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Fluid Journal : Fall 2014
10 The Fluid Journal Fall 2014 Figure 6. Effects of different treatments on specific energy of samples from Hays with fall 2011 fertilizer application. MIXed procedures in SAS 9.3, we conducted two-way ANOVA analysis. In Table 2, the data in red indicate there is a significant difference level. We only report the data that has significant difference levels (in red). Garden City. For the sample from Garden city of June 2013, we only collected biomass data. Owing to the severe windy weather situation, all residue left on the ground was blown away. We were not able to collect any standing residue during our fieldwork. In October 2013, we skipped the Garden City site owing to the weather. Hays. Figure 5 shows the aboveground biomass difference between 2011 fall application treatment and 2012 spring application treatment. According to the graph, 2011 fall application plots have less biomass. Longer fertilizer application periods seem to decompose more wheat straw. Theoretically, longer reaction time could make the wheat-straw weaker than shorter application periods. Also, strong winds can take wheat straw with lower resistant ability away from plots. Therefore, fall application plots may have less residue remaining compared to the spring application plots. However, this phenomenon was only observed at the Hays site (Table 2). Also, treatment did not make any difference on aboveground biomass in any of the three sites. Figure 6 shows the specific energy required by the shearing test for the samples from fall fertilizer applications in treatment plots at Hays. Specific energy decreased significantly with increasing amounts of UAN usage. However, there was no significant difference between Urea 40 and Urea 60 on specific energy measured. Furthermore, ATS seems to have no effect on specific energy. For spring 2012, in fertilizer application samples at Hays--similar to fall application--UAN decreased the specific energy requirement significantly compared to ATS treatments (Figure 7). However, there was no difference between treatments with different UAN application rates. Since there was timing and treatment interaction, we needed to look at the timing effects individually. Figure 8 shows the effects of timing on specific Table 2. Analysis of variance results of summer 2012 sample 2012 summer Biomass Specific Energy Shear Stress F-value P-value F-value P-value F-value P-value Colby Trt* 0.26 0.933 0.66 0.655 1.14 0.361 time 2.85 0.102 0.21 0.652 0.24 0.630 trt*time 1.41 0.251 0.34 0.883 0.74 0.602 Hays trt 0.62 0.686 4.6 0.003 2.3 0.066 time 0.05 0.825 5.96 0.020 1.82 0.186 trt*time 0.5 0.772 2.09 0.090 1.51 0.211 Garden City trt 1.51 0.212 3.81 0.007 0.97 0.450 time 0.37 0.548 0.54 0.466 1.6 0.214 trt*time 1.27 0.298 1.38 0.256 2.56 0.044 Figure 5. Aboveground biomass at Hays, summer 2012.