查看更多>>摘要：Mycorrhizas are known to improve host plant nutritional status as a consequence of water transport from the soil to the host plant through the external mycelium as a direct effect or improved host plant nutrition primarily, phosphorus as an indirect effect. The direct hyphal water transport is quantified to be meager and a major part of the benefits of mycorrhizal symbiosis is indirect and nutritionally related. In arid and semi-arid regions where drought occurrence is very frequent and soil moisturecontent is highly restricted, mycorrhizas can assist in exploiting the soil beyond the rhizosphere that helps the host plant to withstand drought stress conditions. The drought tolerance in mycorrhiza-inoculated plants is quite complex and such responseis due to a series of processes such as improved nitrogen(N) availability in soils, extensive root surface area and cationic exchange capacity, collective N assimilatory pathways in plant-mycorrhizal system,luxuriant uptake of nutrients besides remobilization of nutrients to support grain growth. These physiological, biochemical, nutritional and morphological changes in the mycorrhizas associated host plants have contributed to the ability of the host plants to survive under limited water environments.Despitemycorrhiza-assisted and N nutritionally enabled host plant drought tolerance is evident, more research is required to gain insights into the mechanisms involved. This review highlights the role of mycorrhizas on N dynamics in the rhizosphere andenhanced host plant N nutrition that collectively contributes to the sustained crop productivity under drought stress conditions.
查看更多>>摘要：The study was conducted to determine the correlation coefficients amongthe grain yield and yield contributing characters in 14 parental lines (4 linesand 10 testers) and their 40 hybrids of pearl millet. Positive and significantcorrelations were observed for 1000 seed weight followed by fodder yieldper plant, harvest index, earhead girth, number of effective tillers per plant,earhead length and plant height while, negative association with days to 50%flowering at both genotypic and phenotypic level with grain yield per plant.Based on correlations analysis, it is concluded that the selection for thesecharacters would help improve the yield potential of pearl millet.
查看更多>>摘要：A field experiment was conducted during late Kharif (September-November)of the year 2018 at Eastern Block Farm, Tamil Nadu Agricultural University,Coimbatore to find out the effect of agronomic bio-fortification with zinc onphysiological parameters, nutrient uptake, yield and economics of babycornunder irrigated condition. The field experiment was laid in randomizedcomplete block design with three replications. The treatments comprised ofT1: No zinc (control), T2: Zinc Sulphate (ZnSO4) at 25 kgha-1 as soil application,T3: ZnSO4 at 37.5 kgha-1 as soil application, T4: Foliar spray of ZnSO4 at 0.5%on 20 and 40 DAS, T5: Foliar spray of ZnSO4 at 1.0% on 20 and 40 DAS,T6: ZnSO4 at 25 kgha-1 as soil application + foliar spray at 0.5% on 20 and40 DAS, T7:ZnSO4 at 25 kgha-1 as soil application + foliar spray at 1.0% on20 and 40 DAS,T8: ZnSO4 at 37.5 kgha-1 as soil application + foliar sprayat 0.5% on 20 and 40 DAS,T9: ZnSO4 at 37.5 kgha-1 as soil application +foliar spray at 1.0% on 20 and 40 DAS. Babycorn hybrid G-5414 was usedto experiment with a plant spacing of 45 cm x 25 cm. The results showedthat the combined application of zinc sulphate @ 37.5 kgha-1 with 0.5%foliar spray at 20 and 40 DAS recorded significantly higher Crop GrowthRate (CGR) (31.07,30.83) gcm-2day-1, Relative Growth Rate (RGR) (110.25,31.67) mgg-1day-1 and Net Assimilation Rate (NAR) (9.65, 4.54) mgcm-2day-1at 25-45 DAS and 45 DAS - harvest intervals respectively. NPK uptake wasrecorded higher in (T8) and green cob yield was recorded higher in (T9) atharvest stage. Green fodder yield and higher benefit cost ratio was obtainedhigher with soil application of zinc sulphate @ 37.5 kgha-1 with 0.5% foliarspray at 20 and 40 DAS.
查看更多>>摘要：Field experiments were conducted during 2017 – 2018 to develop fertiliserprescriptions equations (FPEs) through IPNS for the desired yield targets ofChrysanthemum on Udic Haplustalf . The fertilisers prescription equations(FPEs) were developed underNPK alone and under IPNS for the desiredyield target of Chrysanthemum by using the basic parameters. The variationobserved in the achievement of targets was within the range of ± 10 per cent(90 – 110%) proving the validity of FPEs. Hence, the Inductivecum Targetedyield approach applied to develop fertiliser equations provides a strong basisfor maintenance of soil fertility with high productivity and efficient nutrientmanagement in “Precision Farming” for sustainable and enduring Agriculture.
