Effect of Dilution of Treated Distillery Effluent (TDE) on Soil Properties and Yield of Sugarcane

Sugarcane is one of the most important cash crops, which plays a pivotal role in India’s agricultural and industrial economy. The treated distillery effluent (TDE) being plant originated, contains all plant nutrients and organic matter. Therefore, it is being used as a cheap source of nutrients and organic manure in agriculture activities in soil besides improving soil physical properties. The experiment was conducted during August, 2010-2011 and 2011-2012 with CO 86032 in a randomized block design with six treatments and was replicated four times. The TDE was discharged @ 1.00, 0.50, 0.33, 0.25 and 0.20 lakh liters·ha-1 to get the dilutions of 1:10, 1:20, 1:30, 1:40 and 1:50 dilutions respectively. It was applied four times at 40 days interval starting from 45th day after planting. The fertilizers viz., N and P @ 75 percent of the recommended dose were applied and K was skipped. The results revealed that irrigation with TDE at 1:10 dilution resulted in higher yield of sugarcane. The TDE did not have any influence on quality parameters of sugarcane. The TDE application favourably influenced the available nutrients and organic carbon content in the soil. Besides, the present findings credibly proved that the TDE application not only enhanced the soil fertility status but also substituted for 25 percent of N and P and 100 percent of K fertilizers to sugarcane crop.

Effect of Diazotrophs and Chemical Fertilizers on Production and Economics of Okra (<i>Abelmoschus esculentus</i>, L.) Cultivars

The effect of diazotrophs and chemical fertilizers on yield attributing characters and economics of okra cultivation was evaluated. Application of highest dose of NPK @100% in combination with vermicompost (5 t ha-1) and biofertilizers with FYM increased the fruit yield of okra (cultivar Mahyco-10) considerably with yield varying between 80.00 q ha-1 to 227.13 q ha-1 and 80.49 q ha-1 to 229.62 q ha-1 during 2010 and 2011 respectively. In okra cv. Utkal Gaurav the fruit yield varied from 47.68 q ha-1 to 129.84 q ha-1 in 2010 and 47.27 q ha-1 to 131.35 q ha-1 in 2011. As regards the net return, highest net profit of Rs 87,630 and Rs. 89,370 ha-1 from the okra was realized over an investment of Rs. 71,360 ha-1 during both the years with a benefit cost ratio of 2.23 and 2.25 when 100% NPK integrated with vermicompost @5t ha-1 and biofertilizers with FYM applied in okra cv.Mahyco-10. The highest net return of Rs. 14,350 in 2010 and Rs. 15,260 in 2011 with an investment of Rs. 63,550 each year was found in cultivar Utkal Gaurav under highest level of nutrient application.

Effects of clump spacing on nutrient distribution and root activity of Dendrocalamus strictus in the humid region of Kerala,peninsular India

The humid agroclimatic conditions of Kerala,India permit the cultivation of an array of bamboo species of which Dendrocalamus strictus Roxb.(Nees.) is an important one on account of its high growth rate and multiple uses. Stand density, a potential tool in controlling the productivity of woody ecosystems, its effect on growth and root distribution patterns may provide a better understanding of productivity optimization especially when bamboo-based intercropping options are considered.Growth attributes of 7-year-old bamboo(D. strictus) stands managed at variable spacing(4×4 m, 6×6 m, 8×8 m,10×10 m, 12×12 m) were studied. Functional root activity among bamboo clumps were also studied using a radio tracer soil injection method in which the radio isotopeP was applied to soil at varying depths and lateral distances from the clump. Results indicate that spacing exerts a profound influence on growth of bamboo. Widely spaced bamboo exhibited higher clump diameters and crown widths while clump heights were better under closer spacing. Clump height was 30% lower and DBH 52%higher at the widest spacing(12×12 m) compared to the closest spacing(4×4 m). With increasing soil depth and lateral distance, root activity decreased significantly. Root activity near the clump base was highest(809 counts per minute, cpm; 50 cm depth and 50 cm lateral distance) at 4×4 m. Tracer study further showed wider distribution of root activity with increase in clump spacing. It may be concluded that the intensive foraging zone of bamboo is within a 50-cm radius around the clump irrespective of spacing. N, P and K content in the upper 20 cm was 2197,21, and 203 kg/ha respectively for the closely spaced bamboo(4×4 m) which were significantly higher than corresponding nutrient content at wider spacings. About 50% of N, P and K were present within the 0–20 cm soil layer, which decreased drastically beyond the 20 cm depth.The results suggest that stand management practices through planting density regulation can modify the resource acquisition patterns of D. strictus which in turn can change growth and productivity considerably. Such information on root activities, spatial and temporal strategies of resource sharing will be helpful in deciding the effective nutrition zone for D. strictus. Further, the study throws light on the spatial distribution of non-competitive zones for productivity optimization yields, especially when intercropping practices are considered.

