Alkaline Calcareous Soils Research Articles

Straw-based biochar mediated potassium availability and increased growth and yield of cotton (Gossypium hirsutum L.)

Potassium (K) being the major limiting factor affecting cotton yield and quality has received massive research attention and the effects of various K fertilization techniques/organic amendments have been studied extensively. However, it is not clear whether the straw based, high pH biochar affects K availability, lint yield and quality of the cotton crop in alkaline calcareous soils. In the present study, we carried out a field experiment on a moderate to strongly calcareous silt loam soil to demonstrate the effect of straw-based biochar and potassium application levels on the growth, seed cotton yield and the lint quality. The experimental treatments comprised of two factors, A) biochar types i) Control no biochar, ii) Rice husk biochar (RHB), iii) Wheat straw biochar (WSB), and iv) Rice straw biochar (RSB), factor B) potassium application levels (i) control, no K fertilizer application, ii) K at 15 kg ha−1, and iii) K at 30 kg ha−1 (4 × 3 × 3, n = 36). Results showed that overall cotton growth and yield was significantly improved with increasing rates of potassium application. Three biochar sources affected seed cotton yield and quality with varying effects. For instance, the RSB increased plant height (11.71% to 22.47%), number of bolls per plant (0.74% to 13.75%), average boll weight (35.44% to 36.22%), the seed cotton yield was increased by 14.48% over the control when rice straw biochar was applied in combination with potassium at 30 kg ha−1. However, the ginning out turn (%) was declined with potassium application in combination with all three-biochar compared to control (no biochar addition). The WSB increased staple length and micronaire by 4.32% and 24.50% without potassium application. The potential effects of straw based biochar and potassium application on seed cotton yield and quality deserve further studies to identify the most suitable biochar as per soil chemical properties.

Optimizing Phosphorus Levels in Wheat Grown in a Calcareous Soil with the Use of Adsorption Isotherm Models

Crop response to phosphorous (P) application is often erratic in most soil types in the world. In alkaline calcareous soils, P retention and mobilization take place due to precipitation and adsorption. P adsorption isotherms are the powerful tools for assessing optimum P levels for different crops and soils. Laboratory and field studies were carried out to evaluate P sorption capacity in a highly calcareous soil and corresponding fertilizer levels for yielding 0.1 to 1.0 mg P L−1 of soil solution. Although Freundlich adsorption isotherm model showed a better fit than Langmuir model, P fertilizer levels used in the field, ranging from 20 to 150 kg P2O5 ha−1, were based on Langmuir model to yield the estimated P solution. Moreover, nitrogen (N) and potassium (K) were applied at the rates of 120 and 60 kg ha−1 as urea and potassium sulfate (K2SO4), respectively, in a basal treatment at the time of sowing. Grains per spike, 1000-grain weight, grain yield, spike length, and biological yield were increased as the level of P increased, but the non-significant differences among 90, 100, and 120 kg P2O5 ha−1 for most of the above parameters suggested that the former rate could be the maximum level for wheat fertilization in the calcareous soil. Similarly, plant N, P, and K were increased with application of P, but non-significant differences were observed from doses 90 to 120 kg P2O5 ha−1. Moreover, the rate of 90 kg P2O5 ha−1 could yield 0.6 mg P L−1 of soil solution as per Langmuir adsorption isotherm model, while as per Freundlich model, this value could reach only 0.3–0.4 mg P L−1, which is close to the published literature. It is concluded that Freundlich adsorption isotherm is more suitable to be used for the calculation of phosphatic fertilizer rate and its adsorption capacity in the given soil than Langmuir adsorption isotherm.

