Chlorophyll Meter Research Articles

Heavy Metals Analysis of Breweries Effluent used in Soil Cultivated with Glycine Max (L.) Merr. Accessions with Biochar Augmentation

Beer production has promulgated the prevalence of heavy metal contamination in the environment (soil and water bodies). The magnitude of breweries wastewater-effluent effect discharged on soil and its effect on crop quality in terms of growth and physiology must therefore be investigated. This study aims to assess the level of seven heavy metals (HM) (lead (Pb), nickel (Ni), chromium (Cr), copper (Cu), cadmium (Cd), zinc (Zn) and iron (Fe)) in breweries wastewater-effluent and its effect on the growth of Glycine max accessions (TGM-3990, TGM-1348, TGM-1732, TGM-2175 and TGM-928) as well as the influence of biochar soil amendment in the induction of HM tolerance in G. max. Effluent properties were analyzed using the A1 portable TDS/EC meter. HM in the wastewater-effluent was determined using Atomic Absorption Spectrometer (AAS). The experiment was set up in a complete block design. 3 seeds G. max accessions were planted in 7kg of sterilized soil (control, effluent and biochar treatments). Growth parameters were taken using standard methods, while the total photosynthetic pigments (TPP) were determined using the atLeaf chlorophyll meter. The wastewater-effluent recorded an electrical conductivity (EC) of 928µS/cm, total dissolved solids (TDS) (464ppm), Temperature (31.9-32.6°C) and pH (5.37). Results for HM concentration showed; Pb (0.20mg/L), Ni (<0.001mg/L), Cr (0.03mg/L), Cu (<0.001mg/L), Cd (<0.001mg/L), Zn (<0.001mg/L) and Fe (8.74mg/L). The trend shows that Fe˃Pb˃Cr˃Cd˃Cu˃Ni˃Zn. Cr, Cd, Cu, Ni and Zn were significantly below the World Health Organization (WHO) and Waste Water Forum (WWF) permissible limit, while Fe and Pb significantly higher. G. max accessions TGM-928 (80%) and TGM-3990 (80%) had better germination percentage (GP), TGM-1348 (60%) had the lowest GP, while TGM-2175 recorded no germination in all treatments. At 6 weeks after planting (WAP), it was observed that irrigation of G. max accessions with breweries wastewater-effluent significantly (p=0.001) stimulated growth parameters such as shoot length for TGM-3990 which recorded; Treatment=19.53±0.94cm; Control=17.10±0.67cm; Biochar=40.83±1.01cm) while TGM-1732 had the highest shoot growth (T=38.57±1.53cm; C=25.00±0.00cm; B=82.33±5.70cm) when compared to their controls. TGM-3990 (T=32.20mg/kg, C=34.10mg/kg, 43.30mg/kg) recorded the least TPP contents, while TGM-928 (T=51.00mg/kg, C=45.60mg/kg, B=43.50mg/kg) recorded the highest TPP in all treatments. Amelioration of soil with biochar significantly (p=0.001) stimulated growth above the effluent treatment and control. Similar trend was observed for leaf area, petiole length, leaf number, stem girth and internode length. This study has shown that breweries effluent has the potential of growth enhancement in G. max cultivation and in combination biochar application reduces the need for additional fertilizer application.

Effects of LED treatments on the growth and nutritional content of lettuce (Lactuca sativa) in a hydroponic vertical farming system