Effect of Silicon and Nitrogen Nutrition on Pest and Disease Intensity in Rice

Nutrition management is the most important for high yield production but it may affect the response of rice plants to pest and diseases due to the change of microclimate under rice plant canopy. The knowledge of nutrition management and its relation with pest and diseases are basis for setting up a high yield production system. Most of the pest and disease control procedures used by farmers can be considered as soil fertility management and these nutrition practices can have impact on the physiological susceptibility of crop plants to pest and diseases by affecting the plant resistance. Silicon content of plants is particularly effective against pest and diseases in rice and certain rice genotypes are more efficient accumulators of silicon, thus making them more resistant. In the absence of natural heritable resistance in rice varieties, resistance could be induced by altemate strategies to suppress certain pest and pathogens. Hence experiments were carried out in two stages during kharif 2010 and 2011 to assess the concentration of silicon in the index leaves of rice plant utilizing 133 varieties in four locations. The silica content of promising varieties ranged from 1.50% to 3.20%, 1.60% to 3.15%, 1.49% to 3.20% and 1.55% to 3.06% with a mean values of 2.50%, 2.48%, 2.51% and 2.43% at Jagtial, Warangal, Rajendranagar and Rudrur centres of Telangana region and not much variation in mean silica content in index leaves at different places. The overall yield from four locations ranged from 2,653 kg/ha to 6,860 kg/ha with a mean of 5,624 kg/ha. The yields recorded at Jagtial, Warangal, Rajendranagar and Rudrur centres ranged from 2,886 to 7,198, 2,653 to 6,831, 2,653 to 6,860 and 4,399 to 5,950 kg/ha, respectively. The lowest mean yield 5,069 kg/ha was noticed at Rudrur and the highest yield 5,940 kg/ha was found at Warangal. The variations in yields might be due to genotypic variations and also due to variations in climatic conditions of different locations.

Organic matter quality of forest floor as a driver of C and P dynamics in acacia and eucalypt plantations established on a Ferralic Arenosols, Congo

Background: Land-use change and forest management may alter soil organic matter(SOM) and nutrient dynamics,due in part to alterations in litter input and quality. Acacia was introduced in eucalypt plantations established in the Congolese coastal plains to improve soil fertility and tree growth. Eucalypt trees were expected to benefit from N2 fixed by acacia. However, some indicators suggest a perturbation in SOM and P dynamics might affect the sustainability of the system in the medium and long term. In tropical environments, most of the nutrient processes are determined by the high rates of organic matter(OM) mineralization. Therefore, SOM stability might play a crucial role in regulating soil-plant processes. In spite of this, the relationship between SOM quality, C and other nutrient dynamics are not well understood. In the present study, OM quality and P forms in forest floor and soil were investigated to get more insight on the C and P dynamics useful to sustainable management of forest plantations.Methods: Thermal analysis(differential scanning calorimetry(DSC) and thermogravimetry(TGA)) and nuclear magnetic resonance(solid state13 C CPMASS and NMR and31 P-NMR) spectroscopy have been applied to partially decomposed forest floor and soils of pure acacia and eucalypt, and mixed-species acacia-eucalypt stands.Results: Thermal analysis and13 C NMR analysis revealed a more advanced stage of humification in forest floor of acacia-eucalypt stands, suggesting a greater microbial activity in its litter. SOM were related to the OM recalcitrance of the forest floor, indicating this higher microbial activity of the forest floor in this stand might be favouring the incorporation of C into the mineral soil.Conclusions: In relation with the fast mineralization in this environment, highly soluble orthophosphate was the dominant P form in both forest floor and soils. However, the mixed-species forest stands immobilized greater P in organic forms, preventing the P losses by leaching and contributing to sustain the P demand in the medium term.This shows that interactions between plants, microorganisms and soil can sustain the demand of this ecosystem.For this, the forest floor plays a key role in tightening the P cycle, minimizing the P losses.