Rock Phosphate-Enriched Compost in Combination with Rhizobacteria; A Cost-Effective Source for Better Soil Health and Wheat (Triticum aestivum) Productivity

Organic materials from various sources have been commonly adopted as soil amendments to improve crop productivity. Phosphorus deficiency and fixation in alkaline calcareous soils drives a reduction in crop production. A two-year field experiment was conducted to evaluate the impact of rock phosphate enriched composts and chemical fertilizers both individually and in combination with plant growth promoting rhizobacteria (PGPR) on wheat productivity and soil chemical and biological and biochemical properties. The present study demonstrates significant increments in crop agronomic and physiological parameters with Pseudomonas sp. inoculated RPEC1 (rock phosphate + poultry litter + Pseudomonas sp.) over the un-inoculated untreated control. However, among all other treatments i.e., RPEC2 (rock phosphate + poultry litter solubilized with Proteus sp.), RPC (rock phosphate + poultry litter), HDP (half dose inorganic P from Single Super Phosphate-SSP 18% P2O5) and SPLC (poultry litter only); RPEC1 remained the best by showing increases in soil chemical properties (available phosphorus, nitrate nitrogen, extractable potassium), biochemical properties (alkaline phosphatase activity) and biological properties (microbial biomass carbon and microbial biomass phosphorus). Economic analysis in terms of Value Cost Ratio (VCR) showed that the seed inoculation with Pseudomonas sp. in combination with RPEC1 gave maximum VCR (3.23:1) followed by RPEC2 (2.61:1), FDP (2.37:1), HDP (2.05:1) and SPLC (2.03:1). It is concluded that inoculated rock phosphate (RP) enriched compost (RPEC1) can be a substitute to costly chemical fertilizers and seed inoculation with Pseudomonas sp. may further increase the efficiency of composts.

Higher biochar rate strongly reduced decomposition of soil organic matter to enhance C and N sequestration in nutrient-poor alkaline calcareous soil

Our knowledge of biochar as a tool for soil carbon (C) sequestration and soil quality in semi-arid regions remains limited in recent years. Moreover, there is a lack of understanding on the comparison between effects of biochar rates on soil organic C (SOC) and nitrogen (N) mineralization in organic C poor soils. Interactive effects of corncob-biochar (B), prepared at 450 °C pyrolysis temperature, and wheat straw (W) on soil native and fresh organic matter were investigated in sandy loam alkaline calcareous soil. The corncob-biochar was applied alone and in combination with wheat straw (WB) at rates equivalent to 0 t ha-1 (unamended control), 22.5 t ha-1 (B1, W1, W1B1), and 45 t ha-1 (B2, W2, W2B2). After treatment applications, soils were incubated under laboratory conditions for 61 days and periodic CO2 evolution rates were measured to calculate the cumulative CO2 efflux and priming effects. The lowest CO2 efflux was found in B2 treatment, whereas CO2 efflux was lower in W1B1 than in W1 treatment. Biochar alone and with wheat straw significantly reduced net C mineralization (NCM) compared to wheat straw only treatments and the effects became stronger as biochar rate increased. This was reflected in data on the priming effect, which also showed that increased biochar rates induced a stronger negative priming (− 87 to − 67%) on SOC. Biochar with wheat straw at both rates enhanced microbial biomass C (MBC) compared to the control, W1, B1, and B2 treatments. However, the W1B1 and W2B2 treatments decreased water-extractable organic C (WEOC) contents compared to W1 and W2. Microbial metabolic quotient (qCO2) and MBC/TOC ratio increased with biochar rate, suggesting more efficient utilization of labile C by microorganisms at higher biochar rate. Biochar alone and with wheat straw reduced soil mineral nitrogen (N) contents than the control treatment and resulted in net negative N mineralization or net N immobilization. Our findings indicate that biochar can reduce decomposition of soil organic matter to facilitate C and N sequestration in low organic C soils. However, our study also suggests the co-application of biochar and organic amendments/residues as labile C source to induce co-metabolism to improve microbial functions and C utilization efficiency in soils that are deficient in organic C.

