Deep placement of urea supergranules in transplanted rice: Principles and practices

1990 ◽  
Vol 25 (1) ◽  
pp. 1-83 ◽  
Author(s):  
N. K. Savant ◽  
P. J. Stangel
Keyword(s):  
Deep Placement ◽  
Urea Supergranules ◽  
Transplanted Rice

Integrated rice straw–urea management for transplanted rice

1996 ◽  
Vol 127 (1) ◽  
pp. 49-55 ◽  
Author(s):  
A. V. Bulbule ◽  
S. C. Talashilkar ◽  
N. K. Savant
Keyword(s):  
Rice Straw ◽  
Field Experiments ◽  
Management Practice ◽  
Southwest Monsoon ◽  
Growth And Yield ◽  
Tropical Region ◽  
Average Increase ◽  
Tropical Zone ◽  
Deep Placement ◽  
Transplanted Rice

SUMMARYFour field experiments were conducted over the 1992 and 1993 seasons (southwest monsoon seasons, June–October) in the warm subhumid tropical region on the west coast of the Maharashtra State, India. The objective was to investigate the effect of recycling limited amounts of rice straw (RS) (as a source of K and Si) integrated with the use of prilled urea (PU) and urea briquettes (UB) at 60 kg N/ha on the growth and yield of rainfed transplanted rice (Oryza sativa L.). The management practice, consisting of basal incorporation of RS (2 t/ha) integrated with deep placement of UB (one 2·1-g UB/4 hills) immediately after transplanting using a modified 20 × 20 cm spacing, produced a significantly higher grain yield (average increase of 1·3 t/ha) and straw yield (average increase of 1·1 t/ha) than did the RS practice integrated with two equal split applications of PU at the same N rate and hill spacing. The additional yields were attributed to the increase of total and productive tillers/m2 and panicle weight. The results indicate the potential of the integrated RS–UB management for increasing yields of rainfed transplanted rice in the warm subhumid tropical zone.

Nitrogen balance studies in rice using 15N-labelled urea and urea supergranules

1989 ◽  
Vol 113 (1) ◽  
pp. 119-121 ◽  
Author(s):  
S. K. Mohanty ◽  
S. P. Chakravorti ◽  
A. Bhadrachalam
Keyword(s):  
Nitrogen Balance ◽  
Rice Field ◽  
Nitrogen Efficiency ◽  
Seasonal Effects ◽  
Split Application ◽  
Deep Placement ◽  
Fertilizer Nitrogen ◽  
Urea Supergranules ◽  
The Poor ◽  
Different Types

Recovery of applied nitrogen by the rice crop is invariably low, often 30–50% (Prasad & De Datta 1979). The poor recovery has been attributed to different types of losses occurring in the rice field. Recovery improved with split application, delayed application or deep placement (Pillai & Vamadevan 1978; Craswell & Vlek 1979), indicating that the management factor plays an important role in increasing fertilizer nitrogen efficiency. To investigate such factors, and seasonal effects, field experimentswere carried out using 15N-labelled urea (PU) and urea supergranules (USG). The recovery of fertilizer 15N by the plant and retention in the soil were studied in both dry and wet seasons.

Relative efficacy of some new urea-based nitrogen fertilizers for growing wetland rice on a permeable alluvial soil

1987 ◽  
Vol 109 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Bijay-Singh ◽  
J. C. Katyal
Keyword(s):  
Ammonium Sulphate ◽  
Release Rate ◽  
N Uptake ◽  
Nitrogen Fertilizers ◽  
Wetland Rice ◽  
Rice Grain ◽  
Deep Placement ◽  
Urea Supergranules ◽  
Coated Urea ◽  
Uptake Data

