Rice & wheat
Wheat (Triticum aestivum L.) is the succeeding alternative cereal crop of Bangladesh afterward to rice. It ranks 1st in respect of total production in the world. Thereabouts one third population of the world use wheat as their staple food (Hunshell and Malik, 1983). It contains superior protein then rice. Wheat is one of the most important staple food crops of the world, occupying 17% (one sixth) of crop acreage worldwide, feeding about 40% (nearly half) of the world population and providing 20% (one fifth) of total food calories and protein in human nutrition (Gupta et al., 2008).
Rice exclusively cannot fulfill the cereal necessity. Wheat is the second substantial cereal crop in Bangladesh. Consequently, efforts are being made to increase the production of wheat. Sum up land acreage of wheat in Bangladesh was 394.6 thousand hectares & the total production was 849 thousand metric tons with an average yield of 2.15 t ha-1 in 2008-2009 (BBS, 2009). Wheat is well adapted to our climate and can play a indispensable role in reducing our food shortage.
Wheat contains plenty of proteins (12.6%), vitamins (B1, B2, B3, and E) and minerals(folic acid, calcium, phosphorus, zinc, copper, iron). As a second cereal crop, its importance is high in Bangladesh and increasing day after day. In Bangladesh, wheat is grown in upland condition during the rain fed season (November- March). The monthly maximum and minimum temperature during this period ranges from 25.8 to 30.5ºC and 13.8 to 20.3ºC in the south east zone and from 24.9 to 32.3ºC and 10.3 to 16.7ºC in the north east zone respectively (Hossain et al., 2001).
Urea (prilled urea) is widely used in the agricultural industry as an animal feed additive and fertilizer with 46% nitrogen. It is an efficacious fountain of nitrogen fertilizers. Urea is water soluble white crystalline solid organic compound. It has the chemical formula of CO (NH2)2. Prilled urea or prills are formed by dropping liquid urea from a prilling tower into droplets that dry into roughly spherical shapes 1mm to 4mm in diameter where as granular urea is slightly larger and harder.
Globally, fertilizer nitrogen (N) applications are approximately 80 million tonnes, with half being applied in developing countries and the other half in developed countries (FAO, 1990). It has been estimated that by the year 2025 the consumption of nitrogen fertilizer will increase 60 to 90 percent, with two-thirds of this being applied in the developing world (Galloway et al., 1995). This inclination in fertilizer use is mostly driven by the need of developing countries to keep food supply up with population growth. It has been projected that by the year 2020 world population will be more than 8 billion people, with more than 90 percent of this additional growth concentrated in developing countries (Sadik, 1992). Most of the irrigated spring wheat in the world is located in developing countries. These areas have high yield potential and high levels of input use contrasted to other wheat-producing regions in the developing world. The International Maize and Wheat Improvement Center (CIMMYT) has defined the wheat irrigated areas as mega-environment one (ME1) which includes the Indo-Genetic plains in India and Pakistan, the Nile River Valley in Egypt and the Yaqui Valley in Mexico among others (Rajaram et al., 1993). These areas already produce 42 percent of the wheat in developing countries, and it is likely that further intensification will take place in order to keep up with food demand. However, the efficiency of N fertilizer use tends to be low in these systems (Byerlee and Siddiq, 1994), and further intensification with current agronomic practices will likely lead to higher inefficiencies and therefore higher N losses. The nitrogen that is lost, in addition to being an expense to the farmers, also has an environmental cost. It has been documented that land conversion and intensification alter the biotic interaction and patterns of resource availability in ecosystems and can have serious local, regional and global environmental consequences (Matson et al., 1997). Accordingly, it is important to identify nitrogen management practices that will allow meeting the increasing claim for food and fiber while diminishing environmental impact and being economically seductive to farmers.
Nitrogen is a very momentous element for crop cultivation but highly deficient in most soils of Bangladesh. Bangladeshi farmers are mainly using urea, the most available source of nitrogen and broadcasting it on the soil surface. It is highly water-soluble and a quick release fertilizer. For this reason, its application to the soil surface may result in a significant loss as ammonia to the atmosphere by volatilization and also by leaching through soil profile, thus, reducing the efficiency of urea which ultimately paid by in plant as poor yield. Khalil et al. (1996) stated that nitrogen use efficiency is only 38.84 and 38.14% with using 120 and 180 kg N ha-1, respectively in wheat.
