Soil enzymatic activity data over eight years at the EFELE site, a long-term field experiment on effects of organic waste products and tillage practices

Land application of organic waste products (OWPs), catch crops and reduced soil tillage are accepted as sustainable management practices in agriculture. They can optimize resources by supplying nutrients to plants and helping to maintain soil fertility. They also can influence soil functions in agricultural production systems. Soil microorganisms can feed on fresh organic matter by producing extracellular enzymes. Enzyme production responds to resource availability and soil C:N:P ratios, which could limit biogeochemical cycling. Allocating resources to produce nutrient-acquiring enzymes requires a large amount of energy to achieve optimal growth. In this context, studying the use of OWPs is important, as alternatives to long-term use of mineral fertilizers, to understand the dynamics of response and how the OWPs influence production of extracellular enzymes in the soil. Effects of OWPs on soil enzymatic activities have been studied widely, but long-term effects remain poorly understood, and no information is available about differences in dynamics among systems for each biogeochemical cycle. The data described here were collected during two trials from an initial state, and they allow assessment of long-term effects of OWP application, mineral nitrogen fertilization, tillage and vegetation cover on soil enzymatic activities. Data are presented for the activities of five soil enzymes measured from 2012 to 2019: β-glucosidase, phosphatase, urease, arylamidase and arylsulfatase. Five additional enzymes were included in 2019 to supplement the analysis of biogeochemical cycles: alkaline phosphatase, phosphodiesterase, α-glucosidase, β-galactosidase and n-acetyl-glucosaminidase. These activities were measured in two trials at the EFELE study site: PROs (five OWPs applied to a corn-wheat rotation) and TS/MO (four treatments that examine interactions between OWP and type of tillage). These data can be used as a reference for future studies of soil enzymes in France and other regions (e.g. for developing reduced-tillage systems and organic or inorganic amendments, and to assess dynamics of the systems).


a b s t r a c t
Land application of organic waste products (OWPs), catch crops and reduced soil tillage are accepted as sustainable management practices in agriculture. They can optimize resources by supplying nutrients to plants and helping to maintain soil fertility. They also can influence soil functions in agricultural production systems. Soil microorganisms can feed on fresh organic matter by producing extracellular enzymes. Enzyme production responds to resource availability and soil C:N:P ratios, which could limit biogeochemical cycling. Allocating resources to produce nutrient-acquiring enzymes requires a large amount of energy to achieve optimal growth. In this context, studying the use of OWPs is important, as alternatives to long-term use of mineral fertilizers, to understand the dynamics of response and how the OWPs influence production of extracellular enzymes in the soil. Effects of OWPs on soil enzymatic activities have been studied widely, but long-term effects remain poorly understood, and no information is available about differences in dynamics among systems for each biogeochemical cycle. The data described here were collected during two trials from an initial state, and they allow assessment of long-term effects of OWP application, mineral nitrogen fertilization, tillage and vegetation cover on soil enzymatic activities. Data are presented for the activities of five soil enzymes measured from 2012 to 2019: β-glucosidase, phosphatase, urease, arylamidase and arylsulfatase. Five additional enzymes were included in 2019 to supplement the analysis of biogeochemical cycles: alkaline phosphatase, phosphodiesterase, α-glucosidase, β-galactosidase and n-acetyl-glucosaminidase.
These activities were measured in two trials at the EFELE study site: PROs (five OWPs applied to a corn-wheat rotation) and TS/MO (four treatments that examine interactions between OWP and type of tillage). These data can be used as a reference for future studies of soil enzymes in France and other regions (e.g. for developing reduced-tillage systems and organic or inorganic amendments, and to assess dynamics of the systems

Value of the Data
• This dataset is based on high-frequency temporal acquisition to detail differences in dynamics enzymatic activities in agricultural soils subjected to different soil management practices. • Communities such as agronomy, agricultural technical institutes and mathematical modellingcan benefit from these data to calibrate and design optimal agricultural practices. • These data can be used in meta-analyses to quantify effects of repeated inputs of OWPs, tillage and crop rotations on organic matter dynamics and changes in soil quality. • Data can be used to design statistical models to predict or evaluate effects of different treatments on soil enzymatic activities.
• Data can be used to develop a vector analysis model of enzymatic activities. This model has been suggested as a good indicator of soil resource limitation [2] and reflects microorganisms' acquisition of C/N/P and nutrient acquisition effort. • The data can be used by other researchers, stakeholders or organizations to quantify and model effects of repeated inputs of OWPs, tillage and crop rotations on organic matter dynamics, functioning of biogeochemical cycles (e.g. C, N, P) and changes in soil quality.

