Open Access Short Research Article

Effect of Nutrient Management on Productivity and Quality of Acid Lime (Citrus aurantifolia swingle)

Y. Angel, A. Vignesh Kumar, S. Abinaya, G. Pradeep Kumar

International Journal of Plant & Soil Science, Page 106-110
DOI: 10.9734/ijpss/2021/v33i2330724

Acid lime (Citrus aurantifolia Swingle) is one of the commercial fruit crops which occupies an important place in the fruit industry, but yield levels of citrus orchards are still very low. An alternate nutrient management system could help in achieving a high yield and quality of acid lime. Thus, an investigation was undertaken on the “Effect of nutrient management on productivity and quality of acid lime (Citrus aurantifolia Swingle)” during 2016 – 2018. The experiment was laid out in randomized block design with twelve treatments, various organic manures, biofertilizers along with inorganic fertilizers including recommended dose of fertilization @ 100%, 75%, 50%, farm yard manure @ 100%, 50%, Vermicompost @ 100%, 50%, Biofertilizers (25 g Azotobacter + 25 g phosphate solubilising bacteria + 150 g vesicular arbuscular mycorrhizal) were applied. The yield and quality characters of acid lime were studied at vegetative and reproductive stages. The observations recorded viz., fruit setting (%), fruit diameter (cm), number of fruits per plant, fruit weight (g), yield per tree (kg) and yield per hectare (tonnes). The results revealed that plants treated with T12 ( 50% RDF+ 75% Vermicompost + Biofertilizers (25 g Azotobacter +25 g PSB +150 g VAM) was observed maximum fruit setting (%), fruit diameter (cm), number of fruits per plant, fruit weight (g), yield per tree (kg), yield per hectare (tonnes). The maximum net income (Rs. 281511.5 / ha) and benefit:cost ratio (4.72: 1) was observed in the treatment T12-50% RDF + 75% FYM + 75% Vermicompost + Biofertilizers (25 g Azotobacter + 25 g PSB + 150 g VAM) which was superior to other treatments.

Open Access Short Research Article

Spatial Behavior of Soil Erodibility in the La Villa River Basin, Panama

Lwonel Agudo Martínez, José Villarreal Núñez, Jhon Villalaz Pérez, Iván Ramos Zachrisson

International Journal of Plant & Soil Science, Page 309-315
DOI: 10.9734/ijpss/2021/v33i2330745

Introduction: Soil erodibility is an important factor in understanding the erosion that takes place in a territory. This is a parameter that can behave erratically in small spaces, but that describes a trend in larger spaces.

Aim: Determine the K factor of soil erodibility in the La Villa-Panama river basin.

Place and Duration of Study: La Villa River Basin-Azuero Peninsula, Panama. 2010-2012.

Methodology: 98 points of the La Villa river watershed were sampled. Factor K was calculated using the adaptation to the sol-erodibility nomogram. The percentage of organic matter, structure class (in the field), permeability (combination permeameter) and the percentages of sand, silt and very fine sand (Bouyoucos method) were determined. To obtain the most complete information possible on the distribution of erodibility, a superficial interpolation of the point values ​​corresponding to the soil samples taken was carried out. The software used was Arcview 3.3 and the Spatial Analyst extension. The interpolation method was IDW (Inverse Distance Weight). The erodibility values ​​were categorized into seven intervals in such a way that it was possible to observe the differences on the map.

Results: The erodibility values ​​were influenced by the content of organic matter and coarse particles (percentage of sand and silt + very fine sand) of the soil. In the province of Herrera, 86% of the land surface and 76% in the province of Los Santos presents susceptibility to erosion in the ranges of 0.032 to 0.043 Ton ha h ha-1 Mj-1 mm-1.

Conclusion: The results indicate that 80% of the soils of the La Villa river basin present a moderately high erodibility factor, with the highest values ​​being registered in the upper middle zone.

Open Access Original Research Article

Agro-Morphological Performances of Common Bean Varieties (Phaseolus vulgaris. L) Introduced in the Central African Republic

G. I. Touckia, H. D. B. Elian, L. Aba-Toumnou, F. A. Rekya, S. Ndaima Orolo, D. B. Zimaga, O. D. Yongo, K. Kokou

International Journal of Plant & Soil Science, Page 1-9
DOI: 10.9734/ijpss/2021/v33i2330712

The common bean (Phaseolus vulgaris L.) is one of the main legumes produced and consumed in the Central African Republic (CAR). But in CAR, the common bean production is constrained by certain biotic and abiotic stress which severely impacts the quantity and quality available in the value chain. To compensate this loss of the production, the Central African Institute for Agronomic Research (ICRA) had introduced in CAR ten varieties of common bean from Rwanda and Cameroon. A four-repeat randomized full-block device was used for testing the performances of these ten varieties of common bean. The measured variables were the vegetative growth, the production, and the sensibility to plant diseases. Overall, the different varieties exhibited a high germination rate (88.6%). The highest rate is observed in variety RWR2245 from Rwanda (100%). Varieties from Rwanda, RWR3194 with 1000 kg ha-1 and BOA5M1-6 with 916.66 kg ha-1 gave better yields followed by varieties Ecapan 025 from Cameroon with 833.33 kg ha-1 and RWR2245 with 833.33 kg ha-1. The yields obtained are roughly referred to the agronomical standard. The varieties NITOU and NUA566 from Rwanda were more susceptible to disease incidence and pest attacks compared to those from Cameroon.

Open Access Original Research Article

Influence of Seed Priming with Nano Iron Oxide on Germination and Seedling Growth of Mungbean

U. Triveni, M. Martin Luther, K. V. Ramanamurthy, T. N. V. K. V. Prasad, C. H. Mukundarao, T. S. S. K. Patro

International Journal of Plant & Soil Science, Page 10-14
DOI: 10.9734/ijpss/2021/v33i2330713

Mungbean is one of the important grain legumes and considered as ‘Green Pearl’ due to its nutritional significance. It is an excellent source of proteins and micronutrients and readily accessible to low income groups in arid and semi-arid regions of Africa and Asia. However, poor nutritional status of the soils in these regions limits the productivity and grain nutritional properties of mungbean. Seed priming with nutrient solutions was identified as viable and cost effective alternative to increase the crop productivity and grain nutritional properties and hence, an in-vitro experiment was conducted for optimizing the concentration of nano iron oxide (FeO) for seed priming in mungbean at Agricultural College, Bapatla, Acharya N.G.Ranga Agricultural University, Andhra Pradesh during 2018. Different concentrations of nano iron oxide were tested in completely randomized block design with three replications. The results revealed that, the nano iron oxide 50 ppm was found effective in increasing the germination percent, shoot length, root length, seedling vigour index and speed of germination of mungbean and has been considered as an optimum concentration for seed priming in mungbean.

