Productivity, Profitability and Nutrient Status of Soil as Influenced by Integrated Nutrient Management in Chickpea-fodder Maize Cropping Sequence

Chickpea (Cicer arietinum L.) is an important pulse crop grown and consumed all over the world. In India, chickpea is grown in an area of 10.56 million hectares with total production of 11.23 million tonnes with productivity of 1063 kg/ha. While in Gujarat, chickpea is grown in an area of 0.29 million hectares producing 0.37 million tonnes with the productivity of 1253 kg/ha.
       
Maize (Zea mays L.) is an important cereal fodder crop. Maize ranks second in position after sorghum among the cereal fodder crops. It is the ideal fodder crop having quick growing habit, high yielding ability, palatability, nutritive value and acceptable to the cattle at any stage of growth. It can be grown within still wider limits and tolerate minimum temperature of about 10^oC and maximum of 45^oC.
       
In cropping system good management practices leads to efficient use of costly inputs, besides reduction in production cost. In legume cereal cropping system, residual effect of fertilizers applied and nitrogen fixed by the legumes can considerably bring down the production cost. In this context, cropping system approaches are gaining importance rather than sole crop.

The present investigation was carried out by laying out a field experiment on chickpea with levels of recommended dose of fertilizer in combination with Rhizobium, PSB, application of farm yard manure in rabi season and levels of recommended dose of fertilizer to fodder maize in summer season during 2017-18 and 2018-19 for two consecutive years on same site without changing the randomization. The soil of experimental field was clay in texture and low in nitrogen (196.80 kg/ha), medium in phosphorus (38.30 kg/ha), high in potassium (315.43 kg/ha) and slightly alkaline in reaction (pH 8.23). The treatment combinations for chickpea were T₁-100% RDF (20 N+40 P₂O₅+00 K₂O kg/ha), T₂- 75% RDF, T₃- 100% RDF+Rhizobium+PSB, T₄- 75% RDF+Rhizobium+PSB, T₅-control and general application of FYM 2.5 t/ha to chickpea in rabi season replicated four times in randomized block design. During summer season each main plot treatment was split into four sub plot treatments with four levels of RDF viz., S₁- 100% RDF (80 N+40 P₂O₅+00 K₂O kg/ha), S₂- 75% RDF, S₃- 50% RDF and S₄- control to fodder maize resulting in twenty treatment combinations replicated four times in split plot design. Chickpea variety GG-2 was used for the study. Sowing was done manually in 3 cm depth previously opened small furrows at 30 cm apart using seed rate of 60 kg/ha on 14^th November in 2017 and 19^th November in 2018. The fodder maize variety, African tall was used for this experiment in summer season. Furrows were opened in each plot at 30 cm apart and seeds were placed in dry soil condition at 5 cm depth were sown manually with seed rate of 40 kg/ha on 16^th March and 22^nd March in 2018 and 2019, respectively.

Effect of integrated nutrient management in chickpea
 
Growth parameters
 
Application of 100% RDF+Rhizobium+PSB (T₃) recorded significantly higher plant height, number of branches per plant and dry matter accumulation per plant (Table 1) at harvest but it was at par with 100% RDF (T₁) and 75% RDF+Rhizobium+PSB (T₄). The plant height in chickpea tended to increase due to quick release of available nitrogen synthesized by root rhizobia to the plant at the time of vegetative growth. The increase in number of branches per plant with increasing fertilizer level and biofertilizers might be due to improvement in nutrient availability that enhanced horizontal expansion of chickpea by encouraging cell division in the meristematic region earlier findings of Singh et al., (2017). At 50 DAS, application of 100% RDF+Rhizobium +PSB (T₃) produced significantly highest volume of nodules per plant (Table 1). It might be due to positive effect of biofertilizers and FYM by increasing the nodulation resulted higher fixation of atmospheric nitrogen and ultimately increased the growth characters.
 

 
Yield parameters
 
The treatment receiving 100% RDF+Rhizobium+PSB (T₃) recorded significantly higher number of pods per plant, seed index, seed yield per plant, seed yield and stover yield (Table 1) but it was found at par with treatment 100% RDF (T₁) and 75% RDF+Rhizobium+PSB (T₄). This was largely attributed due to better growth of plant in terms of plant height, number of branches and dry matter accumulation per plant which resulted into adequate supply of photosynthates for development of sink. The complementary role was played by combined application of inorganic fertilizer with biofertilizers in producing seed and stover yields of chickpea. These results are in close confirmity with Singh et al., (2017).
 
Soil analysis
 
The soil available nitrogen and phosphorus (Table 2) recorded after harvest of chickpea was significantly higher due to application of 100% RDF+Rhizobium+PSB (T₃) but it was found at par with 100% RDF (T₁) and 75% RDF+ Rhizobium+PSB (T₄). This could be attributed to the fact that addition of inorganic fertilizers with biofertilizers and FYM to chickpea crop residues such as roots, stubbles, leaves, nodules and bodies of Rhizobia rich in nitrogen and greater N fixation. Significantly higher available phosphorus might be due to the lower loss of nutrients due to slow available nutrients in soil. These results are in agreement with the findings of Dewangan et al., (2017).
 

