WEBVTT 1 00:00:08.160 --> 00:00:09.860 Hello, plant scientists. 2 00:00:09.860 --> 00:00:12.960 Today we're going to learn about Dr. Sam Wortman 3 00:00:12.960 --> 00:00:16.640 and a study he conducted on biodegradable plastic 4 00:00:16.640 --> 00:00:18.910 and fabric mulch performance. 5 00:00:18.910 --> 00:00:22.570 So we're going to learn a little bit about Dr. Wortman, 6 00:00:22.570 --> 00:00:25.810 we're going to learn about the study he conducted, 7 00:00:25.810 --> 00:00:29.180 and at the end, we're going to look at some data 8 00:00:29.180 --> 00:00:33.630 he collected and how we can read that data. 9 00:00:33.630 --> 00:00:37.030 So Dr. Sam Wortman is an assistant professor 10 00:00:37.030 --> 00:00:39.540 at the University of Nebraska-Lincoln 11 00:00:39.540 --> 00:00:42.670 and he focuses on environmental horticulture. 12 00:00:42.670 --> 00:00:44.860 His interest is in local, urban, 13 00:00:44.860 --> 00:00:47.430 and organic vegetable production, 14 00:00:47.430 --> 00:00:49.520 and he's studying biomulches 15 00:00:49.520 --> 00:00:51.850 because they can be used as alternatives 16 00:00:51.850 --> 00:00:53.790 to polyethylene mulch, 17 00:00:53.790 --> 00:00:57.170 which is commonly used in vegetable production. 18 00:00:57.170 --> 00:00:59.300 And growers are concerned 19 00:00:59.300 --> 00:01:02.100 about the disposal of polyethylene film 20 00:01:02.100 --> 00:01:06.170 and are seeking alternatives that provide the same benefits, 21 00:01:06.170 --> 00:01:09.103 and so that is why he is conducting this recent. 22 00:01:11.690 --> 00:01:13.820 So growers use polyethylene mulch 23 00:01:13.820 --> 00:01:16.570 because it helps control weed growth, 24 00:01:16.570 --> 00:01:18.330 it increases yields, 25 00:01:18.330 --> 00:01:20.560 it helps with temperature management, 26 00:01:20.560 --> 00:01:24.510 it has a low cost and it helps improve growth. 27 00:01:24.510 --> 00:01:26.120 And it's an environmental concern 28 00:01:26.120 --> 00:01:28.430 because it has to be removed and disposed of 29 00:01:28.430 --> 00:01:30.750 after each growing season. 30 00:01:30.750 --> 00:01:32.700 The most common way it is disposed of 31 00:01:32.700 --> 00:01:35.610 is by being stockpiled on farms. 32 00:01:35.610 --> 00:01:39.430 There are options to recycle it, but they are very limited, 33 00:01:39.430 --> 00:01:43.050 and hauling it to a landfill is very costly, 34 00:01:43.050 --> 00:01:46.903 and burning isn't an option because they are carcinogenic. 35 00:01:48.400 --> 00:01:53.120 Alternatives to polyethylene mulch are organic mulches, 36 00:01:53.120 --> 00:01:58.070 paper-based mulches, bioplastics and biofabrics. 37 00:01:58.070 --> 00:02:02.430 But bioplastics and biofabrics were used in the experiment 38 00:02:02.430 --> 00:02:05.890 because previous research that was conducted 39 00:02:05.890 --> 00:02:08.810 shows that they have the greatest potential 40 00:02:08.810 --> 00:02:10.263 to be an alternative. 41 00:02:12.310 --> 00:02:15.270 So seven treatments were used in the study. 42 00:02:15.270 --> 00:02:20.240 Bare soil was used as a control to compare six biomulches, 43 00:02:20.240 --> 00:02:24.370 and of the six biomulches, there were four biofabrics 44 00:02:24.370 --> 00:02:27.160 that varied in thickness, weight, and color, 45 00:02:27.160 --> 00:02:29.510 and highlighted in the yellow box 46 00:02:29.510 --> 00:02:31.953 there are two bioplastics. 47 00:02:33.510 --> 00:02:38.510 From 2013 to 2015 at the University of Illinois 48 00:02:39.220 --> 00:02:43.210 in Urbana, Illinois, the experiment was conducted. 