Critical manganese deficiency level for soybean grown in Ustochrepts

A greenhouse study with 15 soils, having a range in DTPA extractable Mn, was conducted to determine the critical deficiency level of Mn in Ustochrepts for predicting response of soybean to Mn application. Soil application of 10 mg Mn kg^–1 soil significantly increased the dry matter yield in deficient soils. Soil Mn was significantly related with Bray's per cent yield (r = 0.72^**) and Mn uptake (r = 0.75^**). Both graphical and statistical models of Cate and Nelson indicated the critical level to be 3.3 mg kg^–1 soil of DTPA extractable Mn. Critical Mn deficiency level in recently matured terminal leaflet blade at V6 growth stage in soybean plant was 22.0µg g^–1 dry matter. The predictability of soil and plant critical Mn level was 87 per cent.     

Evaluation of chromium release during the decomposition of leather meal fertilizers applied to the soil

Greenhouse studies of 14 soils, having a range in DTPA extractable Mn, were made to determine the critical deficiency level of Mn in ustochrepts for predicting response of green gram to Mn application. Soil Mn was significantly related with Bray's per cent dry matter yield (r = 0.68^**). Soil application of 20 mg Mn kg^–1 soil significantly increased the yield. Both graphical and statistical models of Cate and Nelson indicated the critical level to be 2.9 mg kg^–1 soil of DTPA extractable Mn. The critical deficiency level in youngest matured terminal leaf (YML) of 40 day green gram plants was 19.0µg g^–1. The predictability of soil and plant critical Mn level was 93 per cent.     

Response of chickpea (Cicer arietinum) to zinc fertilization and its critical level in soils of semi-arid tropics

In a greenhouse experiment the response of chickpea (Cicer arietinum) to zinc fertilization was examined using 27 soils from the semi-arid tropics. The critical level of DTPA extractable soil Zn was evaluated. Zinc additions to the soil increased the dry matter yield of six weeks old plant shoot, grain and straw significantly at the 5 mg kg^–1 level, but tended to decrease it at the 10 mg kg^–1 level.The DTPA extractable Zn of the soils ranged from 0.28 to 1.75 ppm and was negatively correlated at 1 per cent level with pH (r = – 0.81) and positively with organic carbon (r = 0.79) and Olsen's P (r = 0.63). The per cent yield increase or decrease over zero zinc ranged from 67 to – 16 in respect of grain yield and was positively correlated with available Zn (r = 0.86^**). Zinc concentration in plants was greatly increased with the application of Zn and accumulation of Zn was higher in grain than straw. The critical level of available zinc in soil below which plant response to Zn fertilization may be expected was 0.48 mg Zn kg^–1 soil. Soils between 0.48 to 0.70 mg kg^–1 of DTPA extractable Zn appear boarderline and a negative response to applied Zn was observed in soils of high Zn category. The results show the suitability of DTPA soil test for demarcating soils on the basis of plant response to zinc fertilization.     

Critical level of DTPA extractable Zn for wheat in alkaline soils of semiarid region of Punjab,India

Field experiments were conducted at 32 locations, chosen for their wide range in DTPA extractable Zn, to determine the critical deficiency level of Zn for predicting response of wheat to Zn application. Soil application of 5.6 kg Zn ha^–1 significantly increased the grain yield in deficient soils. Soil extractable Zn was significantly related with per cent grain response and absolute grain yield. Both the graphical and statistical methods of Cate and Nelson indicated the critical level to be 0.75 mg kg^–1 soil of DTPA extractable Zn. This level gave a predictability value of 82 per cent.     

Critical soil level of zinc for wheat grown in alkaline soils

Wheat plants were grown to study the effect of Zn application in a screen house experiment involving 19 alkaline soils having a range of DTPA extractable Zn and widely divergent physical and chemical properties. Soil Zn was positively correlated with organic carbon, clay, Olsen's P and Bray's per cent yield (r = 0.54^*, 0.67^**, 0.54^* and 0.84^**) respectively. There was a significant increase in the leaf, grain and total dry matter yield of plants due to Zn fertilization but no such effect was obvious in stem. Concentration of Zn in different plant parts increased significantly with its application in all the soils irrespective of the initial Zn status. Statistical method indicated 0.65 mg kg^–1 as the critical level of Zn in alkaline soils below which responses to Zn fertilization may be expected in case of wheat.     

