Harvest Of Rice Crop Research Articles

Residual Effect of Humic Acid, PSB and Phosphorus Nutrition on Soil Chemical Properties after Harvest of Rice Crop under the Subtropical Condition of Jammu

Field experiments were conducted during Kharif season of 2022 at the Research Farm, WMRC, SKUAST- J, Chatha. The soil of the experimental site was sand clay loam in texture, slightly alkaline in reaction, low in organic carbon and available nitrogen but medium in phosphorus and potassium. The experiment was laid out in Factorial RBD with three factors replicated thrice. Twenty treatment combinations comprising of five Humic acid treatments (Control, Soil Application of Humic acid @ 2.5kg/ha & 5kg/ha (Market ready), and Soil Application of Humic acid @ 2.5kg/ha & 5kg/ha (FYM), two PSB treatments (With and without PSB) and two levels of Phosphorus nutrition (100% Recommended N:100% Recommended P - 15:40 kg/ha and 100% Recommended N:75% Recommended P - 15:30 kg/ha). The utilization of Humic acid at a rate of 5 kg/ha, sourced from both Market Ready and Farm Yard Manure (FYM), combined with seed treatment employing (PSB) and a nutrient application of 100% recommended nitrogen (N): 100% recommended phosphorus (P) - 15:40 kg/ha, exhibited a more pronounced and favorable residual impact on soil properties. This was evidenced by notable improvements in organic carbon, available nitrogen, phosphorus, and potassium levels, surpassing their initial values but shows in non-significant results. Furthermore, this treatment employing humic acid application, PSB & Phosphorous nutrition showed improvement in seed yield and straw yield but failed to show significant results in residual rice crop.

Utilization of Rice Field Conch Shells as a partial substitution of Cement and Fine Aggregate for Split Tensile Strength of Concrete

Aceh is one of the provinces in Indonesia which has a very large area of rice field production. However, there are many pests that hinder agriculture in Indonesia. One of them is the rice field conch shells which has the potential to cause very high losses to the rice crop harvest. The aim of this research was to determine the ratio of the split tensile strength of concrete using rice field conch shells as a partial replacement for cement and fine sand against normal concrete by 0%, 5%, 10%, and 15%. In addition, it was also seen the effect of immersing concrete specimens using rice field conch shells substitution in tap water and water collected from paddy's farm. This study used the ACI (American Concrete Institute) 211.1-91 and ASTM (American Society for Testing and Materials) methods. The specimens consisted of cylinders with dimensions of 15 cm x 30 cm, totaling 40 specimens with a design concrete compressive strength of 17.00 MPa. The curing of the specimens was carried out using tap water and water collected from paddy's farm for 28 days in the soaking tub. The results showed that 5% substitution of rice field conch shells in cement and fine sand using the tap water immersion method showed a 3% increase in the tensile strength of concrete in comparison with normal concrete. Meanwhile, immersion using the water collected from paddy’s farm method showed a decrease in the value of the split tensile strength of the concrete.

Response of Graded Fertility Levels and Zinc Application Method with and without Farm Yard Manure on Physicochemical and Biological Properties of Soil under Rice Crop

The field experiment was conducted during Kharif season 2022 at Student’s Instructional farm of Acharya Narendra Deva University of Agriculture and Technology Kumarganj, Ayodhya Uttar Pradesh, India. The experiment was laid out in Randomized Block Design (RBD) with three replications and ten treatments. The experiment comprised of ten treatments viz., T1: Control, T2: 100% RDF (150, 60, 40 N, P2O5, K2O kg ha-1), T3: 100% RDF + 25 kg ZnSO4 ha-1 soil application, T4: 100% RDF + 0.5% ZnSO4 spray at tillering stage, T5: 100% RDF + 0.5% ZnSO4 spray at tillering stage + PI stage, T6: 75% RDF + 25 kg ZnSO4 ha-1 soil application, T7: 75% RDF + 0.5% ZnSO4 spray at tillering stage, T8: 75% RDF + 0.5% ZnSO4 spray at tillering stage + PI stage, T9: 75% RDF + 25% FYM-N +0.5% ZnSO4 spray at tillering stage + PI stage and T10: 75% RDF + 25% FYM-N +25 kg ZnSO4 ha-1 soil application. The application of 75% RDF + 25% FYM-N +25 kg ZnSO4 ha-1 soil application has non-significantly effect on Bulk density, pH, Electrical Conductivity of soil after harvest of rice crop. The application of 75% RDF + 25% FYM-N +25 kg ZnSO4 ha-1 soil application has significantly influenced Organic carbon, Available N, P, K and Zn in soil.