查看更多>>摘要：High temperature is a critical barrier in most cotton growing areas, limitingcotton growth and development. The present study aimed to evaluate theeffects of foliar spray on KC 3 cotton variety grown under ambient (32.66°C)and high temperature (37.21°C) stress in open-top chamber (OTC) with atemperature of 5°C from the ambient temperature for 10d from flowering toboll development stage. Foliar spray of kaolin @ 3% and calcium carbonate @5% were sprayed separately to the set of pots both in ambientand elevatedtemperature on 70th day of flowering. Observations on morphological andphysiological parameters were recorded on viz., plant height (cm plant-1), leafarea (cm2 plant-1), relative water content (%), canopy temperature (°C), SPAD,chlorophyllfluorescence (Fv/Fm ratio). Kaolin @ 3% foliar spray significantlyincreased the plant height, leaf area, relative water content, chlorophyllcontent and reduced the canopy temperature both in high temperature andambient temperature conditions. Among thesetreatments, T2 - kaolin 3%(Ambient) followed by T5 - Kaolin 3% (elevated temperature of 5 °C) recordedhigher values as compared to calcium carbonate treatment both in ambienttemperature and high temperature condition.
查看更多>>摘要：High temperature stress is a major environmental factor that affects cropgrowth, development and yield, it especially limits rice yield. Hence, anexperiment was conducted to study the impact of high temperature onmorpho-physiological parameters and yield of rice genotypes. Ten ricegenotypes were used in this study viz., N22, ADT 36, ADT 37, ADT 43, ADT45, CO 51, ASD 16, MDU 6, TPS 5 and Anna (R) 4. The study was carriedout at OTC (Open Top Chamber) with the treatments of ambient, ambient+2O C and ambient +4O C. Stress was imposed from anthesis to early grainfilling period. Observations on plant height, the number of tillers, leaf area,SPAD (Chlorophyll index) and chlorophyll stability index (CSI) were done afterthe stress imposement and grain yieldwas calculated after harvest. Resultsrevealed that, the significant changes were observed in morpho-physiologicaltraits and grain yield of rice genotypes among the treatments and with thegenotypes. N22 (10% and 19%) and Anna (R) 4 (12% and 22%) recordedless reduction of grain yield in ambient +2O C and ambient +4O C comparedwith ambient, due to less reduction of total chlorophyll content, SPAD values,leaf area and increased plant height. These parameters resulted in higherbiomass which indirectly contributed to higher grain yield in N22 and Anna(R) 4 under high temperature.
查看更多>>摘要：Field investigations were conducted to assess the effect of conservationagricultural practices on soil biological properties and yield of cotton duringthe kharif season of 2018 and 2019. The experiments were laid out in asplit plot design with four main factors viz., conventional tillage with irrigationschedule of 0.8 IW/CPE ratio (M1), conventional tillage with irrigationschedule of 0.6 IW/CPE ratio (M2), minimum tillage with irrigation scheduleof 0.8 IW/CPE ratio (M3) and minimum tillage with irrigation schedule of0.6 IW/CPE ratio (M4). Sub plot had six treatments of weed and nutrientmanagement viz., crop residue mulch with 100% RDF (S1), crop residuemulch with 75% RDF (S2), pre-emergence application of pendimethalinfb one hand weeding with 100% RDF (S3), pre-emergence application ofpendimethalin fb one hand weeding with 75% RDF (S4), mechanical weedingtwice with 100% RDF (S5) and mechanical weeding twice with 75% RDF (S6).Total microbial populations viz., bacteria, fungal, and actinobacteria werehigher in cotton rhizosphere soil with the minimum tillage of irrigation at0.8 IW/CPE ratio (M3) in the main plot treatments. Cotton rhizosphere soilwith crop residue mulch with 100% RDF (S1) recorded a higher microbialpopulation and it was statistically similar with pre-emergence applicationof pendimethalin fb one hand weeding with 100% RDF (S3) in the subplot treatments. Among the treatment combination, minimum tillage withirrigation at 0.8 IW/CPE ratio (M3) and crop residue mulch with 100% RDF(S1) recorded a higher microbial population. Similarly, a higher seed yieldof cotton was also recorded with minimum tillage and irrigating the crop at0.8 IW/CPE ratio and pre-emergence application of pendimethalin fb onehand weeding along with application of 100% RDF (M3S3).