Methods and rates of application of Mn and its critical levels for wheat following rice on coarse textured soils

Two field experiments were conducted on Mn-deficient soils to evaluate the efficiency of rates, methods and time of MnSO₄.H₂ O application for wheat. Manganese sulphate was broadcast and mixed in soils at the rate of 5 to 50kg Mn ha^–1 before seeding and 10 to 40 kg Mn ha^–1 as top dress at 28 days — just before first irrigation. Three sprays of 1% MnSO₄·H₂O unneutralised solutions were applied, the first at 26 days — 2 days before first irrigation and the others afterward at weekly intervals. Both the methods caused a significant and marked increase in grain yield. Three foliar sprays were as effective as soil applications of 20 to 40 Kg Mn ha^–1 before seeding. The difference in grain yield resulting from soil applications of Mn before seeding and applications at the first irrigation was not significant. The DTPA-Mn status of 20 fields, selected on the basis of varying degree of Mn deficiency, was related to grain yield (r = 0.77^**). Also grain yield of all the experiments had a significant correlation with Mn content of grain (r = 0.55^** to 0.82^**) and straw (r = 0.77^** to 0.82^**). The critical limits calculated by statistical method were 1.25, 2.18 and 3.5 mg Mn kg^–1 soil for severe deficiency, deficiency and latent deficiency respectively for wheat.     

Determination of critical level of zinc in non-calcareous soils for predicting response of wheat to applied zinc

Studies were conducted in ten non-calcareous arid brown soils (India) to determine the critical level of soil Zn for predicting response of wheat to zinc fertilization. The per cent mean response at 5 mg kg^–1 added Zn varied from 1.3 to 51.4 with a mean value of 17.5 per cent over control in terms of grain yield (g pot^–1). Further, Zn application resulted in significant increase in Zn concentration in various plant parts in all the soils irrespective of the initial Zn status. The critical level of Zn in soil and plant below which response to applied Zn may be expected was found to be 1.75 mg kg^–1 for 0.1 N HC1 extractable soil Zn and 1.7 mg kg^–1 for plant tissue Zn.     

Effect of excess boron fertilization on status and availability of boron in calcareous soils

Field experiments were conducted at Al-Qatif area in the eastern region of Saudi Arabia to study the status and availability of B under B fertilization regime in three types of calcareous soils and to evaluate the response of two alfalfa varieties, Hassawi (local variety) and Hyden (american variety), to increasing levels of added B.Boron was applied at 7 rates as Na₂B₄O₇.10H₂O. Four cuttings were taken from each site at different intervals. Data showed that extractable B by hot-water and NH₄HCO₃-DTPA (8 days after borax application) was significantly (p <0.001) affected by soil type and B applications. The amount of B recovered by hot-water from the three soils, 200 days after borax application, was in the following order: sandy loam > sandy clay loam > clay loam.Total dry matter of alfalfa (4 cuttings) was significantly (p <0.05) affected by soil type, borax application rates and alfalfa variety.The critical level of B in plant as determined by Cate and Nelson analysis, ranged from 148 to 652 mg kg^–1 dry matter for Hassawi cultivar and 138 to 521 mg kg^–1 for Hyden cultivar in the first harvest. However, the upper critical levels for the 2nd, 3rd and 4th harvests were 800, 875 and 935 mg B kg^–1 dry matter for Hassawi and 603, 723 and 812 mg B kg^–1 for Hyden varieties, respectively. Nevertheless, the lower critical levels for 2nd, 3rd and 4th harvests ranged from 148 to 153 mg B kg^–1 dry matter for Hassawi and 138 to 142 mg B kg^–1 for Hyden.     

