SITE-SPECIFIC FERTILIZATION FOR LOWLAND  RICE PRODUCTION IN WEST KALIMANTAN

Sustainability of rice production under flooding conditions has been challenged by water shortage and food demand. Applying higher nitrogen fertilization could be a practical solution to alleviate the deleterious effects of water stress on lowland rice (Oryza sativa L.) in semi-arid conditions. For this purpose, field experiments were conducted during the summer of 2017 and 2018 seasons. These trials were conducted as split-split based on randomized complete blocks design with soil moisture regimes at three levels (120, 100 and 80% of crop evapotranspiration (ETc), nitrogen fertilizers at two levels (N1—165 and N2—200 kg N ha−1) and three lowland Egyptian rice varieties [V1 (Giza178), V2 (Giza177) and V3 (Sakha104)] using three replications. For all varieties, growth (plant height, tillers No, effective tillers no), water status ((relative water content RWC, and membrane stability index, MSI), physiological responses (chlorophyll fluorescence, Relative chlorophyll content (SPAD), and yield were significantly increased with higher addition of nitrogen fertilizer under all water regimes. Variety V1 produced the highest grain yield compared to other varieties and the increases were 38% and 15% compared with V2 and V3, respectively. Increasing nitrogen up to 200 kg N ha−1 (N2) resulted in an increase in grain and straw yields by 12.7 and 18.2%, respectively, compared with N1. The highest irrigation water productivity (IWP) was recorded under I2 (0.89 kg m−3) compared to (0.83 kg m−3) and (0.82 kg m−3) for I1 and I3, respectively. Therefore, the new applied agro-management practice (deficit irrigation and higher nitrogen fertilizer) effectively saved irrigation water input by 50–60% when compared with the traditional cultivation method (flooding system). Hence, the new proposed innovative method for rice cultivation could be a promising strategy for enhancing the sustainability of rice production under water shortage conditions.

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Studies on nitrogenase activity of diazotrophic isolates from different rice production systems

Journal of Applied and Natural Science ◽

10.31018/jans.v8i1.787 ◽

2016 ◽

Vol 8 (1) ◽

pp. 284-289

Author(s):

S. Kanimoli ◽

K. Kumar

Keyword(s):

Acetylene Reduction ◽

Tamil Nadu ◽

Production Systems ◽

Nitrogenase Activity ◽

Rice Production ◽

Lowland Rice ◽

Aerobic Rice ◽

Marked Variation ◽

Reduction Assay ◽

First Time

The present study was carried out to evaluate the nitrogen fixing ability of diazotrophs isolated from the rhizosphere soils of rice which were grown in three different rice growing systems. A total of hundred and ten isolates obtained were subjected to Acetylene Reduction Assay (ARA) and ninety eight isolates recorded significant amount of nitrogenase activity in a range of 185.73 to 3794.55 nmoles of ethylene mg of protein-1 h-1. The highest nitrogenase activity was recorded by Derxia (3794.55 nmoles of ethylene mg of protein-1 h-1) isolated from Trichy (lowland). Among the three different rice production systems, isolates obtained from lowland rice (Derxia â€“ 3794.5 nmoles of ethylene mg of protein-1 h-1) recorded higher nitrogenase activity followed by Aerobic (Pseudomonas - 2194.89 nmoles of ethylene mg of protein-1 h-1) and SRI (Azotobacter - 1971.85 nmoles of ethylene mg of protein-1 h-1) rice isolates. The results revealed marked variation in the ARA of the diazotrophic isolates obtained from lowland, SRI and Aerobic rice. The nitrogenase activity of diazotrophs from rice fields have been reported earlier but the nitrogenase activity of diazotrophs from three different rice production systems from various parts of Tamil Nadu is reported for the first time from India.

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A Site-Specific Fertilizer Recommendation Based on the Phosphorus and Potassium Status in Mempawah District, West Kalimantan

Journal of Tropical Soils ◽

10.5400/jts.2020.v25i2.93-106 ◽

2020 ◽

Vol 25 (2) ◽

pp. 93

Author(s):

Muhammad Hatta

Keyword(s):

Soil Analysis ◽

Nutrient Status ◽

Soil Samples ◽

Paddy Fields ◽

Site Specific ◽

West Kalimantan ◽

Fertilizer Recommendation ◽

Fertilizer Recommendations ◽

Phosphorus And Potassium ◽

A Site

The recommendations of Phosphorus (P) and Potassium (K) fertilization for rice are still not site-specific yet due to a lack of required soil data information. The P and K status of the paddy fields that provide information on the low, medium, and high P and K nutrient status are very useful for determining recommended the site-specific fertilizer in the the district area. The purpose of the research was to determine the site-specific fertilizer recommendation for paddy field based on their P and K status. This research was based on the field survey and the soil analysis in the laboratory. The soil samples were taken using a grid system, and the P and K levels were assessed by using a 25% HCl extraction. Soil samples were taken in a composite manner on all paddy fields in which their status have been identified. The composite soil samples were determined from 10 - 15 individual samples (sub-samples) with a sampling distance of each sub-sample of 25-50 m in the field. The soil samples were taken in the overlay with a depth of 0-20 cm. Taking sub-samples were done by a diagonal or a zigzag method according to the conditions of paddy fields. The results of the study presented that the nutrient status of P and K and the fertilizer recommendations in paddy fields for rice plants located in 9 sub-districts in Mempawah Dsitrict had shown that nutrient status of P, on average, were from moderate to high levels, meanwhile, the nutrient status of K was from low to high levels. Recommendations for fertilizing rice fields in several sub-districts in Mempawah Regency are mostly 150 kg NPK (15:15:15) ha-1, 200 kg Urea ha-1 and 25 kg KCl ha-1.

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