Sustainable Management with Mycorrhizae and Phosphate Solubilizing Bacteria for Enhanced Phosphorus Uptake in Calcareous Soils

Low availability of phosphorus (P) in calcareous soils is a major problem for sustainable improvement in cereals crops yield. A higher amount of calcium in soils precipitates the P, thus making it immobile in soil. Inoculation of arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB) could be helpful in the sustainable management of immobile P in soil. However, their combined use in releasing P from rock phosphate (RP) in alkaline calcareous soils have been little investigated. In this regard, two successive field experiments were conducted to assess the interactive inoculation potential of AMF and PSB strain Bacillus sp. PIS7 with RP on the yield and P uptake of maize (Zea mays L.) and wheat (Triticum aestivum L.) crops in alkaline calcareous soil. The first field experiment was conducted in a complete randomized block design with 10 treatments and three replications by inoculating maize seeds with AMF and Bacillus sp. PIS7 inoculum alone and in combination with RP. Their performance was compared with single super phosphate (SSP) inorganic fertilizer. Afterward, the residual effects of inoculated AMF and Bacillus sp. PIS7 were investigated on wheat as a subsequent crop. Maize and wheat yield parameters, P uptake, AMF root colonization, and PSB population was measured. The results of both trials indicated the beneficial effects of AMF and Bacillus sp. PIS7 with RP in increasing the plants grain yield and P uptake until the second season after inoculation, as compared to controls. Likewise, maize and wheat roots colonization, PSB population density, and post-harvest soil properties were also improved by the combined inoculation of AMF and Bacillus sp. PIS7 with RP. It is concluded that PSB solubilizes the unavailable forms of P in combination with RP fertilizers in soil, and AMF ultimately transfers it to plants for growth promotion. Moreover, the combined inoculation of AMF and PSB with ground RP had more potential to improve maize-wheat yields and P uptake comparable to those obtained by using expensive phosphatic fertilizers in P deficient calcareous pH soils.

Developing a nano-Fe Complex to Supply Iron and Improve Salinity Tolerance of Pistachio under Calcium Bicarbonate Stress

ABSTRACT Iron (Fe) is chronically low in saline sodic soils. The effect of nano iron (Fe) particles complexed with salicylic acid (nFe-SA) on the Fe supply and salinity tolerance of Pistacia vera ‘Akbari’ seedlings were compared with seedlings grown in a control Hoagland nutrient solution amended with Fe-EDDHA. The saline treatments were prepared by adding 0 (control), 100, and 200 mM NaCl to the nutrient solutions. Moreover, calcium bicarbonate (0.2% w/v) was added to all these treatments. Plant growth, water relations, injury indexes, and mineral composition were investigated after 75 days. Growth and chlorophyll content of the plants was the same with both nFe-SA and Fe-EDDHA treatments under non-saline conditions. Increasing salinity stress restricted plant growth, and reduced leaf relative water content and water potential. Leaf abscission due to Na accumulation was the major cause of biomass loss and plant growth inhibition. Salinity also reduced leaf inorganic nutrient concentrations and produced leaf oxidative damage. However, under salinity stress, the nFe-SA treated plants had less leaf abscission and growth limitation than the Fe-EDDHA plants. The nFe-SA application decreased plasma membrane damage and chlorophyll degradation. Salinity stress increased Zn, Cu, and Fe concentrations in the Fe-EDDHA treated plants. However, low chlorophyll concentration in these plants indicated that inorganic nutrients were not functional. The results suggest nFe-SA can be an effective and environmentally friendly Fe source in saline and calcareous alkaline soils.