Effects of lanthanum on nitrification and ammonification in three Chinese soils

The effects of lanthanum on nitrification and ammonification in three Chinese soils were evaluated through an incubation experiment. Soils were collected from experimental plots under rice/rape rotation in Yingtan, Jiangxi province (red soil), under rice/wheat rotation in Wuxi, Jiangsu province (paddy soil), and under corn/wheat rotation in Fengqiu, Henan province (Fluvo-aquic soil). Soil nitrification was stimulated slightly by La at lower concentrations, and the stimulation rate reached about 20% in red soil at 150 mg La kg^–1 dry soil, and 14% in fluvo-aquic soil at 300 mg La kg^–1 dry soil. When more La was added in soils, nitrification was inhibited, with a maximum inhibition rate of 42, 44 and 66% in red soil, fluvo-aquic soil, and paddy soil, respectively. Soil ammonification was not significantly different between control and up to 600 mg La kg^–1 dry soil in red soil, but it was significantly reduced in doses of 900 and 1200 mg La kg^–1 dry soil. Significant reduction in soil ammonification was also found in doses from 60 to 1200 mg La kg^–1 dry soil except for 600 mg La kg^–1 dry soil in fluvo-aquic soil. In contrast the ammonification in paddy soil was strongly stimulated by La, reaching about 25 times that of control at 900 mg La kg^–1 dry soil. We assumed that application of La accelerates the transformation of nitrogen in soils at low dosage, and the currently applied dosage in agriculture in China cannot inhibit soil nitrification and ammonification even after long term successive application.     

Critical levels for soil pH,available P,K, Zn and Mn and maize ear-leaf content of P,Cu and Mn in sedimentary soils of South-Western Nigeria

In the sedimentary soils of South-western Nigeria, actual and expected relative yields of maize were plotted against soil physical factors, soil avalilable nutrients and ear-leaf content of maize. These were used to set critical ranges of these factors for optimum production. Regression equations were obtained for each of the soil and plant factors for predicting yield, thereby making possible yield prediction with levels of each of these factors in these soils if all other factors are constant.The critical range concept combined with the soil physical and chemical properties and plant nutrient content could be a useful diagnostic tool for soil ammendment in crop production. Critical ranges were set as follows:pH, 6–6.5; available P (Bray's Pl), 10–16 mg Kg^–1; Exchangeable K, 0.6–0.8 me K100g^–1; available Zn, 5–10mg kg^–1; available Mn, about 25 mg Kg^–1; Ear-leaf P, 2.5–3.0%; Ear-leaf Cu, 10–20 mg Kg^–1; Earleaf Mn, about 50 mg Kg^–1.     

The distribution and transformation of iron and manganese in soil fractions in a savanna Alfisol under continuous cultivation

Data on the responses of micronutrients in definable soil fractions to cultivation and management are required to design judicious fertilization practices to improve soil fertility in the savanna. Iron and manganese fractions are particularly sensitive to cultivation and management practices. The objectives of this study were to determine the sizes and changes in Fe and Mn fractions in a savanna Alfisol cultivated for 50 years and fertilized with (i) NPK, (ii) farmyard manure (FYM), (iii) FYM + NPK, (iv) a control plot, and (v) a natural site adjacent to the experimental field. The mean concentration of total Fe (Fe_T) ranged from 9.4 g kg^–1 in the surface layer to 45 g kg^–1 in the subsurface layer, whereas total mangenese (Mn_T) concentration ranged from 79 mg kg^–1 in the surface layer to 279 mg kg^–1 in the subsurface layer. The distribution of Fe_T followed the distribution of clay in the soil profile across the field. The distribution of Mn_T did not, however, follow the characteristic depth distribution of clay as observed for Fe_T, suggesting that Mn movement and distribution in this soil might be independent of clay movement and distribution. The concentrations of DTPA extractable Fe and Mn were much higher than the critical levels delineated for soils. Application of FYM increased the concentration of amorphous oxide bound Fe over the natural site and reduced the concentration of residual or inextractable Fe in the soil. Similarly, fertilization with FYM reduced the concentration of residual Mn, and increased the exchangeable, amorphous oxide bound and reducible Mn compared to the natural site. It seems that sole application of FYM or application in combination with NPK rather than NPK alone can mobilize non-labile Mn and Fe sources into labile and plant available forms of Fe and Mn in a savanna Alfisol.     