查看更多>>摘要：Field experiments were conducted at Coconut Research Station, Aliyarnagarduring 2016 – 2019 to assess the performance of rice-based croppingsequences for water-scarce conditions of the Parambikulam Aliyar ProjectCommand area of Tamil Nadu. Five cropping sequences viz., rice–sesame(T1), rice–groundnut (T2), rice– sunflower (T3), rice–castor (T4) and rice–blackgram (T5) were experimented adopting Randomized Block Design with eachsequence replicated four times. Results revealed that compared to the othernon-legume sequences experimented, the contents of KMnO4-N and organiccarbon in the post harvest soil, productivity of rice and economic efficiencywere higher in rice–black gram followed by rice–groundnut sequence. Rice–castor sequence recordedthe highest land utilization efficiency of 76.7 %and was the lowest in rice–black gram sequence (53.4 %). Rice equivalentyield was the highest on sequential cropping with sunflower (5755 kg ha-1)followed by groundnut (5028 kg ha-1). Production efficiency was the highest inrice– groundnut (47.5 kg ha-1 day-1) followed by rice–castor (42.5 kg ha-1 day-1) systems. Net returns and benefit-cost ratio were higher in rice–sunflowerand rice–black gram sequences followed by rice–groundnut and was thelowest in rice–sesame sequence. In terms of soil fertility, system productivityand economic returns, rice–sunflower, rice–black gram and rice–groundnutsystems are highly remunerative for water-scarce conditions of ParambikulamAliyar Command Area of TamilNadu.
查看更多>>摘要：Ground water quality of Horticultural College and Research Institute (HC & RI), Periyakulam located in Theni District, Tamil Nadu was assessed during January 2021. Ground water samples were collected from bore wells and their quality parameters were assessed. pH values ranged from 6.88 to 7.81; electrical conductivity values ranged from 0.20 to 1.28 dSm~(-1) and most of the samples were under high salinity class (C3) (84.6%). Calcium, magnesium, sodium and potassium content ranged from 1.68 to 4.72 m.e L~(-1), 0.72 to 10.6m.e L-1, 1.35 to 10.3 m.e L-1 and 0.05 to 0.23 m.e L~(-1) respectively. Most of the samples were found to be magnesium dominating and magnesium exceeds the calcium content in most of the water samples. Magnesium toxicity will be exhibited in the continuous use of water to crops. No carbonates were noticed. Bicarbonates, chloride and sulphate concentration varied from 2.0 to 13.4 m.e L-1 , 1.12 to 7.52 m.e L~(-1) and 0.02 to 0.99 m.e L-1 respectively. The sequence of cations were found in the order of Mg~(2+) >Na~+> Ca~(2+) >K~+ and anions followed the sequence of HCO~(3-) >Cl~- > SO_4~(2-). Total hardness in the study area varied from 120 to 686 mg L-1 and majority of the samples (61.5 %) were very hard. RSC values varied from -3.76 to 5.24 meL~(-1) and most of the samples come under the moderate category (61.5%) followed by safe (38.5%). RSBC varied from 0.32 to 9.48 m.e L~(-1) and majority of the samples come under the safe category (61.5%) followed by unsafe (23.1%) and moderate (15.4%). SAR valuesranged from 0.83 to 5.11 and all the samples were found to be low sodium category (S1). There is no sodicity problem existing in the ground waters. In the present study, the permeability index ranged from 39.4 to 80.3 per cent and the majority of the samples come under the permeability hazard class II, which can be used for irrigation without any permeability problem in the soils. As per CSSRI, Karnal classification, majority of the ground water samples coming under good (76.9), followed by marginallyalkaline (15.4%) and alkaline (7.7%). Marginally alkaline and alkaline waters should be managed carefully to avoid a negative impacts on soil and crops.
查看更多>>摘要：In order to assess the effect of graded levels of applied magnesium (Mg)(0, 5, 10, 15, 20 and 25 kg ha-1) on the soil available major nutrients, fieldexperiments were conducted in 14 farmer’s holdings at Pudukkottai districtwith hybrid maize (NK 6240) as a test crop. Dry matter production (DMP) ofthe whole plant (above ground) at harvest stage of maize was significantlyinfluenced by the application of 100% NPK + 10 kg Mg ha-1 and recorded thehighest mean as 25620 kg ha-1 at harvest stage. A noticeable increase ingrain and stover yield of maize crop was manifested by applying 100% NPK+ 10 kg Mg ha-1 which recorded the highest mean yield as 11.6 t ha-1 and14.0 t ha-1, respectively. It reported a 14.31 and 22.25 per cent increase ingrain and stover yields, respectively, over control.
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