.8 %)
was collected for a greenhouse study. Both NH4-N and NO3-N extracted from
ion strips and potentially mineralizable nitrogen (PMN) were used as the
proxies for N mineralization. Linear mixed effect models indicated that
fresh matter whole biomass and dry matter vine biomass were 0.45 and 0.54
times greater at 3.8 % SOM compared to 1.1 % SOM at an optimal soil pH of
5.2, respectively. Similarly, total N uptake in the whole and vine biomass
was 0.51 and 1.0 times higher at 3.8 % SOM than 1.1 % SOM, respectively.
While PMN demonstrated a positive correlation with SOM, it only partially
mediated the effect of SOM on productivity, specifically in N uptake in
the vines. However, for most productivity measures, including PMN with SOM
in the models did not substantially reduce the estimated SOM effect on
productivity, indicating that SOM affected productivity mostly through
mechanisms other than N acquisition by plants available through
mineralization of OM. The study underscored the complex interplay between
SOM and potato productivity, urging further research into the multifaceted
roles of SOM in sandy soils.

尽管诸多研究均证实了土壤有机质（Soil Organic Matter, SOM）对作物产量的正向作用，但针对沙质土壤中SOM提升对马铃薯生产力的影响，现有定量研究仍较为匮乏。本研究旨在评估沙质土壤中SOM水平变化对马铃薯生产力的影响，并探究氮（Nitrogen, N）矿化是否为其主要介导因子。研究团队从美国威斯康星州的9块农田采集土壤样品（SOM含量范围为1.1%~3.8%），用于开展温室培养试验。本研究采用离子交换膜（Ion Strips）提取的铵态氮（Ammonium-N, NH₄-N）与硝态氮（Nitrate-N, NO₃-N），以及潜在可矿化氮（Potentially Mineralizable Nitrogen, PMN）作为氮矿化的替代指标。线性混合效应模型（Linear Mixed Effect Models）结果显示，在土壤pH值为最佳水平5.2的条件下，当SOM含量为3.8%时，植株全株鲜生物量与藤茎干生物量分别较SOM含量1.1%的处理组高出0.45倍与0.54倍。类似地，当SOM含量为3.8%时，植株全株与藤茎的总氮吸收量分别较1.1% SOM时高出0.51倍与1.0倍。尽管潜在可矿化氮（PMN）与SOM呈显著正相关，但它仅能部分介导SOM对马铃薯生产力的影响，且该介导作用仅体现在藤茎的氮吸收过程中。然而，针对多数生产力指标而言，在模型中纳入PMN与SOM后，SOM对生产力的预估效应并未出现显著降低，这表明SOM对生产力的影响主要并非通过植物可通过有机质矿化获取的氮素途径实现。本研究揭示了SOM与马铃薯生产力之间的复杂相互作用，并呼吁未来开展更多研究，以探究SOM在沙质土壤中的多重作用机制。