Granular nitrogen like urea super granules (USG) a slow releasing fertilizer is being marketed as an N source instead of conventional prilled urea. The International Fertilizer Development Center (IFDC), have conclusively demonstrated that compacted USG, that is, urea with 1–3 g granules, are an effective N source (Savant et al., 1990). In general, one or more USG are deep placed (7–10 cm depth) by hand at the center of every four rice seedling hills in rice soils during or after rice transplanting. (Savant et al.,1998) have shown that N loss is significantly reduced, which results in a significant increase in rice grain yield under flooded conditions compared with split applied PU.
Wheat is a rabi crop. During rabi season our farmers are concerned to grow boro rice and maize as their yield is higher than wheat. Wheat has been pushed down to the marginal land due to the increased area of boro rice and maize. Thus we obtain poor yield from wheat. It is very urgent to meliorate wheat yield with high yielding variety cultivating on the main land. The solely way is to bring back wheat on the main land with high yield potentiality through different managements of fertilizers like urea. With all these fact under consideration the present study was taken with following objectives:
(1) To study the growth of wheat under different method of nitrogen managements.
(2) To look through the effect of different methods of nitrogen placement on yield of wheat.
(3) To validate the findings of nitrogen management from the economic point of view.
REVIEW OF LITERATURE
Urea is the most frequently used Nitrogen fertilizer globally. Urea can be applied in different ways. In Bangladesh crystal urea is applied mostly as top dressing. But top dressing sometimes induces imbalance in yield components and decreases yield. It was observed that urea super granules (USG) can minimize the loss of N from soil and hence the affectivity increased up to 20-25% (Hasanuzzaman et al., 2009).
Nitrogen fertilizer when applied as USG was reported to have increased grain yield by around 18% and saved around 32% N in wetland rice over prilled urea and appeared to be a good alternative N fertilizer management for rice production (Annon., 2004).
Hasan et al. (2002) determined the response of hybrid (Sonar Bangla-l and Alok 6201) and inbred (BRRI Dhan 34) rice varieties to the application methods of urea super granules (USG) and prilled urea (PU) and reported that the effect of application method of USG and PU was not significant in respect of panicle length, number of unfilled grains panicle-1 and 1000-grains weight.
Haque (2002) reported that application of fertilizers greatly increased tuber yields of potato and point placement of USG further boosted up the yield of potato tubers.
Miah and Ahmed (2002) conducted an experiment and found that deep placement of urea super granules (USG) has been proven to improve N efficiency. In terms of N recovery, agronomical and physiological efficiency, rice varieties utilized N more efficiently when applied as super granules in deep placement
Ahmed et al. (2000) conducted a field experiment to study the effect of point placement of urea super granules (USG) and broadcasting prilled urea (PU) as sources of N in T. aman rice. USG and PU were applied @ 40, 80, 120 or 160 Kg N ha-1. They reported that USG was more efficient than PU at all respective levels of nitrogen in producing panicle length, filled grains panicle-1 and 1000-grain weight.
Mishra et al. (2000) conducted a field experiment in 1994-95 in Bhubaneswar, Orissa, India, and reported that rice cv. Lalate was given 76 kg N ha-1 as USG at 0, 7, 14 for 21 days after transplanting (DAT and reported that USG application increased plant height.
Ahmed et al. (2000) also found that USG was more efficient than PU at all respective levels of nitrogen in producing all yield components and in turn, grain and straw yields of aman rice. Placement of USG @ 160 Kg N ha-1 produced the highest grain yield (4.32 t ha-1) which was statistically identical to that obtained from 120 kg N ha-1 as USG and significantly superior to that obtained from any other level and source of N.
Balaswamy (1999) found that in an experiment deep placement of nitrogen as urea super ganules reduced the weight of weeds resulting in more panicles and filled grains and increased the grain yield of rice over the split application of prilled urea by 0.43 and 0.3 t ha-1 and basal application of large granular urea by 0.73 and 0.64 t ha-1 in 1985 and 1986, respectively.
Department of Agricultural Extension conducted 432 demonstrations in 72 Upazilla as of 31 districts in Bangladesh during the 1996-97- winter season of boro rice. It was reported that USG plots, on an avenge, produced nearly 5 percent higher yields than the PU treated plots while applying 30-40% less urea in the form of USG (Islam and Black, 1998).
Vijaya and Subbaiah (1997) showed that plant height of rice increased with the application of USG and were greater with the deep placement method of application both N and P compared with broadcasting.
Singh and Singh (1997) conducted a field experiment in 1987 in Uttar Pradesh, India. Dwarf rice cv. Jaya was given 90 or 120 kg N ha-1, as urea super granules, large granular urea or neem cake coated urea. N was applied basally, or in 2 equal splits (basally and panicle initiation). They found that grain yield was highest with 120 kg N (4.65 ha-1), was not affected by N source and was higher with split application.