Effect of nitrogen management through nano-fertilizer in rice (Oryza sativa L.)

The present investigation entitled “Effect of Nitrogen Management through Nano-fertilizer in Rice (Oryza sativa L.)” was conducted during Kharif season of 2021 at instructional farm of Barrister Thakur Chhedilal College of Agriculture and Research Station Bilaspur (Chhattisgarh). Resulted that all the growth parameters and yield attributes which were significantly superior under the treatment 50 % RDN as basal + foliar spray of nano urea at tillering stage + foliar spray of nano urea at PI stage. Application of 50% RDN as basal + foliar spray of nano urea at tillering stage + foliar spray of nano urea at PI stage resulted higher gross income Rs. 146896.76 ha-1, Net income Rs. 97394.70 ha-1, B:C ratio 1.97 which was significantly superior over rest of the treatments. In the treatment 50% RDN as basal + foliar spray of nano urea at tillering stage + foliar spray of nano urea at PI stage was observed as the best treatment in increasing the grain yield (55.18 q ha-1) and straw yield (59.70 q ha-1) of rice crop. Availability of N, P2O5 and K2O in soil after harvest of rice crop were estimated higher with treatment 50 % RDN as basal + foliar spray of nano urea at tillering stage + foliar spray of nano urea at PI stage. Content and uptake of Nitrogen, Phosphorus and Potassium by rice crop were estimated higher under the treatment 50 % RDN as basal + foliar spray of nano urea at tillering stage + foliar spray of nano urea at PI stage.

Juvenile Heat Tolerance in Wheat for Attaining Higher Grain Yield by Shifting to Early Sowing in October in South Asia.

Farmers in northwestern and central India have been exploring to sow their wheat much earlier (October) than normal (November) to sustain productivity by escaping terminal heat stress and to utilize the available soil moisture after the harvesting of rice crop. However, current popular varieties are poorly adapted to early sowing due to the exposure of juvenile plants to the warmer temperatures in the month of October and early November. Therefore, a study was undertaken to identify wheat genotypes suited to October sowing under warmer temperatures in India. A diverse collection of 3322 bread wheat varieties and elite lines was prepared in CIMMYT, Mexico, and planted in the 3rd week of October during the crop season 2012–2013 in six locations (Ludhiana, Karnal, New Delhi, Indore, Pune and Dharwad) spread over northwestern plains zone (NWPZ) and central and Peninsular zone (CZ and PZ; designated as CPZ) of India. Agronomic traits data from the seedling stage to maturity were recorded. Results indicated substantial diversity for yield and yield-associated traits, with some lines showing indications of higher yields under October sowing. Based on agronomic performance and disease resistance, the top 48 lines (and two local checks) were identified and planted in the next crop season (2013–2014) in a replicated trial in all six locations under October sowing (third week). High yielding lines that could tolerate higher temperature in October sowing were identified for both zones; however, performance for grain yield was more promising in the NWPZ. Hence, a new trial of 30 lines was planted only in NWPZ under October sowing. Lines showing significantly superior yield over the best check and the most popular cultivars in the zone were identified. The study suggested that agronomically superior wheat varieties with early heat tolerance can be obtained that can provide yield up to 8 t/ha by planting in the third to fourth week of October.

