Response of Soybean to Sowing Depth and Phosphorus Fertilizer Rate in Dilla, Humid Tropics of Ethiopia

Abstract

An important aspect for improved crop variety is putting seeds at a desired depth with use of optimum fertilizer. These increase the likelihood of germination, emergence thereby improved productivity. The study was conducted with the objective of evaluating response of soybean varieties to planting depth and phosphorus application.  A combination of 2 x 3 x 4 factorial experimental design was replicated three times in RCBD. Awassa 04 and Awassa 95 soybean varieties with 3 sowing depth (3.5, 5.5 and 7.5 cm) and 4 phosphorus fertilizers (0, 23. 46 and 46 kg per ha) were used at Dilla university. There were significant depth x phosphorus x variety for leaf number, number of pod plant-1 and thousand seed weights. The highest grain yield of  1273.67 and  1270.00 (t/ha) were obtained from 5.5 cm depth x 46 kg phosphorus ha-1 while the lowest grain yield of 1046 and 1040.33 were obtained from 3.5 cm depth x 69 kg of phosphorus ha-1 for Awassa 04 and Awassa 95, respectively.  The maximum number of leaf plant-1 was recorded from 5.5 cm x 46 kg while plant height and branch number (43.11 cm and 5.56) were collected from 7.5 cm x 0 kg; and 7.5 cm x 0 kg ha-1 respectively. The highest means were recorded from 3.5 cm x 23 kg (9.63) and 5.5 x 23 kg (23.00), respectively. Maximum number of pod plant-1 (97.33) was recorded from 5.5 cm x 0 kg. Highest thousand seed weight (2803.33 gram) was obtained from 3.5 cm x 0 kg. The optimum standard germination was recorded from 5.5 cm x 46 kg ha^-1. Planting depth 5.5 cm x 46 kg ha^-1 phosphorus is recommended to be used to increase soybean productivity. In general, further investigation is required to confirm the current investigation.

Keywords: soybean, depth, phosphorus, Dilla, Humid Tropics