Alfalfa responses to foliar and soil applications of manganese

Abstract

Manganese (Mn) deficiency often occurs in crops grown on well‐limed sandy soils of the Atlantic Coastal Plain region of the United States. This study was conducted to compare the responses of established alfalfa (Medicago sativa S.) to various application methods of manganese sulfate (MnSO₄) fertilizer. Experiments conducted in farmers’ fields at three New Jersey locations determined the effects of applied Mn on forage yield, tissue Mn concentration, and leaf chlorophyll meter readings. An untreated control was compared to the following treatments: foliar Mn applied once before each harvest, foliar Mn applied twice before each harvest, and a one‐time broadcast Mn application in April Or May at 22.4 kg Mn/ha to the soil surface. The rate of foliar Mn used in 1990 was 1.12 kg Mn/ha and in 1991 was 0.56 kg Mn/ha at each treatment time. Forage yield increases were greater with foliar than soil‐applied Mn but there were no differences between foliar‐applied Mn treatments. Total seasonal forage yields were increased (P<0.05) at all three locations with foliar‐applied Mn but at only one location with soil‐applied Mn. When averaged across all locations, forage yields were 6.4% higher than the control for the foliar‐applied Mn treatments compared to 2.9% higher for the soil‐applied Mn treatment. A Mn concentration of 21 mg/kg was determined as the critical level in the upper 15 cm of alfalfa tissue at the early bloom growth stage. Foliar Mn applied twice between harvests most effectively increased tissue Mn concentrations. Soil‐applied Mn initially increased tissue Mn concentration, but there was little long‐term benefit from this treatment. Applied Mn was observed to improve leaf color and chlorophyll meter readings of Mn‐deficient alfalfa. Results indicate that foliar Mn applied before each harvest was a more effective treatment for correction of Mn deficiency of alfalfa than a one‐time soil application of Mn.     

Effect of manganese and soil pH on the iron content of crops grown on podzol soils

In a greenhouse study on three podzol soils with pH values of 5.4–5.6, liming to pH 7.6 or higher decreased the Fe concentration of pea plant tissues from 47 to 42 ppm. In the case of barley, liming the soil increased the mean tissue Fe concentration from 104 to 119 ppm at pH 7.6 and to 107 ppm at pH 7.7. Field experiments on wheat, oats, alfalfa, and timothy showed that Mn applied to the soil or as foliar spray did not affect the Fe concentration of cereal or forage plant tissues. Liming did not affect the Fe concentration of cereal kernels but on a few locations it increased the Fe concentration of the boot stage tissue. The Fe concentration in oats was higher than that in wheat. Based on the results of a survey, it was found that forage legumes contained more Fe than did timothy. The survey also showed that a few Fe values in timothy and cereals would be considered low, although Fe deficiency has not been experienced in this region. A number of the samples would be in the deficiency range from the animal nutrition standpoint.     

Manganese relationships in spring wheat and spring barley production in Northern Idaho

Abstract

Manganese is often limiting in cereal crop production in the Kootenai River Valley of Northern Idaho; however, attempts to relate DTPA‐extractable Mn in soils to crop yield response have not been successful. Consequently, Mn plant tissue diagnosis may be an alternate diagnostic tool. The objectives of this study were to: (1) determine the critical nutrient concentration (CNC) of Mn in spring wheat and spring barley tissue in the Kootenai River Valley of northern Idaho, (2) examine yield response of spring wheat and spring barley to Mn fertilization, and (3) assess relative efficiencies of foliar and surface broadcast Mn applications to these crops. Paired plots with four replications consisting of a foliar Mn application rate of 1.5 kg ha^‐1 and a control were located at four sites in 1988 and at ten sites in 1989. Soil, plant tissue samples and grain yield data were evaluated by linear plateau regression to determine CNCs of Mn for spring wheat and spring barley tissue. In addition, five randomized complete block experiments were conducted in 1989 and 1990 to evaluate Mn fertilizer rates and sources (foliar vs. surface applied) on spring wheat and spring barley production. Tissue Mn was highly correlated by linear plateau regression to both spring wheat (r² = 0.74**) and spring barley (r² = 0.70**) grain yield. The Mn CNC was established at 11.0 mg Mn kg‐¹ plant tissue for spring wheat and 10.1 mg Mn kg^‐1 plant tissue for spring barley. The Mn CNCs were established at 92.4 and 93.0% of maximum yield for spring wheat and spring barley, respectively. DTPA‐extractable Mn was not significantly correlated to grain yield for either crop (r² = 0.02, NS). Based on study results, Mn analysis of spring wheat and spring barley plant tissue was diagnostic of eventual grain yield. When tissue diagnosis showed plants to be deficient in Mn, the deficiency was corrected by applying Mn fertilizer as a surface broadcast or a foliar spray. However, foliar application of Mn was more efficient than broadcast application.     