On Farm Assessment of INM Techniques on Soil Health and Yield of Rice in Sahibganj, Jharkhand

On-farm trial was conducted to assess the Integrated Nutrient Management (INM) techniques on yield of rice and soil health after harvest during 2018-19 and 2019-20 at ten locations. The result of three treatments viz. Farmer’s Practice, Technology Option 1 and Technology Option 2 indicated that TO1 and TO2 significantly increased the yield and yield attributing characters over farmer’s practice (FP). Significantly high yield of rice grain (41.2 q per ha) was recorded with INM techniques. The data on available N, P and K status of soil after harvest of rice crop was significantly higher under TO2 as compared to FP. Highest net-return (Rs. 44,214 per ha) with B:C ratio of 2.44 was reported under TO2. INM techniques also resulted in lowest technology gap (8.78 q per ha) and technology index (17.56%) over other treatments which suggests it’s feasibility at farmer’s field.

A novel crop-stand establishment technique for Blackgram (Vigna mungo (L.) Hepper) under Rice-pulse cropping system in delta regions

Blackgram (Vigna mungo (L.) Hepper) is one of the most important and extensively grown pulse crops around the world. The present practice of farmers has been sowing the blackgram seeds, preferably 7-10 days, prior to harvest of rice under rice-pulse cropping system in delta regions. It ensures zero tillage and also utilization of residual soil moisture to hasten germination of blackgram seeds. The major constraint here is plant population maintenance and low productivity of the pulse crop. The objective of the experiment was to find out suitable stand establishment method for cultivating blackgram, after harvest of rice crop, in stubbles under rice-pulse cropping system and also to fix seed rate to get optimum yield. Accordingly, the field experiment was conducted at central farm of Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai during 2019 – 2020 with different crop-stand establishment techniques and performance of blackgram assessed in terms of growth and yield. A perusal of the results on growth and yield of blackgram indicated that the grain yield ranged from 364.58 kg to 713.54 per ha of land. The maximum yield was registered in the treatment T7: Broadcasting (37.5kg/ha) followed by tiller (9 Tyne) ploughing with a yield of 713.54 kg/ha and was significantly different from other treatments. A similar trend was also observed with haulm yield.

Long term effects of rice establishment methods on physical properties and rice productivity in vertisols of Chhattisgarh plain

The farmer field study was carried out during 2016 at village Saida, Takhatpur Tehsil in Bilaspur district of Chhattisgarh to evaluate the “Long term effects of rice establishment methods on physical properties and rice productivity in Vertisols of Chhattisgarh plain”. The trial was laid out in Randomized block design with twelve replications and three treatments in rice based cropping system in Vertisols. The study on the long-term effect of rice establishment methods on soil physical, chemical, biological properties and crop productivity were evaluated after harvest of rice crop. In this study, three rice establishment methods i.e. transplanting, broadcast-biasi and direct seeded line sowing were laid in main treatment. A study was undertaken to characterize the soil resources of the investigation field. The residual effect of rice establishment methods on soil physical properties like bulk density, hydraulic conductivity, penetration resistance, water holding capacity and crack volume were significantly affected by the treatments. Transplanting method significantly increased the bulk density of surface soil (0-15 cm) and sub-surface layer i.e. (15-30 and 30-45 cm) but non-significant affect was obtained at lower (45-60 cm) depth. The hydraulic conductivity was found maximum in surface layer under direct seeded method and increases as per depth was decreased. Penetration resistance was recorded significantly increase with increase in depth. Water holding capacity was significantly increased with direct seeded (LS) method and minimum was recorded in transplanting method. Crack volume was significantly higher in transplanting method over other methods of rice cultivation.

Experimental investigation of imbert downdraft gasifier using rice straw briquettes

ABSTRACT The mechanized harvesting of rice crop has led to open-field burning of rice straw that liberates a large amount of greenhouse gases (GHGs), which have a negative effect on the environment. Gasification is an efficient technology for the conversion of biomass to producer gas with minimal greenhouse gas emissions. The present study was planned to convert the abundantly available rice straw into briquettes and its thermochemical conversion into producer gas for thermal energy utilization. The performance of imbert type gasifier was investigated using rice straw briquettes as fuel by studying the influence of airflow rate on fuel consumption rate and temperature profile inside the combustion zone. The augmentation of airflow rate from 0.0022 to 0.0042 m3/s led to a significant increase in feedstock consumption rate (63.3%). The time taken for boiling of water also increased with an increase in airflow rate which may be attributed to the corresponding decrease in calorific value of producer gas. Rice straw briquettes with cotton stalks as a binder (90:10) can act as a clean alternative fuel for gasification and the producer gas generated can be used for various thermal applications.

