Comparative analysis of the relationship between Cs and K in soil and plant parts toward control of Cs accumulation in rice

Figures & data

Table 1 Soil properties

Soil	Origin	Coarse sand	Fine sand	Silt	Clay	pH (KCl)	pH (H2O)	TC (g kg^−1)	TN (g kg^−1)	Available P† (mg P kg^−1)	CEC (cmol kg^−1)	Exchangeable K‡ (mmol kg^−1)	Exchangeable ^133Cs‡ (µmol kg^−1)	Total ^133Cs‡ (µmol kg^−1)
		(%)
S1	Kounosu, Saitama	10.6	26.1	22.2	41.1	5.0	6.0	27.0	3.3	331	22.6	21.0	0.15	8.2
S2	Ishioka, Ibaraki	23.6	40.9	10.3	25.2	4.7	5.7	22.6	2.8	222	17.8	17.0	0.29	21.6
S3	Takanezawa, Tochigi	16.3	26.9	22.9	33.9	5.1	5.9	57.4	5.2	313	29.7	20.0	0.79	27.0
S4	Kounosu, Saitama	8.3	23.6	21.3	46.8	5.1	6.0	17.3	2.2	168	22.5	1.0	0.35	37.4
S5	Tsukubamirai, Ibaraki	14.4	34.5	30.6	20.5	5.3	6.0	18.0	1.8	153	20.2	4.5	1.31	54.4
S6	Tsukubamirai, Ibaraki	19.9	32.9	23.4	23.8	5.4	5.9	20.0	2.0	290	21.3	1.6	0.82	43.9
S7	Tsukubamirai, Ibaraki	22.9	32.4	21.3	23.4	5.3	6.0	19.4	2.0	173	17.3	1.7	1.14	38.0
S8	Tsukubamirai, Ibaraki	10.3	30.7	34.8	24.2	6.1	6.3	19.6	2.4	20	24.0	6.1	0.53	7.0
S9	Tsukubamirai, Ibaraki	16.6	40.2	20.0	23.2	4.9	5.6	35.3	3.4	235	22.5	0.7	0.82	29.6

†Available P was determined by the Truog method.

‡Methods for exchanegable K and Cs, and total Cs, are described in Kondo et al. (2014). TC; Total Carbon or Total C. TN; Total Nitrogen or Total N. CEC; cation exchange capacity.

Table 2 Comparison of clay mineralogy of soils

Soil	Vermiculite	Smectite	HIV^†	Chrolite	Mica	Mi–Vr^‡	Kaoline	Crystalline constitutents (%)
S1	++	-	++	+	++	++	+++	89
S2	+	-	+	+	+	+	++	70
S3	+	-	+	+	+	+	++	56
S4	++	-	++	+	++	++	+++	89
S5	+	-	+	+	+	+	++	76
S6	+	-	+	+	+	+	++	77
S7	+	-	+	+	+	+	++	74
S8	+	-	++	+	+	+	++	53
S9	+	-	+	+	+	+	++	71

-, not detected; +, scarce; ++, common; +++, abundant.

^†HIV, 2:1–2:1:1 hydroxy-interlayered vermiculite.

^‡Mi–Vr, interstratified mica–vermiculite.

Table 3 Dry weight and panicle number at maturity

Soil	Dry weight (g pot^−1)			Panicle number (no. pot^−1)
	Aboveground	Brown rice	Root
S1	96.9a	33.3a	5.8ab	22a
S2	93.4a	29.2a	6.3ab	20a
S3	108.9a	36.2a	8.1a	25a
S4	96.3a	33.9a	6.1ab	23a
S5	101.4a	32.6a	6.3ab	24a
S6	96.1a	30.0a	6.5ab	22a
S7	96.8a	33.1a	7.0a	25a
S8	54.6b	19.1b	4.1b	9b
S9	99.6a	30.8a	7.8a	20a

Values with same letter are not significantly different (P < 0.05).

Figure 1 Relationship of cesium-133 (¹³³Cs) uptake in aboveground parts with (a) exchangeable potassium (K) and (b) exchangeable ¹³³Cs among soils (**indicates P < 0.01).

Figure 2 Relationship between cesium-133 (¹³³Cs) uptake in aboveground parts and exchangeable cesium-133/potassium (¹³³Cs/K) ratio among soils (** indicates P < 0.01).

Figure 3 Relationship between cesium-133 (¹³³Cs) concentration in brown rice and exchangeable cesium-133/potassium (¹³³Cs/K) ratio among soils (** indicates P < 0.01).

Figure 4 Relationship between the concentration in brown rice and shoots for cesium-133 (¹³³Cs) (a) and potassium (K) (b) among soils (** indicates P < 0.01).

Figure 5 Distribution into brown rice in aboveground parts in terms of dry matter (DW) and essential elements in comparison with cesium-133 (¹³³Cs) on the average of nine soils (bars indicate maximum and minimum values).

Figure 6 Relationship between cesium-133 (¹³³Cs) distribution in brown rice in aboveground parts and potassium (K) concentration in stems (** indicates P < 0.01).

Figure 7 Relationship between cesium-133 (¹³³Cs) distribution in aboveground parts in the whole plant and potassium (K) concentration in root (** indicates P < 0.01).

Table 4 Slope in the linear regression between cesium-133/potassium (¹³³Cs/K) concentration in plant part and exchangeagble cesium-133/potassium (¹³³Cs/K) in soil

Plant part	Slope	r
Root	0.2165	0.809*
Stem	0.0095	0.973**
Active leaf	0.0079	0.952**
Dead leaf	0.0135	0.936**
Rachis	0.0085	0.901**
Husk	0.0084	0.927**
Brown rice	0.0170	0.924**

* and ** indicate significance at P < 0.05 and 0.01, respectively.

Kondo M, Maeda H, Goto A et al 2014. Exchangeable Cs/K ratio in soil is an index to estimate accumulation of radioactive and stable Cs in rice plant. Soil Sci. Plant Nutri., doi:10.1080/00380768.2014.973347

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