Influence of time of nitrogen application on number and size of potato (Solunum .luberosum) tubers

Abstract

In potato (Solanum tuberosum L.) split phosphorus @ 80 kg P20,/ha through single application of nitrogen is beneficial, as it superphosphate and potassium @ 100 kg minimizes the leaching loss of N. K20/ha as muriate of potash was applied at Application of N generally increases tuber planting. As the N was applied through urea, number as well as size (Pushkamath, 1976) it was mixed thoroughly with the soil to and at higher levels it increases vegetative prevent direct contact with sprouts. Seed- growth and delays the tuber initiation. tubers of cultivar Kufri Bahar weighing 40 Although split applicatiog of N has been g were planted in 50 crn x 20 cm spacing. - - tried earlier, the effect of N applied before The planting was done during the third week and after the tuber initiation on tuber number of October and harvesting in the first week and size is less understood. Hence an attempt of February. was made to study the effect of N applied at In Kufri Bahar potato-tuber initiation and after tuber initiation on number and size begins at about 30 days, after planting and of potato tubers at final harvest. continues fbr at least 2 weeks under short- Tlie field experiment was conducted at day conditions. Therefore top-dressing was New Delhi during the winter (rabi) season of done at 30 or 45 days afterplanting. 1989-90, in a randomized block design with Application of 150 kgha either as basal 4 replications. The soil of the experimental or in splits recorded significantly higher - z, field was sandy loam in texture, containing tuber yield than 75 kg Nha (Table 1). The organic carbon 0.46%, and available N, P highest tuber yield was recorded with 50 kg and K 18 1.8, 12.8 and 200 kglha Nlha at planting + 100 kg as top-dressed at respectively, with a pH 8.2. Two levels of N, 30 days after planting. Increase in tuber i.e. the recommended level (150 kglha) and yield in this treatment may be attributed to reduced Ievel (75 kgnla), were applied in 3 higher number as well as weight of large- split combinations- at the time of tuber sized tubers (weighing more than 5 cm). The initiation (30 days after planting and after results confm the findings of Hay and tuber initiation 45 days after planting), and Walker (1989). Higher tuber yield in this basal application of 150 kgha as the control. treatment could also be ascribed to greater --.. 1 The details of the treatment combinations vegetative growth, as reflected by higher are given in Table 1. A uniform dose of ground cover. This could be owing to better