In order to estimate the amounts of the manure elements absorbed by chestnut trees, all parts of a 8 years old tree in the orchard of Shimane Agricultural college were separated, weighed and analysed. The root system was separated by the brock method-depth 30, 60, 100cm and radius 1,2m. New and old tissues of trunk, branches and roots were divided.
i) The dry matter weights of these parts of the tree were as follows;
Leaves 6.39kg, fruits 2.64kg, burs 2.10kg, one year old branches 1.25kg, larger branches and trunk 22.80kg, fine roots 3.70kg, other roots 15.61kg and total 54.49kg. All the new tissues formed in the current year amounted to 26.22kg.ii) 98% of all roots were found within 60 cm from the soil surface and roots elongated horizontally above 2m were recognized more than 10%.
iii) The amount of these new tissues was about 48.1% of total weight of the tree and sum of leaves, fruits, one year old branches and fine roots was about 61.3% of total new tissues.
iv) The analytical data of each part showed that N content in leaves and fruits, P_2O_5 content in fine roots and burs, K_2O content in leaves, burs and fruits, CaO content in leaves, one year old branches and other branches and MgO content in leaves, one year old branches and fine roots were higher than that of the other parts.
v) Total amounts of manure elements contained in this tree were 361.9g of N, 148.5g of P_2O_5, 181.7g of K_2O, 431.5g of CaO and 114.6g of MgO and amounts of these elements in the new tissues were 232.0g of N, 87.9g of P_2O_5, 129.1g of K_2O, 221.0g of CaO and 64.4g of MgO. Sum of these elements in fruits, leaves, one year old branches and fine roots was N 78%, P_2O_5 73%, K_2O 85%, CaO 64% and MgO 71% of each total amount of these elements in the new tissues.
vi) From these data, amounts per 10a of the manure elements absorbed by chestnut trees were 7.66kg of N, 2.90kg of P_2O_5, 4.26kg of K_2O, 7.29kg of CaO and 2.12kg of MgO based on those trees were planted at the rate of 33 trees per 10a and produced 220kg fruits.