Introduction: LED-integrated hydroponic vertical farming system (HVFS) may address food security challenges arising from urbanisation, while antioxidants in vegetables may prevent cardiovascular disease. This study aimed to explore the LED effects on yield, antioxidant properties, and vitamin C content in Butterhead lettuce (BL) and Italian lettuce (IL). Methods: Three LED combinations were used: 77% red, 14% green, and 9% blue lights (77R:14G:9B); 7% red, 41% green, and 52% blue lights (7R:41G:52B); and 25% red, 67% green, and 8% blue lights (25R:67G:8B). The concentration and pH of nutrient solution in HVFS ranged from 0.878-2.061ppm and 6.0-6.6, respectively, with a 12:12 light-dark cycle. Chlorophyll and anthocyanin contents were measured using chlorophyll and anthocyanin meters, respectively. Total phenolic and vitamin C content were measured using Folin-Ciocalteu colorimetric assay. Total flavonoid and antioxidant activity were determined through aluminium chloride colorimetric assay and 2,2-diphenyl-1-picrylhydrazyl (DPPH) colorimetric assay, respectively. Completely randomised design was adapted with three replications. Results: BL exhibited greater yield, anthocyanin and chlorophyll contents, while IL had higher vitamin C content. Significantly (p<0.001) higher yields were produced under 77R:14G:9B and 25R:67G:8B. Significantly higher phenolic (p<0.001) and flavonoid (p=0.003) contents were produced under 25R:67G:8B. Vitamin C was significantly (p=0.037) higher under 25R:67G:8B than 7R:41G:52B. Conclusion: LED treatment with higher proportion of red light generated greater yield, whereas higher proportion of green light gave higher phenolic, flavonoids, and vitamin C accumulation. This study provided preliminary data on boosting crop yield and phytochemical contents, which may improve food self-production and population health.

Precision harvesting technology of flue-cured tobacco based on SPAD value

The correct control of the maturity of flue-cured tobacco leaves is an important guarantee for improving the intrinsic quality of tobacco leaves, and it is also the premise for ensuring and improving the quality and external quality of cured tobacco leaves. In order to quantify the maturity of flue-cured tobacco, the chlorophyll meter was used to measure the leaves with different harvesting maturity levels of the middle and upper leaves, and the correlation between the measured value of chlorophyll meter (SPAD) and chlorophyll, yield and output value was established, and the precise harvesting technology of fixed leaf position was verified. The results showed that the SPAD values of the 3rd, 6th, 9th and 12th leaves had a linear relationship with the chlorophyll content, reaching a significant level, and the SPAD values of the four leaf positions showed a quadratic curve relationship with the yield quality of the cured tobacco leaves, and the SPAD threshold when the yield quality was optimal was obtained through the regression equation, combined with the measured SPAD values of each leaf position, the prediction interval of the SPAD values of the four leaf positions was as follows: 3rd leaves (10.9, 15.0), 6th leaves (13.7, 17.3), 9th leaves ( 16.9, 20.6), 12th leaves (20.7, 24.0), the tobacco leaves harvested at this time are 8~10 mature, the maturity is good, the yield quality of tobacco leaves is high, and the maturity grade of the middle and upper leaves is higher.

Effect of Composted Organic Waste on Miscanthus sinensis Andersson Yield, Morphological Characteristics and Chlorophyll Fluorescence and Content

The aim of this research was to determine the impact of composted mushroom substrate and composted municipal waste on the quality and yield of Miscanthus sinensis Andersson biomass. The plant was grown on anthropogenic soil, cultured earth type and hortisol subtype, with a pH of 6.81. Before planting rhizomes, experimental plots were treated with composted mushroom substrate and composted municipal waste, applied separately or in combination, each dose introducing 170 N kg·ha−1 to the soil. During the experiment, observations of plant development and growth were carried out, and the yield was determined. Each growing season’s measurements were taken of the grass height, the number and diameter of stems and the number of leaf blades and of nodes per stem. In order to determine the level of plant stress, relative chlorophyll content and chlorophyll fluorescence parameters were determined. The measurements were carried out in a non-invasive way, using the SPAD-502 chlorophyll meter and OS30p+ plant stress meter. For the research hypothesis, it was assumed that the one-time addition of composted mushroom substrate and composted municipal waste to the soil would increase yields. The experiment also aimed to assess the impact of both types of compost on the yield and morphological characteristics of Miscanthus sinensis. Its yields increased steadily, and, in the third year of cultivation, were higher by 52%. The highest average yields were noted on plots fertilized only with composted mushroom substrate (KPP100%), with 8.44 Mg·ha−1 DM, and with compost from municipal waste (KOM100%), with 7.91 Mg·ha−1 DM. The experience presents a solution to the problem of increasing amounts of organic waste and represents an improvement in cultivation techniques to increase crop yields, improve their quality and increase resistance to biotic and abiotic stress. This paper highlights the possibility of applying environmentally friendly organic waste materials to energy crops used as a sustainable energy source.