Data Description
This article includes descriptive statistics of the two trials, and figures that show effects of OWPs, catch crops, tillage and their combined effects on changes in soil enzymatic activities at the EFELE site. Data have been collected every year since the trials began in 2012 (i.e. 8 years of data currently available).
Tables show the main soil physico-chemical properties of the surface horizon in the 48 plots of the two trials at the beginning of the experiment (March 2012) ( Table 1 ), descriptive statistics of soil activities in the PROs trial ( Table 2 ) and TS/MO trial ( Table 3 ), and the contents of the three dataset files ( Table 4 ). The dataset is composed of three Excel files that contain raw data ( Table 4 ). It includes data on enzymatic activities; mineral N, P and K applications; OWP application rates and composition.

Study site
EFELE is an experimental site (Le Rheu, France; 48 °06 07 N, 1 °47 44 W) of the SOERE PRO network ( https://www6.inra.fr/valor-pro ). This network is composed of 3 experimental sites in Table 1 Main soil physico-chemical properties of the surface horizon (0-25 cm for the PROs trial, 0-15 cm for the TS/MO trial) in the 48 plots of the two trials at the beginning of the experiment (March 2012).
Two trials are underway at EFELE ( Fig. 1 ): -PROs, a complete randomized-block trial with 4 replicates, each block composed of 9 plots of 109 m 2 each. Five OWPs were selected by combining typological criteria, such as animal Raw applications (t ha-1), contents (dry matter (g 100 g-1), ammonium (g N kg −1 raw product), total N (g N kg −1 raw product), organic matter (g OM kg −1 DM), organic carbon (g C kg −1 DM, phosphorus (g P 2 O 5 kg −1 DM), potassium (g K kg −1 DM) and magnesium (g Mg kg −1 DM)) and pH OWP_application, DM, NH 4 , total N, OM, organic C, P 2 O 5 , K, Mg and pH   The crop rotation consists of maize ( Zea mays L.) and winter wheat ( Triticum aestivum L.), with a catch crop (CC) of white mustard ( Sinapis alba ) sown at the beginning of September, two months after the wheat harvest. Rates of mineral N fertilizer applied to crops were calculated using the mineral N balance-sheet method recommended in France [3] . Poultry manure (PoM), pig slurry (PS) and the digestate of pig slurry (PS-DIG) were applied in early spring every year to the growing wheat and before the sowing of maize, while cattle manure (CM) and composted   pig manure (CPigM) were applied every two years before the sowing of maize. For these two treatments, the N fertilization of wheat came from mineral fertilizers.
The soil is classified as a Luvisol-Redoxisol derived from aeolian silt deposited on schist material [4] . Physical and chemical properties of the topsoil were measured at the beginning of the trials ( Table 1 ). The climate is temperate oceanic, with a mild winter and warm summer. Mean annual rainfall is 711 mm, and mean annual temperature is 11.2 °C.

Soil sample collection
Soil samples have been collected every year, in early spring, from 2012 to 2019. Each sample is composed of 8 soil cores, extracted at random locations in each plot, from the 0-25 cm horizon (PROs trial) or 0-15 and 15-25 cm horizon (TS/MO trial) that are homogenized and sieved to 5 mm. The moisture content of the samples is measured after drying at 105 °C for 48 h according to [5] .
Measurements were performed on 96-well microplates (PS, Nunc, and VWR) with a Xenius reader (SAFAS, Monaco) with 4 g of soil (in triplicate) in water or buffer suspension. According to the ISO standard, PDE and ARN are incubated in Tris 50 mM pH 7.5 and ALP in Tris 50 mM pH 11. The other enzymes are incubated in distilled water. Incubations of PHOS, ARS, GLU, ALP, PDE, αGLU, GAL and NAG are performed at 37 °C. Soil suspensions are incubated with substrates: 4-nitrophenylphosphate for 30 min for PHOS and PAK, 4-nitrophenyl sulfate for 4 h for ARS, 4-nitrophenyl β-glucopyranoside for 1 h for GLU, bis-nitrophenylphosphate for 1 h for PDE, 4nitrophenyl α-glucopyranoside for 1 h for αGLU, 4-nitrophenyl β-galactopyranoside for 3 h for GAL, and 4-nitrophenyl N-acetyl-βd -glucosaminide for 2 h for NAG. One well per triplicate is incubated without substrate for soil controls. The reaction is stopped with CaCl 2 and Tris pH 12. URE activity is quantified by mixing a soil solution with urea (tests) or water (controls) and incubating it for 3 h at 25 °C. The quantification of NH4 + is achieved by adding ammonium salicylate and ammonium cyanurate. For ARN, the soil solution is incubated with l -leucine βnaphthylamide for 2 h, and the reaction is stopped with ethanol. The β-naphthylamine produced is colored with p-(dimethylamino)cinnamaldehyde (DMCA).
The concentration of the product released is reported to a range of para-nitrophenol (for PHOS, ARS, GLU, ALP, PDE, αGLU, GAL and NAG), NH 4 Cl (for URE) or β-naphthylamine (for ARN).
Enzymatic activities are calculated and expressed in mU (nanomole equivalent of product released per min) per g of dry soil.

Not applicable
CRediT

Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.