Effect of magnesium fertilization on yield and leaf composition of tomato plants

Tomato plants were grown for 2 years at 4 different rates of Mg fertilization on a Princeton loamy sand at pH 4.8 with 29 kg exchangeable Mg/ha. Calcareous limestone was used to provide a pH treatment in the second year. Magnesium deficiency symptoms were observed on plants grown on plots having ≤ 38 kg/ha NH₄OAC‐extractable Mg. Application of 56 kg Mg/ha corrected Mg deficiency and produced a significant increase in yield. Application of calcitic limestone also produced significant yield increases, but did not affect the development of Mg deficiency symptoms. Tomato yield was increased 27.9% by Mg application and 17.7% by lime application. Highest tomato yield was obtained with application of 112 kg Mg/ha. Symptoms of Mg deficiency were observed when the Mg concentration in recently mature leaf tissue was in the 0.30 to 0.32% range. Magnesium concentration in leaf tissue increased linearly with increasing Mg rate. Leaf Mg concentration at various growth stages of the tomato plant was variable depending on Mg treatment. Magnesium fertilization rate bad little effect on Ca or K leaf concentrations. Application of Calcltic limestone increased leaf tissue Ca and reduced leaf tissue Mg and Mn concentrations.     

The effect of foliar application of Moringa leaf extract on biomass,grain yield of wheat and applied nutrient efficiency

Moringa leaf extracts (MLE) from two varieties of Moringa oleifera Lam. were applied to leaves of wheat (Triticum aestivum L.) in two glasshouse experiments. MLE was extracted from the leaves of using three different solvents (hexane, butanol; ethyl-acetate). The extracts were applied as foliar sprays at different growth stages of wheat (T. aestivum L.) grown on two soil types with either adequate or low phosphorus (P) nutrient additions at Albany, Western Australia. Sprays were applied at the 4–5 leaf (tillering) and the 7-leaf (Boot) stage either as a single spray or a combination of sprays at tillering and boot stage. The application of MLE either at tillering or boot stage increased the dry weight of shoots (biomass) and grain yield of wheat. A foliar spray of MLE applied at tillering increased biomass at the boot stage by ～37% and grain yield increased by ～34% compared to nil MLE spray. A single spray of MLE increased grain yield by ～30% when applied at boot stage. A single application at tillering gave a better yield response than a single spray at the 7-leaf or boot or than a double spray applied at tillering and boot stage. A 50% dilution of the extractant concentration gave the same grain yield response as the original concentration applied at tillering stage. The hexane extracts gave the significantly higher grain yield responses. Plant tissue and grain analysis showed no significant difference in protein and nutrient concentration of wheat grain from plants sprayed with and without MLE. A MLE spray at boot also increased grain yield by 44% on the red sandy-loam soil where P application was at sub-optimum levels, ～80% of P requirement for maximum yield. The partial factor productivity (PFP) index indicated that the P and potassium (K) use improved where MLE was applied as a foliar spray. For example, the PFP of P and K for grain yield increased by about 30%, where MLE was sprayed to foliage. The results of this study indicate that MLE extracted can potentially be a viable option to increase wheat grain yield and fertilizer efficiency use, particularly P and K, in Mediterranean wheat production system.     

Effect of Molybdenum Foliar Sprays on Yield,Berry Size,Seed Formation,and Petiolar Nutrient Composition of “Merlot” Grapevines