Real Time Nitrogen Management of Maize using CCM 200 Plus During Dry Season in Eastern Coastal Plains of India

Despite the increasing availability of chlorophyll meters in the market, their adoption remains limited due to the absence of region-specific thresholds. One such meter, the CCM 200 plus produced by Opti-Sciences Inc., stands out for its non-destructive nature, cost-effectiveness and reliability. However, specific thresholds for this meter in the eastern coastal plains of India, particularly for maize crops, are lacking. The current study was carried out at the P.G. Research Farm, MSSSoA during summer season of 2022-23 encompassing three chlorophyll content indices (CCI less than 35, CCI less than 40, CCI less than 45) with and without basal nitrogen applications, alongside fixed-time nitrogen management (FTNM) and Absolute N Control (no nitrogen) which were allocated in randomized block design with three replications. The findings indicated that both CCI less than 45 with basal nitrogen application and CCI less than 40 with basal nitrogen application demonstrated statistically similar maize grain yields, surpassing FTNM by 18.1% and 12.4%, respectively. However, adopting CCI less than 40 with basal nitrogen application resulted in savings of 30 kg N/ha compared to CCI less than 45 with basal nitrogen application for maize cultivation in the Eastern Coastal Plains of India.

Response of tomato to innovative organo-mineral fertilizers

Organo-mineral fertilizers (OMFs) with low organic carbon (Corg) content have been associated with higher mineral fraction nutrient use efficiency. However, the extraction of peat, which is typically used in these OMFs, from endangered ecosystems causes long-time stored Corg to mineralize and to be released back into the atmosphere as carbon dioxide (CO2). This study analyzes the replacement of peat in OMFs with biowaste materials. These materials, considered organic byproducts that microorganisms and other living things can decompose through composting and aerobic or anaerobic digestion, offer a viable opportunity. This study investigated three stabilized biowastes—green compost (GC) from pruning residues, municipal solid waste compost (MSWC), and manure-based vermicompost (VC)—as the organic matrices for granular OMFs. These matrices were impregnated with dissolved ammonium sulfate and urea and used to coat diammonium phosphate granules. Each biowaste OMF contained 7.5% Corg, 20% mineral N, and 10% mineral P2O5 (OMF20 − 10). Fertilizers with high nutrient concentrations have the advantage of requiring low application volumes, facilitating their application in the field. Biowaste OMFs were compared with peat OMFs with the same Corg-N-P2O5 concentration. Peat and MSWC were also used to create OMFs containing 7.5% Corg, 10% mineral N, and 5% mineral P2O5 (OMF10 − 5). A 75-day tunnel trial was conducted under semi-controlled conditions using tomato plants (Solanum lycopersicum L.) fertilized to an equivalent of 81 mg N kg−1 soil and 18 mg P kg−1 soil. Controls included no fertilization (N0P0) and mineral N and P fertilization (MFNP). The Soil Plant Analysis Development (SPAD) chlorophyll meter and the BBCH (from German Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie) scale as well as the number of shoots were measured over time, as berry and total aboveground yield, N and P uptakes, and N and P use efficiencies (NUE and PUE, respectively) were calculated at harvest. All treatments outperformed the control N0P0 in most indicators. Peat20 − 10 did not have more berry yield than other OMF20 − 10; however, the higher number of shoots indicated a higher potential yield in the event of prolonging the experiment. At the end of 75 days, VC20 − 10 and MSWC20 − 10 showed similar PUE to peat, suggesting that those materials can be used as replacements. In the case of OMF10 − 5, MSWC10 − 5 had yield and N and P uptakes like peat OMFs, confirming the potential use of MSWC as peat replacement even at different nutrient concentrations. This research provides reassuring evidence of the effectiveness of biowaste OMFs, offering a positive outlook for sustainable agriculture. However, their use is not recommendable for short growing seasons.