Characterization of Acidity in Acid Sulphate Soils of Kerala

The acidity characteristics of acid sulphate soils of Kuttanad, Kerala, were studied in detail by collecting surface, profile and subsurface soil samples from 20 locations of six soil series viz., Ambalapuzha, Purakkad, Thotapally, Thuravur, Kallara and - Thakazhi that belonged to acid sulphate soils. The soils were extremely acidic showing a range of pH （H：O） varying from 2.5 to 5.2. Lowest pH was recorded by Thakazhi series and the highest by Thotapally. The potential acidity of soils ranged from 14.71 cmol.kg-1 to 110.5 cmol-kg1 with Thakazhi series showing the highest value. The contribution of hydrolytic acidity to potential acidity ranged from 70.2% to 97.2%. In all soil series, exchangeable A13＋ was greater than exchangeable H~. A significant correlation was observed among pH （KCI）, pH （H20） and pH （CaCI2） in all series.

Resistance and resilience of soil biological indicators:A case study with multi-walled carbon nanotube

Soil ecosystem is experiencing stresses due to climate change,and soil inhabitants try to demonstrate their inherent resistance and resilience against those stresses.Application of nanomaterials as agricultural inputs could bring shifts in resistance and resilience patterns of soil microbes and associated enzymes,especially under short-term heat stress.With this background,the impacts of multi-walled carbon nanotube(MWCNT)on the resistance and resilience of soil biological indicators were evaluated.An incubation experiment was conducted with varied MWCNT concentrations(0,50,100,250,and 500 mg kg-1soil)for 90 d after 24-h heat stress at 48±2?C to assess the impacts of MWCNT on soil enzyme activities and microbial populations vis-à-vis their resistance and resilience indices under short-term exposure to heat stress.Enzyme activities were reduced after exposure to heat stress.Resistance indices of enzyme activities were enhanced by MWCNT application on day 1 after heat stress,whereas there was no recovery of enzyme activities after 90-d incubation.Like soil enzyme activities,resistance index values of soil microbial populations followed the similar trend and were improved by MWCNT application.Multi-walled carbon nanotube has the potential to improve resistance indices of soil enzyme activities and microbial populations under heat stress,although they could not recover to their original state during periodical incubation after heat stress.This study helps to understand the relative changes of biological indicators under MWCNT and their ability to withstand heat stress.

Plant growth-promoting rhizobacteria(PGPR)and its mechanisms against plant diseases for sustainable agriculture and better productivity

Plant growth-promoting rhizobacteria(PGPR)are specialized bacterial communities inhabiting the root rhizosphere and the secretion of root exudates helps to,regulate the microbial dynamics and their interactions with the plants.These bacteria viz.,Agrobacterium,Arthobacter,Azospirillum,Bacillus,Burkholderia,Flavobacterium,Pseudomonas,Rhizobium,etc.,play important role in plant growth promotion.In addition,such symbiotic associations of PGPRs in the rhizospheric region also confer protection against several diseases caused by bacterial,fungal and viral pathogens.The biocontrol mechanism utilized by PGPR includes direct and indirect mechanisms direct PGPR mechanisms include the production of antibiotic,siderophore,and hydrolytic enzymes,competition for space and nutrients,and quorum sensing whereas,indirect mechanisms include rhizomicrobiome regulation via.secretion of root exudates,phytostimulation through the release of phytohormones viz.,auxin,cytokinin,gibberellic acid,1-aminocyclopropane-1-carboxylate and induction of systemic resistance through expression of antioxidant defense enzymes viz.,phenylalanine ammonia lyase(PAL),peroxidase(PO),polyphenyloxidases(PPO),superoxide dismutase(SOD),chitinase andβ-glucanases.For the suppression of plant diseases potent bio inoculants can be developed by modulating the rhizomicrobiome through rhizospheric engineering.In addition,understandings of different strategies to improve PGPR strains,their competence,colonization efficiency,persistence and its future implications should also be taken into consideration.