Open Access Original Research Article

Forecasting of Kharif Cereal Production in Odisha by Using Spline Regression Technique

Harsha S. Basanaik, Abhiram Dash

International Journal of Plant & Soil Science, Page 15-24
DOI: 10.9734/ijpss/2021/v33i2330714

Cereals are prime determinant of agricultural status of the state mainly during kharif season. Forecasting of the production of kharif cereals is of utmost importance to formulate the agricultural policy and strategy of the state. The ARIMA model can be reliably used to forecast for short future periods because uncertainty in prediction increases when done for longer future periods. The predictions obtained from the ordinary regression model are valid only when the relationship between the independent variables and the dependent variable does not change significantly in the future period which can be rarely assumed. It is expected that the spline regression will overcome the respective discrepancies in both ARIMA and ordinary regression techniques of forecasting with the assumption that the future period which needs forecasting follows the same pattern as the last partitioned period.

The entire period of data is split into different periods based on the scatter plot of the data The suitable regression models, such as, linear, compound, logarithmic and power model are fitted to the data on area and yield of kharif cereals by using the training set data. Selection of best fit model is done on the basis of overall significance of the model, model diagnostic test for error assumptions and model fit statistics. The selected best fit model is then cross validated with the testing set data. After successful cross validation of the selected best fit models, they are used for forecasting of the future values for their respective variables.

The models found to be best fit and thus selected for cross validation purpose are compound spline model for both area and yield of kharif cereals respectively. Forecasting of area, yield and hence production of kharif cereals for six years ahead i.e., for the year 2020-21 to 2025-26 by using the selected best fit model after successful cross validation. The forecast values for production of kharif cereals are found to decrease despite increase in forecast values of yield which is due to decrease in forecast value of area.

Open Access Original Research Article

Screening of French Bean (Phaseolus vulgaris L.) Genotypes against Alternaria Leaf Spot Caused by (Alternaria alternata) under Dryland Conditions of Kashmir

Sabiya Bashir, Mohammad Najeeb Mughal, Zahida Rashid, Shabeena Majid, Sabeena Naseer, Zahoor A. Dar, Shafeeq A. Hakeem, Faisal Rasool

International Journal of Plant & Soil Science, Page 25-30
DOI: 10.9734/ijpss/2021/v33i2330715

Sixty-three genotypes of  french bean was screened against leaf spot (Alternaria  alternata) in sick plots at Research Farm of Dryland Agriculture Research Srinagar, Rangreth during  Kharif  2018 and 2019. The highest mean disease incidence ranged from 0.00 to 85.00 per cent  with  the mean disease intensity ranged from 0.00 to 53.26 per cent .One genotype namely  ‘Local Pulwama’ was highly susceptible in their disease reaction. Among the screened germplasm, ‘Highly Resistant’ genotypes was SKU-R-601, SKUA-R-105, SKU-R-927, DARS-25, DARS-66, DARS-R-615,  while as ‘Susceptible’ genotypes was  DARS-8, DARS-12,  DARS-11, SKUAST-R-155, SKU-R-928, DARS-7, DARS-R-4, Bhaderwah (L),  Local  Kupwara black and Raj Jawala. Local Pulwama was found to be a highly susceptible (HS) genotype.  Twenty nine genotypes namely., DARS-16, DARS-9, DARS-54, DARS-39, VL-125, DARS-63, ENTO-504, SKUAST-204,SKU-R-925, DARS-60, DARS-109, DARS-43, DARS-44, SKU-R-23, DARS-4, DARS-74, SKU-R-105, DARS-40, DARS-23, DARS-18, SKU-R-71, WB-341, SKU-R-605, Uri local, Shopian (L), SKU-R-23, DARS-71, SSGB-729, DARS-R-19 showed resistant reaction to disease. The selection for resistance was based on the reaction of varieties on leaves.

Open Access Original Research Article

Analysis Growth Rate in Area, Production and Productivity of Sapota in Gujarat, India

Tushar Pakwar, Ashok Kumar Koshariya, Kedar Vijaykumar Swami, Alpesh K. Leua

International Journal of Plant & Soil Science, Page 31-40
DOI: 10.9734/ijpss/2021/v33i2330716

The present investigation was "Analysis growth rate in area, production and productivity of Sapota in Gujarat". A multi stage random sampling design was used for selecting the sample. The study covered 2 Districts, 2 talukas, 12 villages and 120 Sapota growers from Valsad and Navsari districts. The primary data were collected for the season of 2011-2012 by personal interview method. In the results revealed that the Valsad and Navsari districts were found to having positive growth rate in area and production (0.20 and 0.73 per cent and 1.59 and 2.30 per cent, respectively). While the productivity of both the districts was positive viz., 0.54 and 0.70 respectively. On the contrary, a lower but positive and significant growth rate was observed in sapota area for the state as a whole, whereas the production and yield showed positive trend (2.01 and 2.55 respectively).  The per hectare total cost of establishment for four year were Rs. 75387.59 for the orchards in Valsad district and Rs. 74025.27 for the orchards in Navsari district. The maintenance cost worked out to be as Rs. 56326.59 and   Rs. 55298.27 in Valsad and Navsari district respectively. The average per ha yield from Valsad district was 10. 61 tonnes and from Navsari district was 11.11 tonnes in 6th year and net returns were Rs. 113527 from Valsad district and Rs. 118877 from Navsari district.

