Growth
Plant height increased significantly with increase in nitrogen levels from 0 to 30 and 60 kg N ha-1. The plant height at 90 kg N ha-1 was comparable with that of 60 kg N ha-1 and significantly superior over 30 kg N ha-1. The plant height and number of leaves differed significantly due to N levels but it was not significant due to P2O5 levels (Table 1). The number of tillers, number of leaves and dry matter production at vegetative stage did not differ significantly due to nitrogen and phosphorous level application.
The dry matter at vegetative stage did not differ significantly influenced due to P
2O
5 levels. The dry matter at harvest was significantly higher with application of 90 kg N ha
-1 (4810 kg ha
-1) over that of 60 kg N ha
-1 (4017 kg ha
-1). Dry matter production in later two levels were comparable with each other and significantly superior over 0 N ha
-1. The dry matter at harvest increased with increase in P
2O
5 level from 0 to 20 and 40 kg ha
-1. It has been reported that with increase in nitrogen application, the availability of nutrients will be higher in soil and there by uptake of nutrients and it is higher at higher levels N
(Gupta et al., 2012).
Yield attributes
The number of fingers per ear head-2, length of the finger, grain weight per earhead and 1000 grain weight differed significantly due to nitrogen levels, however, it was not significant due to phosphorus levels and interaction of nitrogen and phosphorus levels (Table 2). The number of fingers per ear head-2 and finger length were significantly higher with application of 90 kg N ha-1 and 40 kg P2O5 ha-1 as compared to 0, 30 and 60 kg N and 0, 20 kg P2O5 ha-1. The grain weight/ earhead increased significantly with increase in nitrogen levels whereas, it was found on parity with 30 and 60 kg N ha-1. The 1000 grain weight was significantly higher with application of 90 kg N ha-1 and 40 kg P2O5 ha-1 as compared to other levels of nitrogen and phosphorus application.
The significant improvement in yield attributes was observed with application of 90 kg N ha
-1 over that of lower levels ultimately helped in increase 40 kg N ha
-1 in yield at 90 kg N ha
-1. Increased uptake of N with increased levels of N application has been reported by (
Sudhakar rao et al., 1991),
Dubey and Shrivas, (1999). There are reports that, P uptake increased with progressive increase in supply of N and P
2O
5 to crops because of more availability of these nutrients and their by higher biomass production (
Arulmozhi et al., 2013) and yield attributes.
Yield
The grain (1054 kg ha
-1) and straw yield (4369 kg ha
-1) was significantly higher with application of 90 kg N ha
-1 and 40 kg P
2O
5 ha
-1 over that of 0, 30 and 60 kg N ha
-1. The grain yield and straw yield observed with 30 (820 kg ha
-1 and 3387 kg ha
-1) and 60 kg N ha
-1 (928 kg ha
-1 and 3273 kg ha
-1) were similar with each other and significantly higher than that of 0 kg N ha
-1 (604 kg ha
-1 and 2180 kg ha
-1) (Table 3). The straw yield in latter two levels was comparable with each other and significantly superior over that of no nitrogen application.
The grain (1020 kg ha
-1) and straw yield (3387 kg ha
-1) recorded with 40 kg P
2O
5 ha
-1 was significantly higher than 0 kg and 20 kg P
2O
5 ha
-1. The grain yield observed in later two levels was comparable with each other. The increased uptake at higher levels of N application helps in improvement in production of photosynthates due to sufficient assimilation of nutrients which in turn results in vigorous plant growth and synthesizes carbohydrates and translocate them to the developing ear heads. This makes in better filling and more grain weight at increased levels of N application leading to increased yield attributes and grain yield (
Chakraborty et al., 2002). Varied responses in straw yield due to varied levels of nutrients have also been reported by
Pilane, 1997 (50 kg N + 25 kg P
2O
5),
Singh, (1999) (75% of 50-40-25 kg N,P,K ha
-1). Increased P uptake by the crops with N and P application might be attributed to their effect on the formation of active and prolific roots, resulting in increased foraging capacity of the plants.
Economics
The cost of cultivation increased gradually with increment of nitrogen and phosphorus levels. Application of 90 kg N + 40 kg P
2O
5 ha
-1 recorded maximum cost of cultivation (Rs. 21222 ha
-1). This was followed by 60 kg N + 20 kg P
2O
5 ha
-1 (Rs. 21012 ha
-1) (Table 4). The minimum cost of cultivation was recorded with 0 kg N and 0 kg P
2O
5 ha
-1 (Rs. 20288 ha
-1). Highest gross, net returns and B: C ratio were recorded with application of 90 kg N and 40 kg P
2O
5 ha
-1 (Rs. 36620 ha
-1, Rs.15398 ha
-1 and 1.73). This was due to high grain and straw yield of finger millet as compared to other treatments whereas, minimum gross and net returns were recorded with 0 kg N and 0 kg P
2O
5 ha
-1.