Soil functions (potential enzyme activity and nitrogen cycling rates) from manipulative experiment adding fertilizer and supplemental late-spring precipitation to a 50-ha northern California grassland underlain by a mosaic of serpentine and non-serpentine soils (November 2012-May 2013)

Experiment added fertilizer and supplemental late-spring precipitation to a 50-ha northern California grassland underlain by a mosaic of serpentine and non-serpentine soils. Measurements of soil functions were taken after three years of consistent treatment application.Contents are as follows:"plot.name": unique name for each of the 132 plots in the experiment"irrigation.line": code indicating which irrigation line carried the supplemental precipitation to the plot"soil.type": whether the plot was on harsh serpentine (Harshserp), lush serpentine (Lushserp), or non-serpentine (Nonserp) soil"treatment": C = control (no fertilizer or water added), F = fertilized (fertilizer added but no water added), W = watered (water added but no fertilizer added), FW = fertilized + watered (both fertilizer and water added)"watering": whether the plot was watered or unwatered"fertilization": whether the plot was fertilized or unfertilized"tpc.native": total proteolytic capacity with native substrate (no substrate added to soil) [mg N-AA / kg dry soil / day]; measured early May 2013"tpc.saturated": total proteolytic capacity with saturated substrate (saturating amount of casein added to soil) [mg N-AA / kg dry soil / day]; measured early May 2013"BG": potential activity of beta-1,4-glucosidase [mmol substrate cleaved / kg dry soil / hour]; measured early May 2013"NAG": potential activity of beta-N-acetylglucosaminidase [mmol substrate cleaved / kg dry soil / hour]; measured early May 2013"AP": potential activity of acid phosphatase [mmol substrate cleaved / kg dry soil / hour]; measured early May 2013"PPO": potential activity of polyphenol oxidase [mmol substrate cleaved / kg dry soil / hour]; measured early May 2013"PER": potential activity of peroxidase [mmol substrate cleaved / kg dry soil / hour]; measured early May 2013"fall.net.mineralization.rate": rate of net nitrogen mineralization during 7-day laboratory incubation at field moisture content [mg NH4-N + NO3-N / kg dry soil / day]; measured on soil samples collected early November 2012"fall.net.nitrification.rate": rate of net nitrification during 7-day laboratory incubation at field moisture content [mg NO3-N / kg dry soil / day]; measured on soil samples collected early November 2012"winter.net.mineralization.rate": rate of net nitrogen mineralization during 7-day laboratory incubation at field moisture content [mg NH4-N + NO3-N / kg dry soil / day]; measured on soil samples collected early February 2013"winter.net.nitrification.rate": rate of net nitrification during 7-day laboratory incubation at field moisture content [mg NO3-N / kg dry soil / day]; measured on soil samples collected early February 2013"earlyspring.net.mineralization.rate": rate of net nitrogen mineralization during 7-day laboratory incubation at field moisture content [mg NH4-N + NO3-N / kg dry soil / day]; measured on soil samples collected mid-March 2013"earlyspring.net.nitrification.rate": rate of net nitrification during 7-day laboratory incubation at field moisture content [mg NO3-N / kg dry soil / day]; measured on soil samples collected early mid-March 2013"latespring.net.mineralization.rate": rate of net nitrogen mineralization during 7-day laboratory incubation at field moisture content [mg NH4-N + NO3-N / kg dry soil / day]; measured on soil samples collected late May 2013"latespring.net.nitrification.rate": rate of net nitrification during 7-day laboratory incubation at field moisture content [mg NO3-N / kg dry soil / day]; measured on soil samples collected late May 2013

本实验在加利福尼亚北部一片面积为50公顷的草原开展，该区域土壤呈蛇纹岩与非蛇纹岩镶嵌分布的格局。研究设置了施肥与春末补充降水的处理组合，在连续三年施加固定处理后，对土壤功能相关指标进行了测定。具体字段说明如下：
"plot.name"：本实验共132个样地，该字段为每个样地的唯一名称
"irrigation.line"：用于标识为该样地输送补充降水的灌溉管线代码
"soil.type"：标注样地所在土壤类型，包含严苛型蛇纹岩土（Harshserp）、丰沃型蛇纹岩土（Lushserp）与非蛇纹岩土（Nonserp）
"treatment"：C为对照组（不施加肥料与补水）、F为施肥组（仅施加肥料，不补水）、W为补水组（仅补水，不施肥）、FW为施肥+补水组（同时施加肥料与补水）
"watering"：标注该样地是否接受补水处理
"fertilization"：标注该样地是否接受施肥处理
"tpc.native"：以原生底物（未向土壤额外添加底物）为底物时的总蛋白水解能力，单位为mg N-AA / kg干土 / 天，于2013年5月初测定
"tpc.saturated"：以饱和浓度酪蛋白为底物时的总蛋白水解能力，单位为mg N-AA / kg干土 / 天，于2013年5月初测定
"BG"：β-1,4-葡萄糖苷酶潜在活性，单位为mmol底物裂解 / kg干土 / 小时，于2013年5月初测定
"NAG"：β-N-乙酰氨基葡萄糖苷酶潜在活性，单位为mmol底物裂解 / kg干土 / 小时，于2013年5月初测定
"AP"：酸性磷酸酶潜在活性，单位为mmol底物裂解 / kg干土 / 小时，于2013年5月初测定
"PPO"：多酚氧化酶潜在活性，单位为mmol底物裂解 / kg干土 / 小时，于2013年5月初测定
"PER"：过氧化物酶潜在活性，单位为mmol底物裂解 / kg干土 / 小时，于2013年5月初测定
"fall.net.mineralization.rate"：田间含水量条件下7天实验室培养的净氮矿化速率，单位为mg NH4-N + NO3-N / kg干土 / 天，基于2012年11月初采集的土壤样品测定
"fall.net.nitrification.rate"：田间含水量条件下7天实验室培养的净硝化速率，单位为mg NO3-N / kg干土 / 天，基于2012年11月初采集的土壤样品测定
"winter.net.mineralization.rate"：田间含水量条件下7天实验室培养的净氮矿化速率，单位为mg NH4-N + NO3-N / kg干土 / 天，基于2013年2月初采集的土壤样品测定
"winter.net.nitrification.rate"：田间含水量条件下7天实验室培养的净硝化速率，单位为mg NO3-N / kg干土 / 天，基于2013年2月初采集的土壤样品测定
"earlyspring.net.mineralization.rate"：田间含水量条件下7天实验室培养的净氮矿化速率，单位为mg NH4-N + NO3-N / kg干土 / 天，基于2013年3月中旬采集的土壤样品测定
"earlyspring.net.nitrification.rate"：田间含水量条件下7天实验室培养的净硝化速率，单位为mg NO3-N / kg干土 / 天，基于2013年3月中旬采集的土壤样品测定
"latespring.net.mineralization.rate"：田间含水量条件下7天实验室培养的净氮矿化速率，单位为mg NH4-N + NO3-N / kg干土 / 天，基于2013年5月下旬采集的土壤样品测定
"latespring.net.nitrification.rate"：田间含水量条件下7天实验室培养的净硝化速率，单位为mg NO3-N / kg干土 / 天，基于2013年5月下旬采集的土壤样品测定