Open Access Original Research Article

Response of Organic Biostimulants and Silicon to Growth, Yield and Quality of Tomato under Soil Salinity Conditions

R. Rajasekar, V. Ravichandran, V. Babu Rajendra Prasad, N. Sakthivel

International Journal of Plant & Soil Science, Page 41-54
DOI: 10.9734/ijpss/2021/v33i2330717

Abiotic stresses strongly affect plant growth, nutrient composition and quality of production; final crop yield can be really compromised if stress occurs in plants’ most sensitive phenological phases. The present field study was conducted to evaluate the effect of biostimulants on improvement of tolerance and yield of tomato plants exposed to salinity. The tomato field soil condition with pH- 8.7 and EC- 4 dS m-1 was recorded. After the first fruit set of tomato, Organic biostimulant (Organic mix with high concentration of carboxylic acids, containing calcium oxide (CaO), ammonium ligninsulfonate and Zinc) were given by soil drenching and Orthosilicic acid as silicon source by foliar spray at every 10 – 15 days interval. The treatments include Organic biostimulant at 0.3ml/plant & 0.6ml/plant, Orthosilicic acid at 0.2% and 0.4%. The observations were taken during greener and red ripening stage. The biostimulants positively affected the plant height and chlorophyll fluorescence. Biostimulants were allowed to maintain the lower level of electrolyte leakage and osmotic potential within the plant. The activities of catalase (CAT) and superoxide dismutase (SOD) enzymes increased with the increases in salinity: biostimulants thereby kept the lower the level of reactive oxygen species. Under saline conditions due to the ionic imbalance, potassium and calcium content in both the shoots and roots were recorded lower, whereas the sodium content was found to be higher than the control plants. Similarly, a significant increase in total soluble solids and firmness of the fruit was recorded in tomato fruits. Yield characters like fruit number per plant, single plant yield, single fruit weight and flower to fruit ratio were positively affected by the application of biostimulants. The organic biostimulant and Orthosilicic acid administered at a greater dose appeared to be the most effective in our investigation.

Open Access Original Research Article

Effect of Drip Fertigation under Different Fertilizer Levels on Nutrient Status in Coconut (Cocos nucifera L) Leaf

Avinash Sarin Saxena, Sankar Chandra Paul, . Juhi

International Journal of Plant & Soil Science, Page 55-63
DOI: 10.9734/ijpss/2021/v33i2330718

A study was conducted during 2017-18 under the All India Co-ordinated Research Project initiated in 2009 at research farm of Bihar Agricultural University, Sabour, Bhagalpur. The aim of this study was compare the nutrient concentration of coconut leaves at different nutrient levels through drip fertigation in a Randomized Block Design (RBD) with four (4) replications. Result was observed that leaf Nitrogen, Phosphorous, Sulphur, Iron, Manganese, Copper and Boron content under different fertigation treatments were not significantly different from each other. The content of micronutrients in leaf were found to increase with increasing levels of fertilizer in the treatments. Cation Exchange Capacity was positively correlated with all the leaf nutrients. Organic carbon did not show remarkable relation with plant nutrient parameters. Soil K content of all three depths was positively correlated with all the leaf nutrient elements. Soil pH value was positively correlated with leaf P content in coconut which explains that leaf P content is directly proportional to the soil pH value. Electrical conductivity (EC) of soil was also positively correlated with P, K and B concentration in coconut leaf. Correlation coefficient value between CEC and leaf nutrient contents explains that 2nd depth of soil is more important for mineral nutrition of coconut palm. Correlation coefficient values between soil P content and leaf nutrient content. Higher correlation coefficient value was found at lower soil depth between available sulphur content in soil and sulphur content in leaf of coconut. This result suggests that inherent supplying capacity of micronutrient of experimental soil is not so influential for higher plant growth, but application of N, P and K fertilizers trigger the absorption capacity for micronutrient from soil. Under different NPK levels, the applied NPK does not have significant effect on leaf N, P, S, Zn content after five (5) years of experimentation while the effect was found to be significant for few elements like K, Fe, Mn, Cu, and B. An increasing trend was observed for leaf nutrient content with increasing levels of fertilizer application.

Open Access Original Research Article

Influence of Nitrogen and Zinc on Growth and Yield of Baby Corn (Zea mays L.)

M. Tharaka, K. RaviChandra, Vikram Singh

International Journal of Plant & Soil Science, Page 64-70
DOI: 10.9734/ijpss/2021/v33i2330719

An experiment was conducted during the Rabi season of 2020 at Fodder Production Farm of Livestock Research Station (Sri Venkateswara Veterinary University), Lam Farm, Guntur. A.P, to find out the effect of basal application of Nitrogen and Zinc on growth and yield of Baby corn (Zea mays L.). The experiment was laid out in Randomized Block Design with 9 treatments and each treatment replicated thrice. Treatments consisted of combination of three levels of Nitrogen (80,100 and 120kg/ha) and three levels of Zinc (10, 20 and 30 kg/ha). It was observed that application of 100 kg Nitrogen /ha + 30 kg Zinc/ha, was found the best treatment for obtaining growth and yield attributes such as Plant height (178.46 cm), Plant dry weight (105.58 g), No. of leaves per plant (12.00), Leaf area index (3.07), No. of cobs per plant (4.19), Length of cob (20.72 cm), Length of the corn (9.06 cm), Girth of the cob (7.34 cm), Corn girth (3.42), Cob yield (16026.53 kg/ha) and Corn yield (2597.47 kg/ha in Krishna zone of Andhra Pradesh, India.

Open Access Original Research Article

Comparative Study of Soil Properties under Gamhar (Gmelina arborea) Based Agrisilvicultural System

Abhay Kumar, M. S. Malik, P. R. Oraon, Rakesh Kumar, Sheela Barla, Swati Shabnam

International Journal of Plant & Soil Science, Page 71-77
DOI: 10.9734/ijpss/2021/v33i2330720

A two year experiment was conducted during kharif and rabi season of 2016-2017 and 2017-2018 at experimental site near Faculty of Forestry in main campus of Birsa Agricultural University, Ranchi, Jharkhand, India. Sole cropping and gamhar based agrisilviculture systems with four different intercrops (arhar, cowpea, greengram and mustard) were under investigation. To study the overall scenario of soil properties under agrisilviculture system, soil samples were analysed at different profile depths (0-15 and 15-30 cm) to measure the changes in soil properties under the influence of gamhar (Gmelina arborea) tree and intercrops grown in between. Soil pH, electrical conductivity (dsm-1), organic carbon (%), available nitrogen, phosphorus and potassium (kg ha-1) were found higher at the soil depth 0-15 cm as compared to 15-30 cm due to addition of organic residue on the surface soil. Soil OC, available N, P and K in 0-15 cm as well as in 15-30 cm profile was found to be statistically significant. It showed an increase from initial value in all the treatments in 2016-17 and 2017-18. The increase was more in gamhar based agrisilviculture system than in sole tree and sole crops in both the years.

