DOI: 10.23637/rex4-soil1314-01
title: Dataset: Exhaustion Land wheat growth, soil moisture and soil available P and N dynamics over two growing seasons

description: Winter wheat was sampled several times over the growing seasons in 2013 and 2014, to measure crop growth and changes in soil moisture, Olsen P, nitrate-N, ammonium-N and CaCl<sub>2</sub>-extractable P on six plots on the Exhaustion Land experiment, with two different P treatments.
Plant uptake of Ca, Cu, K, Mg, Mn, P, S and Zn, and baseline soil properties in 2012 are published as separate datasets.
description: Soil and crop samples were taken at frequent intervals throughout the wheat growth period, commencing at growth stage 11 or 13 (Zadoks decimal system). Winter wheat variety Xi-19 was sown in the autumn. 

Samples were taken from six plots: two P treatments - **Control** (P0) and **P added** (P3), each from three main plots: **Plot 3** (FYM 1876-1901) **Plot 7** (NPKNaMg 1876-1901) and **Plot 9** (P only 1876-1901). 

**Annual P treatments:** 
- **Control (P0)**: no P fertiliser applied since 1901 
- **P added (P3)**: 131 kgP/ha 1986-1992, 20kgP/ha 2000-2008, 15kgP/ha since 2009, all as triple superphosphate.
description: An Excel file, 01-soil1314.xlsx, contains the Exhaustion Land crop growth, soil moisture, Olsen P, nitrate-N, ammonium-N and CaCl<sub>2</sub> -extractable P. CSV files are also provided.
description: Crop and soil samples were taken from four x 0.25m<sup>2</sup> sample areas from each plot. 

**Soil Samples** were taken with a 2.5cm diameter stainless steel auger, at two depths, 0-23cm and 23-46cm. Five cores were taken from each sample area and aggregated. 
- **Soil Moisture %** from soil sieved &lt;2mm, oven-dried for 16 hours at 105 degrees C. 
- **PO<sub>4</sub>-P**, by Olsen P. Air-dried, sieved &lt;2mm soil, 0.5 M sodium bicarbonate at pH 8.5 (Olsen et al, 1954), mg P/kg soil
- **NH<sub>4</sub>-N** determined on fresh &lt;44m sieved soil, extracted with 2M KCl. Samples were shaken for 2 hours, filtered, the extract analysed with continuous colorimetric flow analysis (Skalar SANPLUS System), mg N/kg soil
- **NO<sub>3</sub>-N** determined on fresh &lt;44m sieved soil, extracted with 2M KCl. Samples were shaken for 2 hours, filtered, the extract analysed with continuous colorimetric flow analysis (Skalar SANPLUS System), mg N/kg soil
- **CaCl<sub>2</sub>-extractable P** determined on air-dried, sieved &lt;2mm soil, extracted with 0.01M CaCl<sub>2</sub>. The extracts were filtered, acidified to 5% HNO<sub>3</sub> and analysed by ICP-MS, after method of Houba et al, 1996. mg P/kg soil. 

**Wheat Samples** were removed at each sample date at ground level using secateurs, washed with deionised water to remove any soil. 
- **Crop dry matter** was determined by oven drying at 16 hours at 80 degrees C. g/m2 at 100% dry matter. 

Since 1986 all the plots have received basal N fertiliser each growing season, 144kgN/ha 1986-1992 and 192kgN/ha 1993-2002. Since 2003 each plot has received 300kgN/ha split into 50, 200 and 50 kg N/ha in March, April and May respectively. Basal K, Mg and S is also applied to all plots.
description: This dataset is derived from measurements made by Sarah Dunham and Javier Hernandez-Allica, and analysed by the Analytical Chemistry Unit, Rothamsted Research, Harpenden. The Analytical Chemistry Unit follows the Joint Code of Practice (JCoPR) and participates in European Quality Assurance programmes. All performance is strictly monitored using certified external standards alongside in-house standard materials. Standards and check samples are monitored and recorded.