Response of rice cultivars to phosphorus supply on an oxisol

Genotypic differences in absorption or utilization of P might be exploited to improve efficiency of fertilizer use or to obtain higher productivity on P-deficient soils. The objective of this study was to evaluate responses by 75 genotypes of upland rice (Oryza sativa L.) to two soil P levels in two field experiments. In the first experiment, soil P levels (Mehlich 1) were 1.5 mg kg^–1 and 5 mg kg^–1, and in the second experiment, 3 mg kg^–1 and 4.7 mg kg^–1 of soil, respectively. Rice cultivars differed significantly in shoot dry matter production at flowering, grain yield, and plant P status. Based on a grain yield efficiency index, cultivars were classified as P-efficient or P-inefficient. Shoot dry matter was more sensitive to P-deficiency but was not related to grain yield. Phosphorus use efficiency was higher under the low P treatment. Phosphorus uptake was significantly correlated with dry matter, P concentration and P-efficiency ratio. Results of this study indicate that genetic differences in P-use efficiency exist among upland rice cultivars and may be exploited in breeding programs.Contribution from National Rice and Bean Research Center of EMBRAPA, Goiania, Goias, Brazil and Appalachian Soil and Water Conservation Research Laboratoy, Beckley, WV, USA.     

Mono- and diammonium phosphates and triple superphosphate as sources of P in a calcareous soil

Recovery of phosphorus from monoammonium phosphate (MAP), diammonium phosphate (DAP) and triple superphosphate (TSP), at rates of 0, 15, 30, or 45 mg P kg^–1 was determined in a pot experiment on a Calcaric Lithosol soil (21% CaCO₃). At the 15 mg P kg^–1 rate DAP was as effective as MAP and more effective than TSP in supplying P, but it was less effective than MAP and TSP at the higher rates of 30 and 45 mg P kg^–1. At the two higher P rates residual bicarbonate extractable P was also significantly lower with DAP. Yield dry matter was not affected by the source of P.     

Effects of coralline lime on nutrient uptake and yield of field-grown sweet corn and peanuts in Oxidic soils of Western Samoa

Effects of coralline lime on yield and nutrient uptake by sweet corn (Zea mays saccharata Sturt.) and peanut (Arachis hypogea) were studied at three locations in Western Samoa. Coarse (0-10 mm) coralline material containing 31.1% Ca and 1.67% Mg was used as lime. There were two modes of application: band and broadcast, and three rates: 6, 12 and 18 ton ha^–1. In the highest rainfall location, marketable yields were increased by 250% for peanut and 160% for sweet corn by liming at 6 ton ha^–1, relative to the unamended control. Peanut yield increases were associated with reduced Mn toxicity and/or with Ca and Mg deficiency. Sweet corn was less susceptible to Mn toxicity, but more responsive to exchangeable Ca. The critical level of exchangeable Ca was found to be about 2.0 cmol(+)kg^–1. Applying lime to a band of 0.25-m wide did not reduce yield relative to broadcast. Soil cultivation caused the lime to spread over a wider band, diluting the applied calcium with a larger soil volume, suggesting that less than 6 ton ha^–1 broadcast coarse coralline lime could still be adequate for most Samoan soils.     

Chemical assessment of the zinc status of some soils of the semi-arid region of India

To find critical tissue levels of Zn for wheat, and to evaluate various chemical extractants, a screen-house experiment was conducted on 21 diverse soils representing semi-arid regions in Haryana State, India. The extractants differed in the amounts of Zn extracted and the order was: 0.1 N HC1 > EDTA-NH₄OAc > EDTA-(NH₄)₂CO₃ > DTPA + CaCl₂. The amounts (mg kg^–1) of extractable Zn associated with a yield reduction of 20% were: DTPA + CaCl₂, 0.60; EDTA — (NH₄)₂CO₃, 0.80; EDTA-NH₄OAc, 0.92 and 0.1 N HCl, 1.20. The corresponding critical Zn concentration in ten weeks old plants was found to be 17 mg gm^–1. The DTPA + CaCl₂ method gave the best correlation (r = 0.85) between extracted Zn and Bray's per cent yield. It is recommended for assessing Zn status of soils of semi-arid region.     