Open Access Original Research Article

Analytical Study of Kharif Food Grain Production in Odisha

Jamana Sripriya, Abhiram Dash

International Journal of Plant & Soil Science, Page 78-85
DOI: 10.9734/ijpss/2021/v33i2330721

The state of Odisha having an agrarian based economy depends largely on agriculture for the livelihood of its population. Food grains are important commodity of crop groups that provide high quality carbohydrates, protein and vitamins. A study on the compound growth rate of area, yield and production of food grains for kharif season in the districts of Odisha and the state as a whole has been attempted in the present study which would be helpful in visualizing the progress of the state with respect to food grain cultivation and proper framing of agricultural policies of the state. The study is based secondary data for the period of 1993-94 to 2017-18 to estimate the compound growth rate and Cuddy-Della Instability Index of area, yield and production of kharif food grains for the districts and the state as a whole. The districts are ranked on the basis of compound growth rate and Cuddy-Della Instability Index in decreasing order and increasing order of their magnitudes respectively. The rank correlation between Compound Growth Rate and Cuddy-Della Instability Index of area, yield and production of food grains during kharif seasons are studied. It is found that despite negative growth rate in area, the positive compound growth rate of yield leads to positive compound growth rate in production of kharif food grains of Odisha. Also it is found that despite stability of area, the instability of yield leads to instability in production of kharif food grains in the state of Odisha.

Open Access Original Research Article

Cytological Studies on Graft Union Development with Perennial Chilli Rootstocks

P. Keerthana, L. Pugalendhi, R. Swarna Priya, H. Usha Nandhini Devi

International Journal of Plant & Soil Science, Page 86-94
DOI: 10.9734/ijpss/2021/v33i2330722

Grafting technology in vegetable crops is becoming increasingly popular as an alternative tool to improve the biotic and abiotic resistance besides improvement in horticultural traits. By utilizing the right combination of resistant rootstock and scion, desired variability can be achieved to improve the yield and quality of vegetables. A study was conducted at the College orchard, Department of Vegetable science, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore during the year 2020-2021 to evaluate the graft compatibility with two chilli rootstocks. The experimental material consisted of two perennial rootstocks viz., CC-CBE-001 and CF-CBE-007 and three scion materials viz., TNAU Chilli Hybrid CO 1, Ranga hybrid and Bangaram hybrid. Wedge grafting was done using 60 days old rootstock and 45 days old scion seedlings with nine treatments. The adhesion line wall thickness of pith cells were determined at different stages after grafting. The wound healing of the scion-rootstock union was studied using microscopic examination of the grafting region on the 5th, 10th, 15th and 20th day after grafting. It was observed that ten days after grafting, vascular bundle was formed and a large amount of callus was produced to bridge the scion and rootstock. Despite interspecific grafting, callus formation, subsequent cell differentiation and vascular connection were established, resulting in effective graft compatibility, according to the anatomical and histological analysis.

Open Access Original Research Article

Screening for Drought Tolerance through Root Morphology and Yield Characters of Groundnut (Arachis hypogaea L.) Genotypes

K. Manoj Kumar, S. Vincent, A. Mothilal, M. Raveendran, R. Anandham, V. Babu Rajendra Prasad, D. Suneel

International Journal of Plant & Soil Science, Page 95-105
DOI: 10.9734/ijpss/2021/v33i2330723

Drought affects the rainfed groundnut (Arachis hypogaea L.)  at different phases of development and it is the serious threats on groundnut productivity causing losses than any other abiotic factor under rainfed agriculture. In the world's semiarid regions, groundnut accounts for 90% of worldwide production. Drought mainly affects the pace and pattern of nutrient and water intake from the soil, affecting the architecture of the groundnut root system. Plant selections with desirable root trait have been a major focus in developing drought resistant Groundnut cultivars. In 2019, 60 groundnut genotypes were cultivated in root block design with two different soil water treatments, as well as in the field during the year under same circumstances. The purpose of this study was to see how different groundnut cultivars fared in terms of yield, yield contributing features, root characters, and their relationships with drought tolerance. Drought resistant genotypes had thicker roots, larger roots, and a deeper root system than susceptible genotypes. Recent series in groundnut genotypes of 60 numbers were sown during kharif 2019 (july-september) under rainfed condition (It includes life irrigation and rainfall received during cropping season). Groundnut genotypes were semi spreading with the duration of 110-120 days. Observation on root morphological character viz., roots length, root volume after 20 days of stress imposition of the crop and yield parameters were observed at the harvest. Among the 60 genotypes, 20 genotypes (VG 17008, VG 17046, VG 18005, VG 18102, VG 18077, VG 19572, VG 19709, VG 18111, VG19561, VG19576, VG 19620, VG 19681, VG 19688 etc.,) similarly, yield character were observed for 60 genotypes and all the genotypes given above recorded higher value in Total number of pods per plant, Number of double seeded pods per plant, Pod yield per plant, Harvest index and Total dry matter production. The methods used in this study identified correlation between yield character and root characters. Groundnut genotypes by assessing yield metrics and their relationship with root trait. These findings lay the groundwork for future study aimed at deciphering the molecular pathways underpinning Groundnut drought resistance.

Open Access Original Research Article

Efficacy of Selected Bio-Agents and Neem Cake on Cercospora Leaf Spot and Growth of Black Gram (Vigna mungo L.)

Narreddula Nijesh Kumar Reddy, Sobita Simon, Abhilasha A. Lal

International Journal of Plant & Soil Science, Page 111-118
DOI: 10.9734/ijpss/2021/v33i2330726

Black gram (Vigna mungo L.) is a vital pulse crop globally and one of the most vital pulse in India. It is understood to be affected by many varieties of diseases, Cercospora leaf spot is certainly considered one among them. Cercospora leaf spot due to Cercospora canescens causes much damage to the production of black gram. The neem cake, Trichoderma viride, Pseudomonas fluorescens, Paecilomyces lilacinus, Carbendazim were tested under field conditions during Rabi 2020-2021 for their efficacy against the disease and growth and yield parameters. A survey was conducted during Rabi, 2020-2021 to know the severity of Cercospora leaf spot of black gram in farmer’s fields in Kurnool district of Andhra Pradesh. In-situ (field) experiment was carried out in randomized block design with five treatments and three replications. The highest plant height at 60 DAS (56.96 cm), fresh weight (35.59 gm), dry weight (14.98 gm), number of pods per plant (18.17 pods/plant), yield (7.96 q/ha) and Benefit Cost ratio (1:3.48) showing better result when treated with treatment neem cake @ 0.5 t/ha + Trichoderma viride @ 2.5 kg/ha.  The treatment T1 – neem cake @ 0.5 t/ha + Trichoderma viride @ 2.5 kg/ha significantly decreased the disease intensity at 30, 45 and 60 DAS (10.02%), (12.02%) and (16.42%) respectively. It is concluded that T1 – neem cake @ 0.5 t/ha + Trichoderma viride @ 2.5 kg/ha found superior in all the growth and yield parameters.