SummaryEfficiency of N contained in some modified urea fertilizers was studied for wetland rice grown in an alkaline, low organic matter Fatehpur loamy sand (Typic Ustipsamment) soil having an average percolation rate of 109 mm/day. In the four field experiments, sulphurcoated urea (SCU) produced significantly more rice grain than urea supergranules (USG) or divided applications of urea or ammonium sulphate. Application of SCU at 58 kg N/ha yielded as much rice grain as was produced by divided application of urea at 116 kg N/ha. The N uptake data suggested that SCU-N was more efficiently translated into grain yield than urea N. Granular (7-day release rate 19%) and forestry (7-day release rate 29%) grades of SCU were equally effective. However, application of half the N basally through SCU and the remaining half top dressed as urea failed to outyield all urea divided in three applications. The indigenous coated materials, rock-phosphate-coated urea and urea gypsum, also did not perform better than divided urea applications as these did not possess a 7-day release rate less than 95%. Urea supergranules placed in the reduced zone of the soil could not come to the level of divided application of urea or ammonium sulphate. The N uptake data indicated that USG-N was correspondingly inefficiently utilized by rice. When the deep placement aspect of USG was combined with slow-release properties of SCU in the form of sulphur-coated urea supergranules (SCUSG), the performance of this product was inferior even to the divided application of urea. Undissolved or partially dissolved granules of SCUSG could be recovered even after the harvest of the crop.

Fertilizer–use efficiency of amended urea materials in flooded rice

1989 ◽  
Vol 112 (2) ◽  
pp. 277-281 ◽  
Author(s):  
H. S. Chauhan ◽  
B. Mishra
Keyword(s):  
N Uptake ◽  
Deep Placement ◽  
Fertilizer Use ◽  
Urea Supergranules ◽  
Neem Cake ◽  
Prilled Urea ◽  
Matter Production ◽  
Neem Cake Coated Urea ◽  
Coated Urea ◽  
Use Efficiency

summaryIn a field experiment on a typic hapludoll in 1983 and 1984, deep placement of urea supergranules at 40 and 80 kg N/ha proved to be the best N source, of five tested, for grain production, but at 120 kg N/ha it was similar to neem-cake-coated urea. The results showed that deep placement of urea supergranules can save fertilizer use by 60% compared with prilled urea to obtain the same yield. Shellac-coated urea and dicyandiamide-coated urea was more effective than prilled urea in 1984. Differences in dry-matter production and grain yield were directly related to N uptake by the plants. On average, apparent recovery of applied N increased from 35% for prilled urea to 55, 52·5,46·5 and 37·5% for urea supergranules, neem-cake-coated urea, shellac-coated urea and dicyandiamide-coated urea, respectively.

Effect of N management approaches and planting densities on nitrogen accumulation by transplanted rice

2005 ◽  
Vol 53 (4) ◽  
pp. 405-415 ◽  
Author(s):  
P. Janaki ◽  
T. M. Thiyagarajan
Keyword(s):  
Grain Yield ◽  
Uptake Rate ◽  
Aboveground Biomass ◽  
N Uptake ◽  
Planting Density ◽  
Transplanted Rice ◽  
The Mean ◽  
N Uptake Rate ◽  
Management Approaches ◽  
N Management

Field experiments were conducted during 1998 and 1999 in June-September with rice variety ASD18 at the wetland farm, Tamil Nadu Agricultural University, Coimbatore, India to find out theeffect of N management approaches and planting densities on N accumulation by transplanted rice in a split plot design.The main plot consisted of three plant populations (33, 66 and 100 hills m-2) and the sub-plot treatments of five N management approaches. The results revealed thatthe average N uptake in roots and aboveground biomass progressively increased with growth stages. The mean root and aboveground biomass Nuptake were 26.1 to 130.6 and 6.4 to 17.8 kg ha-1, respectively. The N uptake of grain and straw was higher in theSesbania rostratagreen manuring + 150 kg N treatment, but it was not effective in increasing the grain yield. The mean total N uptake was found to be significantly lower at 33 hills m-2(76.9 kg ha-1) and increased with an increase in planting density (100.9 and 117.2 kg ha-1at 66 and 100 hills m-2density). N application had a significant influence on N uptake and the time course of N uptake in all the SPAD-guided N approaches. A significant regression coefficient was observed between the crop N uptake and grain yield. The relationship between cumulative N uptake at the flowering stage and the grain yield was quadratic at all three densities. The N uptake rate (µN) was maximum during the active tillering to panicle initiation period and declined sharply after that. In general, µNincreased with an increase in planting density and the increase was significant up to the panicle initiation to flowering period.thereafter, the N uptake rate was similar at densities of 66 and 100 hills m-2.

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