Effects of urea fertigation of apple trees on soil pH,exchangeable cations and extractable manganese in a sandy loam soil in New Zealand

Changes in soil pH, exchangeable aluminium (Al), calcium (Ca), magnesium (Mg), and potassium (K) and extractable manganese (Mn) were investigated after urea fertigation of a sandy loam soil in an apple orchard in New Zealand. Urea at three rates (0, 25, 50 kg N ha^–1 yr^–1 or 0, 16.9, 33.8 g N emitter^–1 yr^–1) was applied in 4 equal fertigations. Soil cores at 4 profile depths (0–10, 10–20, 20–40 and 40–60 cm) directly below and 20 cm from the emitter were sampled approximately 4 weeks after each fertigation and in the following winter. Results obtained showed that the largest changes in soil pH and cations occurred in soils directly below the emitter in the 50 kg N ha^–1 yr^–1 treatment where the soil pH decreased by 1.6 pH units at all soil depths. The lowest pH of 4.3 was observed at a depth of 27 cm. Exchangeable Al and extractable Mn levels increased to 11 meq kg^–1 and 78µg g^–1 respectively. Estimated losses of Ca, Mg and K from the upper soil profile depth (0–10 cm) represented 23, 63 and 27% of their respective total exchangeable levels. At lower profile depths (>20 cm), accumulation of displaced K was evident. Variable, and generally non-significant, chemical changes recorded in soils 20 cm from the emitter were attributed to restricted lateral water movement, and therefore urea movement, down the profile.The present study showed that one season of urea fertigation by trickle emitters, applied to a sandy loam, at half the rate conventionally applied to apple orchards (50 kg N ha^–1 yr^–1) resulted in pH and mineral element imbalances which were potentially and sufficiently severe to inhibit tree growth.     

Efficiency of fall-applied urea for barley: Influence of date of application

Fall application of N fertilizers is often inferior to spring application for increasing yields of spring-sown cereal grains. The objective of this study was to determine the influence of date of application on efficiency of fall-applied N. Fall application dates were related to recovery of fall-applied N as mineral N in soil in spring, and related to yield and N uptake for spring-sown barley. Urea at a rate of 50 or 56 kg N ha^–1 was incorporated into the soil to a depth of 10 cm. There were 2 or 3 application dates in the fall and one in the spring at sowing. Linear regression indicated recovery of fall-applied N as soil mineral N in spring increased from 30% with urea added on 19 September to 79% with addition on 6 November, but the predictability was low (r = 0.54^**). Increase in grain yield, expressed as relative efficiency of fall- versus spring-applied N, was only 23% on 19 September but rose to 76% by 6 November (r = 0.68^**). Results were similar for N uptake in grain. Other approaches to predicting the relative efficiency of fall- versus spring-applied N for yield increase were based on fall soil temperature at 5 cm depth, instead of fall calendar date. Soil temperature on the day of N application gave inferior correlation (r = –0.55^**), but the use of number of days from application to first day of 0°C soil temperature gave a fairly close correlation (r = –0.77^**). Soil degree-days accumulated from application to first day of 0°C soil temperature gave a similarly close correlation (r = –0.78^**). In all, the efficiency of fall-applied urea was markedly increased by delaying the application into the late fall; and calendar date, number of days or soil degree-days from application to soil freezing all predicted the efficiency fairly well.(Contribution No. 599)     

Distribution of acid extractable P and exchangeable K in a grassland soil as affected by long-term surface application of N, P and K fertilizers