Open Access Original Research Article

Impact of Human Activities on the Distribution of Termite Communities in Teak Plantations (Tectona grandis L. F., Verbenaceae) in the Korhogo Communal Area (North Côte d'Ivoire)

Tenon Coulibaly, Franceline Doh, Ekien Alloua A. Bertille Kadio, Kindo Yves-Joël Boko, Alexandre Moïse Akpa Akpesse, Kouassi Philippe Kouassi

International Journal of Plant & Soil Science, Page 140-150
DOI: 10.9734/ijpss/2021/v33i2330729

Aims: This study aimed to assess the impact of human activities on termites in teak plantations in the Korhogo communal area.

Methodology: Termites were sampled from October to November 2020 using the transect method recommended by Jones and Eggleton (2000). The study was carried out in three teak plantations undergoing different levels of human activities, with a forest fragment as reference area. Five types of human activity were assessed and the overall proportion of human pressure on each habitat was calculated. The species richness (S), Shannon index (H'), Evenness (E) and the relative abundance were calculated of termites for each habitat type. Analyses of variance (ANOVA) were used to compare the species richness and abundance of termites.

Results: The results showed that the village plantation of teak (PVT) had the highest degree of human pressure (50.94%), followed by the teak plantation of the forest of Mount Korhogo (TFMK) (29.24%). The teak plantation of Botanical Garden (TJB) was under low pressure (6.60%). A total of 30 species grouped in 19 genera and 8 sub-families of termites were identified in all plots. Termite diversity was high in the forest fragment (19.67 ± 1.15) and in the teak plantation of Botanical Garden (21.33 ± 2.08), but low in the village teak plantation (11 ± 1). The abundance of termites evolves in the same direction as the species richness.

Conclusion: Anthropogenic activities affect the trophic composition of termites, particularly the humivore group. Reconstruction of the fauna and flora of the teak forests would be beneficial for the conservation of termite species. In this region, teak forests would thus play a role as a refuge for termite communities, which are recognised as the main soil fertilising organisms in the tropics.

Open Access Original Research Article

The Use of Mathematical Model to Predict Levels of N and K for Optimum Yield

Jyotiranjan Behera, M. K. Mahanti

International Journal of Plant & Soil Science, Page 151-158
DOI: 10.9734/ijpss/2021/v33i2330730

Sometimes, yield from a commercial plantation is reduced because of inadequate availability of fertilisers to the plant due to various reasons such as poor quality of fertilizers used, loss of fertilizers in the field during cultivation due to natural causes etc. One way of preventing such loss in yield is to apply remedial fertiliser doses in the field in an intermediate stage of cultivation. To implement such a method effectively, a mathematical model has been proposed in this work.

The model first determines the amount of fertilisers needed at the beginning of cultivation to optimize yield. It then ascertains at an intermediate stage of cultivation whether the plant receives adequate fertilisers for producing optimum yield. In case it is found out that required fertilisers are not available to the plant, the model decides how much more remedial fertilizer doses should be applied at the intermediate stage so that yield will not be affected. A potato plantation has been considered to illustrate the applicability of the proposed mathematical model.

Open Access Original Research Article

Comparison of Genetic Parameters among Selfed Lines and Random Mated Population A (PDM 53 x PDM 4441) and Population B (HKI 1105 x HKI 323) and Identification of Transgressive Segregants

Asha T, Sanjeev K. Deshpande, B. D. Biradar, Mahabaleshwar G Hegde

International Journal of Plant & Soil Science, Page 159-177
DOI: 10.9734/ijpss/2021/v33i2330732

The present study was conducted to compare the genetic variability parameters among selfed lines of population A (PDM 53 x PDM 4441) and population B (HKI 1105 x HKI 323) and also random mated population A (PDM 53 x PDM 4441) and random mated population B (HKI 1105 x HKI 323) using original inbred parents and three commercial checks, HM-4 (National check), CPB 468 and TENDER (Private check). High heritability coupled with high genetic advance was observed for number of cobs per plant, husked cob weight, dehusked cob weight, baby corn yield with and without husk per plant among selfed populations and a similar trend was observed in random mated populations except for ear length and days to 50 % silking. In total the variability observed was more in random mated populations than selfed lines because allelic frequency differences occur in random mated populations and the pool of gametes originating from male and female is different when compared to the pollen source in selfed populations. The frequency of transgressive segregants were more in random mated Population A (PDM 53 x PDM 4441) and the most promising transgressive segregant identified can be used in the further breeding programmes.

Open Access Original Research Article

Growth Rate Estimation of Rabi Pulse Production of Odisha by Using Spline Regression Technique

Rakesh Kumar Rout, Abhiram Dash

International Journal of Plant & Soil Science, Page 178-188
DOI: 10.9734/ijpss/2021/v33i2330733

Pulses are considered to be important crop for ensuring nutritional security in Odisha. Proper estimation of growth rate in production of pulse crops allows for more effective cropping system planning and formulation of the agricultural policy of the state. To capture any abrupt changes and the variation in data in different phases of a long time period, spline regression technique is used as it can fit different models in different segments of the time period as necessary without losing the continuity of the model. The present study deals with the estimation of growth rate of area, yield and production of all rabi pulses in Odisha by using best fit spline regression model. To fit the spline regression model, the entire period of study is divided into different segments based on the scatter plot diagram which is further confirmed by testing the significance of change in coefficient of variation between the consecutive segments by chi square test. The regression model found to be suitable from the study of scatter plot of data are linear, compound, logarithmic, power, quadratic and cubic model. The best fit model is selected on the basis of error assumption test and model fit statistics such as R2, adjusted R2 and Mean Absolute Percentage error (MAPE). The respective selected best fit model is used for the estimation of growth rates of area, yield and production of rabi pulses in Odisha for each segment and the whole period of study. Among the spline regression models, the respective linear spline regression model is found to be best fit for area, yield and production of rabi pulses and are used for growth rate estimation of these variables. It is found that though the growth rate in area and yield of rabi pulses are not significant, the growth rate of production is found to be significant for the whole period of study which shows that the interaction effect of area and yield on production seems to dominate.

