Effect of integrated use of rock phosphate, molybdenum and phosphate solubilizing bacteria on lentil (Lens culinaris) in an alluvial soil

A field experiment was conducted at Gamari, Agra, Uttar Pradesh during the winter (rabi) season of 2009–10 and 2010–11 on phosphate-deficient soil, to study the combined effect of rockphosphate (RP) with molybdenum and phosphate-solubilizing bacteria (PSB) on yield and quality of lentil (Lens culinaris Medik.) and soil fertility. Application of 60 kg P₂O₅ + 2 kg Mo/ha + Pseudomonas striata recorded significantly taller plants (49 cm), highest branches/plant (10.4), pods/plant (103.5) and test weight (28.5 g). The lentil crop responded significantly up to 60 kg P₂O₅/ha as rockphosphate and increased the grain and straw yields by 17.2 and 19.8% respectively. Application of 2 kg Mo/ha proved superior to the control with respect to grain and straw yields. Pseudomonas striata inoculation along with 2 kg Mo/ha or 60 kg P₂O₅/ha as rockphosphate improved the yield of lentil significantly over the control. The maximum grain (1.75 t/ha) and straw (3.9 t/ha) yields, and protein content were recorded with conjunctive use of 60 kg P₂O₅/ha as rockphosphate + 2 kg Mo/ha + Pseudomonas striata inoculation. The utilization of nutrients by lentil and status of available N (166 kg/ha), P (13 kg/ha) and Mo (0.074 mg/kg) improved significantly owing to P source + Mo + inoculation with Pseudomonas striata over the control. Maximum net returns (63,150/ha) and benefit: cost ratio (4.30) were obtained with 60 kg P₂O₅ + 2 kg Mo/ha + P. striata and 30 kg P₂O₅ + 2 kg Mo + P. striata inoculation respectively. The P-use efficiency decreased and apparent P recovery increased with increasing dose of phosphorus.