The origin of soil selenium in a typical agricultural area in Hamatong River Basin, Sanjiang Plain, China

The origin of soil selenium (Se) is relatively complex, and analysis of the origin of soil Se is of great significance in clarifying the cause of its richness and the impact of human activities on soil environmental quality, as well as assisting in the scientific planning of Se-rich land use, improving land use value, and promoting regional economic development. In this study, in order to identify and clarify the origin of soil Se and the causes of its richness in a typical agricultural area in the Hamatong River Basin of the Sanjiang Plain, we tested the Se concentrations in soil, atmospheric deposition, irrigation water, chemical fertilizer, rock, and rice crop samples from the study area. Geostatistical analysis indicated that the soil Se is mainly controlled by natural factors such as soil parent material. Elemental geochemical analysis indicated the soil Se is mainly derived from the granite occurring in the Wanda Mountains. Elemental mass balance analysis indicated that the atmospheric deposition is the most important source of soil Se input, with a contribution of 84.90%, followed by irrigation and fertilization. Deep percolation is the main pathway of soil Se output, with a contribution of 74.17%, followed by rice crop harvest and volatilization. In addition, the soil Se is derived from a natural source, its richness can be attributed to the effect of anthropogenic factors, such as fossil fuel combustion and fertilization, superimposed on the high natural background value of soil Se.

Influence of Rice Residue Management Techniques and Weed Control Treatments on Soil Available Plant Nutrients in Rice-Wheat Cropping System

Rice-wheat is the predominant cropping system of fertile soils of Indian, Pakistan, Bangladesh and Nepal falling in the alluvial Indo-Gangetic Plains (IGP). Management of rice residues produced after the harvest of rice crop and before sowing of the next wheat crop is a big challenge in that area. Mostly farmers burn rice residues assuming it low profile fodder and of little use. Burning of rice residues deprives the fields from many plant nutrients as they are lost during burning along with environmental pollutions and other issues. A field study was conducted for two consecutive years at the experimental area of the Department of Agronomy, Punjab Agricultural University, Ludhiana (India) to assess the impact of different rice residue management techniques and weed control treatments in wheat on soil available plant nutrients in rice-wheat cropping system. The experiment was laid out in split plot design with three replications. In main plots, five rice residue management treatments viz., no rice residue, rice residue 5 t·ha-1 (surface), rice residue 6 t·ha-1 (surface), rice residue 7 t·ha-1 (surface) and rice residue 5 t·ha-1 (incorporation) were settled and in sub plots, four weed control treatments i.e. clodinafop 60 t·ha-1, sulfosulfuron 25 t·ha-1, mesosulfuron + iodosulfuron 12 t·ha-1 and control (unweeded) were arranged. Results of the study revealed that surface application as well as incorporation of rice residues improved the organic carbon and NPK status than no rice residues. Among the residue management practices, incorporation of rice residues 5 t·ha-1 significantly improved the soil organic carbon, available nitrogen, phosphorus and potassium than no rice residue treatment in the 0 - 15 soil layer during both the years. Same trend was observed for 15 - 30 cm soil layer but differences were less wide than 0 - 15 cm soil layer. Among the weed control treatments, organic carbon was not significantly influenced. Herbicide treated plots registered significantly higher available nitrogen, phosphorus and potassium than control (unweeded) treatment in the 0 - 15 cm soil layer during both the years.