Kumar et al. (1996) reported that application of USG in the sub soil gave 22% higher grain yield of rice than control.
Khalil et al. (1996) stated that nitrogen use efficiency is only 38.84 and 38.14% with using 120 and 180 kg N/ha as prilled urea, respectively in wheat.
Miah et al. (1990) found that LAI was significantly higher in USG receiving plots than urea at heading and the total dry matter production was affected significantly by the forms of N fertilizer. USG applied plots gave higher TDM compared to urea irrespective of number of seedling transplanted hill-1. At the same time it also noticed that the difference between treatments for TDM was narrower at early growth stages but became larger in later stages.
Prilled urea (PU), Mussoorie rock phosphate urea (MRPU), large granular urea (LGU) or nimin [neem seed extract]-coated urea (NCU) or PU, MRPU, LOU and NCU as 66% basal incorporation + 33% top dressing at panicle initiation and found that grain yield was highest with N applied as a basal application of USG or MRPU applied in 2 split applications. Rashid et al. (1996) conducted field experiments in two locations of Gazipur district during boro season (Jan-May) of 1989 to determine the nitrogen use efficiency of urea super granules (USG) and prilled urea (PU) in irrigated rice cultivation. It was observed that 87 kg N ha-1 from USG produced the highest grain yield. However, 58 kg N ha-1 from USG and 87 kg N ha-1 from PU produced statistically similar grain yield to that of 87 kg ha-1 from USG.
Das and Singh (1994) pointed out that the grain yield of rice cv. RTH-2 during Kharif season was greater for deep placed USG than USG for broadcast and incorporated or three split applications of PU. Mishra et al. (1994) conducted a field trial with rice cv. Sita giving 0 or 80 kg N ha-1 as urea, urea super granules, neem coated urea. They reported that the highest grain 3.39 t ha-1 obtained by urea in three split applications.
Bhale and Salunke (1993) conducted a field trial to study the response of upland irrigated rice to nitrogen applied through urea and USG. They found that grain yield increased with up to 120 kg urea and 100 kg USG.
Bhardwaj and Singh (1993) observed that placement of 84 kg N as USG produced a grain yield t ha-1 which was similar to placing 112 kg USG and significantly greater than nitrogen sources and rates.
Singh et al. (1993) pointed out that application of 30 or 60 kg N ha-1 as PU or USG gave the highest grain yield and N uptake increase with the rate of N application and were highest with deep placed USG. N use efficiency was the highest with 30 Kg N ha-1 from deep placed USG.
Zaman et al. (1993) conducted two experiments on a coastal saline soil at the Bangladesh Rice Research Institute (BRRI), Regional station, Sonagazi in 1988 and 1989 aus seasons to compare the efficiencies of prilled urea (PU) and urea super granules (USG) as sources of N for upland rice. The N doses used as treatments were 29 kg ha-1 and 58 Kg ha-1 for both PU and USG. The test variety was BR-20. They found that USG consistently produced significantly higher grain yield and straw yield than PU.
It was reported that the grain yield of millet was the highest with Bitumen-Coated Urea Super granules (BCUSG) and the lowest with urea and in case of wheat, among N sources residual effects were in the order BCUSG> USG>BCU> urea (Sarker and Faroda, 1993).
Modified urea materials under different moisture regimes influence NH3 volatilization loss and significantly less NH3-N loss was observed for USG treatments than from surface applied urea (Muneshwar et al., 1992).
Roy et al. (1991) compared deep placement of urea super granules (USG) by hand and machine and prilled urea (PU) by 2 to 3 split applications in rainfed rice during 1986 and 1987. They reported that USG performed better than PU in all the parameters tested. Filled grains panicle-1 was significantly identical with USO and PU three split treated plots with the highest from PU three split treated plots. Significant difference was observed in 1000-grain weight and highest grain weight was obtained from USG (by hand) treated plots. Thakur (l991a) observed that yield attributes differed significantly due to levels and sources of nitrogen at 60 kg N ha-1 through USG produced the highest panicle weight, number of grains panicle-1, and 1000- grain weight.
Sen and Pandey (1990) carried out a field trial to study the effects of placement of USG (5, 10 or 15 cm deep) or broadcast PU @ 38.32 kg N ha-1 on rice of tall long duration Mashuri and dwaf, short duration Mashuri. They showed that all depths of USG placement resulted in higher yield characters than broadcast PU; however, differences except for panicle lengths were not significant.