Open Access Original Research Article

Assessment of Quality of Farm Saved Paddy Seeds Collected from Cauvery Delta Region

S. Selvamani, B. Sushmitha, R. Kowsalya, T. Eevera, S. Venkatesan

International Journal of Plant & Soil Science, Page 189-199
DOI: 10.9734/ijpss/2021/v33i2330734

Paddy is cultivated on a large scale in Cauvery delta region of Tamil Nadu. Due to non-availability of adequate quantity of certified seeds at their village level most of the farmers of this region using their farm saved seeds to raise the next season crop. In order to know the quality of farm-saved paddy seeds of delta region, a total of 20 seed samples from 17 distinct varieties were collected from various villages in the Thanjavur district of Tamil Nadu during Rural Agricultural Work Experience programme. The samples were subjected to physical and physiological seed quality parameters evaluation at Seed Science and Technology laboratory of Anbil Dharmalingam Agricultural College and Research Institute, Thiruchirappalli. Only 15% of samples such as Seeraga samba, Karuppukavuni and RNR 1548 alone showed 80% seed germination. The average germination percent was 50.05. Based on our observations, farmers of this region store their seeds in gunny bags without proper drying and not following any pre-storage seed treatment to protect the seeds against storage pathogens and insects.  Hence, awareness should be made among the farmers of this region regarding post harvest handling and management of farm produce harvested and stored for seed purpose. The government of Tamil Nadu should educate farmers about post-harvest handling of seeds through the Department of Agriculture to increase productivity and production of our country.

Open Access Original Research Article

Effect of Foliar Spray of Boron and their Time of Application on Yield, Quality and Economics of Beetroot (Beta vulgaris L.)

Tanay Bhatnagar, K. D. Ameta, Mohan Singh, Jitendra Kumar Tak, Ramesh Chand Choudhary

International Journal of Plant & Soil Science, Page 219-225
DOI: 10.9734/ijpss/2021/v33i2330736

The present investigation was carried out at Hi-Tech Unit, Department of Horticulture, Rajasthan College of Agriculture, MPUAT, Udaipur. The twelve treatments comprising of various combinations of 4 levels of boron, i.e., B 0 - 0, B 1 - 100, B 2 - 150 and B 3 - 200 ppm and three spray application times, i.e., D 1 - 30, D 2 - 45 and D 3 - 60 DAS. The treatments for beetroot crop were evaluated with three replications under factorial randomized block design. The experimental results show that different concentrations of boron, application times and their combinations significantly affected yield and quality of beetroot. Among treatments with different concentration of boron maximum yield per plot (45.44 kg), yield of root (454.45 q/ha), dry matter (18.08 %), protein on dry weight basis (2.54 %), ascorbic acid content (3.48 mg 100g-1), total soluble solids (16.10 oBrix) and beta carotene content (1438.34 IU) were recorded with treatment B3D1 (200 ppm boron spray at 30 DAS) and alsosignificantly produced higher gross return (₹ 238340.00), maximum net return (₹ 170230.00) and benefit cost ratio of 2.50, i.e., generating highest net return of ₹ 2.50 per rupee invested.

Open Access Original Research Article

Assessing the Toxic Effects of Insecticides on Honey Bees in the West Gonja District of the Savannah Region of Ghana

Joseph Lambon, Abdul-Rahaman Issahaku

International Journal of Plant & Soil Science, Page 226-245
DOI: 10.9734/ijpss/2021/v33i2330737

Aims: To examine the toxic effects of insecticides on bees in farming communities in the Savannah Region of Ghana.

Study Design:  The study employed five different doses of insecticides to 3 groups of 10 honey bees in each group using 3 types of insecticides. The number of dead bees were registered and used for the estimation of LC50 of each insecticide.

Place and Duration of Study: The experiment was conducted at Damongo Agricultural Training College, Ghana, between August 2019 and September 2019.

Methodology: We collected bees from farms in the West Gonja District of the Savannah Region of Ghana. Controller Super 2.5 EC, Pyrinex 48 EC and Golan SL were insecticides used for the experiment. Live adult bees were randomly obtained from beehives at 2:00 am from the farms when the bees were not aggressive. The bees were collected by hand and placed into a perforated plastic container and transported from the site of collection to the experimental site. They were allowed to acclimatize to the experimental conditions for a period of three hours under room temperature of 24 °C  and a relative humidity of 49 percent throughout the study.

Results: Mortalities were recorded 10 minutes after administering the concentrations and thereafter at every 10 minutes continuously till 60 minutes. The LC50 was calculated using Where N is the number of honey bees in each group

Controller Supper 2.5 EC at a concentration of 6.7 ml/L gave the highest mean mortality (10 bees) at the 50th minute while the concentration of 1.0 ml/L gave the lowest mean mortality (0.0 bees) in the same 50th minute.

Conclusion: The LC50 for the three insecticides used were within the recommended concentrations provided by the Environmental Protection Agency of Ghana. The overall mortalities occurred when honey bees were exposed to different concentrations of all the three insecticides.

Open Access Original Research Article

Rapid Screening of Small Millet Varieties for Seedling Stage Drought Stress Tolerance

Neethu Francis, R. Ravikesavan, K. Iyanar, M. Raveendran, T. Chitdeshwari, A. Senthil

International Journal of Plant & Soil Science, Page 246-252
DOI: 10.9734/ijpss/2021/v33i2330739

Aim: Drought is one of the most important abiotic stresses that affect the yield of crops globally. The present investigation was conducted to identify small millet genotypes tolerant to seedling stage drought stress.

Study Design: The experiment was laid out in Completely Randomized Design (CRD) with three replications with genotypes and stress treatments as factors.

Place and Duration of Study: It was carried out at Department of millets, Centre for plant breeding and genetics, Tamil Nadu Agricultural University, Coimbatore, during 2019.

Methodology: Ten varieties of various small millets, CO 7 (foxtail millet), CO 4 and ATL 1 (little millet), CO 15 and CO 9 (finger millet), ATL 1 and CO (PV) 5 (proso millet), MDU 1 and CO 2 (barnyard millet) and CO 3 (kodo millet), were used for the study. In vitro screening of the seedlings in Polyethylene Glycol (PEG)-induced water stress at four levels (0, -3, -5 and -7 bars) were carried out based on germination percent, shoot and root length, plant height stress tolerance index (PHSI), root length stress tolerance index (RLSI) and seedling vigour index (SVI).

