Relationship of soil properties to pyroxasulfone bioactivity in a range of prairie soils

Figures & data

Figure 1. Forty-seven locations throughout the Canadian prairies where soil was collected.

Table 1. Number of soil samples and range of properties of 47 western Canadian soils used in this study.

Number of samples	Organic matter (%)	pH	Clay (%)	Sand (%)
13	1.5–3	5.5–7.9	6.8–55.3	0.0–60.9
16	3–5	5.0–7.7	14.4–59.4	4.3–52.4
9	5–7	6.0–7.8	16.1–50.1	15.7–62.7
9	7–22	6.4–7.6	15.4–48.6	21.0–68.7

Table 2. Stepwise multiple regression analysis for sugar beet shoot length inhibition (%) in response to 184 g ai kg⁻¹ pyroxasulfone in soil and selected soil characteristics.

Step	Regression coefficients					R^2	Standard error
	Constant of regression	Organic matter (%)	pH	Clay (%)	Sand (%)
1	33.77	−2.14***	–	–	–	0.398	11.95
2	−6.77	−2.30***	6.05**	–	–	0.492	11.10
3	−11.98	−2.26***	8.12***	−0.40**	–	0.577	10.25
4	−14.58	−2.22***	8.20***	−0.36	0.02	0.577	10.37

**, ***significance at 1% and 0.1% level of probability, respectively.

Table 3. Average shoot length inhibition (mean ± SE) of sugar beet for each soil subgrouping in response to varied pyroxasulfone concentration as evaluated by a 7-day laboratory bioassay in 47 western Canadian soils.

Organic matter (%)	pH	Texture	Number of samples	Shoot length inhibition (%)
				92 g ai kg^−1 (120 g ai ha^−1)	184 g ai kg^−1 (240 g ai ha^−1)	368 g ai kg^−1 (480 g ai ha^−1)
1.5–3	Above 7	Coarse sand	4	33 ± 2	47 ± 3	–
		Medium - fine	3	18 ± 4	33 ± 3	–
	Below 7	Coarse sand	5	15 ± 5	29 ± 4	–
		Medium - fine	1	7 ± n/a^a	18 ± n/a	–
3–5	Above 7	Coarse sand	2	13 ± 4	32 ± 7	–
		Medium - fine	8	17 ± 4	32 ± 5
	Below 7	Coarse sand	4	8 ± 2	17 ± 2	–
		Medium - fine	2	6 ± 3	19 ± 7	–
5–7	All	Medium - fine	9	2 ± 1	15 ± 2	–
7–22	All	Medium - fine	9	–	2 ± 2	13 ± 3

^anot available

Table 4. Estimated pyroxasulfone field application rates.

Organic matter (%)	pH	Texture	Field application rate (g a.i. ha^−1)
		Coarse sand	<120
1.5–3	Above 7	Medium - fine	120
		Coarse sand	120
	Below 7	Medium - fine	240
		Coarse sand	120
3–5	Above 7	Medium - fine	120
		Coarse sand	240
	Below 7	Medium - fine	240
5–7	All	Medium - fine	240
7–22	All	Medium - fine	480