The proper placement of fertilizer can also increase its use efficiency as reported by Eriksson (1990).
On the other hand Rekhi et al. (1989) conducted an experiment on a sandy loamy soil with rice cv. PR 106 providing 0, 37.5 or 75 or 112.5kg N ha-1 as 15 N-labeled PU or USC. They noted that application of PU produced the highest plant height.
Mirzeo and Reddy (1989) worked with different modified urea material and levels of N @ 30, 60 and 90 Kg ha-1. They reported that root zone placement of USG produced the highest number of’ tillers at 30 and 60 days after transplanting (DAT).
Das (1989) reported that the dry matter yield of rice were higher with application of USG of various forms and methods of application of N fertilizers to rice grown under flooded conditions, placement of N as USG (1 and 2 g size) in the root zone at transplanting was the most effective in increasing dry mater production and were the lowest with urea applied as a basal drilling (Rambabu et al. 1983).
Jee and Mahapatra (1989) observed that number of effective tillers m-2 were significantly higher with 90 kg N ha-1 as deep placed USG than split application of urea. Rama et al. (1989) mentioned that the number of panicles m-2 increased significantly when nitrogen level increased from 40 to 120 kg N ha-1 as different modified urea materials and USU produced significantly higher number of panicles 12 m-2 than split application of PU.
Rymar et al. (1989) reported that slow release fertilizers (N as encapsulated urea, granular oxamide and oxamide powder) are more effective than the conventional fertilizers (ammonium sulphate or urea).
Haque, (1998) reported that urea super granule point placement in rice has been found to be a good practice for poor farmer. It can reduce loss of urea-N and improve its efficiency by more than 60% in flooded rice with a surplus of about 15-20% rice yield over conventional urea broadcast application.
Presently, urea super granule is a proven concept for use in rice production. (Diamond, 1988; Kumar et al., 1989; Savant and Stangel, 1990)
In a field trial, Sarder et al. (1988) found that, 94.8 kg N ha-1 as basal application of USG gave longer panicle and total number of filled grains penicle-1 than the other N sources.
Singh and Singh (1986) worked with different levels of nitrogen as USG, sulphur coated and PU @ 27, 54 and 87kg ha-1. They reported that deep placement of USG resulted in the highest plant height than PU.
They also reported that the number of tillers m-2 was significantly greater in USG than PU in all levels of nitrogen.
Nayak et al. (1986) carried out an experiment under rainfed low land conditions with the amount of 58 kg N ha-1 as USG placed in root zone. They showed that USG was significantly superior to as sulphur coated urea (SCU) or applying in split dressing, increasing panicle production unit-1 area.
Rajagopalan and Palanisamy (1985) found that 75 kg ha N as USG gave the tallest plant (83 cm).
EvaIuation of rice program during 1975 to 78 showed that deep placement of USG is an effective means of increasing rice yields compared with traditional split application of PU (Craswell and De Datta, 1980).
According to Creswell and De Datta (1980), broadcast application of urea on the surface soil causes loss upto 50% but point placement of USG in 10 cm depth can save 30% nitrogen over prilled urea, increase absorption rate, improve soil health and ultimately increase rice yield (Savant et al., 1991).
The N uptake and recovery of applied N were the highest in the USG + urea treatment and N use efficiency was highest with urea alone (Saha, 1984). In a field experiment, wheat grain yield increased with increasing residual N rate and was highest after deep placement of 120 kg N as USG (Das and Sing, 1994).
From reviewing the findings it is imperative to use super granuler urea to crop cultivation for higher yield with saving urea cost and minimizing pollution of environment.
MATERIAL AND METHODS
The experiment was carried out at the experimental farm of the Sher-e-Bangla Agricultural University(SAU), Dhaka-1207, Bangladesh, during the period from November 2008 to March 2009.
3.2 Site selection
The experimental field was located at 90o 22/ Elongitude and 230 41/ N latitude at an altitude of 8.6 meters above the sea level. The land was located at 28 Agro Ecological Zone (AEZ 28) of “Madhupur Tract” (Appendix I). It was deep red brown terrace soil and belongs to “Nodda” cultivated series. The soil was clay loam in texture having PH ranges from 5.47 to 5.63. Organic matter content was very low (0.82%).
3.3 Climate and weather
The climate is subtropical with low temperature and minimum rainfall during December to March was the main feature of the rabi season.
3.4 Planting materials
One crop namely wheat (Triticum aestivum) was used in this experiment.