Bt cotton influencing enzymatic activities under varied soils

The enzymatic activity was evaluated under both Bt and non-Bt systems in varied soil type. The study was conducted during the 2010 wet season (July to December) in a net-house at the Institute of Agricultural Sciences of Banaras Hindu University. It was carried out on three different soil ordersi.e.entisol, inceptisol and alfisol. Bt cotton (cvNCS-138) and its non-transgenic isoline (cvNCS-138) were grown until maturity. A no crop pot was maintained with three replications for all the three soil orders. Study design was a factorial experiment under a completely randomized block design with three replications. The study concludes that soil under Bt cotton cultivar produced significantly higher amount of phosphatase activity than both nonBt and no crop treatments at three growth stages. And the value decreased as the crop growth period advanced. The interaction effect between soil type and Bt-crop was found to be significant in different growth stages throughout the growing season. Results from the study revealed that a significant reduction (9.4%) of the dehydrogenase activity and soil respiration (5%) in the rhizosphere of Bt cotton over non-Bt isoline.

The Golden Spice Turmeric (<i>Curcuma longa</i>) and Its Feasible Benefits in Prospering Human Health—A Review

From the evolution of the mankind, Turmeric has been used in conventional medication. India is in lead for producing, marketing and exporting the Turmeric and its value added products. Curcuma longa (Turmeric) is an Indian rhizomatous medicinal herb from the Zingiberaceae family that is common and widely available across the globe. The components of Turmeric are curcumin, demethoxycurcumin and bisdemethoxycurcumin and these are collectively known as curcuminoids. Curcumin, the active ingredient of Turmeric is generally investigated by the scientific community for its wide range of antioxidant activity, anti-Inflammatory properties and anti-cancer activity, anti-metabolic syndrome activities, neuroprotective activity, antimicrobial effects, anti-arthritis effects, anti-viral effects, anti-asthma and anti-diabetic effects, anti-obesity, cardio and liver toxicity protection activity, anti-depression and anxiety activities. Turmeric has been widely used as a typical household treatment for cough, sore throat, respiratory ailments and could be an effective immunity booster against SARS-CoV-2 therapy during the ongoing pandemic situation. Safety evaluation studies indicate that both turmeric and curcumin are well tolerated at a very high dose without any toxic effects. Thus, turmeric and its constituents have the potential for the development of modern medicine for the treatment of various diseases. So in this review, we describe the various metabolic roles of curcumin and activities for the benefit of human health.

Environmental Fate of Petroleum Hydrocarbons in Soil:Review of Multiphase Transport,Mass Transfer,and Natural Attenuation Processes

The increasing use of petroleum-derived fuels over the last few decades has subsequently augmented the risk of spills in the environment. Soil pollution with petroleum hydrocarbons(principally caused by leaks in pipelines and underground storage tanks) is one of the major sources of soil degradation. Once in soil, fuel hydrocarbons suffer from a wide variety of multiphase processes including transport(advection, diffusion, and dispersion) among and within phases(aqueous and non-aqueous liquid, gas, and soil solids), mass transfer among phases(volatilization, sorption, and solution), and other natural attenuation processes, such as biodegradation and plant uptake and metabolism. This review identifies and describes the major processes occurring in soil that have a significant influence on the environmental fate of petroleum hydrocarbons. The definition of the processes involved in pollutant migration and distribution in soil and the formulation of adequate equations using accurate parameters(e.g., diffusion coefficients, velocity of advective flows, and mass transfer coefficients) will allow prediction of the final fate of soil pollutants. In addition to transport and mass transfer processes,which are more widely studied, the incorporation of attenuation mechanisms driven by microorganisms and plants is essential to predict the final concentration of the pollutants in the whole multiphase scenario. This work underlines the importance of the determination of accurate parameters through the performance of laboratory and/or field-scale experiments to develop precise pollutant migration models.

