Potential growth of hairy vetch as a winter legume cover crops in subtropical soil conditions

Figures & data

Table 1 Initial chemical properties of the different soils used in the three different experiments

	Experiment 1 (Akadama soil)	Experiment 2 (Akadama soil)	Experiment 3
			Yellow soil	Red soil	Dark red soil	Gray soil
pH	5.8 ± 0.0	6.7 ± 0.0	5.9 ± 0.0	5.7 ± 0.0	6.4 ± 0.1	7.5 ± 0.1
EC (mS m^−1)	12.3 ± 0.4	34.6 ± 0.8	2.5 ± 0.1	3.8 ± 0.2	3.0 ± 0.0	10.7 ± 0.1
Total C (g kg^−1)	13.6 ± 0.4	14.4 ± 0.1	3.2 ± 0.1	70 ± 0.1	8.2 ± 0.2	28.9 ± 0.2
Total N (g kg^−1)	1.2 ± 0.1	1.2 ± 0.0	0.3 ± 0.0	0.7 ± 0.0	1.0 ± 0.1	0.6 ± 0.0
NH4 ^+ (mg kg^−1)	2.7 ± 0.5	5.0 ± 1.2	3.3 ± 1.2	7.0 ± 0.7	5.0 ± 1.2	8.0 ± 1.7
NO3 ^− (mg kg^−1)	12.8 ± 0.7	6.7 ± 0.0	1.2 ± 0.5	3.1 ± 1.7	0.9 ± 0.0	3.5 ± 0.7
P2O5 Abs Coef. (g kg^−1)	21.1 ± 0.0	21.2 ± 0.2	3.3 ± 0.1	5.8 ± 0.5	8.2 ± 0.1	8.9 ± 0.2
Available P2O5	nd	nd	3.1 ± 0.0	1.1 ± 0.0	34.0 ± 3.0	499.7 ± 5.2
Ex. K^+ (mmol kg^−1)	9.3 ± 1.3	97.5 ± 0.9	6.6 ± 1.3	2.6 ± 0.7	7.4 ± 1.3	6.8 ± 0.4
Ex. Ca^2+ (mmol kg^−1)	48.4 ± 4.5	14.3 ± 1.4	21.6 ± 3.9	45.7 ± 3.5	146.1 ± 7.4	303.7 ± 8.6
Ex. Mg^2+ (mmol kg^−1)	7.0 ± 1.3	6.3 ± 0.7	8.3 ± 0.3	140 ± 0.7	17.1 ± 1.2	10.4 ± 0.4
EC, electrical conductivity; P2O5 Abs Coef., phosphate absorption coefficient; Available P2O5, Ca-bound phosphate; Ex., exchangeable; nd, not detected. Values are mean ± standard deviation (n = 3).

Figure 1 (A) Shoot biomass and (B) root biomass, (C) N-fixing activity and (D) shoot P content of clover and vetch species grown at two different P levels (P-non-limiting and P-limiting) in Experiment 1. WC, white clover; CC, crimson clover; RC, red clover; PC, pink clover; HV, hairy vetch; NLV, narrow leaf vetch; TV, tiny vetch; CMV, Chinese milk vetch; DM, dry matter; ND, not detected; UN, unmeasured. Numbers in parentheses indicate the percentages of the P-limiting to P-non-limiting ratios. Vertical bars represent significant differences according to a least significant difference test (n = 3); columns with the same letter are not significantly different (NS) at P < 0.05.

Figure 2 (A) Shoot biomass, (B) root biomass and (C) N-fixing activity of hairy vetch and clover species harvested from February to April in Experiment 2. HV, hairy vetch; WC, white clover; CC, crimson clover; RC, red clover; PC, pink clover; DM, dry matter. Vertical bars represent significant differences according to a least significant difference test (n = 3); columns with the same letter are not significantly different (NS) at P < 0.05.

Figure 3 (A) Nitrogen uptake and (B) C/N ratio of shoot and root parts of hairy vetch and clover species harvested from February to April in Experiment 2. HV, hairy vetch; WC, white clover; CC, crimson clover; RC, red clover; PC, pink clover. Vertical bars represent significant differences according to a least significant difference test (n = 3); columns with the same letter are not significantly different (NS) at P < 0.05.

Figure 4 (A) Phosphorus and (B) K, (C) Ca and (D) Mg uptakes by the shoots and roots of hairy vetch and clover species harvested from February to April in Experiment 2. HV, hairy vetch; WC, white clover; CC, crimson clover; RC, red clover; PC, pink clover. Vertical bars represent significant differences according to a least significant difference test (n = 3); columns with the same letter are not significantly different (NS) at P < 0.05.

Figure 5 Biomass of the shoots of hairy vetch grown in four different soils in Experiment 3. YS, yellow soil; RS, red soil; DS, dark red soil; GS: gray soil; DM, dry matter. Columns with the same letter are not significantly different (NS) at P < 0.05.

Table 2 Nutrient concentration and uptake of hairy vetch grown under four different soils in Experiment 3

	N	P	K	Ca	Mg
Concentration (g kg^−1)
Yellow soil	28.5a	2.1b	14.4a	8.4b	1.8a
Red soil	31.9a	2.1b	17.4a	10.4b	1.9a
Dark red soil	30.2a	3.3a	14.8a	9.8b	2.4a
Grey soil	30.8a	3.3a	18.2a	13.6a	2.3a
LSD (P < 0.05)	NS	0.6	NS	2.8	NS
Accumulation (g m^−2)
Yellow soil	11.5a	0.9a	5.7a	3.4a	0.7a
Red soil	13.3a	0.9a	7.4a	4.4a	0.8a
Dark red soil	15.4a	1.7a	7.5a	4.9a	1.2a
Grey soil	14.3a	1.5a	8.4a	6.4a	1.1a
LSD (P < 0.05)	NS	NS	NS	NS	NS
Within a column, means with different letters are significantly different using Fisher’s least significant difference (LSD) test at P < 0.05 (n = 3); NS, no significant difference.