NAME: Joe Curtis
MODULE: Agro- Environ. Systems
Submission date: 22/10/2010
Semester: Fall 2010
Title: How soil management can affect soil quality
Three Labs 1, 2 & 3, compared three agricultural fields with different soil management histories, trying to find out how these different soil managements affected the measured soil parameters. The three different soil management histories are given below: a. Corn field: tilled every year after corn harvest and left bare all winter. In the spring, it is tilled and cultivated and then planted with corn. It is irrigated all summer and in the fall, if needed. Herbicides are used to control weeds and pesticides for pest control. b. Agrocenter, tilled field: tilled every year after the end of summer and planted with winter crops. In the spring, it is tilled again and cultivated and planted with summer crops. It is irrigated only during the summer. In the fall, there was no irrigation. Weeds were managed manually during the summer, and were left without management in the fall. The field had been tilled and plant residue was incorporated in the soil two weeks before soil sampling. It was managed organically, without pesticide applications. c. Agrocenter, non-tilled field: Same management as b, but it was still covered with dense plant growth when we sampled it. Materials & Methods needed
* 18 Cylindrical core samplers, of 5-cm diameter and 5-cm height * Knife or spatula
* 18 Soil samples ( 3 x 2 samples from 3 different field and 3 different depths ( 5, 10 and 15 cm) * Top loading balance
* PH tester instrument (glass electrodes).
* EC tester instrument (Electrical Conductivity).
* Oven to dry the core samples at 105 0C
Laboratory methods have been employed to measure soil parameters such as: Bulk density (g/cm3): The dry weight of soil divided by its volume, working an indicator of soil compaction. Soil moisture (%): The percent of water volume contained in equal volume of soil core. Soil porosity (%): The percent of the soil core taken up by pores in the soil. Water filled pore space (%): The percent of soil pore space covered by soil moisture. Soil PH: The value showing the acidity or alkalinity of the soil, affecting biological and nutrient availability. Soil EC: The value showing the water-soluble salts accumulation in the soil, affecting Plant growth, microbial activity, and salt tolerance Each Lab measured and recorded for each field, the above soil parameters values. Then all three Labs shared the findings to each other to calculate the mean and the standard deviation values, for each parameter, for each field. The results from the experimental data are displayed in attached Excel tables for discussion, addressing how the different soil management histories affect the measured soil parameters. In the same Excel Tables, Statistical standard deviation (SD+-) and % Relative Standard Deviation (RSD) have been calculated to check the significance of the results. Mean of all parameter values are shown in respective Graphics. Each Lab followed the below procedure steps:
1. We took 3 x 2 soil samples from 3 different agroecosystems (Corn field, Agrocenter, non-tilled field, Agrocenter-tilled field) with different management histories, using 18 core samplers. 2. We weighed and labeled each core.
3. We determined the volume in cubic centimeters of each core π*r2 (core internal radius r=2.5 cm) 4. We collected core samples at three sites of the top 15 cm soil layer, taking properly 6 samples using the 5 cm height cores. 5. We weighed the cores with their soil.
6. We put the cores in the drying oven at 105 0C for 24 hours. 7. We recorded :
* The mass of each empty core (a)
* The mass of each core with the moist soil (b) * And the mass of each core with its dry...