Effect of zinc and nitrogen fertilization on summer rice (Oryzasativa)

Abstract

Zinc deficiency appears to be the most texture, slightly acidic in reaction (pH 6.5), important nutritional factor limiting growth medium in available N (322 kgha), availa- and yield of wetland rice (Oryza sativa L.) ble P (Olsens P 14.5 kglha) and available K next to nitrogen and phosphorus. It is a (1 56 kg/ha). major component and activator of several Sarathi (1 15 days) rice was transplant- enzymes and involved in metabolic ed on 25 and 15 February during 1991 and activities, viz. auxin metabolism, protein 1992 respectively at 15 cm x 1a0 cm spacing. synthesis, nucleic acid and carbohydrate The maximum mean grain and straw metabolism, and utilization of nitrogen and yields of 45.8 and 62.1 qlha respectively . phosphorus. Krishnamurthy (1979) reported were obtained at the highest level of nitro- synergistic effect between applied nitrogen gen. The increase over 0,30 and 60 kg N/ha and zinc in rice. was 49.8, 20.7 and 7.3% for grain and 56.1, Hence an investigation was camed out to 25.2 and 10.1 % for straw yield respectively. study the effect of zinc and nitrogen Application of zinc increased the grain fertilization on grain and straw ,yields of and straw yields significantly over no zinc summer rice. application, which might be owing to better A field experiment was conducted at the utilization of N and P for grain production Central Research Station, OUAT, Bhu- through greater metabolic activities. Com- baneshwar, during summerseason of 1991 bined application of N and Zn increased the and 1992. The treatments consisting of 2 grain and straw yields by 7.2 and 12.9% re- --- sources of zinc (S1, ZnS0, and S,, Zn- spectively over alone application of N. The EDTA), 2 methods of application (MI, soil increase in both grain and straw yields was and M,, foliar application) supplemented owing to their synergistic effect. Similar re- with 4 levels of nitrogen (0, 30, 60 and 90 sults were obtained by Vyas et al. (1990) in kglha). The treatments were tried in rand- irrigated rice. omized block design with 3 replications. The sources and methods of application Zinc sulphate (22% Zn) @ 25 kg/ha and Zn- of Zn influenced the yield significantly in EDTA (12% Zn) @ 500 g/ha along with 10 both the seasons. Among the sources, kg carder were applied basal. Foliar sprays ZnSO, increased the grain and straw yields of ZnSO, at 0.4% and Zn-EDTA at 0.05% by 2.5 and 4.2% respectively over Zn- - concentration were given at 25 and 35 days EDTA, which was due to optimal supply of 1 after transplanting. Zn from ZnS0, as well as, beneficial effect The experimental soil was sandy loam in of sulphur present in it.