Information on the fate and distribution of surface-applied fertilizer P and K in soil is needed in order to assess their availability to plants and potential for water contamination. Distribution of extractable P (in 0.03 M NH₄F + 0.03 M H₂SO₄ solution) and exchangeable K (in neutral 1.0 M ammonium acetate solution) in the soil as a result of selected combinations of 30 years (1968–1997) of N fertilization (84–336 kg N ha^–1), 10 years of P fertilization (0–132 kg P ha^–1), and 14 years of K fertilization (0 and 46 kg K ha^–1) was studied in a field experiment on a thin Black Chernozem loam under smooth bromegrass (Bromus inermis Leyss.) at Crossfield, Alberta, Canada. Soil samples were taken at regular intervals in October 1997 from 0–5, 5–10, 10–15, 15–30, 30–60, 60–90 and 90–120 cm layers. Soil pH decreased with N rate and this declined with soil depth. Increase in extractable P concentration in the soil reflected 10 years of P fertilization relative to no P fertilization, even though it had been terminated 20 years prior to soil sampling. The magnitude and depth of increase in extractable P paralleled N and P rates. The extractable P concentration in the 0–5 cm soil layer increased by 2.2, 20.7, 30.4 and 34.5 mg P kg^–1 soil at 84, 168, 280 and 336 kg N ha^–1, respectively. The increase in extractable P concentration in the 0–15 cm soil depth was 1.5 and 12.8 mg P kg^–1 soil with application of 16 and 33 kg P ha^–1 (N rate of 84 N ha^–1 for both treatments), respectively; and it was 81.6 and 155.2 mg P kg^–1 soil with application of 66 and 132 kg P ha^–1 (N rate of 336 N ha^–1 for both treatments), respectively. The increase in extractable P at high N rates was attributed to N-induced soil acidification. Most of the increase in extractable P occurred in the top 10-cm soil layer and almost none was noticed below 30 cm depth. Surface-applied K was able to prevent depletion of exchangeable K from the 0–90 cm soil, which occurred with increased bromegrass production from N fertilization in the absence of K application. As only a small increase of exchangeable K was observed in the 10–30 cm soil, 46 kg K ha^–1 year^–1 was considered necessary to achieve a balance between fertilization and bromegrass uptake for K. The potential for P contamination of surface water may be increased with the high N and P rates, as most of the increase in extractable P occurred near the soil surface.     

Relationship between extracted phosphorus and sorghum yield in a Vertisol and an Alfisol under rainfed cropping

Little attention has been devoted to calibrating the soil tests for P in the field for crops grown under rainfed conditions in different soil types. Field experiments were conducted during the 1990 rainy season (June-September) at the ICRISAT Center, Patancheru (near Hyderabad), India on nearby Vertisol and Alfisol sites having a range in extractable P, for establishing relationships between extractable P and sorghum yield.In the Vertisol, 90% relative grain yield of sorghum was obtained at 2.8 mg kg^–1 Olsen extractable P while in the Alfisol, 90% relative grain yield was achieved at 5.0 mg P kg^–1 soil. These results suggest that a single critical limit of available P does not hold true for grain sorghum in the two soil types under similar agroclimatic conditions and that the critical limit is lower for the clayey Vertisol than the sandy Alfisol.     

Investigation into manganese deficiency in mature oil palms(E. guineensis) in Malaysia

Manganese deficiency was confirmed on prominently chlorotic palms with small canopies grown on very sandy colluvium. An experiment to assess the effects of the Mn deficiency on palm growth and yield was carried out. The effectiveness of the application of MnSO₄ at various rates to correct the deficiency was tested. Manganese concentration < 25µg Mn g^–1 in Frond 17 was found to be indicative of deficiency. Soil application of MnSO₄ at 150 g palm^–1 plus 60 g palm^–1 as foliar spray was most effective for short term correction. Higher rates (300 g MnSO₄ palm^–1) were required for soil application only. Cumulative yield over 42 months after treatment showed significantly higher number of harvested fresh fruit bunches. Full recovery of canopy size, colour and vigour took up to two years.