Results: Analysis of variance of the genotypes and PEG treatments revealed significant variation for genotypes, treatments and genotype x treatment interactions at P< 0.001. A declining trend for germination percent, shoot length and root length was observed as the stress levels were increased. However, at mild and moderate stress root length was slightly increased. Under mild (-3 bars) and high stress (-7 bars), CO 7 (foxtail millet) recorded the highest SVI percent over control values (165% and 65% respectively). Under moderate stress CO 4 (little millet) recorded the highest SVI (191%). The lowest SVI values under high stress, 4% and 8%, were recorded for ATL 1 (little millet) and CO 3 (kodo millet) respectively.

Conclusion: Based on invitro screening of small millet varieties for seedling stage water stress, foxtail millet variety CO 7 and kodo millet variety CO 3 can be concluded as the tolerant and susceptible varieties respectively. Further a controlled field experiment may be carried out to understand the field level tolerance of the varieties and their growth stages to drought.

Open Access Original Research Article

Sowing Dates and Varieties of Wheat can Affect Yield, Nutrient Content in Grain, Straw and Soil after Crop Harvest

Bhawani Singh Prajapat, Ram A. Jat, Deen Dayal Bairwa

International Journal of Plant & Soil Science, Page 253-258
DOI: 10.9734/ijpss/2021/v33i2330740

The present study aimed to determine the Sowing dates and varieties of wheat can affect yield, nutrient content in grain, straw and soil after crop harvest. A field experiment was conducted during Rabi season (2015-16) at Instructional Farm, Department of Agronomy, College of Agriculture JAU, Junagadh to evaluate the identification of the suitable date of sowing and variety of wheat (Triticum aestivum L.) for South Saurashtra, Gujarat under changing climatic conditions. The experiment consisted of 12 treatment combinations of four dates of sowing in main plots (05th November, 15th November, 25th November and 05th December) and three varieties in sub plots (GW 322, GW 366 and GW 173) was carried out in split-plot design with three replications. Significantly maximum grain yield, N, P and K in grain and straw was recorded with sowing on 15th November and with the sowing of GW 366. Higher available N, P2O5 and K2O in the soil after harvest was found on 05th December and GW 173.

Open Access Original Research Article

Tanzanian Bat Guano as an Alternative Source of Phosphorus for Organic Rice Production

Asha Ally Hatibu, Mawazo Jamson Shitindi, Ernest Melkiory Marwa

International Journal of Plant & Soil Science, Page 259-276
DOI: 10.9734/ijpss/2021/v33i2330741

Many tropical and subtropical soils are low in phosphorus. This is partly because of excessive weathering, high phosphorous (P) fixation rates, and low P levels in soil parent materials. Continuous removal of P from soils by crops, coupled with limited application of P fertilizers, is also among the contributing factors for low P in soils. Phosphorus is among the most limiting macronutrient in rice (Oryza sativa L.) production. This study was conducted to evaluate the suitability of bat guano collected from Kisarawe (BGK-A and BGK-B) and Sukumawera caves (BGS) in Tanzania. The screen-house experiment at the Sokoine University of Agriculture was designed as a 4 × 6 factorial experiment conducted as a randomized complete block design (RCBD). Guano and triple superphosphate (TSP) were used as standard fertilizer at six P application rates. The yield of rice in response to applied TSP was comparable to applied guano but in the order TSP > BGK-A > BGS > BGK-B. All parameters increased with an increase in applied amounts of P from guano and TSP. Besides this study revealed the significant (P = .05) interaction between P sources and P rates on plant height (PH), micronutrient concentration and dry matter (DM).  The study showed the correlation between grain yield (GY) and other crop components of dry matter (DM), the number of panicles (NP), Panicle height (PAH), plant height (PH) and number of tillers (NT). A significant and positive correlation was found for the GY-DM (r = 0.58, P = .05), GY-PAH (r = 0.65, P < .001), and GY-NT (r = 0.420, P = 0.1). But strong positive correlation was found between GY-PH (r = 0.76, P < .001) and GY-NP (r = 0.84, P < .001). It was concluded that studied guanos can be used as an alternative source of P, especially for   smallholder farmers.

Open Access Original Research Article

Evaluation of Silicon Nutrition on Yield, Growth Attributes and Available Nutrient Status of Paddy in Coastal Zone of Odisha

Aliva Das, Prasanna Kumar Samant, Gayatri Sahu, Gour Hari Santra

International Journal of Plant & Soil Science, Page 277-288
DOI: 10.9734/ijpss/2021/v33i2330742

A field experiment was conducted in the central farm, Regional Research and Technology Transfer Station, Coastal Zone OUAT, Bhubaneswar, Odisha, India during kharif 2020 using cv-Lalat variety of Rice. The experiment was laid out in randomized block design (RBD) with ten treatments and three replications. In this experiment BOF (Basic Oxygen Furnace) slag was used as a source of silica for application to rice crop. 200, 300 and 400 kg SiO2/ha was applied in combination with 50% STD (Soil Test Dose) and 75% STD to assess the efficacy of Silica with reduction in fertilizer dose by 50% and 25%. It was shown that increase in number of effective tillers (7.8) per plant and length of the panicle (25.8 cm), but no significant increase was marked in case of 1000 grain weight (gm.) over control. In case of grain yield, straw yield and harvest index, 100% STD (T4) registered maximum (36.9q/ha) grain yield which was 29.4% more than that of control. Of course, grain yield in case of T9 i.e., 75% STD+300 kg SiO2/ha was at par 36.2q/ha indicated efficacy of silica application by reducing fertilizer dose. Harvest index was not affected by Si treatments. However, maximum HI (0.478) was observed in T9. Available N, P, K and S status in post-harvest soil was increased due to application of silica along with fertilizer over control indicated better availability of nutrients which plays a vital role in increasing production and productivity of rice. The study revealed that the DTPA extractable Fe and Mn content decreased, and Cu and Zn content increased with increased application of silica. Though 100% STD (T4) was found to be very effective as compared to other treatments but 75% STD + 300kgSiO2/ha was also equally effective so far as yield, growth attributing characters, available nutrient status of paddy.