Abstract

Field experiments with irrigated “Merlot” vines were carried out at 3 sites in the Mount Lofty Ranges of South Australia over 3 years to examine the effects of molybdenum (Mo) foliar sprays on bunch yield, berry size, and nutrient composition of petioles. Bunches were divided into different size grades for black and green berries. Basal petioles were sampled at flowering and veraison for nutrient analyses. In year 3, seed number per berry was assessed at sites 2 and 3. Two Mo foliar sprays (each spray contained 118 g Mo as sodium molybdate/ha in 410–800 L/ha of water) applied before flowering increased yield per vine and bunch weight in all experiments in year 2 and at site 3 in year 3. Yield responses ranged from 221% at site 1 to 750% at site 2 in year 2 and 70% for site 3, year 3. Average bunch weight increased from 243% at site 2 to 425% at site 1 for year 2 and by 69% at site 3 in year 3, and was the main yield component affected by Mo application. In year 1, the application of Mo did not affect yield or bunch weight at any site. In year 2, the application of Mo increased the yield of 5–15 mm colored berries by 301, 499, and 258% at sites 1, 2, and 3, respectively, and by 70% at site 3, year 3. Mo application increased the percent of berries, which had one or more functional seeds (when assessed at sites 2 and 3 in year 3). Molybdenum concentrations in petioles sampled at flowering and veraison increased in response to applied Mo in all years. Petiolar Mo concentrations in unsprayed vines were consistently higher in year 1 compared with other years. The effect of applied Mo on the concentration of other nutrients in basal petioles sampled at flowering and veraison were small and of little practical importance. Nitrate-N did not accumulate in the petioles of unsprayed plants in any year. Changes in petiolar Mo concentrations between flowering and veraison were dependent on supply. Nitrate-N, total-N, and phosphorus (P) concentrations declined with time, while calcium (Ca), manganese (Mn), and iron (Fe) tended to increase. At flowering, Mo concentrations in basal petioles of 0.05–0.09 mg/kg were associated with significant bunch yield response to applied Mo. Molybdenum deficiency can be a major factor in the occurrence of berry development disorders such as shot berry formation and hens and chickens (millerandage) in “Merlot” grapevines. The increased percent of colored berries with one or more functional seeds and the decrease in the proportion of green berries suggests that Mo application affected pollination and/or fertilization, and thereafter berry development.     

Response to micronutrient on carrots grown on a virgin sphagnum peat

Field studies were conducted over a period of years on a virgin sphagnum peat bog in St. Charles, New Brunswick to determine the effect of trace elements on carrot (Daucus carota L.) root yield and nutrient concentration. Addition of the trace elements, boron (B), molybdenum (Mo), copper (Cu), and zinc (Zn), did not affect the marketable carrot root yields, although yields differed significantly from year to year. Addition of B at 10 kg/ha resulted in leaf tissue B concentrations as high as 75 mg/kg. Addition of foliar Mo at 0.14 kg/ha and soil Mo at 0.56 kg/ha raised the leaf tissue Mo concentrations to 3 to 4 mg/kg. Copper applications at 30 kg/ha raised the leaf tissue Cu concentration to 12 mg/kg. Zinc addition at 10 kg/ha did not increase the leaf Zn levels which ranged from 44 to 58 mg/kg. The leaf tissue B, Mo, Cu, and Zn levels as low as 29, 0.17, 4, and 44 mg/kg, respectively, were not related to deficiency of these elements. Such leaf tissue concentrations of B, Mo, and Cu are marginal for optimum crop production on this bog and should be monitored periodically to detect any significant trends through continuous use of this bog in crop production.     

低锌旱地施锌方式对小麦产量和锌利用的影响

西北地区是我国典型的旱地低锌区。本文选择黄土高原中部两个典型地点,通过田间试验,在两个施氮水平下,研究了不施锌、 土施锌、 叶喷锌和土施+叶喷锌4种方式对冬小麦产量、 锌的吸收和累积以及锌肥利用效率的影响。结果表明,不同施锌方式对小麦产量均无显著影响,但均提高了小麦子粒锌含量,提高幅度因施锌方式而异。与不施锌相比,叶喷和土施+叶喷锌肥可使小麦子粒锌含量提高40%左右,平均达到 40 mg/kg;单独土施锌肥虽使土壤有效锌提高3倍左右,但子粒锌含量无显著变化。叶喷锌肥的锌利用效率远高于土施和土施+叶喷处理,每公顷喷施1 kg锌可使小麦子粒锌含量提高6.70~13.04 mg/kg;子粒锌利用率为6.02%~9.40%, 达到土施锌肥的80倍左右;总锌利用率为19.78%~30.91%,是土施锌肥的132~221倍。施氮水平对小麦产量及锌肥利用效率均无显著影响。可见,在旱地低锌区,与土施锌相比,叶喷是更加经济有效、 环境友好的锌肥施用方式,是提高小麦锌营养品质切实可行的措施。     

Effects of liming on yield,forage cation composition,and tetany potential of wheat in Kansas

Abstract

We studied the effects of liming on dry matter production, nutrient composition, and grain yields of wheat in field experiments conducted on two soil types at three locations during the 1976–77 and 1977–78 growing seasons. Lime sources were commercial agricultural lime, finely divided stack dust, and dolomitic limestone (which contained 10.6% Mg). Lime applied at 2,800 kg/ha in the 1976–77 and 10,750 kg/ha in the 1977–78 experiments provided Mg from the dolomite at rates of 300 and 1,140 kg/ha, respectively.

