Comparison of paddy soil fertility under conventional rice straw application versus cow dung compost application in mixed crop–livestock systems in a cold temperate region of Japan

Figures & data

Table 1. Carbon and nutrients content of rice straw (RS) and cow dung compost (CDC) applied to the fields.

Treatment	Total C (g C kg^−1)	Total N (g N kg^−1)	C/N	Total P (g P kg^−1)	Total K (g K kg^−1)	Total Si (g Si kg^−1)
All fields
RS (n = 41)	413 ± 15	5.9 ± 0.8	70.7 ± 9.3	1.0 ± 0.2	6.2 ± 1.8	45.1 ± 10.8
CDC (n = 38)	395 ± 24	13.2 ± 2.9	31.0 ± 5.1	5.3 ± 2.6	11.3 ± 5.4	58.9 ± 12.0
P value	< 0.01	< 0.01	< 0.01	< 0.01	< 0.01	< 0.01
14 neighboring field pairs
RS (n = 14)	411 ± 18	5.8 ± 0.9	72.3 ± 10.3	1.0 ± 0.3	6.5 ± 2.1	45.2 ± 13.7
CDC (n = 14)	396 ± 25	13.3 ± 2.8	30.6 ± 4.6	5.2 ± 2.6	11.2 ± 5.8	58.9 ± 11.6
P value	0.09	< 0.01	< 0.01	< 0.01	0.01	< 0.01

Values are mean ± SD. The P value is the probability level of two-tailed Welch’s t-test.

Table 2. Application rates of rice straw (RS) and cow dung compost (CDC) and carbon and nutrients inputs from RS and CDC.

Treatment	Application rate^† (t ha^−1)	Total C (kg C ha^−1)	Total N (kg N ha^−1)	Total P (kg P ha^−1)	Total K (kg K ha^−1)	Total Si (kg Si ha^−1)
All fields
RS (n = 41)	4.6 ± 0.9	1882 ± 375	26.8 ± 5.0	4.4 ± 1.1	28.4 ± 9.9	206.5 ± 64.9
CDC (n = 38)	3.9 ± 1.5	1545 ± 635	52.6 ± 27.7	21.6 ± 16.9	46.5 ± 34.4	227.2 ± 98.7
P value	0.03	< 0.01	< 0.01	< 0.01	< 0.01	0.28
14 neighboring field pairs
RS (n = 14)	4.4 ± 0.8	1793 ± 341	24.9 ± 3.8	4.4 ± 1.1	27.8 ± 9.7	198.4 ± 70.3
CDC (n = 14)	4.5 ± 1.8	1811 ± 771	61.0 ± 28.5	23.5 ± 16.1	53.9 ± 39.2	265.5 ± 110.1
P value	0.75	0.94	<0.01	<0.01	0.03	0.07

Values are mean ± SD. The P value is the probability level of two-tailed Welch’s t-test.

^†Dry weight.

Table 3. Soil fertility of paddy fields under conventional rice straw (RS) application and cow dung compost (CDC) application in mixed crop–livestock systems.

Treatment	SOC (g C kg^−1)	TN (g N kg^−1)	C/N	CEC (cmolc kg^−1)	AN (g N kg^−1)	AP (g P kg^−1)	Ex. K (g K kg^−1)	Ex. Ca (g Ca kg^−1)	Ex. Mg (g Mg kg^−1)	BS (%)	ASi (mg Si kg^−1)	pH (H2O)	BD (g cm^−3)
All fields
RS (n = 41)	47.8 ± 23.3	3.63 ± 1.34	12.7 ± 2.0	22.3 ± 6.8	0.24 ± 0.05	0.16 ± 0.06	0.18 ± 0.13	1.73 ± 0.60	0.28 ± 0.10	52.6 ± 12.5	27.2 ± 10.4	5.6 ± 0.3	0.74 ± 0.12
CDC (n = 38)	50.5 ± 17.6	3.87 ± 1.05	12.8 ± 1.4	24.3 ± 7.8	0.25 ± 0.05	0.14 ± 0.06	0.20 ± 0.12	2.13 ± 1.31	0.31 ± 0.14	55.0 ± 15.5	24.5 ± 11.8	5.7 ± 0.3	0.76 ± 0.11
P value	0.57	0.37	0.81	0.23	0.20	0.11	0.45	0.09	0.22	0.45	0.30	0.07	0.60
14 neighboring field pairs
RS (n = 14)	47.7 ± 22.6	3.58 ± 1.23	12.8 ± 2.5	22.0 ± 7.5	0.22 ± 0.04	0.14 ± 0.05	0.21 ± 0.18	1.72 ± 0.64	0.27 ± 0.11	53.4 ± 15.5	24.0 ± 10.7	5.7 ± 0.3	0.74 ± 0.11
CDC (n = 14)	51.1 ± 21.6	3.89 ± 1.32	12.8 ± 1.7	23.0 ± 4.7	0.24 ± 0.04	0.14 ± 0.06	0.21 ± 0.12	1.80 ± 0.57	0.30 ± 0.10	51.4 ± 10.9	23.6 ± 13.0	5.7 ± 0.3	0.78 ± 0.15
P value	0.69	0.53	0.92	0.69	0.41	0.83	0.99	0.73	0.50	0.71	0.94	0.69	0.45

SOC, soil organic carbon; TN, total nitrogen; C/N, carbon/nitrogen ratio; CEC, cation exchange capacity; AN, available nitrogen; AP, available phosphorus; Ex. K, exchangeable potassium; Ex. Ca, exchangeable calcium; Ex. Mg, exchangeable magnesium; BS, base saturation percentage; ASi, available silicon; BD, bulk density. Values are mean ± SD. The P value is the probability level of two-tailed Welch’s t-test.

