INTEGRATED NUTRIENT MANAGEMENT IN SWEET CORN

Author : B. DIVYA SREE Title of the thesis : INTEGRATED NUTRIENT MANAGEMENT IN SWEET CORN Degree to which it is submitted : MASTER OF SCIENCE IN AGRICULTURE Faculty : AGRICULTURE Department Major Advisor : : AGRONOMY Dr. A.S. RAO University : ACHARYA N. G. RANGA AGRICULTURAL UNIVERSITY Year of Submission : 2014 A field experiment entitiled “Integrated nutrient management in sweet corn”. was conducted during rabi, 2013-14 at Agricultural College Farm, Bapatla. The experiment was laid out in a randomized block design with seven treatments viz.,100% recommended NPK(120:60:60 kg N, P2O5, K2O ha) (T1), 75% NPK + 3 t FYM(T2), 50% NPK + 6 t FYM(T3), 75% NPK + 2.5 t Vermicompost(T4),50% NPK + 5 t Vermicompost(T5), 75% NPK + Azospirillum @ 2.5 kg ha(T6), 50% NPK + Azospirillum @ 5 kg ha(T7) and replicated thrice. The experimental soil was clay loam in texture, slightly alkaline in reaction, low in organic carbon(0.71%) and available nitrogen, medium in available phosphorus, high in available potassium. Maximum plant height (97.5cm) was recorded with application of entire dose of recommended NPK through fertilizer (T1) which was on par with the application of 75% of the recommended dose through fertilizers along with vermicompost 2.5 t ha (T4) and 75% recommended dose through fertilizers along with FYM 3 t ha which was significantly superior over other treatments. Days taken to reach the stage of 50 per cent tasseling and silking was not significantly influenced by the integration of different organic and inorganic sources. Application of 100% RDF(T1) to sweet corn recorded the lowest percent of barrenness (6.0) and was on par with the treatment receiving 75% of the recommended dose through fertilizers along with vermicompost 2.5 t ha(6.7). Yield parameters viz., cobs per plant did not differ significantly among treatments while length of cob, number of grains per cob, no. of kernel rows per cob, grain weight per cob, test weight recorded were the highest when the crop was fertilized with entire dose of recommended NPK through fertilizers (T1), which was on par with 75% of the recommended dose through fertilizers along with vermicompost 2.5 t ha (T4) and 75% recommended dose through fertilizers along with FYM 3 t ha(T2) and proved significantly superior to all other treatment combinations. Green cob yield and green fodder yield of sweet corn were highest with the application of entire dose of recommended NPK through fertilizers (T1). However, it was on par with that obtained at 75% of the recommended dose through fertilizers along with vermicompost 2.5 t ha (T4)and 75% recommended dose through fertilizers along with FYM 3 t ha(T2). The harvest index was not significantly influenced by the treatments. The protein content did not differ significantly among the treatments whereas the sugar content proved to be significantly higher in treatment receiving 75% of the recommended dose through fertilizers along with vermicompost 2.5 t ha (T4) which was on par with application of 100% RDF. Maximum N and K uptake were recorded with the application of recommended dose of chemical fertilisers which was on par with 75% of the recommended dose through fertilizers along with vermicompost 2.5 t ha (T4) whereas the P uptake was high in case of 75% of the recommended dose through fertilizers along with vermicompost 2.5 t ha (T4) Significantly higher soil available N, P and K were observed with the treatment receiving 50% of the recommended dose through fertilizers along with Azospirillum @ 5 kg ha (T7) which was on par with 50 per cent RDN+ 50 per cent N through FYM. Highest net returns (Rs. 102895 ha) and returns per rupee invested (2.2) were registered with the application of recommended dose of chemical fertilisers(T1) followed by 75% recommended dose through fertilizers along with FYM 3 t ha(T2). From the present study, it can be concluded that among the integrated organic and inorganic sources tested, application of 75% of the recommended dose through fertilizers along with 2.5 t ha vermicompost (T4) or 3t FYMha(T2) are beneficial in registering higher yields and profit. Chapter