Soil pH was significantly increased by liming, but Mg saturation percentages were significantly greater only at the 1,140 kg/ha rate. Forage dry matter and grain yields were not increased by lime applied at the lower rate, but significant increases were found in dry‐matter production in the late fall and spring samplings of the 1977–78 experiment. Those increases in plant growth and dry matter production were probably due to reductions in the soluble Mn and Al concentrations in the soil. Forage N and P concentrations were generally not influenced by liming. Potassium concentrations in forage from the limed plots were usually equal to or greater than those in forage from unlimed plots. Calcitic limestone sources generally increased forage Ca concentrations, but liming with dolomite more often than not depressed Ca concentrations below levels found in the check plots. Dolomite, when applied at the 1,140 kg/ha rate, effectively increased the forage Mg concentration, although the concentration exceeded 0.2% only during the early growth stages. Liming generally showed no significant reduction in the tetany potential of the wheat forage as predicted by the equivalent ratio K/(Ca + Mg).     

Assessment of ZN Interaction with Nutrient Cations in Alkaline Soil and its Effect on Plant Growth

An experiment was conducted to assess the zinc (Zn) availability to wheat in alkaline soils during Rabi 2009–2010. Wheat seedlings in pots having 2 kg alkaline sandy soil per pot were treated with 5, 10 and 15 kg Zn ha^?1 as soil and with 0.5 and 1.0% zinc sulfate (ZnSO₄) as foliar application. Results showed that Zn increasing levels in soil helped in phosphorus uptake up to boot stage but its conversion to grain portion lacked in Zn treated plants. Potassium (K) uptake also increased up to 6.24% in boot stage with treatment of 10 kg Zn ha^?1 + 1.0% ZnSO₄ foliar spray. Zinc (Zn) concentration increased in plant tissues with the increasing level of Zn application but this disturbed the phosphorus (P)-Zn interaction and, thus, both of the nutrients were found in lesser quantities in grains compared to the control. Despite of the apparent sufficient Zn level in soil (1.95 mg kg^?1), improvement in growth and yield parameters with Zn application indicate that the soil was Zn deplete in terms of plant available Zn. The above findings suggest that the figure Zn sufficiency in alkaline soil (1.0 mg kg^?1) should be revised in accordance to the nature and type of soils. Furthermore, foliar application of Zn up to 1.0% progressively increased yield but not significantly; and it was recommended that higher concentrations might be used to confirm foliar application of Zn as a successful strategy for increasing plant zinc levels.     

Influence of soil pH and molybdenum fertilization on the productivity of Maryland tobacco. I. Field investigations

Abstract

To gain information on soil factors which may limit productivity of tobacco on Coastal Plain soils in Maryland, studies were conducted on Monmouth sandy loam soils in 1982 to 1984 and in 1988. The 1982–1984 study involved the application of dolomitic lime in 1982 at rates of 0, 3.6, 7.3, and 14.6 M ton/ha which achieved pH values of 4.4, 4.7, 5.0, and 5.3, respectively, in combination with annual applications of supplemental molybdenum (Mo) at rates equal to 0, 0.28, 0.55, and 1.1 kg/ha. The 1988 study involved lime application rates of 6.0, 17.0, and 25.0 M ton/ha to achieve pH values of 5.0, 5.6, and 6.0, respectively, in combination with Mo rates equal to 0, 0.5, and 1.0 k/gha. Studies were also conducted in 1988 involving the application of 0, 0.55, and 1.10 kg/ha supplemental Mo without lime additions to two sites having pH values of 5.0 and 5.5, respectively. Cured leaf yields, total nitrogen (N) and alkaloid levels were measured in all studies. Leaf Mo levels were monitored in the 1988 studies. Applications of 14.6 M ton/ha of lime in 1982 induced significant yield increases which averaged 13.8% over controls in the 3‐year study. No significant benefits from supplemental Mo were found at the 0 and 3.6 M ton/ha lime treatments (< pH 4.7) in the 1982–84 study or in any of the 1988 studies. However, 1.1 kg/ha Mo applied in combination with 7.3 and 14.6 M ton kg/ha lime increased yields by 16 to 22% above the control treatments in the 1982–84 study, and by 17.8% and 18.7% when applied in combination with 6.0 and 25.0 M ton/ha, respectively, in 1988. In 1988, leaf Mo increased with increased Mo rates, especially at higher pH values. Treatment effects on total N and alkaloid levels were non‐significant in most instances suggesting that N metabolism activities in the control plants were not being limited by plant available Mo (0.10 μg/g) in the soil.     