Proximal canopy sensing of twenty-two bread wheat genotypes for nutritional quality, yield attributes and grain yield under Mediterranean climate

To ensure nutritional security of rapidly increasing population, research interest has revitalized in determining the nutritional quality traits of staple food crops, especially wheat. Besides higher yield potential, research gaps exist regarding nutritional quality assessment of promising wheat genotypes grown under the Mediterranean climate. A field study was conducted to determine the relationship between yield components and quality characteristics of 22 bread wheat genotypes using the SPAD meter, GreenSeeker (NDVI), and CM-1000 chlorophyll meter at different growing stages (Stem elongation, Heading, Anthesis and Milk stage). The recorded findings revealed that G-41 genotype surpassed the rest of bread wheat genotypes by recording the maximum grain yield, whereas G-60 genotype exhibited the highest protein and wet gluten content. Among response variables, SPAD and NDVI values at the heading stage and CM-1000 values at the milk stage were found to be statistically insignificant. According to the correlation and biplot analysis, a significant positive correlation was found between the SPAD values measured for the stem elongation, anthesis and milk stage and yield and quality characteristics. Significant positive correlations were found between the NDVI values at the stem elongation, anthesis, and milk stages and the yield components, and between the CM-1000 value at the heading stage and the grain yield.

Cultivar effect on proximal optical sensor measurements and estimation of leaf N content in muskmelon and sweet pepper

In intensive vegetable crops, there is a requirement for monitoring tools that assess crop nitrogen (N) status to reduce N use and the potential for nitrate (NO3-) leaching loss. Monitoring with proximal optical sensors can regularly provide information to vegetable growers to assist with optimal crop N management. Reference values for proximal optical sensor measurements that indicate crop N sufficiency or deficiency are increasingly available in the literature. Available values are species specific; however, their use may be problematic if proximal optical sensor measurements are affected by cultivar. Little is known on whether differences between cultivars, within a species, affect optical sensor measurements and their relationships with crop N status, particularly in vegetable crops. This study evaluated the effect of cultivar on a) measurements with the SPAD-502 chlorophyll meter, Normalized Difference Vegetation Index (NDVI) measured with the Crop Circle ACS 470 canopy reflectance sensor, and Nitrogen Balance Index (NBI-R) measured with the Multiplex fluorimeter, and b) the relationships of these measurements with leaf N content. The study was conducted with four cultivars of muskmelon (Tezac, Bosito, Magiar and Jacobo) and three of sweet pepper (Melchor, Machado and CLX PLRJ 731). In both muskmelon and sweet pepper, there were significant differences between cultivars in SPAD and in NBI-R. The range of differences between the cultivars was 2.2−9.7 and 0.6−2.8 SPAD units in muskmelon and sweet pepper, respectively, and 0−0.16 and 0.020.08 NBI-R units in muskmelon and sweet pepper, respectively. Significant differences between cultivars in the NDVI were only obtained in muskmelon; the range of differences between the four cultivars was 0.01–0.04 NDVI units. The relatively large cultivar effect with SPAD and NBI-R values with muskmelon may limit the use of reference values in this species. For avoiding cultivar effects in the two species evaluated, NDVI is preferrable to SPAD and NBI-R. In general, the slopes and intercepts of linear relationships between optical sensor measurements and leaf N content, for each cultivar of each species, were not significantly different to the slope and intercept of the relationship calculated with pooled data of all cultivars of each species. This indicated that the sensitivity of optical sensors to assess leaf N content was similar between cultivars of each species.

