An experiment was carried out at the Horticulture Farm, Bangladesh Agricultural University, Mymensingh during 1998-99 growing season to study the effect of nitrogen and plant spacing on the growth and yield of potato (var. Diamant). Different nitrogen levels viz. 0, 127.0, 190.5 and 254.0 kg N/ha significantly influenced plant height, foliage coverage, number of main stem per hill, days required for 80% maturity of the crop, fresh weight of haulm (g/hill), number of tubers per hill, weight of tubers per hill, total yield of tubers per hectare and yield of seed and non-seed tubers per hectare. Application of 254.0 kg N/ha gave the highest yield of tubers (24.33 t/ha) and seed tubers (19.14 t/ha). Significant variation was observed due to the effect of the three plant spacings viz. 60 x 15, 60 x 20 and 60 x 25 cm2 in respect of the above-mentioned parameters except days required for 80% maturity of the crop and yield of non-seed tubers per hectare. The highest yield of tubers (19.19 t/ha) and seed tubers (15.63 t/ha) was obtained at the closest spacing (60 cm x 15 cm). The combined effect of different levels of nitrogen and plant spacing revealed that 254.0 kg N/ha applied at the closest spacing gave the highest yield of tubers (27.26 t/ha) and seed tubers (21.68 t/ha).
Key Words: Potato, Diamant, Nitrogen, Spacing, Growth, Yield
Potato (Solanum tuberosum L.) is one of the most important non-cereal food crops and regarded as a staple food in many countries of the world (Ahmad, 1977). It is one of the most important vegetable crops in Bangladesh contributing alone as much as 54% of the total annual vegetable production of this country (BBS, 1997). But the average yield of potato is 11.26 t/ha in Bangladesh which is quite low in comparison to that of the leading potato growing countries of the world such as the Netherlands (43.68 t/ha), USA (38.89 t/ha) and even much lower than the average yield of potato (16.13 t/ha) in the globe (FAO, 1997). Among the plant nutrients, nitrogen is so important in potato production that the value of the other inputs cannot be fully realized unless nitrogen is applied to the crop in an optimum amount (Grewal et al., 1992). Under Bangladesh conditions, use of both under and over dose of nitrogen has been reported (Hussain, 1998). The use of under dose of nitrogen results in reduction of yield of potato. On the other hand, excess use of nitrogen results in wastage of fertilizer and also has negative impact on the environment. Plant spacing is also considered as another important yield-contributing factor for potato production. The yield of tubers per hill increased significantly with increase in plant spacing but the yield of tubers per hectare did not follow the same trend (Sultana and Siddique, 1991). Increased spacings decreased the total yield of potato but closest spacings gave the highest total yield (kamal and Khan, 1973). While working with potato at different spacings, Eddowes (1975) reported that higher total yield in potato was always positively correlated with closer spacing and seed weight per hectare. As the growing period of potato is relatively short in Bangladesh, it is necessary to find out the optimum dose of nitrogen and plant spacing to use the short span of winter season to get the higher yield of potato. Considering the above factors, the present study was undertaken to study the effect of nitrogen and plant spacing on the growth and yield of potato var. Diamant under Bangladesh Agricultural University farm conditions.
MATERIALS AND METHODS
The present study was conducted at the Horticultural Farm, Bangladesh Agricultural University, Mymensingh, during the period from November, 1998 to February, 1999. The selected plot was medium high land and silty loam in soil texture belonging to the Old Brahmaputra Flood Plain (UNDP, 1988). The pH of the soil was 6.23. Potato variety used in the experiment was Diamant. The size of the seed tubers...