Dry matter accumulation reflects growth and metabolic efficiency of a plant, which ultimately influences the economic yield. Total dry matter production by rice plants increased progressively with the advancement of growth stages and reached peak at maturity (Figure 1& 2) and a particular growth pattern has been observed in both the years through application of different source of nutrient (Figure 1.) as well as different date of planting (Figure 2.).
The partitioning of drymass between different parts of a plant was dramatically altered at different growth stages by date of planting and nutrient management are presented in Table 1&2 as well as in figure 1, 2 & 3. Overall Plant parts and total drymatter increased progressively with advancement of crop age up to 90 DAT thereafter the increase was marginal (Figure 1&2).
Irrespective of period of observation, highest translocation of drymatter took place towards stem followed by leaf in vegetative stages and during harvest stages the trend followed was Stem> Panicle > leaf (Figure 4). In all the tables from the year mean it has been observed that year 2019-20 had higher dry matter than 2018-19.
Drymatter partitioning to Leaf: Dry matter of leaf was significantly higher in case of earlier planting at all the stages. Mean maximum dry matter of leaf (198.02 g m-2) has been observed at 60 DAT (PI stage) thereafter decreases in both the year.
A significant increase in drymatter of leaf was observed from tillering to harvesting stages with STBFR+ organic combinations i.e. GM and FYM in comparison to only inorganic treated plot. Effect of STBFR+GM treated plot was significantly higher over the other two treated plot in all the stages. At harvesting stage mean dry matter of leaf in STBFR+GM treated rice was significantly higher by 5.57, 11.79 over other two treatment respectively.
Drymatter partitioning to Stem: Data in respect of dry matter of stem at various stages of plant growth was presented in table 1 & 2. Date of planting had significant effect in improving drymatter production of stem at all the growth stages and higher drymatter of stem has been observed at 90 DAT (771.9 g m-2) thereafter it decreased marginally. On an average 10 July planting recorded 3.32 per cent more drymatter over 15 days late planting at harvesting stage.
Nutrient management had significant effect in increasing dry weight of stem till 90 DAT thereafter decreases. Different organic inorganic combination was significantly higher over inorganic treatment alone. Highest drymatter of stem was observed in case of STBFR+GM (776.5 g m-2) at 90 DAT, which was 1.26, 3.87 per cent higher over STBFR+ FYM and STBFR treated plot respectively.
Drymatter partitioning to Reproductive parts:
Data representing dry weight of reproductive parts were presented in Table 2. It indicates dry weight has been increased from 90 DAT to harvesting stage due to grain filling.
At 90 DAT as well as harvesting stage 15 days early planting gave higher dry matter of (panicle) reproductive parts of the plant. At harvesting stage earlier planting recorded higher dry weight of reproductive parts than late planting condition by 3.74 per cent. Persual of the data indicates STBFR+ GM significantly better over other two treatments in both the year. Average data in table 2 indicated highest dry weight of reproductive parts in STBFR+GM treated plot which was 2.06, 8.09 per cent higher over STBFR+FYM and STBFR treated plot respectively.
Total dry matter:
Dry matter accumulation per metre square increased progressively with age till maturity of the crop (Table 3). Average dry matter production was 210.5, 876.1, 1163.8, 1204.8 g m-2 at 30, 60, 90 DAT and at maturity stage respectively. Difference in drymatter of rice due to different date of sowing was significant at all the four stages of plant growth. Irrespective of year 10 July planted crop shows highest dry matter accumulation compared to 15 days delay in planting. The drymatter obtained under earlier planting method at harvesting stage (1204.83 g m-2) was higher than late planting by 3.78 per cent.
Significant difference in rice dry matter was observed due to change in sources of nutrient. At 30 DAT (tillering stage) STBFR+GM based treatment shows higher dry weight i.e 207.8 g m-2 which was significantly higher than STBFR+FYM (204.2 g m-2) followed by STBFR (201.3 g m-2) treated plot. Similar trend of significant difference in rice drymatter was observed due to various inorganic and organic treated plot at other 3 stages shows highest drymatter at STBFR+GM treated plot by 1.76, 1.94, 2.08 per cent over STBFR+FYM; 3.23, 5.90, 6.29 per cent over STBFR treated plot respectively.
The interaction effect of all the drymatter partitioned at harvesting stage was represented in Figure 4 indicates that 10 July planting along with STBFR+GM have higher drymatter in stem, leaf, grain than other treatment combinations.