Benefits of Biochars and NPK Fertilizers for Soil Quality and Growth of Cowpea (Vigna unguiculata L. Walp.) in an Acid Arenosol

Fertilization is required for optimum plant growth, particularly in unfertile soils, while optimizing nutrient use effciency is an alternative to reduce inorganic fertilizer needs and reduce environmental problems caused by nutrient leaching. This study investigated soil properties and cowpea yield responses to biochars(BCs) made from different feedstocks, baby corn peel biochar(BC1), branches of mango tree biochar(BC2), and rice husk biochar(BC3), applied in combination with nitrogen-phosphorus-potassium(NPK) fertilizers.The experiment was conducted in a greenhouse, using an acid sandy soil(Arenosol) that was submitted for 70 d to the following eight treatments: i) control;ii) full dose of NPK(a commercial compound fertilizer(12-24-12 of N-P2O5-K2O)+ urea(46% N));iii) BC1+ half dose of NPK;iv) BC1 + full dose of NPK;v) BC2 + half dose of NPK;vi) BC2 + full dose of NPK;vii) BC3 + half dose of NPK;and viii) BC3 + full dose of NPK. All biochars were applied at a rate of 0.9%(weight/weight), and each type of biochar was combined with half and full doses of NPK fertilizers. Soil pH increased significantly(P < 0.05) in treatments with BC1 and BC2,while cation exchange capacity(CEC) and available P were higher in the treatments with BC1;BC1 and BC2 also induced higher activity of enzymes related to the P cycle and higher cowpea yield. Similar soil properties and cowpea yield parameters were obtained with the full and half doses of NPK fertilizers for each type of biochar used. In conclusion, biochars in the combination with NPK fertilizers improved soil chemistry and enzymatic activities, allowing reduced fertilizer application and food production costs in the acid soil studied.

ACCUMULATION OF TRANSITION METALS IN Fe-Mn CONCRETIONS FROM SELECTED SOILS IN NORTH HUAI REGION,JIANGSU AND ITS ENVIRONMENTAL-GEO-CHEMICAL SIGNIFICANCE

In an attempt to provide more data about the mechanics of transition metal occurrence and translocation in soil environments, Fe-Mn concretions are separated from bulk samples of representative soil types and the element contents are determined. The results are reported and discussed in the sense of environmental geochemistry in this article.

Short-Term Effect of Nitrogen Intensification on Aggregate Size Distribution, Microbial Biomass and Enzyme Activities in a Semi-Arid Soil Under Different Crop Types

There is a lack of quantitative assessments available on the effect of agricultural intensification on soil aggregate distribution and microbial properties. Here, we investigated how short-term nitrogen(N) intensification induced changes in aggregate size distribution and microbial properties in a soil of a hot moist semi-arid region(Bangalore, India). We hypothesised that N intensification would increase the accumulation of macroaggregates > 2 mm and soil microbial biomass and activity, and that the specific crop plant sowed would influence the level of this increase. In November 2016, surface(0–10 cm) and subsurface(10–20 cm) soil samples were taken from three N fertilisation treatments, low N(50 kg N ha-1), medium N(75 and 100 kg N ha-1 for finger millet and maize, respectively),and high N(100 and 150 kg N ha-1 for finger millet and maize, respectively). Distribution of water-stable aggregate concentrations,carbon(C) and N dynamics within aggregate size class, and soil microbial biomass and activity were evaluated. The high-N treatment significantly increased the concentration of large macroaggregates in the subsurface soil of the maize crop treatment, presumably due to an increased C input from root growth. Different N fertilisation levels did not significantly affect C and N concentrations in different aggregate size classes or the bulk soil. High-N applications significantly increased dehydrogenase activity in both the surface soil and the subsurface soil and urease activity in the surface soil, likely because of increased accumulation of enzymes stabilised by soil colloids in dry soils. Dehydrogenase activity was significantly affected by the type of crop, but urease activity not. Overall, our results showed that high N application rates alter large macroaggregates and enzyme activities in surface and subsurface soils through an increased aboveground and corresponding belowground biomass input in the maize crop.