Growth Responses of Okra (Abelmoschus esculentus L. Moench) to Selected Plant Growth Regulators

This study was conducted to evaluate the effects of two types of plant growth regulators (PGRs) which are gibberellins (GA3) and Paclobutrazol (PBZ) on the growth and photosynthetic pigment (chlorophyll) of Okra (Abelmoschus esculentus L. Moench) plants. Exogenous applications of GA3 and PBZ with different concentrations (i.e. 20, 40, 80 and 100 mg/L) were sprayed on two-week-old Okra plants under the nursery stage. The control plants were only treated with distilled water. The stem diameter (mm) of treated and control plants was measured weekly. At the end of the experimental period, data on growth characteristics such as plant height (cm), leaf area (cm2) and number of leaves were recorded. The estimation of chlorophyll was measured using the SPAD-502 Chlorophyll Meter. Results showed that the plant morphological characteristics of Okra plants were significantly affected by the application of GA3 and PBZ (P<0.0001). In addition, stem growth (expressed as stem cross-sectional area- mm2) of Okra plants was significantly increased with increasing GA3 concentrations. In contrast, applying PBZ reduced Okra plants' stem growth. This study highlighted the major effects of GA3 and PBZ on the growth of Okra plants when planted under tropical climate conditions.

Cunninghamia lanceolata Canopy Relative Chlorophyll Content Estimation Based on Unmanned Aerial Vehicle Multispectral Imagery and Terrain Suitability Analysis

This study aimed to streamline the determination of chlorophyll content in Cunninghamia lanceolate while achieving precise measurements of canopy chlorophyll content. Relative chlorophyll content (SPAD) in the Cunninghamia lanceolate canopy were assessed in the study area using the SPAD-502 portable chlorophyll meter, alongside spectral data collected via onboard multispectral imaging. And based on the unmanned aerial vehicle (UAV) multispectral collection of spectral values in the study area, 21 vegetation indices with significant correlation with Cunninghamia lanceolata canopy SPAD (CCS) were constructed as independent variables of the model’s various regression techniques, including partial least squares regression (PLSR), random forests (RF), and backpropagation neural networks (BPNN), which were employed to develop a SPAD inversion model. The BPNN-based model emerged as the best choice, exhibiting test dataset coefficients of determination (R2) at 0.812, root mean square error (RSME) at 2.607, and relative percent difference (RPD) at 1.942. While the model demonstrated consistent accuracy across different slope locations, generalization was lower for varying slope directions. By creating separate models for different slope directions, R2 went up to about 0.8, showcasing favorable terrain applicability. Therefore, constructing inverse models with different slope directions samples separately can estimate CCS more accurately.

Can SPAD Values and CIE L*a*b* Scales Predict Chlorophyll and Carotenoid Concentrations in Leaves and Diagnose the Growth Potential of Trees? An Empirical Study of Four Tree Species

Photosynthetic pigments are fundamental for plant photosynthesis and play an important role in plant growth. Currently, the frequently used method for measuring photosynthetic pigments is spectrophotometry. Additionally, the SPAD-502 chlorophyll meter, with its advantages of easy operation and non-destructive testing, has been widely applied in land agriculture. However, the application prospects of its test results in horticultural plants have not yet been proven. This study examines the reliability of SPAD values for predicting chlorophyll concentrations. Using fresh and senescent leaves from four common horticultural plants, we measured SPAD values, photosynthetic pigment concentrations, and leaf color parameters. A generalized linear mixed model demonstrated that SPAD values are a reliable indicator for predicting chlorophyll concentrations, yet interspecific variations exist. Based on the predictive power of SPAD values for chlorophyll, we first propose an Enrichment Index (CEI) and a Normal Chlorophyll Concentration Threshold (NCCT). The CEI can be used to compare SPAD values among different species, and the NCCT value can serve as a more accurate indicator for assessing the growth potential of old trees. However, due to a limited sample size, further research with larger samples is needed to refine the diagnosis of plant growth potential and enhance the management of ornamental plant cultivation.

Chlorophyll Content Evolution of Wheat Triticum aestivum L. var. Alex under Different Salinity Doses

Salinity stress has effects on plants as harmful as those caused by drought. This research aim was to evaluate the changes in wheat total chlorophyll content estimation under salinity stress. The experiment was set up on October 15, 2022, by sowing wheat seeds var. Alex in field conditions, in mezo-phyto-cosmos, under six treatments, 0, 15, 30, 45, 60, and 75 mM NaCl. The total chlorophyll content estimation of leaves, flag leaves, and spikes was measured with a chlorophyll meter. The assessments were taken periodically for leaf greenness during in (Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie) BBCH 11, 14, 51 and at the end of the experiment for flag leaves and spikes greenness. The highest values for leaves total chlorophyll were registered at all treatments except 75 mM NaCl at the fourth evaluation. For flag leaves chlorophyll content, measured at the end of the experiment, the highest value was registered in the control treatment, significantly higher compared to the 15, 45, 60, and 75 mM NaCl by 38%, 86%, 88%, and 91%. The spike chlorophyll content showed no significant differences between all the treatments. Higher doses of saline treatment significantly affect the leaves chlorophyll content, decrease the flag leaf, and spike greenness.

