SREE REKHA, MPADMA, S2020-03-042020-03-042019http://krishikosh.egranth.ac.in/handle/1/5810144181D5953A field study on “Crop residue and nitrogen management in pulsemaize sequence” was conducted over two years (2017-18 and 2018-19) on clay soils of Agricultural College Farm, Bapatla. The experimental trial was conducted in split-split plot design, replicated thrice with P1-cowpea, P2blackgram, P3-greengram and P4-fallow as four main plots during kharif season. The main plots were divided into three subplots after the harvest of pulses viz., R1-residue retained, R2-residue incorporated and R3-residue removed. Each residue management sub plots were further subdivided into sub-sub plots with four nitrogen levels to maize i.e., N1-75% RDN, N2-100% RDN, N3-125% RDN and N4-150% RDN. Among pulses cowpea produced higher seed and haulm yields during the two years trial when compared to blackgram and greengram. The soil microbial count enhanced in the plots where pulses were included and the higher values were with cowpea. The undecomposed crop residue by litter bag method was lesser for blackgram and greengram as compared to cowpea and fallow. Residue retained plots had greater undecomposed matter than residue incorporated plots. The plant height at various stages of plant growth from 30 DAS till harvest for rabi maize was remarkably higher with preceding cowpea than blackgram-maize, greengram-maize sequence and fallow-maize plots. However, the plant height during 2018-19 at 90DAS and at harvest for rabi maize remained comparable for preceded cowpea and greengram. Dry matter accumulation was not affected by preceding pulses. The plant height and drymatter accumulation were enhanced in residue retention plots and remained xvi comparable with residue incorporated plots. Nitrogen @150% RDN has resulted marked increase in growth characters i.e plant height and drymatter accumulation. The interaction effect of preceding pulses and nitrogen levels has significant on drymatter at harvest during 2017-18. Days to 50% tasseling and days to 50% silking were not influenced by preceding pulses and residue management while 150% nitrogen resulted in earlier tasseling and silking. Leaf relative chlorophyll content (SPAD) was higher in maize preceded with cowpea, residue retained and 150% nitrogen at 50% tasseling and 50% silking during both the years of study. Cob length, number of kernel rows cob-1, number of kernels row-1, number of kernels cob-1, kernel weight cob-1 and 100- kernel weight of rabi maize were enhanced in cowpea as preceding crop and remained comparable with blackgram-maize and greengram-maize sequence than fallow-maize. Residue retention plots had higher values for all yield attributing characters and remained comparable with residue incorporated plots. Incremental enhancement in nitrogen resulted in remarkably increased values of yield attributing characters among which 150% RDN proved its significant and superior over other levels during both the years of study. Shelling percentage was not affected by preceding pulses, residue management and nitrogen levels. Kernel and stover yields of maize were markedly enhanced with preceding cowpea, residue retained plots and nitrogen @ 150%. Interaction for pulses (P) and nitrogen levels (N) during 2017-18 and interaction for residue management (R) and nitrogen levels (N) were found to be significant during 2018-19 for kernel yield of maize. The nitrogen content was influenced by nitrogen levels but not by preceding pulses and residue management. The uptake of nitrogen, phosphorus and potassium by both kernel and stover along with total uptake were higher in maize preceding with cowpea, residue retained plots and nitrogen @ 150% RDN. Soil available N, P2O5 and K2O were higher in preceding pulse crops, residue retained and incorporated plots. Increased nitrogen levels (150% RDN) had higher values of post harvest soil available N, P2O5 and K2O during both the years of study. The total maize equivalent yield was higher in preceding blackgram during 2017-18 while it was with preceding greengram during 2018-19. 150% RDN with residue retention had higher values of total maize equivalent yield. The higher gross return, BCR, net return and return per rupee investment were noticed with cowpea-maize sequence wherein residue retained plots with nitrogen application @ 150% RDN to maize. From the above, it can be inferred that maize with preceding cowpea residue retention can be adopted in Krishna agro-climatic zone of Andhra Pradesh for higher profitability along with nitrogen @150% RDN to maize.en-USnullThesis