Open Access Original Research Article

Characterization of Pigeonpea Genotypes Based on DUS Traits

M. S. Ranjani, P. Jayamani

International Journal of Plant & Soil Science, Page 289-297
DOI: 10.9734/ijpss/2021/v33i2330743

The research entails morphological characterization of pigeonpea genotypes based on qualitative traits which aids in varietal description and ensure genetic purity. The study was conducted at the Department of Pulses, Tamil Nadu Agricultural University during kharif, 2019 and rabi, 2019-2020. The experiment was conducted in Randomized complete block design with two replications. The 68-short duration pigeonpea genotypes were characterized and grouped based on 17 qualitative traits. The morphological characterization revealed that, more variation was identified for traits viz., pattern of streaks on standard petal, plant height, seed colour, seed shape and seed size. Sixty - eight genotypes were subjected to cluster analysis and were grouped into four major clusters with an average similarity of 80%. The similarity coefficient ranged from 0.65 to 1.00. The cluster I consisted of 60 genotypes. Two sub-groups were formed from Cluster I. The sub-group I had 59 genotypes at 84 per cent similarity, whereas the sub-group II consisted of the genotype ICPL19050. Cluster II was made up of six genotypes. The cluster II was divided into two sub-groups at 84 per cent similarity. Clusters III and IV were solitary clusters, each with a single genotype. The characterization of genotypes with specific traits could be used to identify the genotypes, maintenance of genetic purity and to utilize in future breeding programmes.

Open Access Original Research Article

Validation of Maize (Zea mays L.) Hybrids for the Study on Variability, Trait Association, and Path Analysis

M. Ramesh Kanna, Hiramani Barman, Kasireddy Sivasankarreddy, Dikshita Gogoi, T. V. Rao, N. Sarma Barua

International Journal of Plant & Soil Science, Page 298-308
DOI: 10.9734/ijpss/2021/v33i2330744

The present investigation was conducted with nine genotypes in randomized block design during Rabi, 2019-20 at the instructional-cum-research farm, Assam Agricultural University, Jorhat. All the characters exhibited significant genotypic mean squares in analysis of variance except anthesis silking interval, kernel rows per ear and 100 kernel weights. High heritability coupled with high genetic advance was observed for the traits plant height, ear height, ears per plant, ear length, kernels per row, chlorophyll content, leaf area index 60 days after sowing (LAI 60 DAS), LAI 90 DAS, harvest index, grain yield per plant and grain yield per hectare. Significant genetic association of grain yield per plant and grain yield per hectare with days to 50% pollen shed, days to 50% silk, days to 100% dry husk, ear height, kernels per row, LAI 60DAS and LAI 90 DAS. Genotypic path analysis revealed that the characters, days to 50% silk, days to 100% dry husk, plant height, ears per plant, ear diameter and harvest index had the highest positive direct effects on grain yield per hectare while days to 50% pollen shed and ear height had the highest negative direct effect on grain yield per hectare. The hybrids namely, PAC 751, CP 333 and PAC 751 ELITE, were found to be the three best hybrids to possess a high estimate of desirable traits such as days to 50% pollen shed, days to 50% silk, days to 100% dry husk, plant height, ear height, ear diameter, leaf area index at 60 days after sowing, lea area index at 90 days after sowing, grain yield per plant and grain yield per hectare.

Open Access Review Article

Efficacy of Beneficial Microbes in Sustainable Management of Plant Parasitic Nematodes: A Review

Rudoviko Galileya Medison, Milca Banda Medison, Litao Tan, Zhengxiang Sun, Yi Zhou

International Journal of Plant & Soil Science, Page 119-139
DOI: 10.9734/ijpss/2021/v33i2330728

The soil inhabits many microbes, including plant parasitic nematodes. Plant parasitic nematodes are reported to cause substantial damage to crops which results in yield and economic losses. Chemical control is the most widely used method to control plant parasitic nematodes. However, the consequences of synthetic chemicals are detrimental to human health, animals, and the environment and face so many strict regulatory measures. Synthetic chemicals are also not reliable with their inability to provide long-term protection. Many studies have shown that the use of beneficial fungi and bacteria has the potential to prevent and suppress plant parasitic nematodes while keeping the environment safe. Several experiments have demonstrated that bioproducts of microbial origin are cheap, safe, and provide long-lasting biocontrol effects against pathogens both in vitro and field conditions. Therefore, this review aims to discuss mechanisms that beneficial microbes and their products use to successfully suppress plant parasitic nematodes. The review also explains the importance of using commercial bionematicides in the sustainable management of plant parasitic nematodes. The existing challenges that are limiting the full application of beneficial microbes, and what needs to be done to fully utilize biocontrol agents in the management of plant parasitic nematodes have also been discussed. To the best of our knowledge, this review has come at the right time to give researchers and plant growers more options when several synthetic chemical nematicides are being banned by regulatory authorities due to their hazardous effects.

Open Access Review Article

Phytoliths: Persistence & Release of Silicon in Soil and Plants – A Review

A. Senthilkumar, B. Bhakiyathu saliha, P. Saravana Pandian, R. Thamizh vendan, A. Gurusamy, P. P. Mahendran

International Journal of Plant & Soil Science, Page 200-218
DOI: 10.9734/ijpss/2021/v33i2330735

Phytoliths are formed from silica carried up from groundwater and some plants. The weathering of silicate minerals at the Earth’s surface provides large amounts of soluble silica, some of which is absorbed by growing plants. In solution, silica exists as mono silicic acid Si (OH4) with pH values of 2–9. It is carried upward in the vascular system and becomes concentrated during transpiration around the leaf stomata. The supersaturated solution begins to polymerize or gel then solidifies and forms solid opaline silica (SiO2:nH2O) bodies (phytoliths) within and between some of the plant cells. Phytoliths were extracted from the 7.4 meter loess core and analyzed morphologically and isotopically from the occluded carbon. Rates of isotopic fractionation between plant and phytolith were determined by measurements from many modern tree, fern, and grass species. The use of phytolith biochar as a Si fertilizer offers the undeniable potential to mitigate desilication and to enhance Si ecological services due to soil weathering and biomass removal. Silicon is accumulated at levels equal to or greater than essential nutrients in plant species belonging to the families Poaceae, Equisetaceae, and Cyperaceae. However, the abundance of silicon in soils is not an indication that sufficient supplies of soluble silicon are available for plant uptake.