Critical load model and pollution indices application for water–soil–plant system assessment around El-Hammam canal, East El-Alamein, Egypt

El-Hammam canal, East El-Alamein City, is one of the national sustainable projects for facing food shortage in Egypt. The current work was conducted to evaluate the water–soil–plant system quality concerning potential toxic elements (PTEs) in this area. Surface water, soil and fruit samples were collected and analyzed for their content of As, Cd, Cr, Cu, Ni and Pb. The studied soils are sandy calcareous alkaline soil with low organic matter content. The potential ecological risk index (PERI) indicated that most soils were of very high PERI owing to the elevated Cd and to less extent As and Ni. Unfortunately, most of the recorded Cd and Pb appeared in the bioavailable fraction. The studied water samples contained acceptable levels of ions for irrigation, except Cd, Cu and Ni. Both apple and peach contained acceptable concentrations of PTEs, except peach that contains an elevated level of As. It was observed that the concentration of PTEs in peach was higher than the apple. The bio-concentration factor values of PTEs in apple and peach indicated that fruits were excluders of the PTEs. The study area contains critical loads of the studied PTEs, especially As, Cr and Ni, which mostly attributed to the plant uptake of PTEs. The uptake of plants (harvested part) of these toxic elements can be cause of many health problems. Pesticide sprays may be the source of these elements leaching on plant surfaces. Finally, the study area content of PTEs can be attributed to the polluted irrigation water and agrochemical.

Neem (Azadirachta indica) oil coated urea improves nitrogen use efficiency and maize growth in an alkaline calcareous soil

Neem (Azadirachta indica) oil coated urea improves nitrogen use efficiency and maize growth in an alkaline calcareous soil

Effect of biochar and phosphate solubilizing bacteria on growth and phosphorus uptake by maize in an Aridisol

Phosphorus (P) availability is limited to crop plants especially in alkaline calcareous soils due to formation of various precipitates. In such soils, use of P solubilizing bacteria (PSB) along with suitable organic amendment such as biochar (BC) might be the possible solution to provide suitable P concentration to plants. Interactive effect of PSB, BC (0 and 2% w/w), and three application rates of P fertilizers (no fertilizer, half dose, full dose) on P availability and plant growth in a calcareous soil was investigated. The maize (Zea mays L.) seeds were primed with PSB in sugar solution and later sown in clay pots filled with soil (10 kg) and mixtures of BC and fertilizers. Three plants were maintained in each pot and grown for 45 days. Soil parameters such as soil pH, EC, nitrogen (N), and Olsen’s P concentrations were determined after harvesting the plants. The plant growth, biomass, P, and N concentrations in plants were also determined. The results depicted that the PSB-primed plants grown in biochar-amended soil supplied with half and full fertilizers showed maximum growth. No significant effect on the seed germination was observed, but the uptake of P was high in those plants where PSB and BC were applied as a cumulative treatment. Only PSB treatment also showed better results except in no fertilizer treatment as compared with PSB + BC + no fertilizer treatment where BC provided P. The plants yielded higher biomass with full fertilizer doses, but significant and maximum increments were observed in BC + PSB + full fertilizer treatment. Similarly, the uptake of N was high in BC treatment plants as compared with the PSB and control. The application of BC and inoculation of PSB can reduce the demand of fertilizer as well as can be proved as a natural conditioner that can sustain and improve the soil’s physical, chemical, and biological conditions. However, field investigations under different agroclimatic conditions are required before final recommendations.

Zinc-biofortified wheat required only a medium rate of soil zinc application to attain the targets of zinc biofortification

ABSTRACT Zinc (Zn) deficiency is prevalent in human populations in developing countries. The present study compared two wheat (Triticum aestivum L.) cultivars [Jauhar-2016 (standard wheat) and Zincol-2016 (Zn-biofortified wheat)] for Zn biofortification with optimum soil Zn application. For this, Zn (at 0, 3, 6, 12 and 24 mg Zn kg−1) was applied to pots having an alkaline calcareous soil. Grain yield, grain Zn concentration and grain Zn bioavailability in both cultivars were significantly increased by Zn fertilization. However, Zn application decreased iron (Fe) and phytate concentration in grains of both cultivars. As compared to Jauhar-2016, Zincol-2016 had significantly higher grain Zn concentration and grain Zn bioavailability at all the respective soil Zn rates excepting only at control. At 6 mg Zn kg−1, Zincol-2016 attained in grains a desired concentration of Zn (53 mg Zn kg−1) and a desired level of human Zn bioavailability (2.8 mg d−1 for women and was 3.0 mg d−1 for men). Jauhar-2016 also attained such comparative levels but only at a plant toxic rate of Zn (24 mg Zn kg−1). Conclusively, soil Zn application (agronomic biofortification) to Zn-biofortified wheat (Zincol-2016) may be a promising approach to decrease human Zn deficiency in population groups dependent on wheat-based diets.

