Research Article
Interaction Effects of Sulphur and Phosphorus on Wetland Rice
Not Available
M.S. Mian
Not Available
A. Islam
Not Available
J.A. Begum
Not Available
A.K.M. Ferdous
Not Available
Sulphur (S) is a constituent of essential amino acids (cystein, methionineand cystine) involved in chlorophyll production and is thus required for protein synthesis and plant functions and structure. The effect of S deficiency on yield is more pronounced during vegetative growth e.g. reduced plant height and stunted growth, reduced number of tillers, fewer and shorter panicles, reduced number of spikelets per panicle etc[1]. Evidence showed that rice soils of Bangladesh are becoming deficient in S day by day[2,3]. Use of high analysis S-free fertilizers such as urea, triple super phosphate, muriate of potash and flooding of land causing S in reduced condition for a considerable period of time result in decreased available S in soil for crops. In addition to above-mentioned causes, the problem of S deficiency is further aggravated where phosphate fertilizer is used abundantly. Phosphorus being a stronger anion and with relative abundance compared to S, dislodges SO42- from the exchange sites in soils and finally making sulphate available and labile to leaching loss along with percolated water.
Phosphorus is the second major element also widely deficient in Bangladesh soils. Two principal reason accounts for this. It is low supply in minerals comprising the parent materials of many soils and it is inclined to form compounds of very low solubility with other common ionic soil components. Since in many soils much of the available P is derived through the mineralization of organic matter, the repeated addition of P fertilizer appears to be the only satisfactory way of supplying plant needs for this very important nutrient. Phosphorus is intimately associated with all life processes and thus it is a vital constituent of every living cell. This element tends to be concentrated in the seed and stimulates early root formation and growth of the plant.
Balanced fertilization is a pre-requisite for obtaining optimum potentiality of high yield of rice. So to increase the production of rice, it is essential to find out optimum combination of S and P along with other nutrients. BRRI dhan29 is a new high yielding variety of rice grown in Boro season of the country. It is felt necessary to evaluate S and P requirement of this variety to asses its optimum growth and achievable yield potential under the agro-climatic condition on Non-Calcareous Dark Grey Floodplain soil of BAU farm. With the above views and objectives in mind, the present experiment was carried out at the BAU farm to investigate the interaction effects of S and P on growth and yield of BRRI dhan29, new high yielding variety of rice in Boro season.
The experiment was carried out during Boro season (dry season) in a typical rice growing soil of Bangladesh, located in the BAU farm at Mymensingh nearly 1 km away from the west of the Brahmaputra river. The soil type of the farm belongs to the Non-Calcareous Dark Grey Floodplain under Sonatola soil series. The reaction of the soil was around neutral (pH 6.8). The soil was silt loam in texture with total N 0.10%, available P 15.60 ppm, exchangeable K 0.21 me 100-1 g soil and available S 11.5 ppm. An analysis of the soil was done following some standard laboratory procedure. A modern rice variety BRRI dhan29 was selected as the test crop. The treatment consisted of 5 levels of S (0, 10, 20, 30 and 40 kg ha-1) and two levels of P (0 and 35 kg ha-1). There were 10 fertilizer treatment combinations as S0P0, S0P35, S10P0, S10P35, S20P0, S20P35, S30P0, S30P35, S40P0, and S40P35.
Nitrogen and potassium fertilizers were applied as blanket dose one day prior to transplanting in all experimental plots @ 100 kg Nha-1 and 50 kg Kha-1 respectively. Urea, TSP, MP and Gypsum were used as the sources of N, P, K and S, respectively. The experiment was laid out in a Randomized Complete Block design with 4 replications of each treatment having unit plot size 10 m2 (4 X 2.5 m). Nitrogen was applied in three equal splits, before transplanting at final land preparation, at active tillering stage at 30 days after transplanting and at the pre-booting stage. Forty-day old seedlings of BRRI dhan29 were transplanted maintaining a spacing of 20x20 cm. Necessary intercultural operations was done as and when required during growth period of crop.
Ten random hills were harvested from each plot at active tittering stage and dry matter yield was recorded after oven drying at 60-70°C for 72 h. Rice plants were harvested at maturity for grain and straw yield. Grain yield was recorded at 14% moisture content while straw yield was recorded as oven dry basis. The data was analyzed as per standard statistical procedures.
Dry mater yield of rice plant at maximum tillering stage: The single effect of S on dry matter yield of rice plants at the maximum tillering stage was significant (Table 1). The increases in dry matter yield of rice plant over control were 18.31, 14.87, 9.09 and 4.95% under the treatments S40, S30, S20 and S10, respectively. The highest dry matter yield (3436 kg ha-1) was obtained with S40 treatment, which significantly differed from the rest of treatments. The single effect of P on dry matter yield of rice plant was also significant (Table 1), although the yield increase over the control was not very much.
Table 1: | Single effect of S and P on dry matter yield of rice plant at the maximum tillering stage |
** = 1% level of significance; NS = Not significant; Figures in a column with same letter (s) do not differ significantly. |
Table 2: | Interaction effect of S and P on dry matter yield of rice plant at the maximum tillering stage |
** = 1% level of significance; Figures in a column with same letter (s) do not differ significantly. |
Padihar and Dikdshit[4] reported that the dry matter yield at the maximum tillering stage increased with increasing level of P application. The interaction effect of S and P on dry matter yield of rice plant was not significant (Table 1). The combined effect of S and P increased the dry matter yield of rice plant over control (Table 2). The highest yield (3456 kg ha-1) of dry matter was found in S40P35 treatment which was statistically similar to S40P0, S30P35 treatments. The lowest dry matter yield (2880 kg ha-1) was obtained in control treatment.