Increased phosphorus availability to corn resulting from the simultaneous applications of phosphate rock, calcareous rock, and biochar to an acid sandy soil

Phosphorus(P)deficiency is one of the main constraints on crop production in Arenosols(acid sandy soil).The high cost of P fertilizers may represent an insurmountable obstacle in many poor countries,leaving the exploitation of their own calcareous and phosphate rocks as the only low-cost and long-term alternative.Biochar is suggested to have positive effects on soil properties;however,there is no published research on the synergistic effects of biochar and rocky materials in modifying soil properties.The aim of this study was to investigate the chemical and biochemical responses of an acid Arenosol treated with phosphate rock(PR),calcareous rock(CR),and biochar(BC),and the implications for corn yield.A soil from Marracuene District,Mozambique was used,where corn was grown for 90 d with the soil treated with:no addition(control),water-soluble zinc phosphite fertilizer(WSP),PR,WSP+CR,WSP+BC,WSP+CR+BC,PR+BC,and PR+CR+BC.Biochar was produced by pyrolysis of babycorn peels for 4 h at 450?C and applied at 11 g kg-1.The soil pHH2 Oincreased from about 4.54 in the control to 7.38 in the PR+CR+BC treatment.Easily oxidizable organic carbon,cation exchange capacity,and available P were higher in the treatments containing BC than in the control.The treatments containing CR and/or BC led to the highest activities of alkaline phosphomonoesterase,phosphodiesterase,andα-glucosidase,which increased P availability and gave the greatest biomass and yields.We suggest that biochar provides additional soluble P and supplies adsorption sites for phosphate,preventing its evolution to unavailable forms.Thus,PR applied together with BC contributed to an 840%yield increase compared to the control.The treatments containing WSP and BC facilitated phosphite oxidation to phosphate and increased crop yield.

Assessment of Potential Nutrient Release from Phosphate Rock and Dolostone for Application in Acid Soils

Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feasibility of using phosphate rock and dolostone as fertilizers or acid-neutralizing agents for application in tropical acid soils. The dissolution rates of different particle-size fractions(0.063–0.25, 0.25–0.5, and 0.5–2 mm) of both rocks were studied by citric acid solution at p H 4 and 2 and water, with extraction times of 1, 3, 5, 7, 12, 24, 72, 144, 240, and 360 h. The results showed that the dissolution of both rocks depended on the particle size,leaching solution, and extraction time. The dissolution rate of rock-forming minerals increased as the specific surface area increased,corresponding to a decrease in particle size. In all cases, the release kinetics was characterized by two phases: 1) a first stage of rapid release that lasted 24 h and would ensure short-term nutrient release, and 2) a second stage of slow release after 24 h, representing the long-term nutrient release efficiency. Both rocks were suitable as slow-release fertilizers in strongly acid soils and would ensure the replenishment of P, Ca, and Mg. A combination of fine and medium particle-size fractions should be used to ensure high nutrient-release efficiency. Much work could remain to determine the overall impact of considerable amounts of fresh rocks in soils.