Ecological criteria for zinc in Chinese soil as affected by soil properties.

The increasing accumulation of zinc (Zn) in agricultural soils has led to the need to assess the potential risk of this element for terrestrial organisms. However, the soil ecological criteria in agricultural soil as a function of soil properties have been sparsely reported. In the present study, we derived the ecological criteria (expressed as predicted no effect concentration (PNEC)) for Zn in soils, based on ecotoxicity data for 19 terrestrial species in Chinese soils, the effect of soil properties on Zn ecotoxicity, differences in species sensitivity, and differences between laboratory and realistic field conditions. First, all ecotoxicity data of Zn for terrestrial organisms in Chinese soils were collected and filtered with given criteria to obtain reliable database. Second, the ecotoxicity data were normalized using Zn ecotoxicity predictive models to eliminate the effect of soil properties on Zn ecotoxicity, and corrected with leaching and aging factors to minimize the differences in Zn ecotoxicity under laboratory and field conditions. Then, species sensitivity distribution (SSD) curves were generated with a Burr Ⅲ function based on corrected ecotoxicity data. The concentration of Zn in soil that provides ecological safety for (100-x)% of species (HCx), was calculated from the SSD curve and HC5 was used for estimation of PNEC. Finally, we developed the predictive models for HCx by quantifying the relationship between the Zn HCx and soil properties. Results showed that soil pH was the most crucial factor affecting Zn HCx values, with HC5 values varying from 38.3mg/kg in an acidic soil to 263.3mg/kg in an alkaline calcareous soil. Both the two-factor (soil pH and OC) and the three-factor (soil pH, OC and CEC) models predicted HCx values well, with determination coefficients (R2) of 0.941-0.959 and 0.978-0.982, respectively. This study provides a scientific and reliable basis for the improvement of ecological risk assessment and the establishment of soil environmental quality standards.

Co-application of sugarcane bagasse biochar, farmyard manure and mineral nitrogen improved growth indices of corn grown in alkaline calcareous soil

Soil quality and crop productivity can be improved by the combined soil application of organic amendments and synthetic fertilizers. We evaluated the sole and combined effects of sugarcane-bagasse biochar (SBB), farmyard manure (FYM) and nitrogen (N) fertilizer on soil properties and corn yield traits. Three N fertilizer rates (0, 50 and 100% of recommended) were used with or without the organic amendments. We observed significant increases in soil nitrate-N (at vegetative and reproductive phases), ammonical-N and microbial-biomass-N contents in responses to a co-application of 0.5% SBB, 0.5% FYM and 100% N fertilizer (p ≤ 0.05). While the same co-application also resulted in the most significant soil organic carbon value, the maximum soil microbial biomass carbon was observed when 0.5% SBB and 0.5% FYM combination was applied along with 50% N fertilizer (p ≤ 0.05). Plant growth indices—shoot length and, fresh and dry weights of shoot and root were also recorded to be the highest where the same organic amendments were applied in addition to a 50% or 100% mineral N fertilizer (p ≤ 0.05). Combined application of the organic amendments effectively improved soil CEC compared to those in responses to individual applications of SBB and FYM (p ≤ 0.05). Conclusively, for increasing the corn yield and improving the soil quality, the co-application of 0.5% SBB and 0.5% FYM was more effective than any of the individual 1% applications; Additions of 50% and 100% mineral N to the organic combination were equally useful for increasing the grain yield.

