Page 4 - การจัดทำค่ามาตรฐานธาตุอาหารพืชในชาน้ำมันเพื่อใช้เป็นค่าวินิจฉัยสำหรับให้คำแนะนำปุ๋ย Preparation of Standard Plant Nutrients in Camellia oleifera Able. for Use as Diagnostic for Fertilizer Recommendations.

ห้องสมุดกรมพัฒนาที่ดิน

(3)

Abstract

Currently, Tea-oil Camellia (Camellia oleifera Able.) cultivation in Thailand have not

been reported the nutrient standards for interpreting soil and plant analysis results. The
objective of this research was to establish standard plant nutrients in Tea-oil Camellia for

diagnosed fertilizer recommendations. The total of 245 soil samples were analyzed for
nutrient status. Also, the 103 samples of Tea-oil Camellia leaves from different levels of

yields including high, medium and low yields and those which were not productive were
analyzed for nutrient status. In addition, the abnormal (brown spotted) leaves were studied

and compared with healthy leaves. The results showed that extractable manganese was

high in soil. Manganese induced negative interaction with phosphorus, potassium, calcium,
magnesium, sulfur, copper and zinc but encouraged Tea-oil Camellia trees to absorb more

manganese in leaves which might be toxic to plants. Therefore, the balance of nutrients in

soil should be adjusted considering the optimum ratio between manganese and other
nutrients for example, manganese/phosphorus 2.5-4.1, manganese/potassium 0.4-0.5,

manganese/calcium 0.0002-0.07, manganese/magnesium 0.04-0.2, manganese/sulfur 0.7-1.8,

manganese/copper 6.2-19.9 and manganese/zinc 0.2.-14.3. While, the sufficient ranges of soil pH,
organic matter, available phosphorus, exchangeable potassium, calcium and magnesium were 5.19-

5.39, 32.72-38.63 g/kg, 8.18-17.54, 219-269, 422-550 and 197-240 mg/kg, respectively. In addition, the
results showed that the concentration recommended for nitrogen, phosphorus, potassium,

calcium, magnesium, sulfur, zinc, copper and iron levels in leaves were in the range 15.28-

16.16, 0.87-0.95, 4.53-5.27, 11.84-13.68, 1.92-2.32, 0.46-0.67 8-13, 15-19 and 116-139 g/kg,
respectively. The yield of Tea-oil Camellia can be enhanced if manganese level is reduced

along with the increase of phosphorus, potassium and sulfur. As the suggested
concentration range from this study is below the recommended values for plants in

general, the responses of Tea-oil Camellia to such nutrients should be studied. Therefore,

should study the response of such nutrients.

Keyword: plant nutrients, antagonist, toxicity, nutrient balance, soil and plant analysis.