Effect of integrated nutrient management on growth and yield of pigeon pea (Cajanus cajan) in changing climatic condition of Bihar

The low yield of pigeon pea is not only due to its cultivation on sub-marginal lands, but also due to poor crop management and soil moisture deficit at critical growth stages, such as flowering and pod development which cause in significant reduction in grain yield (Pandey et al., 2013).  Imbalanced application of fertilizer resulted in poor yields, deterioration of soil fertilities and emergence of multiple nutrient deficiencies. Situation, therefore, warrants for adoption of organic based resources that supply nutrients to the plants through microbial mediation and in the process enrich soil organic carbon.Farmyard manure and vermicompost are important source of organics which not only provides balanced nutrition to the plant but also sustains crop productivity, provides good substrate for growth of micro organism maintained favorable nutrition balance and soil physical properties (Mahetele and Kushwaha, 2011). Under present changing climate scenario where food and nutritional security are under threat, it has become imperative to ameliorate the soil - plant - atmosphere as a whole rather than facing the crop plant alone. With this back ground, the present investigation was under taken to achieved maximum productivity without deteriorating the soil fertility with the optimum use of inorganic, organic and bio-fertilizer in pigeon pea at experimental area of Krishi Vigyan Kendra, Khodawandpur, Begusarai and other two multi locations.

A multi-locational field experiments was conducted during 2013-14 and 2014-15 at Krishi Vigyan Kendra, Khodawandpur, Begusarai and farmers’ fields at Gadhpura and Barauni blocks. The soil was sandy loam in texture at all the locations. Ten treatments of different fertility levels [T₁-control, T₂- Recommended dose of fertilizer (20kg N  + 40 kg P and 20 kg  K/ha.), T₃-FYM @5.0 t/ha, T₄- vermicompost @ 2.0 t/ha, T₅-Rhizobium + PSB (seed inoculation), T₆- T₂+ T₃, T₇-T₂+ T₄, T₈- T₂+ T₅, T₉- T₃+ T₅ and T₁₀- T₄+T₅] were tested  in randomized block design with the three replications. The FYM and vermicompost were applied in the field five days before sowing of crop. Before sowing seed was inoculated with bio-fertilizer (Rhizobium and Phosphate solubilizing Bactria as (PSB) @ 20g/kg seed and the treated seeds were dried in shade for an hour, thereafter seed was use for sowing. The pigeon pea variety MAL -13 using a seed rate 20 kg/ha was sown in rows in 60 cm apart and plant to plant distance of 20 cm. It was maintained by thinning at 02 weeks after sowing. The sowing time was 1^st week of August and harvested in 3^rd week of April next year. The entire fertilizer was applied at the time of sowing. The nutrient content of FYM and vermicompost and experimental field at different locations were given in Table 1 and 2 respectively. The soil of the experimental plots were medium in organic carbon, available nitrogen and phosphorus and low in available potassium at Gadhpura whereas medium in Barauni and Khodawandpur. One hand weeding was done at 30 days of sowing. The crop received 1052.6 mm of mean annual rainfall during the crop growth period.  Recommended package of practices were followed for raising the crop. At Krishi Vigyan Kendra, Khodawandpur, Begusarai the plant height, days to 50% flowering, number of branches/plant, leaf area, number of pods/plant, pod length, number of grains/pod and 100 seed weight were recorded at harvest where as at other locations data on only grain and stalk yield were recorded. Soil samples were collected from 0-15 cm depth from different locations to determine available nutrient content as per method described by Jackson (1973). The data collected during the course of experimentation were statistically analyzed, as per the methods described by Gomez and Gomez (1984).
 

 

Growth and yield attributes
 
Data (Table 3) clearly revealed that among the integrated nutrient management application of RDF (100%) and vermicompost (2tones/ha) showed significant effect on yield attributes except 100 seed weight. All the yield attributes like plant height (193 cm), number of primary branches (18/ plant), number of secondary branches (31/plant), number of pods (229/plant), pod length (5.2 cm), number of grains (4.2/pod) were significantly higher in recommended dose of fertilizers with vermicompost (T₇) except days to 50% flowering and leaf area. The next better treatment in this regard was T₆ at RDF+FYM, except days to 50% flowering, plant height and leaf area index but statistically superior over the treatment control. Seed inoculation with Rhizobium and PSB proved its superiority over untreated control with respect to plant height, number of branches, pod length and 100 seed weight in pigeon pea. Inoculation of bio-fertilizers with organic manure (T₁₀) recorded higher value of all the growth attributes at 50% flowering and which was significantly superior to seed inoculation with Rhizobium + PSB.  The overall improvement of this crop was owing to its pivotal role in early root formation, its proliferation, photosynthesis, increased microbial activity in root nodules, symbiotic nitrogen which in term resulted in greater transformation of photosynthesis towards the sink development. Similar results have been reported by Goud et al., (2012), Pandey et al., (2013), Kumar et al., (2014) and Jat et al., (2015).
 

 
Grain and stalk yield
 
It was revealed from the Table 4 that all the treatments significantly influenced the grain and stalk yield of pigeon pea at all the three locations. At all  locations, though application of RDF+vermicompost resulted in highest grain and stalk yield, yet it was at par with the treatment of T₂, T₄, T₆, T₈, T₉ and T₁₀ during both the years in mean values. The application of RDF increased the grain yield of pigeon pea significantly (21.4%) over control treatment in Khodawandpur. The application of FYM@5t/ha or seed inoculation of Rhizobium+PSB tended to increase the grain and stalk yield over control.Seed inoculation with bio-inoculants influenced the grain and stalk yield over no inoculation. Thus, combined inoculation improved the nutrients status of soil through their synergistic effect on nitrogen fixation and solubilization of native soil phosphorus which increased availability and uptake of these nutrients by the crop plant resulted in enhanced yield indices and grain yield of the crop. It is well known fact that nitrogen and phosphorus are essential constituents of proteins and chlorophyll along with their movement in many other compounds of physiological importance in plant metabolism. Hence, increase in yield due to application of organic manure, fertilizer and bio-fertilizer together might be responsible for synthesis of plant growth hormone, development of root system and therefore high nutrients utilization by the crop plant (Meena and Sharma, 2010). Further, the organic manure also attribute in supplying of adequate quantities and balanced proportion of plant nutrients of the crop as per the need (Pandey et al., 2015 and Arabhanvi and Pujar, 2015).
 

       
Pooled data revealed that application of recommended dose of fertilizer fetched higher benefit-cost ratio by Khodawandpur, however, the benefit-cost ratio was at par by Gadhpura in comparison with RDF + Bio fertilizers. Similarly, use of RDF + vermicompost obtained significantly higher benefit-cost ratio over control. Very low increment in cost of production and higher yield levels owing to combined inoculation of these bio-inoculants resulted higher economic returns over the control (Pandey et al., 2013).

Results of the study suggested that application of RDF+vermicompost@2t/ha improved the yield attributes and yield of pigeon pea and balance fertilization supports sustained and enhance productivity of pigeon pea.