Influence of Phosphorus Fertilizers Application on Phosphorus use Efficiency and Grain Protein of Winter Wheat in Alkaline-Calcareous Soil, Southern Algeria

hree field experiments (2008 to 2011) were conducted to evaluate the ability of winter wheat (Triticum durum Desf. var. Carioca) to utilize and acquire soil phosphorus and nitrogen under different sources of phosphate fertilizers (Fosfactyl, Single super phosphate and Mono-ammonium-phosphate) and rates of applications (30, 60, 90 and 120 kg Pha-1) with a fixed level of nitrogen fertilization. Results revealed a significant effect of P rates on phosphorus use efficiency (PUE) and nitrogen use efficiency (NUE); however, P sources fertilizer had non-significant effect in all three cropping seasons. PUE and NUE decreased markedly with increasing P supply that did not result in an improvement of P and N uptake. Grain protein content was significantly influenced by phosphorus fertilization in 2008-09. The best values were obtained by Single super phosphate and P rate 60 kg ha-1.

Agronomic potential of biochar prepared from brewery byproducts

This work investigated the effect of biochar produced from brewery byproducts, spent grain and surplus yeast on the physicochemical characteristics of a calcareous loam soil and plant growth of maize (Zea mays L.). Maize is a plant which needs high nitrogen fertilization, while the effect of acidic or neutral biochars on alkaline calcareous soils has only been assessed in a few studies. The effect of biochars on dry weight, as well as the level of macro- and micronutrients in soil, and above- and belowground plant tissues, were investigated, in a 30 day experiment after seedling emergence of maize (Zea mays L.), in the presence and absence of nitrogen fertilization.The results indicated that biochar from organic brewery by-products significantly increased the dry weight of the aboveground part of the plant by 59–186%, relative to the control, without the addition of inorganic N fertilization, and by 46–157% with the addition of inorganic N fertilization. The dry weight of the belowground plant tissues significantly increased by 83–92% and 46–106%, relative to the control, with or without the addition of inorganic N fertilization, respectively. Biochar addition, especially at 5% application rate individually or in a mixture, significantly increased the phosphorus content of plant tissues. The content of potassium in the plants was affected mainly by the addition of biochar derived from surplus yeast, while the concentration of calcium and magnesium in plant tissues was positively affected by spent grain biochar, in absence of inorganic nitrogen fertilization. Addition of biochars produced from brewery byproducts improved soil fertility parameters, particularly the contents of total organic carbon (by 133% and 118% with or without fertilization, respectively), total nitrogen (by 120% and 81% respectively) and available phosphorus in the studied loam calcareous soil. Overall, biochar from brewery wastes showed the potential to enhance plant growth and nutrient availability, thus it is a promising organic fertilizer for sustainable agriculture.

Different nitrogen and biochar sources’ application in an alkaline calcareous soil improved the maize yield and soil nitrogen retention

We investigated effect of biochars (BCs) and nitrogen (N) fertilizers on soil selected characteristics, growth of maize, and soil N transformations in a pot experiment. Maize was grown in soil amended with control (no BC), and three BCs different in feedstock (rice-straw biochar (RSBCC), vegetable-waste biochar (VMBC), poultry-manure biochar (PMBCC), and N application (control, 0.25 g N kg−1 soil using urea and NH4NO3). At harvest, agronomic parameter, soil (pH, EC, SOM, total N, and NO3-N), and plant analyses were done. The results showed the improvement in soil nutrient contents and yield with application of BC and N. The soil pH diminished in BC treatments where N was used. The soil EC was increased in RSBC treatment than the control but decreased in NH4NO3 application irrespective of all BC treatments. The SOM was improved in all BC treatments under N. The NH4 concentration in plants and total soil N were significantly enhanced in BC treatments even without N. The plant growth and nutrient uptake were more influenced in NH4NO3 than urea. Comparing BCs showed overall better performance of PMBC than RSBCC and VWBC. Overall, the combined supply of PMBCC and NH4NO3 has advantages of improving plant growth, and soil fertility by changing N dynamics.