The effect of phosphorus and mulching on the efficiency of phosphorus use and productivity of wheat grown on a mountain Alfisol in the Western Himalayas

Abstract. A field experiment was conducted over two years in one of the mountain Alfisols of the Western Himalayas to study the effects of phosphorus and mulching on phosphorus use efficiency (PUE) and productivity of wheat (cv. S-308) at difference growth stages. The source of phosphorus was single superphosphate at 0, 26, 52 and 78 kg P/ha whereas the sources of mulching materials were pine needles ( Pinus longifolia ), lantana weed ( Lantana camara ) at 8 t/ha and transparent polyethylene sheet compared with no mulch.
The phosphorus use efficiency (PUE) at tillering, flowering and harvesting was greatest at the lowest dose of P and decreased as the P levels were increased. However, the increased levels of P up to 78 kg/ha, significantly improved the dry matter yield at tillering stage (30%) and flowering stage (93%) and also the grain yield (139%) and straw yield (148%) at the harvest stage. The application of mulching materials in general, and polyethylene in particular, significantly increased the phosphorus use efficiency and the productivity of wheat by 27% at tillering stage; 17% at flowering stage, and by 98 and 110% in the case of grain and straw yield at harvest stage.
Although the polyethylene mulch effect was physically superior to the other materials, the latter gave greater financial returns. Consequently, the economic optimum application of P in association with 8 t/ha of lantana mulch was found to be 53 kg/ha over two years, whereas, in the absence of mulching, it was 58 kg/ha.     

锌肥不同施用方式及施用量对我国主要粮食作物增产效果的影响

【目的】施用锌肥是改善作物缺锌、 提高产量和籽粒锌含量的重要措施。锌肥的施用效果受多种因素的影响,通过总结自70年代以来锌肥施用对我国主要粮食作物小麦、 玉米、 水稻产量的影响,分析不同年代、 锌肥施用方式、 锌肥用量对这三大作物产量影响的进程,探讨锌肥的适宜用量和施用方式。【方法】利用万方数据库、 中国知网,查阅了1970至2013年间,我国主要粮食作物水稻、 小麦和玉米锌肥施用相关的田间试验文献333篇,剔除文献中没有产量数据、 没有具体施肥相关信息如施肥量、 施肥方式等文献,有效样本数总计为1656个。采用相关分析、 方差分析等统计分析方法,Microsoft Excel 2010软件分析。【结果】锌肥增产效果受锌肥施用方式、 施用量、 年代的影响,具体结果如下, 1)锌肥施用方式土壤施用、 叶面喷施和种子处理在小麦上的平均增产率分别为11.3%、 10.0%和11.1%; 在玉米上的平均增产率分别为13.7%、 12.7%和12.1%; 水稻上的平均增产率分别为15.0%、 9.8%和9.7%。与叶面喷施和种子处理相比,无论是小麦、 玉米还是水稻,土施锌肥的增产效果最好。2)锌肥施用量小麦、 玉米和水稻的增产率随土施锌肥量增加而增加,当施锌量达到一定量后,随施肥用量的进一步增大,增产率有所降低。小麦、 玉米和水稻土施锌肥的合适用量分别为1545 kg /hm2、 2030 kg/hm2、 2030 kg/hm2。小麦增产率与喷施锌肥的浓度关系不明显,叶面喷施浓度在0.4%~0.5% ZnSO47H2O时增产效果最佳; 而玉米、 水稻增产率和叶面喷施锌肥的浓度变化趋势与土施锌肥变化趋势一致。过去40年玉米和水稻适宜喷施锌肥浓度分别是0.1%~0.3%、 0.2%~0.4% ZnSO47H2O。3)施肥年代随着年代的变化,不同作物施用锌肥的增产幅度不同。随着年代的推进,同一锌肥施用方式在小麦上增产率呈逐渐增高的趋势; 锌肥土施和叶面喷施在玉米上的增产率呈下降趋势; 锌肥土施在水稻上的增产率呈下降趋势,而叶面喷施在水稻的增产率呈先降低后增加的趋势; 种子处理方式在水稻和玉米上的增产率随年代的变化不明显。【结论】施用锌肥能有效提高小麦、 玉米和水稻的产量,但是其增产效果受锌肥施用方式、 施用量、 年代的影响。因此,今后在锌肥施用方面,农户应根据作物、 土壤、 环境等条件,选择恰当的施肥方式及锌肥用量,来提高锌肥的增产效果。     