49 00:02:43.210 --> 00:02:45.290 A total of five trials were conducted 50 00:02:45.290 --> 00:02:47.180 over that span of time, 51 00:02:47.180 --> 00:02:49.270 and you can see in the photos 52 00:02:49.270 --> 00:02:52.770 that each trial was arranged as a randomized block design 53 00:02:52.770 --> 00:02:55.120 with four replicate blocks. 54 00:02:55.120 --> 00:02:58.660 In 2013, you can see in the photo on the left 55 00:02:58.660 --> 00:03:02.330 was the cucumber trials, and that had two trials, 56 00:03:02.330 --> 00:03:04.940 one in the field and one in high tunnels. 57 00:03:04.940 --> 00:03:09.143 In 2014, which is the photo on the right, 58 00:03:10.290 --> 00:03:12.310 again, two trials were conducted, 59 00:03:12.310 --> 00:03:14.590 one in the field and one in high tunnel 60 00:03:14.590 --> 00:03:16.670 using tomatoes and peppers. 61 00:03:16.670 --> 00:03:20.030 And in 2015, only one trial was conducted 62 00:03:20.030 --> 00:03:22.393 in the field using cucumbers. 63 00:03:24.240 --> 00:03:27.350 So what type of data did Dr. Wortman collect? 64 00:03:27.350 --> 00:03:31.640 He collected data on soil temperature, soil moisture, 65 00:03:31.640 --> 00:03:34.050 weed emergence, crop yield, 66 00:03:34.050 --> 00:03:36.450 decomposition of biomulches in the soil, 67 00:03:36.450 --> 00:03:38.740 and mulch deterioration. 68 00:03:38.740 --> 00:03:42.070 In a few slides we are going to look at data, 69 00:03:42.070 --> 00:03:44.100 and the data that we are going to look at 70 00:03:44.100 --> 00:03:48.500 will be from the 2013 cucumber field trials 71 00:03:48.500 --> 00:03:52.223 for the decomposition of biomulches in the soil. 72 00:03:54.720 --> 00:03:58.130 So we need to learn how the data was collected. 73 00:03:58.130 --> 00:04:01.970 So the biomulch was incorporated into the soil 74 00:04:01.970 --> 00:04:03.680 after each growing season, 75 00:04:03.680 --> 00:04:07.450 and it was incorporated into the top 15 centimeters 76 00:04:07.450 --> 00:04:09.210 using a rotary tiller. 77 00:04:09.210 --> 00:04:11.300 And you can see in the photo 78 00:04:11.300 --> 00:04:16.113 the biomulch before and after incorporation into the soil. 79 00:04:19.030 --> 00:04:22.440 After the mulch was incorporated into the soil, 80 00:04:22.440 --> 00:04:26.073 it was then sampled at zero, six, and 12 months. 81 00:04:26.960 --> 00:04:29.570 And to get the samples, a golf hole cutter, 82 00:04:29.570 --> 00:04:31.050 which you can see in the photo, 83 00:04:31.050 --> 00:04:35.060 was used to remove eight core samples per plot at random 84 00:04:35.060 --> 00:04:37.510 from each experimental unit. 85 00:04:37.510 --> 00:04:39.770 The soil samples once collected 86 00:04:39.770 --> 00:04:42.840 were then sieved to recover mulch residues 87 00:04:42.840 --> 00:04:44.020 and then recovered mulch 88 00:04:44.020 --> 00:04:46.713 was then washed, dried, and weighed. 89 00:04:48.270 --> 00:04:50.900 So now we have background information 90 00:04:50.900 --> 00:04:54.880 on the experiment conducted by Dr. Wortman. 91 00:04:54.880 --> 00:04:57.780 So let's think, if we conducted this study, 92 00:04:57.780 --> 00:05:02.270 and in our cucumber field trial for 2013 93 00:05:02.270 --> 00:05:06.330 for the decomposition of the biomulches in the soil, 94 00:05:06.330 --> 00:05:10.470 here is data for two of the biodegradable fabrics. 95 00:05:10.470 --> 00:05:12.740 This is what you would be looking at. 96 00:05:12.740 --> 00:05:16.690 And so here is BK-1-270, 97 00:05:16.690 --> 00:05:21.540 and below it is BK-2-360, my two biofabrics. 