Phosphate fertilizer premixing with farmyard manure enhances phosphorus availability in calcareous soil for higher wheat productivity.

Fixation reactions reduce the concentration of soluble phosphorus (P) and affect crop growth in alkaline calcareous soils. In lab and greenhouse studies, phosphoric acid (PA) or diammonium phosphate (DAP) were evaluated at various P rates (0, 18, 36 and 54 mg kg-1 soil), either as non-mix (designated as NM-PA and NM-DAP, respectively) or after premixing with farmyard manure (FYM) at 400 mg kg-1 soil (designated as PM-PA and PM-DAP, respectively). The amended soil was incubated at 25 °C and 70% water holding capacity for 7 weeks; thereafter, 32P dynamics were measured using the Freundlich kinetic model. A greenhouse study was also conducted using the same thirteen treatments (as used in incubation experiment) and wheat cultivar (Galaxy 2013) was grown following standard agronomic practices. The results showed that application of PM-PA at the highest rate, which caused maximum change in Pr (ΔPr = 59%) in laboratory condition, also produced maximum P uptake by grain (190.3 mg pot-1) and grain yield (44.1 g pot-1) of wheat in greenhouse experiment. Similarly, regression analysis showed that an increase in Pr values caused a corresponding increase in crop parameters. The results suggested that pre-mixing P fertilizer with FYM could be a viable technique to increase P supply and enhance productivity of wheat in alkaline calcareous soils.

Sustaining zinc bioavailability in wheat grown on phosphorus amended calcisol

The deficiency of zinc (Zn) and phosphorus (P) occurs widely in alkaline calcareous soils, and the antagonism between these two elements is also a major cause of low Zn uptake in wheat, leading to low productivity and quality. The present study investigated the different methods of Zn application for wheat cultivars [i.e. Faisalabad-2008 (Fsd-08) and Zincol] grown on P amended calcisol. Data regarding yield component, estimated Zn bioavailability and phytate content in grain were recorded. Compared to zero P control, application of phosphoric acid (PA) and di-ammonium phosphate (DAP) to wheat cultivar Fsd-08 increased biological yield by 49.1 and 76.4%, grain yield by 45.5 and 43.1%, and grain-P by 79.2% and 25.6%, respectively. The Zn-treatment (irrespective of mode of its application) produced higher grain Zn content, however, application of PA and DAP decreased grain Zn concentration by 26.5 and 30.5%, respectively relative to zero P treatments. Almost similar trend was observed in Zincol cultivar in terms of increase in yield parameters and grain-P and Zn content of wheat. The phosphate application also affected phytate to Zn molar ratio (PZR) which was usually found lower in Zincol (range: 12–35) while higher in Fsd-08 (range: 12–43). Overall, PA application was found to have higher beneficial effects in terms of increasing yield parameters and grain-Zn in wheat cultivars. In crux, the current investigation suggests that Zn application; especially foliar sprays sustained higher grain content while Zincol cultivar in particular accumulated higher grain-Zn grown on calcareous soils applied with phosphate fertilizers.

