Plant growth and developmental studies
The observations on growth attributes
viz., plant height (cm), tillers per hill, leaf area per hill, days to 50% flowering and days to physiological maturity were recorded at the heading stage (80 DAT/DAS) and presented in Table 1. The plant height ranged from 88 cm in CE
4 [ZT rice-ZT wheat] to 78.7 cm in CE
1 [CT rice-CT wheat]. Tillers per hill was maximum in CE
4 [ZT rice-ZT wheat] (14.9) and minimum in CE
1 [CT rice-CT wheat] (9.4). Similarly, Leaf area was highest at 1088.3 cm
2 hill
-1 in CE
4 [ZT rice-ZT wheat] as compared to 856.5 cm
2 hill
-1 in CE
1 [CT rice–CT wheat]. The data on growth parameters showed more variations among crop establishment methods. The different crop establishment methods found a significant effect on growth parameters
viz., plant height, tillers hill
-1 and leaf area in two years pooled data at the heading stage of crop growth. The maximum values were recorded in zero till DSR (CE
4) over conventional till puddled transplanted rice (CE
1) followed by CTDSR (CE
3). The days to 50% flowering and days to physiological maturity were reduced under zero-till DSR (CE
4) (69.3 and 112.8 days) and was maximum (77.9 and 118.4 days) in conventional till puddled transplanted rice (CE
1). Various nutrient management practices had a significant influence on growth attributes
viz., plant height, number of tillers hill
-1, leaf area, days to 50% anthesis and days to physiological maturity in pooled data of both years. At the heading stage, significantly higher growth attributes were recorded by nutrient application based on RWCM- SSNM approach (N
3) compared to farmer’s practice (N
1) followed by recommended fertilizer dose (N
2) treatment. Interaction failed to reach the level of significance except for the leaf area. Similar results were reported earlier by researchers
(Hobbs et al., 2002; Yadav et al., 2014 and
Singh et al., 2018).
Physiological and biochemical studies
The applicable data (Table 2) related to physiological and biochemical parameters
viz., relative water content, total chlorophyll content and protein content as influenced by crop establishment methods and nutrient management practices were studied. The same were recorded at 80 DAS/DAT during both years of study. The first fully mature and expanded leaves were used for the analysis. The relative water content, chlorophyll content and protein content of leaves was recorded significantly highest in treatment CE
4 (ZT rice - ZT wheat) (96.84%, 1.61 mg g
-1 FW and 6.31 mg g
-1 FW) due to absorption of moisture in the soil by crop residues followed by CE
3 (96.03%, 1.51 mg g
-1 FW and 5.92 mg g
-1 FW)and the least was recorded in CE1(93.73%, 1.31 mg g
-1 FW and 5.11 mg g
-1 FW). The pooled data of two years for crop establishment methods differed significantly at 80 DAS/DAT. Under sub plot
i.
e. nutrient management practices, RWC and total chlorophyll content did not differ significantly. The maximum values were recorded in N
3 (SSNM-RWCM) followed by N
2 (Recommended fertilizer dose) and the minimum was observed in N
1 (Farmers practice). Although the data obtained for protein content was found significant with 5.80 mg g
-1 FW in N
3 (SSNM-RWCM) and 5.65 mg g
-1 FW in N
1 (Farmers practice). The treatment combination of CE
4 with N
3 has higher values due to the optimum use of resources and efficient use of nutrients indirectly increasing the yield of the crop. Similar results were also found in
Bhattacharya and Singh (1992).
Yield components and yield
The relevant data (Table 3 and 4) related to yield attributes
viz., number of panicles, number of spikelets panicle
-1, test weight, number of filled grains panicle
-1, panicle length, fertility percentage, grain yield, straw yield, biological yield and harvest index as influenced by crop establishment methods and nutrient management practices were studied. The maximum yield was recorded in CE
4 followed by CE
3 and the least was recorded in CE
1 and among the subplots highest in N
3 (SSNM-RWCM) followed by N
2 (Recommended fertilizer dose) and least in treatment N
1 (Farmers practice). The enhanced values in yield components could be due to increasing leaf area leading to higher photosynthesis and accumulation of more assimilates which led to increased grains per panicle and fertility percentage
(Balasubramanian and Hill, 2002). The number of panicles per hill, number of filled grains panicle
-1 and fertility percentage showed significant differences in CE methods and nutrient management practices in the pooled data of two years. The maximum number of panicles per hill,number of filled grains panicle
-1 and highest fertility percentage was recorded in CE
4 followed by CE
3 and the least was recorded in CE
1 and among the subplots highest in N
3 (SSNM-RWCM) followed by N
2 (Recommended fertilizer dose) and least in treatment N
1 (Farmers practice).Panicle length,numbers of spikelets panicle
-1 and test weight (g) did not differ significantly among treatments of CE methods and nutrient management practices in the pooled data of two years although the maximum number of spikelets per panicle and test weight was recorded in treatment CE
4 (ZT rice - ZT wheat) and N
3 (SSNM-RWCM) respectively.
The highest grain yield (kg plot
-1 and q ha
-1) showed significant differences in CE methods and nutrient management practices in the pooled data of two years. The highest grain yield (13.45 kg plot
-1 and 49.21q ha
-1) was recorded in CE
4 followed by CE
3 and the least was recorded in CE
1 (11.21 kg plot
-1 and 41.82q ha
-1) and among the subplots highest in N
3 (SSNM-RWCM) (12.61 kg plot
-1 and 47.02 q ha
-1) followed by N
2 (Recommended fertilizer dose) and least in treatment N
1 (Farmers practice) (11.98 kg plot
-1 and 44.71 q ha
-1). The straw yield (q ha
-1) and biological yield (q ha
-1) also differed significantly in CE methods and nutrient management practices in both the years of study. The highest straw yield and biological yield was recorded in CE
4 followed by CE
3 and the least was recorded in CE
1 and among the subplots highest in N
3 (SSNM-RWCM) followed by N
2 (Recommended fertilizer dose) and least in treatment N
1 (Farmers practice). The harvest index did not differ significantly among treatments of CE methods and nutrient management practices in both the year of study, although the highest harvest index was recorded in treatment CE
4 (ZT rice - ZT wheat) and N
3 (SSNM-RWCM) respectively.