MSSBAUER STUDY OF MAGNETISM AND CONTENT OF KRASNOZEM MAGNETIC MINERALS

The magnetism and content of soil magnetic minerals are the foundation of the soil magnetic genesis research and the application of the soil magnetism to the applied geophysics, archaeology and the environmental science. According to Mssbauer spectra

Evidence of functional and structural changes in the microbial community beneath a succulent invasive plant in coastal dunes

Coastal dunes represent priority habitats for conservation due to the provision of valuable ecosystem services such as land protection,water supply or biodiversity conservation.Soil microbial communities are of crucial importance to maintain plant diversity due to harsh environmental conditions,water limitation and nutrient scarcity.Invasive alien plants represent a major threat to ecosystem conservation.Here,we explored different impacts of Carpobrotus edulis,a succulent plant invading coastal areas worldwide,on the function and structure of bacterial communities.Sand represents a challenging substrate due to low organic matter content and limited microbial activity.We optimized bacterial extraction for functional evaluation before assessing ecosystem impacts produced by C.edulis.We compared 12 extracting procedures combining different soil storage,sample amount and extracting solutions on the functional activity of sand communities through the community-level physiological profile.We further explored the function(using Biolog Ecoplates)and structure[using polymerase chain reaction–denaturing gradient gel electrophoresis(PCR-DGGE)]of bacterial communities from dunes invaded by C.edulis.Saline solution consistently increased bacterial cells detected by cytometry(P≤0.001).Principal component analysis suggested a limited temporal framework(0–24 h)in which community function can be explored without significant alterations in C substrate consumption.Changes under C.edulis invasion exhibited a different pattern of C substrate utilization comparing native and non-native zones(interspecific),but also between native zones(intraspecific),suggesting that functional impacts are site-dependent.Complementary,results obtained from PCR-DGGE indicated that the bacterial community structure of native dunes significantly differed from dunes invaded by C.edulis.

QTL and QTL × Environment Effects on Agronomic and Nitrogen Acquisition Traits in Rice

Agricultural environments deteriorate due to excess nitrogen application. Breeding for low nitrogen responsive genotypes can reduce soil nitrogen input. Rice genotypes respond variably to soil available nitrogen. The present study attempted quantification of genotype x nitrogen level interaction and mapping of quantitative trait loci （QTLs） associated with nitrogen use efficiency （NUE） and other associated agronomic traits. Twelve parameters were observed across a set of 82 double haploid （DH） lines derived from IR64/Azucena. Three nitrogen regimes namely, native （0 kg/ha; no nitrogen applied）, optimum （100 kg/ha） and high （200 kg/ha） replicated thrice were the environments. The parents and DH lines were significantly varying for all traits under different nitrogen regimes. All traits except plant height recorded significant genotype × environment interaction. Individual plant yield was positively correlated with nitrogen use efficiency and nitrogen uptake. Sixteen QTLs were detected by composite interval mapping. Eleven QTLs showed significant QTL × environment interactions. On chromosome 3, seven QTLs were detected associated with nitrogen use, plant yield and associated traits. A QTL region between markers RZ678, RZ574 and RZ284 was associated with nitrogen use and yield. This chromosomal region was enriched with expressed gene sequences of known key nitrogen assimilation genes.

Variable rate fertilizer application technology for nutrient management:A review

The efficient and effective application of fertilizers to crops is a major challenge.Conventionally,constant rate or equal dose of fertilizer is applied to each plant.Constant rate fertilizer application across entire field can result in over or under incorporation of nutrients.Fertilizer application is influenced by soil parameters as well as geographical variation in the field.The nutrient management depends on selection of nutrient,application rate and placement of nutrient at the optimal distance from the crop and soil depth.Variable rate technology(VRT)is an input application technology that allows for the application of inputs at a certain rate,time,and place based on soil properties and spatial variation in the field or plants.There are two approaches for implementing VRT,one is sensor based and another is map based.The sensor based approach;with suitable sensors,measures the soil and crop characteristics on-the-go calculating the amount of nutrients required per unit area/plant and micro controlling unit which uses suitable algorithms for controlling the flow of fertilizer with required amount of nutrient.In map based approach;Grid sampling and soil analysis are used to create a prescription map.According to the soil and crop conditions,the microcontroller regulates the desired application rate.The sensor-based VRT system includes a fertilizer tank,sensors,GPS,microcontroller,actuators,and other components,whereas the map-based system does not require an on-the-go sensor.Both approaches of VRT for fertilizer application in orchards and field crops are reviewed in this paper.The use of this advance technology surely increases the fertilizer use efficiency;improve crop yield and profitability with reduced environment impacts.