Effect of soil and crop management practices on sodicity stress alleviation and rice productivity under water scarce condition

Abstract

The prominent issue faced by the farmers of Cauvery Delta regionin Tamil Nadu particularly Tiruchirapalli District is the lack of timely release of water for rice nursery preparation and transplanting. Hence wet seeding of rice is recommended for timely cultivation. On the other hand, sodic nature of the soil warrants rice cultivation only. Therefore, the present investigation was carried out to study the different soil and crop management practices on alleviating sodicity stress and improving rice (variety ADT 3) productivity under water-scarce conditions. The experiment was laid in a split plot design with six mainplots,including rice wet seeding, daincha (Sesbania aculeata) application as green manure, anti-oxidant microbial consortia (AOMC) spray and four sub-plots with graded levels of NPK based on soil test values with three replication. Results showed that the daincha incorporation @ 6.25 t/ha followed by rice wet seeding + AOMC spray @1.5 % with 125 % soil test based NPK had significantly increased thechlorophyll content, SPAD values, proline content and grain and straw yields which remained on par with daincha incorporation @ 6.25 t/ha followed by rice wet seeding + AOMC spray @1.5 % with 100 % soil test based NPK.Significantly lower ESP at 5% level and higher phosphatase activity in soil was also recorded by daincha incorporation @ 6.25 t/ha followed by rice wet seeding + AOMC spray @1.5 % with 125 % and 100 % soil test based NPK. Gross return, net return and B:C ratio were also higher in the plot, which received daincha incorporation @6.25 t/ha followed by rice wet seeding + AOMC spray @1.5 % with 100 % soil test based NPK. The present study reveals that the inclusion of ectophytic microbial population spray in rice plants and the management practices helps the crop to tolerate the sodicity stress under water-scarce condition by maintaining required physiological functions like proline synthesis and enzyme activities etc which need to be further explored at the genotypic level.