Productivity of spinach beet as influenced by varieties and nutrient doses

Abstract

The investigation entitled “Productivity of spinach beet as influenced by varieties and nutrient doses” was carried out at College of Agriculture, Vellayani, Thiruvananthapuram to assess the suitability of five varieties of spinach beet under protected and open conditions, to standardize the nutrient doses and to work out the economics. The experiment was laid out in split plot design in the Instructional Farm, College of Agriculture Vellayani at 8.50 N latitude, 76.9 0 E longitude, under protected and open conditions as two separate experiments during August- November 2015 and 2016 respectively. The treatments included five varieties (V1: All Green; V2: Pusa Bharathi; V3: Punjab Green; V4: Indam Kolkatta; V5: Trendy) in main plots and three nutrient levels ( N1: 40:20:40 kg NPK ha-1; N2: 60:30:60 kg NPK ha-1; N3: 80:40:80 kg NPK ha-1) in sub plots with four replications. The soil belonged to the order oxisol. The results of the experiment under protected condition revealed that among the five varieties tested, Punjab Green was found superior in terms of the number of leaves, leaf area index (LAI) and yield. The maximum leaf yield recorded by Punjab Green was 4.78 kg m-2 followed by All Green (4.56 kg m-2). Plant height, total number of leaves plant-1 and LAI were significantly higher at N3 (80:40:80 kg ha-1)compared to the lower doses. The same NPK level recorded the highest yield of 4.70 kg m-2 which was significantly superior to the other levels. The interaction effects were significant with v1n3 recording maximum leaf yield (5.06 kg m-2) followed by v3n3 (5.01 kg m-2). Nutrient uptake (NPK), protein and Fe contents were the highest in Punjab Green which was significantly superior to the other varieties, while vitamin C was the highest in Pusa Bharathi. Spinach beet fertilized with 80:40:80 kg NPK ha-1 showed significantly higher values for NPK uptake, Ca content and vitamin C. Soil pH was found to increase with higher levels of nutrients and organic carbon content decreased from the initial values. Available NPK status in soil were found to increase with the increased NPK application. The var. Punjab Green showed maximum net returns ( 881.59from 10m2) and benefit-cost ratio (1.44) and among nutrient levels, nutrient dose of 80:40:80 kg NPK ha-1 was found to be the most economical (net returns from 10 m2 - 835.54, B:C ratio- 1.42). Taking into account the interaction effects, the varieties All Green and Punjab Green at 80:40:80 kg NPK ha-1 could be recommended for cultivation under protected conditions. In open field condition, the var.All Green recorded significantly taller plants with the highest number of leaves, LAI and leaf yield. Among the different nutrient levels, N3 (80:40:80 kg NPK ha-1) was found to be significantly superior in yield attributes and leaf yield in spinach beet. The interaction of Pusa Bharathi and 80: 40: 80 kg NPK ha-1 registered significantly higher yield (4.14 kg m-2) followed by All Green at 80 :40 : 80 kg NPK ha-1 (4.02kg m-2). Nutrient uptake, vitamin A, C, protein and Ca contents were significantly high in the var. All Green and inthe nutrient dose of 80 :40:80 kg NPK ha-1. Interaction effect of the above combination (v1n3) also recorded higher values for the plant nutrient contents. Available N, P and K contents in soil significantly increased with increase in NPK levels. Economic analysis revealed that the interaction v2n3 (Pusa Bharathi and 80 :40 : 80 kg NPK ha-1) was most profitable ( net returns 495.39 from 10 m-2 and B:C ratio 1.25) followed by v1n3( net returns 418.36 from 10 m-2 and B:C ratio 1.21). The variety Punjab Green and All Green were the most suitable varieties for cultivation in polyhouse while All Green and Pusa Bharathi could be recommended for cultivation in the open. The Ca, protein chlorophyll content and NPK uptake were the highest in Punjab Green and All Green in the polyhouse and open respectively. The NPK dose of 80:40:80 kg NPK ha-1was found to be the suitable nutrient dose under both conditions irrespective of the variety. Taking into account the economics of cultivation, the combinations, All Green + 80:40:80 kg NPK ha-1 was the most profitable in the polyhouse while Pusa Bharathi + 80:40:80 kg NPKha-1, for cultivation in the open.