Copper induced iron deficiency in wheat (Triticum aestivum L)

A pot experiment was conducted to study the interaction effects of phosphorus and copper on wheat. The soils used were calcareous loamy sand (ls) and non calcareous sandy loam (sl). Four levels of Cu (0, 5, 10 and 20 mg Cu kg−1 soil) and six levels of P (0, 25, 50, 100, 200 and 400 mg P kg−1 soil) were applied in all possible combinations with three replications. Soil pH decreased with Cu application while Olsen P increased with P application in both soils. Growth and yield of wheat improved significantly with graded levels of applied P. However, when any level of P was combined with 20 mg Cu kg−1 soil, severe iron chlorosis of leaves, a drastic reduction in growth and chlorophyll content was observed in calcareous ls only. The results indicated that it was Cu and not P that induced Fe deficiency in wheat grown in alkaline calcareous soil and the Cu requirement of the crop seemed to be much lower in the calcareous ls. Root dry matter, grain and straw yield decreased with increasing levels of applied Cu in ls but in sl maximum increase of 62.5, 74.3 and 63.7 per cent in root, grain and straw yield was observed with a combined application of 400 mg P and 5 mg Cu kg−1 soil over control. Accumulation of Cu in roots decreased the Fe absorption by roots which indicated that Fe chlorosis of wheat leaves is expected when Cu: Fe concentration ratio in root is > 0.30.

Improvement in phosphorus nutrition of wheat plants grown in a calcareous sandy soil by incorporating chemical phosphorus fertilizer with some selected organic substances

Established fertilizer recommendations for wheat is urgently required to enhance the application efficiency of commercial phosphorus (P) fertilizers. This study evaluated the effect of inorganic P combined with some organic supplements i.e., citric acid (CA) or pigeon manure juice (PMJ), on alkaline-calcareous soil as well as plant measurements and phosphorus efficiency parameters of wheat (Triticum durum ’Boussalem’). Different concentrations of P in solution i.e., 0.05, 0.10, 0.15, 0.20, and 0.40 mg l−1, were worked out theoretically using the Freundlich model. A greenhouse study was conducted on a permanent layout with three replicates. As a result, phosphorus in the control was 0.493 mg P pot−1. However, in amended pots with organic substances, the averages of P uptake were 0.701 and 0.785 mg P pot−1, respectively for PMJ and CA treatments. A lower P requirement of 0.195 and 0.245 mg P l−1 may be required in CA and PMJ treatments, compared to the control treatments (0.345 mg P l−1). In addition, the phosphorus absorption efficiency (PAE) was higher in the CA and PMJ treatments. So, it is recommended to apply P fertilizers with poultry manure juice as an alternative solution in order to improve the efficiency of inorganic P fertilizers and consequently reduce their application rates in alkaline calcareous soils.

Influence of Boron Application on Root Growth of Green Gram in Loam Textured Soils

Boron (B) is one of the important essential plant micronutrient elements and plays a significant role in physiological and biochemical processes in the legumes and brassica crops. Some of the alkaline calcareous soils are B deficient soils. Root of the crop acts as zone of nutrient absorbing. On its growth and functioning, uptake of any nutrient takes place. A greenhouse experiment with green gram crop was designed to study the effect of B application on root in some alkaline calcareous loam textured soils for two years. Three soils with percent calcium carbonate content 0.75 (S I), 2.1 (S II) and 4.56 (S III) were collected from different sites of Ludhiana and Bhatinda districts, Punjab, India. The treatments comprised of four levels of soil applied B viz. 0.5, 0.75, 1.0 and 1.5 mg B kg-1 and two levels of foliar applied B viz. 0.1 and 0.2 percent borax solution with common control. Soil applied B had more influence on root mean dry matter yield than foliar applied B. Among all soil applied B, 0.5 mg kg-1 was best treatment. Soil applied B was more uptake by root as compared to foliar applied B. Among all three calcareous soils, Soil I with lower calcium carbonate was best soil in respect of root mean yield in comparison to Soil III with higher calcareous soils. At grand growth stage, the optimum yield (0.895 mg pot-1) was obtained when root B concentration was 10.6 mg kg-1 and the soil applied B level was 0.84 mg kg-1 while at maturity stage, the optimum yield (1.28 mg pot-1) was obtained when root B concentration was 10.6 mg kg-1 and the soil applied B level was 0.87 mg kg-1.