Effects of Long Term Organic and Conventional Farming on Physical and Chemical Properties of Soil

Field experiment was conducted to compare the soil status of organic and conventional farming system under rice and wheat cropping system. Laboratory analysis was made on the soil samples collected from a longterm organic farm (SOF) at Department of Soil Science, Khalsa College, Amritsar and compared with the soil samples collected from different conventional fields (SCF) after the harvest of rice crop to investigate the effect of organic sources and chemical fertilizers. The results of the study revealed that soil physical properties viz., bulk density, particle density and porosity varied from 1.26 g/cm3 to 1.31g/cm3 (SO) and 1.35 g/cm3 to 1.44 g/cm3 (SC), 2.62 g/cm3 to 2.67 g/cm3 (SO) and 2.62 g/cm3 to 2.68 g/cm3 (SC) and 50.19 to 52.80 per cent (SO) and 45.48 to 48.49 per cent (SC), respectively. Soil pH showed slightly acidic to alkaline (6.75 to 7.34) range in organic soil samples while conventional soil samples showed alkaline range (7.98 to 8.28). The electrical conductivity (EC) of conventional farming system was significantly higher than organic farming system. The highest value (0.421dS/m) of EC was observed in conventional farming system field while lowest (0.391 dS/m) in organic field. Soil organic carbon (OC) content in surface soil ranged between 0.74 to 0.85 per cent and 0.26 to 0.35 per cent in organic and conventional farming systems, respectively. Similar trends were observed in soil status of available N, P and K under organic and conventional farming systems.

Status of Dhaincha Incorporated Soil After Rice Harvest in (Boro) Rice–Dhaincha–Rice (T. Aman) Cropping Pattern

AbstractAn experiment was conducted at Field Laboratory of the Department of Crop Botany, Bangladesh Agricultural University, Mymensingh, to find out the effect ofdhainchaincorporation on subsequent rice crop yield and postharvest soil nutrient status. The experiment was laid out in a randomized complete block design having three replications. Ninedhainchaaccessions were used as experimental materials along with a control (withoutdhainchaplant). Seeds ofdhainchaaccessions were sown in experimental plot @ 60 kg ha−1. Sixty days olddhainchaplants were mixed up with soil. Soil samples were collected twice, before sowing ofdhainchaseeds and after rice crop harvest. Forty five days old healthy rice seedlings were transplanted in the well prepareddhainchaincorporated plots at the spacing of 15 cm x 25 cm (plant-plant x row-row). The pH and nutrient status were improved indhainchaincorporated soil over the control. The highest grain yield (5.81 t ha−1) was obtained fromdhainchaAcc. 33 incorporated plot followed by Acc. 25 (5.73 t ha−1) and the lowest in control (4.35 t ha−1). Due to the incorporation ofdhainchabiomass in soil, the rice grain yield increased 7.82% to 33.56% over the control. Among thedhainchaaccessions, number 33 showed the best performance in terms of influencing grain yield. A precise conclusion to be built up through collection of large number of germplasms from Bangladesh is needed.

Yield attributes, yield and uptake of nutrients as influenced by basal and foliar application of nutrients on rice fallow blackgram

An investigation was carried out to fine tune nutrient management techniques for improving the yield of rice fallow blackgram at the Wetlands of Tamil Nadu Agricultural University, Coimbatore in a split plot design. Three fertilizer application practices viz. recommended dose of fertilizer to preceding rice crop, recommended dose of fertilizer (last split through DAP based on N equivalent) to the preceding rice crop and basal application of fertilizer to blackgram of N and P2O5 @ 12.5:25 kg ha-1 (10 days prior to harvest of rice crop) formed the main plot treatments and foliar sprays viz., control, 1% urea, 2% DAP, 1% KCl and 2% DAP + 1% KCl twice at flowering and pod filling stages of crop growth constituted the subplot treatments. The treatments were replicated thrice. The results revealed that basal application of N and P2O5 fertilizers @ 12.5:25 kg ha-1 (10 days prior to harvest of rice crop) to blackgram favoured the nutrient uptake. Similarly the NPK uptake at harvest (64.64, 6.75 and 46.51 kg ha-1) and yield (1037 kg ha-1) were significantly influenced when foliar spray of 2% DAP + 1% KCl was given at flowering and pod filling stages of crop growth. Interaction between basal application of fertilizer N and P2O5 @ 12.5:25 kg ha-1 just before the harvesting of preceding rice crop along with foliar spray of 2% DAP + 1% KCl twice at flowering and pod filling stages was significant for NPK uptake, yield attributes and yield.

