Effect of in situ incorporation of legume green manure crops on nutrient bioavailability, productivity and uptake of maize

Maize, being a nutrient exhaustive crop and also grown as a monocrop season after season, is leading to drastic deterioration of the soil fertility status. Hence green manure legumes initially grown in situ and later incorporated before flowering stage into the soil will help to rejuvenate the soil health. An experiment was conducted at Agricultural Research Station, Vizianagaram for three consecutive years during kharif 2015, 2016 and 2017 to evaluate the effect of green manures on soil health, nutrient bioavailability and yield attributes of the succeeding maize crop. Three green manure legumes viz., sunhemp, dhaincha and green gram were grown in situ and incorporated into the soil before sowing of the maize crop in the respective treatments and different doses of fertilizer levels were applied to study the cumulative effect of green manures and inorganic fertilizers on the growth and yield attributes, economics and nutrient uptake of succeeding maize. Pooled data of all three years proved that the grain and straw yield was found to be the highest in the treatment of in situ incorporation of dhaincha with 100% RDF (65.2 q/ha and 74.0 q/ha). Moreover, the soil available nitrogen was also found highest in the same treatment (230 kg/ha), whereas the available P2O5 (73 kg/ha) and K2O (318 kg/ha) was found highest in the treatment with in situ incorporation of sunhemp with 100% RDF, but these treatments are at par with in situ incorporation of dhaincha with 75% RDF. The soil available Fe was found high in the treatment with in situ incorporation of dhaincha with 100% RDF (12.98 ppm), whereas soil available Mn was found highest in the treatment with in situ incorporation of sunhemp with 100% RDF (12.43 ppm) but at par with in situ incorporation of dhaincha with 100% RDF and in situ incorporation of dhaincha with 75% RDF. The N and K uptake by maize plant was found highest in the treatment with in situ incorporation of dhaincha with 100% RDF (110.0 kg/ha and 87.5 kg/ha) whereas the uptake of P was found highest in the treatment with in situ incorporation of sunhemp with 100% RDF (39.1 kg/ha), but both the treatments are at par with each other in the uptake of N, P and K nutrients and significantly higher than sole crop of maize with 100% RDF.