3.5 Plant characteristics and variety
BARI gom-19 (Shourav) is a high yielding variety of wheat. The variety was released by WRC (Wheat Research Centre) of BARI in 1998. This variety is suitable for late sowing. It completes its life cycle within 102-110 days. The height of the plant is 90-100 cm. It produces 5-6 tillers plant-1. The stem is hard enough and does not lodge in wind and storm. Leaves are flat, droopy and deep green. Flag leaf is wide and droopy in nature. The number of spikelet spike-1 is 42 – 48 and size of grains are medium to large and the color of the grains is white. The weight of 1000 seed is 40-45g. Plant requires 60-70 days to emerge spike. It has ability to give 3.5-4.6 t ha-1 in favorable condition. This variety is tolerant to leaf spot and leaf rust diseases. This variety is heat tolerant that is why in case of late sowing it gives better yield. The variety gives 10-12% more yield than the traditional ones. (BARI, 2005).
3.6 Granular urea
The weight of urea super granules (USG) was 1.8 g/granule.
3.7 Experimental treatments
There was different urea application treatments were as follows:
T1 = Prilled urea broadcasted (conventional)
T2 = Prilled urea placed in furrow
T3 = Prilled urea placed between two rows of wheat
T4 = Prilled urea + seed in furrow
T5 = Line sown seed + line placed prilled urea
T6 = Line sown seed + Prilled urea given on soil of seeded furrow
T7 = Wheat seed + urea super granule (USG) in the same furrow at 8cm distance
T8 = USG placed in between two wheat lines at 8 cm distance.
3.8 Experimental Design and Layout
The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. The experimental unit was divided into three blocks each of which represents a replication. Each block was divided into 8 plots in which treatments were applied at random. The distance maintained between two plots was 0.75 m and between blocks was 1.5 m. The plot size was 4 m x 2.5 m. It is mentioned here that the wheat was sown maintaining row spacing as 20 cm. The seeds were sown as continuous in each line following the seed rate.
3.9 Details of the field operations
The cultural operations were carried out during the experimentation are presented below:
3.9.1 Land preparation
The experimental field was first ploughed on November 01, 2008. The land was ploughed thoroughly with a power tiller and then laddering was done to obtain a desirable tilth. The clods of the land were hammered to make the soil into small pieces. Weeds, stubbles and crop residues were cleaned from the land. The final ploughing and land preparation was done on November 13, 2008. The layout was done as per experimental design on November 13, 2008.
3.9.2 Fertilizer application
The entire amount of TSP, MP and Zypsum was given in the plots during final land preparation. 2/3 of urea was applied for wheat plots during land preparation as basal dose except treatment 7 and 8 as those were given super granular urea (USG). Rest 1/3 urea was applied to wheat plots except treatment 7 & 8 at 21 days after sowing at crown root initiation stage with irrigation.
3.9.3 Seed collection and sowing
The wheat seeds (cv. Shourav) were collected from Wheat Research Centre of Bangladesh Agricultural Research Institute (BARI) of Joydebpur, Gazipur.
Seeds were treated with Vitavax 200 @ the rate of 3 g kg-1 of seeds and sown in line on November 14, 2008 and seeds were covered with loose friable soil. The recommended seed rate of wheat was 125 kg ha-1.
3.9.4 Germination test
Germination test was performed before sowing the seeds in the field. Filter papers were placed on four petri dishes and the papers were soaked with water where 100 seeds were placed at random in each petri dish. Data on germination were determined as percentage basis by using the following formula:
|Number of germinated seeds|
|Number of seeds set for germination|
Germination test (%) = x 100
Weeds were controlled through three weeding at 20, 35, 50 days after sowing (DAS). The weeds identified were Kakpaya ghash (Dactyloctenium aegyptium L), Shama (Echinocloa crussgalli), Durba (Cynodon dactylon), Arail (Leersis hexandera), Mutha (Cyperus rotundus L), Bathua (Chenopodiunm album), Shaknatey (Amaranthus viridis), Foska begun (Physalis beteophylls), Titabegun (Solanum torvum) and Shetlomi (Gnaphalium luteolabum L).
Germination of seeds was ensured by light irrigation. Two Irrigations were given at crown root initiation and heading stages (22 and 53 DAS). During irrigation care was taken so that water could not flow from one plot to another or overflow the boundary of the plots. Excess water of the field was drained out.
3.9.7 Harvesting and sampling
At full maturity, the wheat crops were harvested plot wise on 9 March 2009. Before harvesting 10 plants of wheat from each plot was selected randomly and uprooted. Those were marked with tags, brought to the threshing floor where seeds and stover were separated, cleaned and dried under sun for 4 consecutive days. Crop of each plot was harvested from 3 m2 separately. Then those were weighted to record the seed yield which was converted into t ha-1.