Nutrient content and uptake by rice plant at maximum tillering stage: Nutrient content and uptake by rice plant are summarized in the Table 3 and 4. Results in Table 3 indicate that the single effect of different level of S on nutrient content and uptake by rice plant was statistically significant except P content. The highest N content (2.84%) was observed in S40 treatment, which was statistically similar to S30, S20 and S10 treatments. Similar result was reported by Chowdhury[5].
Table 3: | Single effect of S and P on nutrient content and uptake by rice plant at the maximum tillering stage |
** = 1% level of significance; NS = Not significant; Figures in a column with same letter (s) do not differ significantly. |
Table 4: | Combined effect of S and P on nutrient content and uptake by rice plant at the maximum tillering stage |
**= 1% level of significance; Figures in a column with same letter (s) do not differ significantly. |
Table 5: | Single effect of S and P on grain and straw yields of BRRI dhan29 |
** = 1% level of significance; * = 5% level of significance; NS = Not significant; Figures in a column with same letter (s) do not differ significantly. |
Table 6: | Combined effect of S and P on nutrient content and uptake by rice plant at the maximum tillering stage |
** = 1% level of significance; Figures in a column with same letter (s) do not differ significantly. |
The highest S content (0.215%) was observed in S40 treatment, which was followed by 0.185% in S30 treatment. Tewari et al.[6] reported that application of S increased the S content in lamina, shoot of rice plant. Incase of K content S40 treatment showed highest concentration of K (2.15%) followed by S30 (1.88%).
It was observed that N uptake by rice plant increased with increasing levels of sulphur and the highest N uptake was observed in S40 treatments (37.22 kg ha-1), which was statistically similar to S30 treatment. The highest S uptake (2.81 kg ha-1) was found in S40 treatment, which differed significantly from other treatments. Sachdev et al.[7] reported that application of S as gypsum increased S uptake by rice plant. Although the effect of S application on P content of rice plant was not significant but incase of P uptake the effect was significant and the highest P uptake (3.57 kg ha-1) was obtained from S40 treatment, which was statistically similar to S20 and S10 treatments. The K uptake by rice plant was increased significantly with the increasing levels of applied S. The highest K uptake (28.11) kg ha-1) was obtained in S40 treatment, which was statistically differed from all other treatments. The single effect of different levels of P on nutrient content and uptake by rice plant was not significant. Similarly, the interaction effect was not significant except P uptake (Table 3).
The combined effect of S and P found significant on both nutrient content and uptake by rice plant (Table 4). The highest N content (2.96%) and N uptake (39.07 kg ha-1) was observed in S40P35 treatment. The N content was statistically similar with all other treatments except S0P35 and the control treatment (Table 4). Incase of N uptake S40P35 and S40P0 treatments were statistically similar. The highest amount of S content (0.22%) and uptake (2.90 kg ha-1) by rice plant was observed in S40P35 treatment. The S content and uptake was statistically similar in S40P35, S40P0 and S30P35 treatments. The highest P content (0.27%) was observed in S40P35 treatment, which was statistically similar to all other treatments except S40P0 and control treatments. The highest P uptake (3.85 kg ha-1) was observed in S40P35 treatment, which was statistically similar to all other treatments except S20P0, S0P35 and control treatments. The highest K content (2.20%) was observed in S40P35 treatment followed by S40P0, S30P0, S30P35 and S20P0 treatments. The highest K uptake (29.04 kg ha-1) was found in S40P35 treatment and statistically similar results were observed in S40P0, S30P35 and S30P0 treatments (Table 4).
Grain yield: The grain yield was significantly influenced due to application of S and P fertilizers. The single effect of S on grain yield was significant and the highest grain yield (4660 kg ha-1) was obtained with S40 treatment (Table 5). Increase in grain yield due to S application was reported by Nair and Gupta[8]. The single effect of P on grain yield was also significant (Table 5). Grain yield obtained 3906.0 kg ha-1 and 3717.4 kg ha-1 under the treatment P35 and P0 respectively. The interaction effect of S and P on grain yield was not significant (Table 5) but the combined effect of S and P was significant (Table 6). The highest grain yield of 4825 kg ha-1 (61.1% increased over control) was recorded in S40P35 combined treatment, which was statistically different from all other treatments (Table 6).
Straw yield: The single effect of different levels of S on straw yield was significant (Table 5). The highest straw yield of 6130 kg ha-1 (52.3% increased over control) was recorded in S40 treatment. The single effect of P on straw yield was found significant (Table 5). The straw yield was recorded 5178.6 kg ha-1 and 4889.2 kg ha-1 under the P35 and P0 treatment respectively. The straw yield increased due to P application was also reported by Mahajan et al.[9]. The interaction effect of S and P on straw yield was found significant (Table 5). The combined treatment effect of S and P on straw yield was also found significant (Table 6). The straw yield increased gradually over the control treatment. The highest straw yield of 6340 kg ha-1 (65.1% increased over control) was found in S40P35 treatment.
The overall results indicate that the application of S and P @ 40 kg ha-1 and 35 kg ha-1, respectively can ensure good growth and reasonably high yield of BRRI dhan29 under the Brahmaputra Floodplain soil condition.