Effect of crop geometry and nitrogen levels on leaf chlorophyll content of cotton (Gossypium hirsutum) at different growth stages under rainfed Vertisols

A field experiment was conducted during the rainy (kharif) season of 2018–19 at the Regional Agricultural Research Station, Acharya N.G. Ranga Agricultural University, Lam, Gunter, Andhra Pradesh on Vertisols under rainfed conditions. To study the effect of crop geometry and nitrogen levels on compact cotton (Gossypium hirsutum L.). Leaf chlorophyll content was measured with the Soil Plant Analysis Development meter (SPAD 502 Plus Chlorophyll Meter) at different crop growth stages. Among the various crop geometry studied, maximum chlorophyll (SPAD index) content, functional leaves per square meter and leaf area index (LAI) were recorded with close crop geometry 60 cm × 10 cm. Among nitrogen levels application of 180 kg N/ha recorded maximum chlorophyll content, functional leaves per square meter and LAI. Combined effect on crop geometry and nitrogen levels on chlorophyll content was recorded significant with closer geometry 60cm x10cm along with an application of 180kg N ha-1 at 90 days after sowing. Dry matter accumulation (kg/ha) at 30 DAS, 60 DAS, 90 DAS and at harvest was significantly affected by crop geometry and levels of nitrogen but not by their interaction.

Optimizing Weed Control: A Study on the Influence of Drone Sprayer Altitude in Herbicide Application

This research aims to determine the spraying distance of herbicides using a drone sprayer to achieve effective weed control. The use of herbicides is crucial to managing the competition for plant nutrients that threaten crop yields. The study analyzes the herbicide distribution patterns on plants sprayed using a drone with a flying speed of 3 m/s, utilizing a flat fan nozzle at different flying distances. During spraying activities, a compact weather station was employed to record environmental conditions, including air temperatures around 33.4-34.4 °C, relative humidity between 56.2-64.3%, wind speeds of 0.1-1 m/s, and wind direction from the southwest or south. There was no rainfall during the spraying sessions. The research results significantly contribute to the development of herbicide spraying technology using drones by carefully considering environmental conditions. Chlorophyll content was measured using the Soil-Plant Analysis Development (SPAD) chlorophyll meter and the Normalized Difference Vegetation Index (NDVI) through drone mapping. The drone sprayer at a 1-meter distance, covering an area of 600 m2, and using a 10 ml herbicide mixed with 10,000 ml water effectively reduced chlorophyll in weed plants. Multispectral data showed significant changes with a shift to red indicating non-vegetative areas after herbicide spraying. There was a decrease in average chlorophyll values measured at 2, 4, 6, 8, and 10 days post-spraying, with the lowest recorded on plots with a 1-meter spraying distance (average chlorophyll value of 19.62 SPAD). Therefore, the drone sprayer at a 1-meter distance proved effective in controlling weeds and reducing chlorophyll in non-target plants, making a crucial contribution to the development of herbicide spraying technology using drones and improving efficiency in agricultural management.

