Effect of nitrogen and sulphur on growth attributes
The growth attributes of linseed as influenced by N and S levels were recorded at 30, 60, 90 days after sowing and at harvest (Table 1). It was indicated that plant height increased at 30,60,90 DAS and harvest and recorded maximum at 60 kg N ha
-1 (13.88, 29.85, 46.55 and 48.18 cm respectively. The increased in plant height with increase in the rate of N may be attributed to enhance vegetative growth, similarly results was also recorded by
Sharief et al., (2005). Plant height was also significantly influenced by S levels, maximum height was observed 12.63, 26.38, 43.32 and 44.85 cm at 30, 60, 90 DAS and at harvest, respectively at highest S level. These findings were corroborated with the findings of
Misra et al., (2013) and
Minz et al., (2017), while the interaction effect of N and S were found to be significant. Combined application of 60 kg N and 40 kg S ha
-1 gave the highest plant height of 15.67, 30.97, 49.93 and 50.73cm respectively at successive stages of growth (Table 3). The fact that nitrogen being a structural constituent of protein seems to be an essential for cell division and cell expansion too. Further, cell division and cell expansion are the prime characteristics of dynamics for increase in height and number of branches. Maximum number of branches were found with the application of 40 kg S ha
-1, these findings was in agreement with the findings of
Banerjee et al., (2001). Sulphur is the constituent of a number of amino acids which are essential for the growth and development of plant tissues. Maximum branches plant
-1 was recorded (Table 4) with the combined application of 60kg N and 40 kg S ha
-1 in all stages of observation as 1.77, 4.83, 9.05 and 9.27 respectively, similar findings at also reported by
Dwidevi et al., (2001).
Effect of nitrogen and sulphur on yield attributes
The increasing N levels had significant differences on number of bolls plant
-1. The highest number of bolls plant
-1 was recorded with application of 60kg N ha
-1 (64.35). Similar result was noticed by
Khajini et al., (2012). Variation on number of boll plant
-1 due to the interaction of N and S was found to be significant (Table 5). Combined use of 60 kg N and 40 kg S ha
-1 gave the higher number of capsules plant
-1 (67.56) as compared to the remaining treatments. The result was in agreement with the findings of
Singh (2001). Under N levels, application of 60 kg ha
-1 recorded the highest number of seed boll
-1 (9.37). The increase in yield attributes results due to proper and balanced supply of nutrients. Maximum number of seed boll
-1 (9.13) was recorded at 40 kg S ha
-1 as compared to other doses of
S. Dutta and Patra (2005);
Singh et al., (2008) recorded similar results. Combination of 60 kg N and 40 kg S gave superior number of seeds boll
-1 (9.91) (Table 6), similar results was also obtained by
Upadyay et al., (2012). Among the nitrogen levels, maximum seed weight was recorded at 60 kg N ha
-1.
Lawania et al., (2015) revealed that seed weight plant
-1 increased significantly with the application of 50 kg N ha
-1 as compared to all other treatments. Increasing levels of nitrogen and sulphur significantly increased the seed weight. The maximum seed weight 2.80 and 2.81g was recorded with the application of 60 kg N and 40 kg S ha
-1 respectively. Application of upto 40 kg S significantly increased seed weight
(Lawania et al., 2015). Interaction effects of nitrogen and sulphur on seed weight were observed to be significant. The highest seed weight was 4.10g was recorded when 60 kg N was applied with 40 kg S ha
-1. Levels of nitrogen and sulphur had no significant effect on test weight. Maximum seed yield was recorded with application of 60 kg N ha
-1 (799.87 kg ha
-1),
Lawania et al., (2015) showed positive yield responses to nitrogen up to 60 kg ha
-1. Amongst S levels, application of 40kg S ha
-1 gave maximum yield (797.54 kg ha
-1), while the lowest yield was associated with control. The increase in yield attributes on addition of sulphur might be due to its deficiency in the experimental soil. The crop received 40 ppm sulphur might have been helped in terms of vigorous root growth, formation of chlorophyll, resulting in higher photosynthesis similar results were reported by
Singh and Sharma (1996). Combination of 60 kg N with 40 kg S ha
-1 gave the highest yield (840.72 kg ha
-1) in comparison with other treatment; the results were in accordance with
Jaggi et al., (1993). Among the nitrogen levels, maximum stover yield was recorded (1619.87 kg ha
-1) at 60 kg N ha
-1, the results corroborate with the findings of
Patil (2016). Sulphur levels also showed significant effect on stover yield. Application of 40 kg S recorded highest stover yield (1557.58 kg ha
-1). The results were similar with
Chaudhary et al., (2016). Combination of 60 kg N and 40 kg S ha
-1 provided maximum stover yield (1713.30 kg ha
-1) in comparison to others treatments, this result was in accordance with the findings of
Jaggi et al., (1993).
Available soil NPKS (kg ha-1)
A critical study of the data on available nitrogen in the soil revealed significant variation due to nitrogen levels. Available N in the soil increased with increasing levels of nitrogen from 0 to 60 (326.50 kg ha
-1), the present findings were similar with the findings of
Gudeta et al., (2017), the N accumulation in seed and straw of the crop to some extent may be responsible for such a decline in nitrogen content in the soil. Moreover, N losses through leaching, denitrification and volatilization are also important for the decline, application of nitrogen from 0-60 kg ha
-1 proved significant increase in the content of soil sulphur. The highest value of 12.81 mg kg
-1 of soil was recorded with the application of 60kg N ha
-1, against the initial available soil sulphur content of 8.50 mg kg
-1 (Table 2). The available sulphur content of soil after harvest of linseed increased with the increasing levels of sulphur from control (8.93 mg kg
-1) to 60 kg S ha
-1 (18.76 mg kg
-1). Similar results was also observed by
Gudeta et al., (2017).
Economic analysis
The maximum gross return was observed under treatment N
60S
40 as ₹86893, while net return was ₹62605.35 under N
60S
0 respectively (Table 6), while treatment recorded least gross return was under treatment N
0S
0 ₹73524.6 and net return ₹53417.1. The highest BC ratio was 2.90 noted to be under N
20S
0 treatment, followed by N
40S
0 (2.90).