CGR (g m-2day-1):
Data pertaining to crop growth rate (CGR) g m-2 day-1 are presented in Table 4. Irrespective of the treatments, the crop growth rate (CGR) progressively increased till 60 DAT and declined thereafter till maturity. CGR is found to be higher between 30-60 days duration. At all the stages early sowing had significant effect over delayed sowing in both the year except harvesting where CGR found to be similar among both the rice planting. Maximum CGR of 20.6 g m-2day-1 observed in early planting at 30-60 DAT. There is 10.13, 2.49, 4.27 and 7.53 per cent increase in growth rate during the period 0-30, 30-60, 60-90 DAT, 90 DAT-harvest, respectively by early planting over 15 days delay in planting.
A significant increase in CGR was observed at 0-30 DAT till 60-90 DAT with the various inorganic organic combinations in comparison to inorganic nutrient applied. Highest CGR was obtained in STBFR+GM treatment at all the stages except at later stages from 90 DAT- harvesting during which different types of nutrient source combination was statistically at par with each other. The mean CGR obtained at all the growth stages by STBFR+GM treatment are 4.26, 20.9, 12.2, 1.6 g m-2 day-1 respectively.
Relative growth rate (g g -1 day-1)
The relative growth rate (RGR) was maximum (77.07 mg g -1 day-1) during 0-30 DAT that decreased progressively to 0.64 mg g -1 day-1 during 90 DAT to harvest. There was a significant influence of date of planting on RGR till 30 DAT thereafter date of planting doesnot have any significant impact on RGR of the crop, but at all the growth stages early planting on 10 July recorded maximum RGR in comparison to 15 days delay in planting.
At 0-30 DAT, RGR was significantly influenced by nutrient management combination, however at other stages nutrient management doesnot have any significant influence on RGR. Among all the sources of nutrient management combinations STBFR+GM (76.90, 21.13, 4.49, 0.65 mg g -1 day-1) treatment shows numerically higher RGR than other treatments.
Root drymatter production
The observations on root drymatter production indicated that, mean dry weight increased progressively with advancement of the crop age culminating with highest value at 90 DAT. Thereafter root dry weight decreased till maturity. Rate of increase in root dry weight was maximum (88%) during the period 30- 60 DAT.
Date of planting significantly influenced root dry weight at all stages of crop growth. Planting on 10 July recorded significantly maximum root dry weight per metre square followed by crop planted on 25 July. At 90 DAT, 10 July planted crop registered highest dry weight i.e. 54.7 g m-2 that decreased by 3.5% due to 15 days delay in planting.
Effect of nutrient management on root dry weight was significant at all the stages of crop growth. STBFR+GM show significantly maximum root dry weight than other two treatments and registered dry weights by this treatment were (19.76, 37.08, 55.40, 47.29 g m-2). At 90 DAT (maximum dry weight stage) STBFR+GM shows higher dry weight by 2.7% and 6.9% against STBFR+FYM and STBFR treated rice.
Grain and Biological yield of rice as influenced by date of planting and source of nutrient in rice have been presented in Table 5. Significant differences in yield of rice were witnessed due to different date of planting. Rice biological yield was significantly superior in earlier planting by 10.38 per cent over 25 July planting. Similarly mean rice grain yield obtained in 10 July planting plot (5008 kg ha-1) was significantly superior over 25 July planting (4481 kg ha-1). The rice grain yield during both the year also follows the same trend record highest in earlier planting (4911, 5106 kg ha-1).
Rice biological and grain yield was highest in STBFR+GM (11172 kg ha-1, 5015 kg ha-1) followed by STBFR+FYM (10803 kg ha-1,4794 kg ha-1) and STBFR (9930 kg ha-1, 4424 kg ha-1). In 2018-19 & 19-20, both yield parameters followed the same trend with respect to source of nutrient. Biological yield increase due to STBFR+GM over STBFR+FYM, STBFR was 3.41, 12.51 per cent respectively.
Total Nutrient Uptake
In case of nutrient uptake N, P and K uptake of grain, straw and total is found to be significantly higher in early planted crop followed by 15 days delay in planting. Earlier planted crop recorded maximum uptake of N (89.0 kg ha-1), P (19.6 kg ha-1) and K (115.9 kg ha-1) respectively (Table 6).
Nutrient management had significant effect on nutrient uptake of rice. Among them STBFR+GM shows higher N (92.7 kg ha-1) and K (115.0 kg ha-1) uptake than STBFR+GM, STBFR alone while P (20.2 kg ha-1) was found in STBFR+FYM treated crop.
Total biomass yield had positive correlation with nutrient uptake especially Nitrogen, Phosphorus, Potassium uptake at maturity (Fig 5). The determination factor was nearly 0.8625 to 0.9591 for every nutrient uptake. So we found a strong relationship between them.