Table 4. Plow layer depth, soil organic carbon (SOC), and nutrient pools of paddy soil under conventional rice straw (RS) application and cow dung compost (CDC) application in mixed crop–livestock systems.

Treatment	Plow layer depth (cm)	SOC (kg C ha^−1)	TN (kg N ha^−1)	AN (kg N ha^−1)	AP (kg P ha^−1)	Ex. K (kg K ha^−1)	Ex. Ca (kg Ca ha^−1)	Ex. Mg (kg Mg ha^−1)	ASi (kg Si ha^−1)
All fields
RS (n = 41)	17.0 ± 2.3	56251 ± 22190	4320 ± 1147	293 ± 53	194 ± 70	208 ± 118	2111 ± 719	344 ± 145	34 ± 14
CDC (n = 38)	15.9 ± 1.6	58284 ± 17034	4498 ± 965	299 ± 54	163 ± 66	231 ± 143	2520 ± 1566	370 ± 168	29 ± 15
P value	0.02	0.65	0.46	0.62	0.05	0.44	0.15	0.48	0.14
14 neighboring field pairs
RS (n = 14)	17.0 ± 2.3	56419 ± 20998	4319 ± 1045	277 ± 47	178 ± 57	233 ± 148	2139 ± 910	337 ± 152	31 ± 17
CDC (n = 14)	15.7 ± 0.9	59244 ± 20270	4559 ± 1129	284 ± 37	165 ± 69	254 ± 167	2131 ± 634	356 ± 125	29 ± 16
P value	0.05	0.72	0.56	0.68	0.61	0.73	0.98	0.72	0.69

SOC, soil organic carbon; TN, total nitrogen; AN, available nitrogen; AP, available phosphorus; Ex. K, exchangeable potassium; Ex. Ca, exchangeable calcium; Ex. Mg, exchangeable magnesium; ASi, available silicon. Values are mean ± SD. The P value is the probability level of two-tailed Welch’s t-test.

Table 5. Standard values used to evaluate the fertility of paddy soil.

Soil fertility indicator	Fertility level	References
SOM	20 g SOM kg^−1 dry soil (Lowland soils)	Ministry of Agriculture, Forestry and Fisheries (MAFF) (2008)
TN	–	–
CEC	12 cmolc kg^−1 dry soil (Lowland soils), 15 cmolc kg^−1 dry soil (Andosols)	Ministry of Agriculture, Forestry and Fisheries (MAFF) (2008)
AN	0.08 to 0.20 g N kg^−1 dry soil	Ministry of Agriculture, Forestry and Fisheries (MAFF) (2008)
AP	0.04 g P kg^−1 dry soil	Ministry of Agriculture, Forestry and Fisheries (MAFF) (2008)
Ex. K	0.08 g K kg^−1 dry soil	Doberman and Fairhurst (2000)
Ex. Ca	0.40 g Ca kg^−1 dry soil	Doberman and Fairhurst (2000)
Ex. Mg	0.24 g Mg kg^−1 dry soil	Doberman and Fairhurst (2000)
BS	70 to 90 % (Lowland soils), 60 to 90 % (Andosols)	Ministry of Agriculture, Forestry and Fisheries (MAFF) (2008)
ASi	62.48 mg Si kg^−1 dry soil	Calculated from Imaizumi and Yoshida (1958); Sumida (1992); Kato et al. (2002).
pH	6.0 to 6.5	Ministry of Agriculture, Forestry and Fisheries (MAFF) (2008)
BD	–	–

SOM, soil organic matter (calculated as 1.724×soil organic carbon); TN, total nitrogen; CEC, cation exchange capacity; AN, available nitrogen; AP, available phosphorus; Ex. K, exchangeable potassium; Ex. Ca, exchangeable calcium; Ex. Mg, exchangeable magnesium; BS, base saturation percentage; ASi, available silicon; BD, bulk density.

Table 6. Linear correlation coefficients (r) of the relationships between soil fertility indicators.

	SOC	TN	CEC	AN	AP	Ex. K	Ex. Ca	Ex. Mg	BS	ASi	pH	BD
SOC	1
TN	0.96**	1
CEC	0.45**	0.47**	1
AN	0.56**	0.62**	0.51**	1
AP	0.29**	0.37**	0.03	0.22*	1
Ex. K	0.20	0.18	0.10	0.12	0.00	1
Ex. Ca	0.20	0.25*	0.77**	0.41**	0.16	−0.05	1
Ex. Mg	−0.12	−0.05	0.64**	0.30**	−0.03	0.09	0.72**	1
BS	−0.22	−0.20	−0.04	0.03	0.22	−0.01	0.54**	0.45**	1
ASi	−0.02	0.08	0.03	0.18	0.60**	−0.19	0.26*	0.23*	0.31**	1
pH	0.24*	0.19	0.40**	0.08	0.23*	0.09	0.63**	0.34**	0.51**	0.07	1
BD	−0.80**	−0.84**	−0.57**	−0.65**	−0.33**	−0.06	−0.37**	−0.16	0.11	−0.15	−0.14	1

SOC, soil organic carbon; TN, total nitrogen; CEC, cation exchange capacity; AN, available nitrogen; AP, available phosphorus; Ex. K, exchangeable potassium; Ex. Ca, exchangeable calcium; Ex. Mg, exchangeable magnesium; BS, base saturation; ASi, available silicon; BD, bulk density.

**P < 0.01, *P < 0.05.

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