3.10 Recording of data
The following data of crops were collected during the study period.
- Plant height from 15 DAS to harvest
- Above ground dry matter plant -1 from 15 DAS to harvest
- Tillers plant-1 from 30 DAS to harvest
- Length of spike from 60 DAS to harvest
- Spikelet spike-1 from 60 DAS to harvest
- 1000 grain weight (g)
- Grain yield (t ha-1)
- Harvest index (%)
3.11 Procedure of recording data
The data was taken at 15 days interval. The detail outline of data recording is given below:
126.96.36.199 Plant height (cm)
For height measurement 10 randomly plants were used from the ground level to tip of the plants and than averaged.
188.8.131.52 Above ground dry matter plant-1 (gplant-1)
Ten plants were collected at different days after sowing (15, 30, 45, 60, 75, 90 DAS and at harvest) and then oven dried at 700 C for 72 hours. The dried samples were then weighed and averaged.
184.108.40.206 Tillers plant-1 (No.)
10 plants were uprooted randomly and then total numbers of tillers were divided by 10.
220.127.116.11 Length of spike (cm)
Lengths of spike were measured from 10 plants and then averaged.
18.104.22.168 Spikelet spike -1 (No.)
The numbers of spikelet spike-1 were measured from 20 spikes.
22.214.171.124 Weight of thousand grain (g)
One thousand cleaned dried seeds were counted randomly from each harvested sample and weighed by using digital electric balance.
126.96.36.199 Grain yield (t ha-1)
Wheat was harvested randomly from 3 m2 area of land of each plot. Then the harvested wheat was threshed, cleaned and then sun dried up to 12% moisture level. The dried seeds were then weighted and averaged. The grain yield was converted into t ha-1.
188.8.131.52 Harvest Index (%)
Harvest index was determined by dividing the economic yield (grain yield) to the biological yield (grain + straw yield) from the same area and then multiplied by 100.
|Grain yield (t ha-1)|
|Grain yield (t ha-1) + straw yield (t ha-1)|
Harvest Index (%) = X 100
3.12 Economic analysis
The cost and return analysis was done for each treatment on per hectare basis.
3.13 Benefit-cost ratio (BCR)
In order to compare better performance, benefit – cost ratio (BCR) was calculated. BCR value was computed from the total cost of production and net return according to the following formula.
|Gross return (Tk. ha -1)|
|Total cost of production (Tk. ha -1)|
Benefit cost ratio (BCR) =
3.14 Statistical analysis
Plot wise yield and yield components were recorded. All the data were statistically analyzed following the MSTATC computer program and the mean comparisons were made by LSD at 5% level of significance.
RESULTS AND DISCUSSION
This experiment was conducted to determine the response of wheat after different management of urea. Data on plant growth characters, yield contributing characters and yield were recorded to asses the trend of growth, development and yield of crops under different management of urea fertilizer. The analysis of variance (ANOVA) of data is given in Appendices. The results have been presented and discussed under the following headings:
4.1.1 Growth attributes of wheat
184.108.40.206 Plant height (cm)
Plant height of wheat increased with the advancement of plant age, starting slowly from early ege than rapidly from 60 DAS. Plant height of wheat was affected by different managements of urea (Fig. 1).
At 15 DAS, the maximum plant height (25.13 cm) was obtained from T6 treatment which was statistically similar with T4 and T7 treatment and the minimum plant height was obtained from T3 treatment (21.62 cm) which was statistically similar with T1, T2, T5 and T8 treatments. At 30 DAS, highest plant height (42.23 cm) was obtained from T6 which was statistically similar with T3 treatment and the lowest (37.50 cm) was obtained from T5 treatment which was statistically similar with T8 treatment.
At 45 DAS, T8 treatment resulted in highest plant height (54.77 cm), which was statistically similar with T6 and T7 treatment. The lowest plant height (47.70 cm) was obtained from T3 treatment and it was statistically similar with T1 and T2 treatments.
77.67 cm plant height was recorded from T6 treatment which was highest and 68.72 cm the lowest plant height was recorded from T1 treatment at 60 DAS.
At 75 and 90 DAS the highest plant height 79.13 cm and 80.88 cm were obtained from T8 treatment whereas lowest plant height 72.47 cm and 74.07 cm were obtained from T1 treatment.
At final harvest, the tallest plant (82.97 cm) was observed in T8 treatment which was statistically similar with T1 and T7 treatments. The shortest plant (76.48 cm) was observed in T3 treatment.
