Urease activity as affected by main effects of P application and subplot effects of cropping system in 2011 and 2012.

Values are means of three replicates. Values followed by the same lowercase letters are not significantly different among different cropping systems with the same P rate in one year at the 5% level by LSD (horizonal comparison); values followed by the same capital letters are not significantly different among different P rates (vertical comparison) or among different cropping systems (horizonal comparison) in one year at the 5% level by LSD. Values under ANOVA are the probabilities (P values) of the sources of variation. Urease activity as affected by main effects of P application and subplot effects of cropping system in 2011 and 2012.所有数值均为三次重复的平均值。标注有相同小写字母的数值，在同一年份、相同磷肥施用量下，不同种植系统间经最小显著差数法（LSD, Least Significant Difference）检验，在5%显著性水平上无显著差异（横向比较）；标注有相同大写字母的数值，在同一年份内，不同磷肥施用量间（纵向比较）或不同种植系统间（横向比较）经LSD检验，在5%显著性水平上无显著差异。方差分析（ANOVA, Analysis of Variance）对应的数值为各变异来源的概率值（P值）。 本数据集为2011年与2012年中，受磷肥施用主效应及种植系统裂区效应影响的脲酶活性。