98 00:05:21.540 --> 00:05:24.270 I have the four replicates for each, 99 00:05:24.270 --> 00:05:28.240 and I have their mass of the remaining biomulch in the soil 100 00:05:28.240 --> 00:05:31.140 at zero, six, and 12 months. 101 00:05:31.140 --> 00:05:34.440 So we're writing our article and we want our reader 102 00:05:34.440 --> 00:05:39.440 to be able to easily look at this data 103 00:05:39.440 --> 00:05:42.640 and understand what is happening. 104 00:05:42.640 --> 00:05:46.010 So to easily compare the biofabrics 105 00:05:46.010 --> 00:05:47.980 at zero, six, and 12 months, 106 00:05:47.980 --> 00:05:51.820 the first thing that we want to do is create a graph. 107 00:05:51.820 --> 00:05:53.250 And so to create the graph, 108 00:05:53.250 --> 00:05:56.850 we wanna take the averages of each replicate 109 00:05:56.850 --> 00:06:00.240 for each treatment at zero, six, and 12 months, 110 00:06:00.240 --> 00:06:02.973 and so we're going to find our average. 111 00:06:04.220 --> 00:06:06.840 So we're going to start by finding the average 112 00:06:06.840 --> 00:06:11.370 for our biofabric BK-1-270. 113 00:06:11.370 --> 00:06:13.483 And so to find the average, 114 00:06:14.412 --> 00:06:17.130 and the average is also considered the mean, 115 00:06:17.130 --> 00:06:18.970 we're gonna take the sum of the data, 116 00:06:18.970 --> 00:06:21.960 so step one, sum up all data points. 117 00:06:21.960 --> 00:06:25.840 So we're gonna add up at for zero months 118 00:06:25.840 --> 00:06:29.070 each mass for each of the four replicates. 119 00:06:29.070 --> 00:06:32.220 So down here, you can see that I've done that 120 00:06:32.220 --> 00:06:37.220 and I come up with 317.58. 121 00:06:37.360 --> 00:06:39.830 And then because we had four replicates, 122 00:06:39.830 --> 00:06:43.570 I'm going to divide that number by four 123 00:06:43.570 --> 00:06:45.580 and I get my average. 124 00:06:45.580 --> 00:06:49.020 And I will do that for six and 12 months 125 00:06:49.020 --> 00:06:52.263 and I will do that for my other treatment as well. 126 00:06:53.960 --> 00:06:56.280 So now that I've calculated my averages 127 00:06:56.280 --> 00:06:59.040 for both of my biofabric treatments 128 00:06:59.040 --> 00:07:01.610 at zero, six, and 12 months, 129 00:07:01.610 --> 00:07:03.420 I'm going to take this data 130 00:07:03.420 --> 00:07:07.423 and put it into Excel to create a graph. 131 00:07:10.130 --> 00:07:14.500 So I created a bar graph in Excel from my averages. 132 00:07:14.500 --> 00:07:15.880 So I have a graph 133 00:07:15.880 --> 00:07:18.980 of the average biomulch remaining in the soil. 134 00:07:18.980 --> 00:07:22.640 And as you can see, my biomulch treatments, 135 00:07:22.640 --> 00:07:25.187 I have BK-1-270 and BK-2-360. 136 00:07:28.570 --> 00:07:30.640 And I can easily compare them, 137 00:07:30.640 --> 00:07:34.870 the blue being immediately after incorporation, 138 00:07:34.870 --> 00:07:38.000 the orange is six months after incorporation, 139 00:07:38.000 --> 00:07:41.430 and the silver is 12 months after incorporation. 140 00:07:41.430 --> 00:07:44.840 So I can easily see what's happening during that timeline 141 00:07:44.840 --> 00:07:47.510 and it's also easier for my readers 142 00:07:47.510 --> 00:07:49.840 to understand what is happening. 143 00:07:49.840 --> 00:07:53.200 And there is more that we can do to understand the data 144 00:07:54.860 --> 00:07:57.630 for the decomposition of biomulch in the soil, 145 00:07:57.630 --> 00:08:00.733 but we are going to save that for a future lecture.