Growth attributes
Based on the analysis of data selected differ significantly under green gram varieties to organic production system. The results revealed that the (Table 1) variety MUM-2 showed significant influence on plant height at harvest (62.47 cm) followed by RMG-975 (62.06 cm) and lowest plant height (50.88 cm) was recorded in the variety SML-668 among the tested varieties. The number of primary branches also showed the similar trends and responded positively underorganic production system. The highest number of primary branches (5.18) recorded in MUM-2 followed by RMG-975 (4.97) might be owingto fulfilment of nutrient requirement of the varieties at initial growth period leads to improved branching. Organic manures and bio-fertilizers influence the soil nutrient availability through better microbial activity and by releasing the nutrients from the soil, which helps in ample absorption and utilization of nutrients by the plants
(Kuar, 2016). The increase in growth parameters might be due to sufficient nutrients supply to plant continuously for various metabolic processes. Balanced and regular supply of nutrients increased the uptake of nutrients also which had possibly contributed to more vegetative growth as well asnumber of branches. Application of organic manures alongwith bio-inoculants increased germination and growth of roots and shoots. It might be probably due to their genetic characters of varieties. The similar findings were also supported by
Chadha et al., (2013), Dwivedi et al., (2018) in pea,
Lal et al., (2017) in coriander,
Lal et al., (2019b) in fennel.
Yield and yield attributes
The results revealed that significant variation was recorded in yield and yield attributes in green gram varieties grown under organic production system. The yield attributes (Table 1) such as number of pods per plant (27.27) and number of seeds per pod (11.27) and seed yield (809.80 kg ha
-1) was also recorded highest in variety MUM-2 followed by RMG-975 (number of pods per plant (26.70) and number of seeds per pod (11.18) and seed yield (802.47 kg ha
-1) and lowest seed yield was recorded in MSG-118 (617.80kg ha
-1) and SML-668 (625.90 kg ha
-1). The variation in yield and yield attributes might be due to the varietal differences and reflects clearly indicates that MUM-2 and RMG-975 green gram varieties were found suitable for organic farming. Attainments of particularly higher or lower yield attributing character among the different varieties are the genetically controlled phenomenon (
Sadeghipur 2008,
Gorade et al., 2014 and
Patel et al., 2020). Such variations in yield attributes among the mungbean varieties have also been observed by
Goswami et al., (2010).
Yield components
viz. number of pod per plant, number of seed per pod and 1000 seed weight showed significant variation among the different varieties (Table 1). Higher value of these characters ensure better crop yield, which in turn are governed by various plant metabolic functions
viz. phloem transportthat determine how efficiently photosynthates are made available to the harvestable plant parts
(Thavaprakash et al., 2006).
Higher crop yield under organic plant management indicated the favourable impact of activated plant metabolic functions considering the positive correlation between enhanced photosynthesis, biomass and yield. When other genetic factors are not altered, increasing photosynthesis leads to yield increase
(Guney et al., 2016) as higher rates of photosynthesis may be caused by greater N allocation to and higher mesophyll conductance, Rubisco. Rubisco is the primary CO
2 fixation enzyme and the amount and kinetic properties of this enzyme strongly affect the photosynthetic rate
(Makino et al., 1992). Also pointed towards the need for developing healthy plants; efficient nutrient absorption, photosynthesis and assimilation being the sole key for enhancing crop productivity. Apart from this medium duration nature and high biomass yielding varieties such as MUM-2, RMG-975 performed better due to availability of nutrients to the crop throughout the crop growth period. Organic manures act as nutrient reservoir and upon decomposition produces organic acids; there by absorbed ions are released slowly during entire growth period leading to higher seed yield and yield components
(Maheshbabu et al., 2008).
Productivity of the crop during the initial year in an organically managed field is lower than in subsequent years as soil fertility levels increase over time as organic materials are added in the organic management system. Similarly,
(Surekha, 2007) revealed that a gradual increase in grain yield with the use of organic fertilizers over a period of time was observed
(Chan et al., 2008). Organic manures usually supply the nutrientsin later stages as they need time to decompose and release the nutrients to soil solution. This may be the reason to better performance of MUM-2 and RMG-975 to organic management. The similar findings were also supported by
Maheshbabu et al., (2008), Lal et al., (2017), Dwivedi et al., (2018), in coriander,
Lal et al., (2019b) in fennel.
