Fertilizer Requirement for Densely Planted Okra ( Abelmoschus esculentus L . )

A study was conducted at Mahailluppallama, in the Low country Dry zone (DL1b) of Sri Lanka, during Maha (2008/2009) to determine the fertilizer requirement of Okra when planted at closer spacings. Three (03) fertilizer levels (T1DOA recommendation/ plant, 2 DOA recommendation/ unit area and T31 1⁄2 times DOA recommendation/ unit area) were tested using Okra varieties Haritha and Green Tender (F1 Hybrid). Concurrently, another set of treatments were employed to find out the effect of removal of leaf immediate belowe the fruit at the time of harvesting on yield. Treatments were arranged according to the Split plot design (Variety as the main plot factor and fertilizer as the subplot factor) with three replicates. Yield per plant, yield per hectare, plant height, number of fruits per plant, fruit length, fruit diameter and the average fruit weight were measured. Yield per plant was significantly higher in T1 (188.3±19.4g) than T2 (154.2±13.1g) while T3 (176.6±19.9 g) was not significantly different from other treatments. Yield per hectare was significantly higher in T1 (8.5±0.60 t/ha) while variety Haritha produced significantly higher yield/ha (8.7±0.38 t/ha) compared to the Hybrid (6.0±0.33 t/ha). There were no significant differences found between plant height, fruit length and fruit diameter with the fertilizer treatments. However, a significant difference was observed in plant height between varieties since the Hybrid was taller, but fruit characteristics such as length and diameter were not significantly different between the two varieties. These results revealed that, fertilizer application on a per plant basis leads to higher yield per hectare at closer spacing. However, it appears that, the same per plant yield together with preferable fruit characteristics could be obtained by providing 1 1⁄2 times the fertilizer recommendation, which is cost effective, compared to fertilizer application as per plant basis. Removal of the immediate lower leaf to the harvested fruit could not produce significant differences in relation to any growth or yield parameters measured. INTRODUCTION Okra (Abelmoschus esculentus L.), which originated in Asia and Africa, is one of the most important warm season fruit vegetables grown throughout the tropics and recognized as one of the world’s oldest cultivated crops. It is a popular vegetable in Sri Lanka, ranked fourth in cultivated extent among the low country vegetables (Anon., 2007). It shows a wide adaptability and is cultivated either as a homegarden crop or on a commercial scale in the 1 Department of Crop Science, Faculty of Agriculture, University of Peradeniya 2 Field Crops Research and Development Institute, Mahailluppallama, Sri Lanka