Different Management of Nitrogen Application Affected Growth Characteristic of Maize (Zea mays L)

A field study was conducted during Kharif 2019-20 at Professor Jayashankar Telangana State Agricultural University (PJTSAU), Rajendranagar, Hyderabad, Telangana, India to evaluate different handheld decision support tools for precision nitrogen management in rainfed maize (Zea mays L.). The study utilized a randomized block design and was replicated three times. The eight treatments included applying nitrogen through the State-recommended dose of 200 kg ha-1 in three splits (RDN), using a leaf color chart (LCC) based on N at thresholds 3 and 4, using a soil plant analysis development (SPAD) chlorophyll meter based on N at thresholds 35 and 40, and using a Green Seeker based on N at NDVI 0.6 and 0.8 in comparison with RDN and absolute control. Based on Green Seeker NDVI at threshold 0.8, the results showed that applying nitrogen resulted in considerably greater yields for maize grain (8408 kg ha-1), stover (9923 kg ha-1), and harvest index (45.8%). with higher yield and growth parameter viz., test weight (36.3 g ), No. of grain rows row-1 (36.7), cob length (18.9 cm), plant height (223.7 cm), leaf area (6385.75 cm2) and dry matter accumulation (18193 kg ha-1) as compared to RDN. Similarly, Green Seeker based N at NDVI 0.8 also registered higher net returns (Rs. 118961 ha-1) and B: C ratio (4.05).

Residual Effect of Nitrogen and Weed Management Practices in Maize on Succeeding Groundnut

Background: Cereal-legume cropping system is considered to be one of the better alternatives for sustaining soil fertility and increasing the yield. At present maize-groundnut cropping system is gaining importance under both rainfed and irrigated situations. Maize, being an exhaustive and weed-sensitive crop, is supplied with large doses of fertilizers and new herbicide molecules.Since maize is exhaustive and weed sensitive crop, there was a usage of excessive fertilizers and new herbicides. There is a need to assess the carry over effect of fertilizers and new generation herbicides in leguminous crops like groundnut. Methods: The experiment was conducted during two consecutive rabi seasons of 2019-20 and 2020-21 on sandy loam soils of S.V. Agricultural College, Tirupati andhra Pradesh. Maize hybrid DHM -117 was sown and maintained with general cultivation practices except for nitrogen and weed management methods was raised after harvest of maize in undisturbed layout to study the residual effect of different nitrogen and weed management practices imposed in maize. Result: Residual effect of nitrogen and weed management practices imposed in preceding maize did not exert any significant influence on germination percentage, phytotoxicity and SPAD chlorophyll meter reading (SCMR) values but efficacy of herbicide residue found to be significant with weed management practices. Growth parameters, yield attributes pod yield, haulm yield and economics were higher in groundnut with brown manuring, which was however, in parity with hand weeding twice at 15 and 30 DAS, pre emergence application of atrazine 1.0 kg ha-1 fb post emergence application of topramezone 30 g ha-1 and pre emergence application of atrazine 1.0 kg ha-1 fb post emergence application of tembotrione 120 g ha-1 and lower with unweeded check and it was remained in parity with application of parthenium water extract15 lha-1 twice at 15 and 30 DAS, application of sunflower water extract 15 lha-1 twice at 15 and 30 DAS, pre emergence application of atrazine 1.0 kg ha-1 fb post emergence application of parthenium water extract 15 lha-1 and pre emergence application of atrazine 1.0 kg ha-1 fb post emergence application of sunflower water extract 15 lha-1 in the order of ascent. None of their interaction effects were found to be significant during both the years of study and in pooled mean.

Pembelajaran Aplikasi Pengukur Kandungan Klorofil pada Daun Tanaman Padi (Oryza sativa L.)

Rice is a staple food in Indonesia, so the demand will continue to increase along with the population growth. Rice cultivation in Indonesia is known for two planting systems, namely wet rice that requires water and dry rice planted in fields that do not require special irrigation. Several regions in Indonesia have types of dry rice, including the almost extinct Fakhaito or black rice from Nias Regency, with a plant age of six months until harvest. The productivity of dry rice is very low, affecting farmers' income due to suboptimal fertilization technology. The aim of this research is to provide learning to students using the SPAD-502Plus chlorophyll meter to detect the growth and health of dry rice plants from Nias. The research results show that treatment with liquid organic fertilizer correlates positively with leaf color, where the amount of chlorophyll is higher in very green rice leaves and vice versa, the amount of chlorophyll decreases in plants with reduced green matter. The use of the SPAD-502Plus chlorophyll meter, by measuring directly, is faster, non-destructive, comfortable, and does not disturb plant growth.