Harvest index
The harvest index determines how much photosynthates are transformed into economic yield. The harvest index was recorded significant among the varieties. However, the highest harvest index was found in the variety SML-668 (23.82%) followed by GANGA-1 (23.65%). Whereas, the minimum harvest index was found in the local variety RMG-492 (20.13%). As harvest index indicates the ratio between the economic parts (
i.e., in this case seeds) and total biomass production, varieties producing higher seed yield have recorded higher harvest index as compared to others
(Layek et al., 2014).
Qualitative characters
Data in Table 2 show that the significant difference recorded in seed quality parameters such as nitrogen and protein percentage of all tested varieties under organic management system. The highest test weight (1000 seed weight) was obtained in variety SML-668 (45.99 gm) followed by RMG-975 (37.07 gm) and minimum test weight recorded in local variety RMG-492 (27.97 gm). The reason may be attributed towards the genetic variability and bold grain size in case of SML-668. Similar result about seed test weight was reported by
Uddin et al., (2009) and
Yadav et al., (2007). The maximum nitrogen and protein percentage was found in variety SML-668 (4.17% and 26.06%) followed by MUM-2 (4.12% and 25.75%) at par with RMG-492 and RMG-975 and minimum was found in variety RMG-62 (3.40% and 21.27%). It is noted that MUM-2 and RMG-975 are the one of the top performing varieties of green gram in organic farming practices. Higher nutrient content in plant tissue favours the higher growth and yield characters. The higher nutrient accumulation at initial growth stages of crop with recommended nutrients is due to availability of nutrient along with faster dry matter accumulation. But in later stages of crop growth organic source released nutrient for longer period which facilitated more nutrient absorption resulting in higher nutrient accumulation. These results are in close conformity with that of
Henri et al., (2008), Uma and Malathi (2009)and
Dhakal et al., (2016).
Soil fertility status of green gram varieties
Soil fertility and nutrient status of green gram crop after harvest the
Rabi crop in fennel-green gram cropping system was significantly influenced under organic production system (Table 3). The highest amount of nutrients N was found in the variety MSG-118 (176.03 kg ha
-1) and PK was found in the variety IPM-02-3 (27.10 and 325.29 kg ha
-1) followed by MUM-2 (174.78, 26.97 and 324.65 kg ha
-1). The lowest nutrient NPK content of soil was found variety RMG-62 (156.80, 24.05 and 309.23 kg ha
-1). Evaluation of soil quality under different treatments pre and post experimentation revealed considerable changes in soil pH and EC. However, slight increase in organic carbon was noted in all plots. Available N, P, K showed increasing trend under all treatments. In each plots, comparative higher value of available-N may be due to efficient fixation of atmospheric N through symbiotic legume-
Rhizobium association
Bohlool et al., (1992). Legume crops add large amount of organic residues through leaf fall and rhizodeposition and the intermediate acids produced during organic residue decomposition also solubilise fixed forms of nitrogen and phosphorus in soil resulting in increased available nitrogen and phosphorus (
Henri et al., 2008). Soil micro-organisms play a significant role in regulating the dynamics of organic matter decomposition and availability of plant nutrients
(Chen 2006). An important feature of green gram crop is its ability to establish a symbiotic partnership with specific bacteria, setting up biological N
2-fixation in its root nodules that supply the plant’s needs for N
2 (
Mahmood and Athar 2008).
This is mainly due to early maturity of crop leads to more residual soil fertility in the respective plots which is attributed by less removal of nutrients. Similar trend was observed in phosphorus and potassium fertility of the soil. Nutrient use efficiency will vary with the efficiency of variety to utilize the applied nutrients. High yielding varieties are always efficient enough to absorb more nutrients since these are metabolically more active. The results are in confirmation with
Chhibba et al., (2000) in fenugreek and
Basu et al., (2008) in fenugreek.