Nutrient status of soils and leaves of Immature rubber in the East Coast of Upper Part of Southern Thailand

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1 Nutrient status of and of Immature rubber in the East Coast of Upper Part of Southern Thailand Saichai SUCHARTGUL 1 Somsak MANEEPONG 2 1 Surat Thani Research Center, Thachana district, Surat Thani Province,Thailand suchartgul@hotmail.com 2 School of Agricultural Technology, Walailak University, Tha Sala district, Nakhon Si Thammarat Province, Thailand In 2009, rubber plantations in Thailand covered 2.70 million ha, the second-largest in the world after Indonesia the majority is in the southern region (1.81 million ha). ( Research Institute of Thailand, 2010) 1

2 The cause of low soil fertility in rubber cultivation Soil fertility decline Why the fertility of is important for rubber cultivation? 2

3 To examine nutrient status of rubber growing- and rubber. K N Mn B Mn P Cu Cu Mo Cl Ca Zn N Fe Mg N Mg Mg Mg K S P Ca S Mo P K Zn K Cu Fe B Mn Fe Cu Ca P S Cl B Mn N Mo Fe Cl Zn Zn B Ca S Cl The 4 year-old RRIM 600 From 43 farmer plantations in the east coast of upper part of southern Thailand A nutrient survey was carried out during June to July 2009 Girths of 100 trees at 150 cm height were measured for growth index in the homogeneous area and space out at least two rows from the edge 3

4 x-cross pattern Analysis 9 holes/plantation within a sup-plot 1 m away from rubber row depth 0 30 cm ph (soil:water = 1:2.5) OM (Walkley&Black method) Avai. P (Bray II) Avai. S (0.01 M KH 2 PO 4 ) Exch. K Ca Mg (1.0 M NH 4 OAc ph 7.0) Fe, Cu, Zn, Mn (DTPA solution) B, Exch. Acidity (1 M KCl) (Jones, 2001) x-cross pattern in a sup-plot at 3-5 months-old from terminal whorl of branches trees/plantation Analysis N (Kjeldahl method) P, K, Ca, Mg, S, Fe, Cu, Zn, Mn And B (digest with HNO 3 : HClO 4 = 2:1) Jones (2001) 4

5 Comparing nutrient analysis results with the diagnostic criteria growing- (Thainugul as cited in Kungpisadan, 1999) general (Jones, 2003) (Pushparajah, N.D. from website) ph Rang Optimum rang extreamly acid ( ) 16 very strongly acid ( ) 72 strongly acid ( ) 12 Exch. Acidity Rang cmol(+)/kg 5

6 Mean girth (cm) a y = x x R 2 = ph Mean girth (cm) 50 b y = x x R 2 = Exchangeable Acidity (cmol(+)/kg) CEC OM N in Rang cmol(+)/kg % % growing cmol(+)/kg growing- General > 1.0 % % % low medium high

7 Avai. P Rang rubber growing Mg/kg general P in % % Exch. K low medium high 0-14 K in Avai. P P in Exch. K Rang rubber growing general K in % % low medium high

8 Exch. Ca Rang rubber growing > 60 general Ca in % % low medium high Exch. Ca Ca in Exch. Mg Mg in Rang % rubber growing - general > % low medium high

9 Rang Avail. S rubber growing - general 5-10 S in % % Extract. Fe low medium high Fe in Rang Exch. S S in Extract. Fe Mg/kg general Mg/kg Fe in Mg/kg Mg/kg low 7 0 medium high

10 Mn in Mn in Cu in Cu in Zn in Zn in B in B in Rang General low 3 0 medium 36 5 high Very high to toxic 74 Mn in Mn in Cu in Cu in Rang Zn in Zn in B in B in General low medium 0 33 high

11 Mn in Mn in Cu in Cu in Zn in Zn in B in B in Rang General low 61 7 medium 35 9 high 5 84 Mn in Mn in Cu in Cu in Zn in Zn in B in B in Rang General low medium 0 0 high

12 At the age of 4 years of rubber plantation in the east coast of upper part of southern Thailand, the was generally very acidic, low in CEC. Both in and were low in N P K, medium to high in Fe and high to toxic in Mn. Ca, Mg, Cu, Zn and B were low in the but medium to high in. 12