Studies on the absorption of nutrient elements in muskmelon. I

Abstract

The purposes of the present study were to deter-mine at which of three levels and in what propor-tions the elements, nitrogen and phosphorus, might best and most economically satisfy the nutritional needs of plants. Muskmelons (var. Earl's Favourite) were planted in 451 boxes each filled with 27 kg paddy soil in the greenhouse on May 6, 1956. To keep the aer-ation for the roots in a favourable condition, 1.5 kg rice straw was used in the bottom of each box. The plants were topped at the 20th leaf on the main stem. The design of fertilizer treatment is presented in Table I. The fruits were set at the 10th node and har-vested approximately 50 days after pollination. The plants were divided into leaves, stem and roots, and these organs were immediately dried in an oven at 65°C and ground with a Wiley Mill to pass a 40 mesh sieve. At the same time the fruits were divided into flesh and seeds, and a wedge from each flesh was removed for chemical analysis. All the data were subjected to variance analysis. The results obtained here are presented in table 2 to 7, inclusive. The results from these data can be sum-marized as follows. 1. The main effects of increasing the levels of nitrogen were to depress soluble solids and the external appearance, to increase nitrogen amounts in the whole plants, to decrease the leaf, stem and fruit weights, and to decrease the potassium, cal-cium and magnesium amounts in the whole plants. 2. The main effects of increasing the levels of phosphorus were to promote the vigorous growth, to increase the fruit and seed weights, to increase nitrogen, phosphorus and potassium amounts in the whole plants, to depress soluble solids, and to im-prove the external appearance. 3. The interactions of nitrogen and phosphorus were observed in nitrogen, potassium and magnesi-um amounts in the whole plants. 4. The plants which received 12g of N and 18g of P2O5 per plant were able to maintain vigorous growth and produced fruits of hign quality. From the results, these amounts seem to be recommend-able for the muskmelon culture. 5. The amounts of N, P2O5, K2O, CaO and MgO in the whole plant received 12g of N and 18g of P2O5 were 6.2, 2.0, 9.7, 4.6 and 1.1 g per plant, respectively.