Masum, 2008 showed that initially there was no significant effect of USG on plant hight but on later stage there was a significant effect of USG. It might be due to continuous availability of N from the deep placed USG that released N slowly and it enhanced growth to crop more than urea.
Similar results were found by Sing and Sing (1986). They reported that USG produced taller plants than prilled urea.
|Days after sowing|
Figure 1: Plant height of wheat at different days under different managements of urea (LSD0.05 = 2.89, 5.09, 9.08, 4.17, 8.75, 8.60 and 5.55 at 15, 30, 45, 60, 75, 90 DAS and at harvest, respectively)
220.127.116.11 Above ground dry weight plant-1 (g)
At 15 DAS, the highest dry matter of wheat (0.07 g) was obtained from T6 treatment which was statistically similar withT7 treatment and the lowest dry matter (0.055 g) was obtained from T3 treatment (Table 1).
At 30 DAS, the highest dry matter weight of wheat (0.54 g) was obtained from T1 treatment. The lowest dry matter (0.37 g) was obtained from T8 treatment.
At 45 DAS, the highest dry weight of wheat was obtained from T6 treatment and the lowest dry weight was found from T5 treatment.
At 60 DAS, the highest dry matter weight of wheat (4.29 g) was obtained from T8 treatment. The lowest dry matter (3.13 g) was obtained from T8 treatment.
At 75 DAS, the maximum dry weight of wheat was obtained from T5 treatment (4.92 g). The minimum dry matter was obtained from T8 treatment (3.43 g).
At 90 DAS, the highest dry matter (6.76 g) was recorded from T1 treatment. The lowest dry matter (4.54 g) was obtained from T6 treatment. At maturity, the highest dry matter of wheat was obtained from T1 treatment (8.79 g). The lowest dry matter (6.66 g) was obtained from T4 treatment and it was statistically similar withT2, T3, T6 treatments.
Rambabu et al. (1983) and Rao et al. (1986) from their studied concluded that USG was the most effective in increasing total drymatter than split application of urea.
Table 1: Above ground dry matter accumulation of wheat plant at different days under different managements of urea
|Treatment||15 DAS||30 DAS||45 DAS||60 DAS||75 DAS||90 DAS||At harvest|
18.104.22.168 Tillers plant-1
At 30 DAS, the highest number of tillers plant-1 of wheat was obtained from T1 treatment (2.53) which was statistically similar withT5 and T7 treatment. The lowest number of tillers plant-1 was obtained from T8 treatment which was statistically similar withT4 treatment (Table 2).
At 45 DAS, the maximum number of tillers plant-1 of wheat (3.0) was obtained from T1 treatment and the minimum number of tillers plant-1 (1.33) was obtained from T4 (Prilled urea + seed in furrow) which was statistically similar withT8 (urea super granules placed in between two wheat lines at 8 cm distance).
At 60 DAS, the highest number of tillers plant-1 of wheat (3.0) was obtained from T1 and T5 treatments. The lowest number of tillers plant-1 (1.33) was obtained from T4 treatment which was statistically similar withT2 and T8 treatments. At 75 DAS, the maximum tillers plant-1 of wheat (3.067) was reordered from T1 treatment and it was statistically similar with T5 andT7 treatments. The minimum (1.66) number of tillers plant-1 was reordered from T4 treatment which was statistically similar withT8 treatment.
At 90 DAS, the highest (3.53) number of tillers plant-1 of wheat was recorded from T1 treatment and it was statistically similar with T7 treatment. The lowest number of tillers plant-1 (2.20) was obtained from T8 treatment.
At maturity, the highest (3.76) number of tillers plant-1 of wheat was shown in T1 treatment while the lowest number (1.93) from T4 treatment. From the above it can be seen that prilled urea increased the number of tillers than USG. Similar results were found by Peng et al (1996)and Schneir et al (1990). They reported that N supply controlled the tiller production of rice plant unless other factors such as spacing or light become limited.
Table 2: Tillers of wheat plant at different days under different managements of urea
|Treatment||Tillers ( no.plant-1 ) of wheat at different days|
|30 DAS||45 DAS||60 DAS||75 DAS||90 DAS||At harvest|
4.1.2 Yield attributes of wheat
22.214.171.124 Length of spike (cm)
The length of spike of wheat varied significantly due to different management of urea (Table 3).
The longest spike of wheat (13.73 cm) was recorded with T5 treatment and the minimum (11.93 cm) from T7 treatment at 60 DAS.