 
Economics
 
Maximum net monetary returns and B:C ratio (Table 3) was recorded with application of 100% RDF+Rhizobium+PSB (T₃) followed by 100% RDF (T₁) and 75% RDF + Rhizobium +PSB (T₄). The increase in gross income, net income and B:C ratio may be due to higher production which might be more availability of nutrients with combined application of nutrient sources. Similar results were also reported by Singh et al., (2017) and Kumar et al., (2018).
 

 
Residual effect of INM to preceding chickpea in rabi on succeeding summer fodder maize
 
Growth parameters
 
The treatment receiving 100% RDF+Rhizobium+PSB (T₃) produced significantly higher plant height, number of leaves per plant and leaf: stem ratio at harvest (Table 4)  and was at par with 100% RDF (T₁). Similarly, the beneficial residual effect of addition of inorganic fertilizers along with biofertilizers and FYM under cropping sequence on growth attributes recorded by Samborlang et al., (2019).
 

 
Yield attributes and yield
 
An examination of data given in (Table 4) on fodder maize revealed that  the green fodder yield, dry matter content and dry fodder yield was significantly influenced due to residual effect of integrated nutrient management applied in rabi chickpea crop. Application of 100% RDF+ Rhizobium +PSB (T₃) to preceding chickpea crop by producing significantly highest green fodder yield, dry matter content and dry fodder yield of fodder maize. The increased green and dry fodder yields of fodder maize due to INM application to preceding rabi chickpea reflected to good crop growth resulted into influenced positively on yield and growth parameters might have positive correlation with green and dry fodder yields of fodder maize. Similar results were also reported by Chaudhari (2019) and Dixit et al., (2015).
 
Soil analysis
 
Available nitrogen and phosphorus (Table 5) in soil after harvest of summer fodder maize crop was found significant due to residual effect of different treatments to rabi chickpea, however, did not influence available potassium in soil during both years of experimentation. Application of 100% RDF+ Rhizobium+ PSB (T₃) recorded significantly higher available nitrogen which was at par with 100% RDF (T₁). Moreover, significantly highest available phosphorus in soil was recorded with application of 100% RDF+Rhizobium+PSB (T₃). This was probably due to increased N-fixation by Rhizobium+PSB inoculation. Biofertilizer also increased available P in soil due to the favourable effect on soil and increased solubilization of unavailable phosphorus by PSB. It could also be attributed to the synergistic effect of Rhizobium + PSB on the available P status of the soil. This resulted reported by Jat and Ahlawat (2006).
 

 
Economics
 
Among the different INM practices, application of 100% RDF +Rhizobium+PSB (T₃) to chickpea was noted the highest net returns of ₹ 12603/ha with B:C ratio of 0.47 followed by 100% RDF (T₁) with net returns of  ₹ 8999/ha and B:C ratio of 0.34 and 75% RDF+Rhizobium+PSB (T₄) with net returns of ` 8576/ha and B:C ratio of 0.32 of fodder maize (Table 6). Similar benefits of residual effect of INM were reported by Samborlang et al., (2019).
 

 
Effect of direct application of recommended fertilizer levels on fodder maize
 
Growth attributes
 
Significantly highest plant height and number of leaves per plant (Table 4) was recorded under treatment of 100% RDF (S₁) over 75% RDF (S₂), 50% RDF (S₃) and control (S₄) at harvest of fodder maize. Adequate nitrogen fertilization of fodder maize influencing plant height, number of leaves per plant and photosynthetic efficiency. Appropriate phosphorus application might have helped in early root development and energy transfer in plant. Similar findings were reported by Kumar et al., (2016).
 
Yield attributes and yield
 
The effect of inorganic fertilizer on yield parameters like green fodder yield and dry fodder yield (Table 4) was found significant. Application of 100% RDF (S₁) produced significantly maximum green fodder yield, dry matter content and dry fodder yield over 75% RDF (S₂), 50% RDF (S₃) and control (S₄). The increase in green and dry fodder yield of fodder maize with increasing levels of fertilizers was due to remarkable improvement in yield. The results are reported by Kumar et al., (2016) and Kumar et al., (2017).
 
Soil analysis
 
Available N and P (Table 5) in soil after harvest of summer fodder maize crop was found significant due to different levels of RDF applied to fodder maize but different treatments did not influence available potassium in soil. Application of 100% RDF (S₁) was found significantly higher available nitrogen being at par with treatment 75% RDF (S₂). Treatment 100% RDF (S₁) registered significantly highest available phosphorus in soil after harvest of fodder maize crop. The improvement in available phosphorus could be ascribed to addition of phosphorus through fertilizers reported by Kumar et al., (2017).
 
Economics
 
Maximum net returns of  ₹ 13553/ha and B:C ratio of 0.49 (Table 6) was obtained with application of 100% RDF (S₁), followed by 75% RDF (S₂) with net returns of  ₹ 9011/ha and B:C ratio of 0.33.

It can be concluded that for getting higher yield, monetary  returns and maintenance of soil status, chickpea crop should be nourished with 75% RDF (15 N+30 P₂O₅+00 K₂O kg/ha) +Rhizobium (10 ml/kg seed)+PSB (10 ml/kg seed) with 2.5 t/ha FYM and summer fodder maize crop should be fertilized with 100% RDF (80 N + 40 P₂O₅+00 K₂O kg/ha) through inorganic fertilizer in chickpea- fodder maize cropping sequence in south Gujarat condition.

None.