Uptake efficiency of 15N-urea in flooded and aerobic rice fields under semi-arid conditions

The sustainability of traditional rice (Oryza sativa L.) cultivation in many Asian countries is being questioned due to severe water shortage conditions, envisaging the need for development of water-saving rice production technologies. A 2-year-field study on a typic Haplustalf soil was conducted to compare traditional transplanted rice–maize system with water-saving aerobic rice–maize system, with an overall objective of investigating the fate of fertilizer nitrogen (N) using 15N-labeled urea. Results from the field experiments showed that the rice plants positively responded to N fertilizer application. The average fertilizer N recovery by rice crop over the 2 years in aerobic rice was 26 kg per 100 kg of applied fertilizer N in the main field and 21 kg per 100 kg of applied N in the microplot, while the recoveries were 41 and 32 kg ha−1 per 100 kg of applied N in traditionally cultivated rice under flooded conditions. The fraction of 15N that was found in soil after the harvest of rice crop ranged from 11.4 to 47.1 kg ha−1 in aerobic rice and 14.2–51.4 kg ha−1 in flooded rice. Average recovery of 15N fertilizer in maize after the first growing season was 3.3 %, and the corresponding recovery in soil was 19 %. An additional 1.3 % of the fertilizer was recovered by crops during the two subsequent seasons. This study indicates the need to develop management practices that improve N use efficiency in aerobic rice by reducing losses to improve yields and reduce N export to the environment.

Residual Effect of Triasulfuron and Other Herbicides against Greengram, Blackgram and Cowpea

Field experiments were carried during summer 2009 and 2010 at Agricultural Research Station, Kathalagere, district Davangere in the southern transitional zone of Karnataka to know the residual effect of triasulfuron and other weedicides against test crops. The soil of the experimental field was red loamy. The field experiment was laid out in randomized block design with 10 treatments viz., After harvest of rice crop, all the plots were sown with three rows each of test crops viz. greengram, blackgram and cowpea. Germination per cent of greengram, blackgram and cowpea did not differ significantly due to residual effect of weed control treatments. At 10 DAS, Pyrazosulfuron @ 25 g a.i. ha -1 recorded lower dry weight of greengram (0.026 and 0.040 g plant -1 during 2009 and 2010, respectively), blackgram (0.033 and 0.054 g plant -1 during 2009 and 2010, respectively) and cowpea (0.072 and 0.121g plant -1 during 2009 and 2010, respectively). Hand weeded twice recorded higher dry weight of these test crops. The pyrazosulfuron @ 25 g a.i. ha -1 recorded significantly lower seed yield of greengram (182 and 147 kg ha -1 during 2009 and 2010, respectively), blackgram (532 and 349 kg ha -1 during 2009 and 2010, respectively) and cowpea (1272 and 499 kg ha -1 during 2009 and 2010, respectively), followed by almix @ 4 g a.i. ha -1 .

Analysis of Rice Growth Using Multi-Temporal Radarsat-2 Quad-Pol Sar Images

Abstract Three time series of quad-polarization RADARSAT-2 images have been acquired from transplanting to harvesting of rice crop. Ground truth data such as rice height and biomass etc. were measured during acquisition of RADARSAT-2 data in Hainan province, southern China. Among different observations, dry biomass and fresh biomass of rice crop have shown a temporal signature with a clear correlation with backscattering coefficient in HV/VH polarization, whose correlation parameters are mainly larger than 0.8, while HH and VV polarizations show unfavorable correlation with crop dry/fresh biomass, whose correlation parameters are lower than 0.6. Variations of scatter mechanism of rice crop from transplantation to maturity have been investigated based on Pauli decomposition and H/alpha/A-wishart classification. For Pauli decomposition, Pauli A component is the main backscatter of rice crop, which valued between 0.2 and 0.6 in the whole rice growth stage. Pauli B component ranks second, valued from 0.1 to 0...