At 75 and 90 DAS and at harvest, the highest 13.09 cm, 14.47 cm and 14.98cm length of spike of wheat was obtained from T1 treatment. The lowest length of spike of wheat 12.28 cm, 12.83 cm and 12.98 cm was obtained from T7 treatment at 75 and 90 DAS and at harvest, respectively.
Table 3: Spike length (cm) of wheat at different days as influenced by different managements of urea
|Treatment||Spike length (cm) of wheat at different days after sowing|
126.96.36.199 Number of spikelet spike-1
Number of spikelet spike-1 of wheat at different days as influenced by different management of urea (Table 4). At 60 DAS, the highest number of spikelet spike-1 of wheat (15.91) was obtained from T1 treatment. The lowest number of spikelet spike-1 of wheat (13.20) was obtained from T7 treatment which was statistically similar withT6 and T8 treatments.
At 75 DAS, the highest number of spikelet spike-1 of wheat (16.267) was shown in T3 treatment which was statistically similar with T1 treatment. The lowest number of spikelet spike-1 of wheat (13.46) was shown in T7 treatment which was statistically similar withT2 and T8 treatments.
At 90 DAS, the highest (16.30) number of spikelet spike-1 of wheat was obtained from T3 treatment and it was statistically similar withT1 and T6 treatments. The lowest number of spikelet spike-1 of wheat (15.32) was obtained from T8 treatment.
At harvest, the highest number of spikelet spike-1 of wheat (16.69) was shown in T 5 treatment which was statistically similar with T1 and T6 treatment. The lowest number of spikelet spike-1 of wheat (14.83) was shown in T7 treatment.
Table 4: Spike length (cm) of wheat at different days as influenced by different managements of urea
|Treatment||Spike length (cm) of wheat at different days after sowing|
188.8.131.52 Thousand grain weight (g)
There was no significant variation in thousand grain weight due to different forms of Nitrogen (Table 5). Maximum thousand grain weight (39.27 g) of wheat was recorded in T6 treatment. The lowest grain weight (36.43 g) was found with T4 treatment (Table 6). In case of rice, 1000 – grain weight is more or less stable genetic character (Yoshida, 1981) and nitrogen management strategy could not increase the grain weight in this case. Hasan et al. (2002) reported that the effect of application method of USG and PU was not significant in respect of 100- grain weight.
Table 5: Thousand grain weight of wheat at different days as influenced by different managements of urea
|Treatment||1000 grain wt. (g)|
184.108.40.206 Grain yield (t ha-1)
Grain yield of wheat affected significantly by different placement of urea (Table 6). The highest grain yield (3.11 t ha-1) of wheat was obtained from T8 treatment which indicates the superiority of urea supergranules over prilled urea and the lowest grain yield (2.43 t ha-1) from T4 treatment. Placement of Nitrogen fertilizer in the form of urea supergranules gave 16% more yield than the split application of urea. Similar finding were obtained from BRRI (2000) and they found that USG gave 18% yield increase over the recommended prilled urea.
Similar results were found by Mishra et al. (2000) and Raju et al. (1987) who observed that among all forms of N, urea supergranules recorded the highest grain yield and proved significantly superior to other sources.
Haque, (2002) also showed that point placement of urea super granules greatly increased yield of potato tubers.
As urea super granule is a slow release nitrogenous fertilizer which dissolves slowly in the soil providing a steady supply of available nitrogen throughout the growing period of crop. Probably due to this reason the plant got enough nutrients for its grain development and that’s why urea super granules treated plots gave better yield than prilled urea.
220.127.116.11 Straw yield (t ha-1)
The highest straw yield was observed in T1 treatment and the lowest straw yield was observed in T6 treatment (Table 6). From the table it can be seen that urea supergranules produced comparatively less straw yield.
18.104.22.168 Biological yield (t ha-1)
It was observed from the table 6 that biological yield was significantly affected by the forms of nitrogen fertilizer. Maximum biological yield (7.44 t ha-1) was observed from the urea supergranules treated plot than prilled urea.
4.1.3 Harvest Index (%)
Harvest Index of wheat was varied significantly due to different management of urea (Table 6). The highest (41.80 %) Harvest Index was obtained from T8 treatment. The lowest (36.93 %) harvest Index was obtained from T1 treatment. Ali (2005) reported that N management strategy did not influence Harvest Index. Miah et al. (2004) also reported that forms of nitrogen fertilizer had exerted very little variation on Harvest Index.
Table 6: Grain, straw, biological yield and harvest index of wheat as influenced by different managements of urea
|Biological yield (t ha-1)||Harvest Index (%)|