Genetic Variability and Correlation for Traits Related to Drought Tolerance in Groundnut (Arachis hypogaea L.) under Different Water Regimes

The understanding of the variability existing in a population base of crop is pivotal to crop improvement. This study examined the variance components, heritability estimates and correlations between some morphological and physiological traits related to drought tolerance in groundnuts under two water regimes, to speed up the selection and breeding of groundnut genotypes tolerant to drought. The experiment was carried at the Research Farm of the Institute for Agricultural Research, Ahmadu Bello University. Data collected for performance evaluation were number of days to 50% flowering, plant height, number of pods/plant, seed weight/plant and pod yield/plant. Physiological traits related to drought tolerance measured included, Harvest Index (HI), SPAD Chlorophyll meter reading (SCMR) at 40, 60 and 80 Days after showing (DAS). Variance components, Genetic Coefficient of Variation (GCV), Phenotypic Coefficient of Variation (PCV) and broad-sense heritability were calculated for all the traits recorded. Results showed that number of pods/plant, seed weight/plant, SCMR at 60 DAS and HI showed a strong positive and highly significant (P<0.01) with pod yield/plant in all watering conditions. Heritability of the traits ranged from 8.16%- 60.00% with pod yield/plant having the highest value and days to 50% flowering having the lowest values in non-stress (NS), while under water stress condition, heritability was low to moderate from 0.53-53.33%. The SCMR at 60 DAS, number of pods/plant and HI had moderate heritability and significant correlation with pod yield/plant under water stress condition, these traits could be useful criteria in drought tolerance selection.

Studies on the Effect of Water Stress on Root Traits in Redgram Genotypes

The experiment was conducted during July–November, 2019 at Regional Agriculture Research Station, Professor Jayashankar Telangana State Agricultural University, Palem, Nagarkurnool district, Telangana State, India. The main treatments had five red gram genotypes and water stress levels were taken as sub-treatment in 3 replications in factorial RBD using specialized root structure made with cement bricks. There was great variability in the yield performance of different Redgram genotypes under drought conditions. The experiment was conducted to select genotypes with efficient root architecture and associated traits under drought stress. Root studies were performed with the Delta T automatic root scanner. The SPAD chlorophyll meter was used to measure the SCMR value. The present study results revealed that genotype, Maruti showed significant superiority for character plant height and SCMR under non-stress, mild stress and severe stress conditions. The same genotype showed superior values for main root length under control and mild stress. Whereas, Laxmi recorded the highest plant height under severe stress and the same genotype also showed significant superiority for total plant dry weight, root dry weight and root area under severe stress. The genotype Laxmi showed significant character, root area and diameter superiority under mild stress. ICPL-20176 recorded significant superiority for main root length under severe stress and root tip for mild stress. The identified genotypes can be used as the parents in future drought-proof breeding useful for cultivating in water stress conditions.

Pembelajaran Aplikasi Pengukur Kandungan Klorofil pada Daun Tanaman Padi: Oryza sativa L.

Rice is a staple food in Indonesia, so the demand continues to increase along with the population growth. Rice cultivation in Indonesia is known for two planting systems, namely wetland rice which requires water and upland rice which is planted in fields without requiring special irrigation. Several regions in Indonesia have almost extinct upland rice varieties, such as the Fakhaito variety or black rice from Nias Regency, with a plant age of up to six months until harvest. Upland rice productivity is very low, affecting farmers' income, accompanied by suboptimal fertilization technology. This research aims to provide learning to students in using the SPAD-502Plus chlorophyll meter to detect the growth and health of upland rice plants from Nias. The results of the study show that treatment with liquid organic fertilizer correlates positively with leaf color, where the amount of chlorophyll is higher in the very green leaves of rice, and conversely the amount of chlorophyll decreases in plants with reduced greenness. The use of the SPAD-502Plus chlorophyll meter is a faster, non-destructive, comfortable, and non-disruptive way to measure plant growth, as the measurement is done directly.