UTILIZING EXHAUST GASES OF DIESEL ENGINES IN DRYING GRAIN RICE

In Egypt, rice crop occupies the first rank in area cultivated as the main food.Percentage of moisture in grain is up to 24% with mechanical harvesting of rice crop. For safe storage of rice seeds, it is required to reduce the humidity to 14%. Due to weather changes it is difficult to dry by the sun. Therefore, the main objective of this study is the use of thermal energy lost with the exhaust gases of diesel engines in drying rice seed. The suggested drying unit is simple made from local raw materials, comprising: a fan to generate air stream carry the heat, heat exchanger for the exhaust gases installed behind the fan, a drying container. Drying tests were conducted using the Sakha 101, whereas the average weight of each sample in drying process was 25 kg, the average humidity was 20.4%, the average temperature of air was 24.6 oC and the average relative humidity of the air was 65.7%. The experiments have shown the following results: The highest temperature of input drying air was 42.2 oC, energy received by drying air was 9.62 MJ/h and capacity of drying unit was 0.074 ton/h achieved with drying air flow rate o7.65 m3/min.

Changes in methanotrophic community composition after rice crop harvest in tropical soils

Four selected tropical field sites from India were studied to assess the diversity and community structure of methanotrophs in rice fields following crop harvest. The rate of methane oxidation ranged from 0.04 to 0.11 µmol L−1 h−1 g−1 dry weight in soils. Methanotrophic population size was high for the agriculture farm of Banaras Hindu University (BHU) site followed by agriculture farm of the Indian Institute of Vegetable Research (IIVR), Ghazipur, and Barkachcha. The cloning, restriction fragment length polymorphism, and sequence analyses of the pmoA gene fragment amplified from soil DNA extracts revealed the presence of type I and type II methanotrophs. The phylogenetic affiliation and community analysis based on the presence or absence of sequences showed that methanotrophs community composition in Barkachcha and Ghazipur soils was similar. IIVR soils, however, were quite different, while BHU soils were intermediate among the sites with regard to methanotrophic community composition. Diversity index of the methanotrophic community was high at the IIVR site. The study revealed that the rice harvest led to a change in type I methanotrophs from all the sites while type II community composition was almost uniform.

Metal Contamination in Nullah Dek Water and Accumulation in Rice

A research study was carried out to determine the electrical conductivity (EC), residual sodium carbonate (RSC), sodium adsorption ratio (SAR), p H and metals in metal-polluted irrigation water from a nullah and those in soils over a period of time, and the effect of metals on rice yield and metal concentrations in rice grain and straw. Two sites (I and II) were selected on the bank of Nullah Dek at Thatta Wasiran in Sheikhupura District (Pakistan), with two rice varieties. Super Basmati and Basmati 385, at both sites. Water samples were collected during rice crop growth at 15-day intervals from August 3 to November 1, 2002. The results showed that Nullah Dek water had an EC >1.0 dS m −1 and RSC of 2.78–4.11 mmol c L −1, which was hazardous for crops, but the SAR was within the safe limit. Cu, Mn Cd and Sr were also within safe limits. The soil analysis showed that Site II was free from salinity/sodicity, whereas Site I was saline sodic. Among metals, Zn was sometimes deficient, Cu, Mn and Fe were adequate, and Sr, Ni and Cd were within safe limits in the soil at both the sites. After the rice crop harvest, concentrations of all metals tested were usually slightly increased, being higher in the upper soil layer than the lower. In addition, Basmati 385 produced higher rice grain and straw yield than Super Basmati. Chemical analysis of rice grain indicated the presence of Zn, Cu, Fe, Mn, Pb and Sr, whereas rice straw contained Zn, Cu, Fe, Mn and Sr, with Cd and Ni both being found in minute quantities.