Effect of zinc application methods on apparent utilization efficiency of zinc and phosphorus fertilizers under basmati rice–wheat rotation

To examine the effect of zinc (Zn) application method on the utilization of phosphorus (P) from applied P fertilizer, a field experiment was conducted on basmati rice–wheat rotation with combinations of Zn levels (0, soil application of 2.5 kg Zn ha ^{– 1} and two foliar applications of 2.0 kg Zn ha ^–1) and P levels (0, soil application of 8.7, 17.5 and 26.2 kg P ha ^–1). The highest pooled grain yields of basmati rice and wheat were obtained with soil application of 17.5 kg P ha ^–1 and foliar applications of 2 kg Zn ha ^–1. Foliar applications of Zn increased the P concentration in grain and straw and the total P uptake by basmati rice and the P concentration in flag leaves of wheat significantly, while soil or foliar application of Zn increased the total P uptake of wheat. Phosphorus application increased the Zn concentration in flag leaves, grain and straw of basmati rice and in grain and straw of wheat and the total Zn uptake of both crops. Phosphorus levels up to 17.5 kg P ha ^–1 increased utilization efficiency of soil or foliar application of Zn. Zinc application increased the P utilization efficiency of basmati rice and wheat up to 17.5 kg P ha ^–1 level; foliar Zn application was more effective in a wheat crop than a rice crop.     

Increased Concentration of Molybdenum in Sown Wheat Seed Decreases Grain Yield Responses to Applied Molybdenum Fertilizer in Naturally Acidic Sandplain Soils

Spring wheat (Triticum aestivum L.) is the major crop in southwestern Australia where 75% of the 18 million hectares comprise sandy duplex and deep sandy soils, including uniform yellow sandplain soils. Some of the sandplain soils in the lower rainfall (< 350 mm annual average) eastern region are naturally very acidic (soil pH, as measured in 1:5 soil:0.01 M calcium chloride, 3.7–4.5) in soil horizons explored by wheat roots so molybdenum (Mo) deficiency and aluminium (Al) toxicity adversely affects grain production of wheat. Liming is not an economic option to ameliorate Mo deficiency and Al toxicity in these soils because uneconomical large amounts are required. However, despite Al toxicity, applying Mo fertilizer produces profitable grain yield. The fertilizer also increases Mo concentration in grain, and if this grain was used to sow the next crop, it may reduce the amount of Mo fertilizer required by the subsequent crop. To test this hypothesis we grew wheat in an experiment on naturally acidic sandplain soil (pH 4.5) when either 0 or 160 g/ha fertilizer Mo was applied. The grain harvested at the end of the growing season had Mo concentrations of 0.07 mg/kg when no Mo was applied (low Mo seed) and 0.27 mg/kg when Mo was applied (high Mo seed). In two further field experiments on naturally acidic sandplain soil (pH 4.3 and 4.4) we sowed low and high Mo seed of the same size (36.4 ± 0.2 mg per seed) when 4 rates of Mo fertilizer (0, 35, 70, and 140 g/ha Mo) was applied to soil. Grain yield responses to the Mo fertilizer were 59% for low Mo seed and 55 g/ha fertilizer Mo was required to produce 90% of the maximum grain yield. Corresponding values for high Mo seed were 15% response and 15 g/ha fertilizer Mo. Rather than sowing wheat seed harvested from acidic soils to sow wheat crops on the acidic sandplain soils, we instead recommend seed harvested from alkaline soils with larger concentrations of Mo in the seed be used reducing the rate of fertilizer Mo required for that crop.

The concentration of Mo in the youngest emerged leaf blades (YEB) that was related to 90% of the maximum grain yield (critical prognostic tissue test value for grain production) was about 0.08–0.09 mg/kg at tillering (Gs24) and at emergence of wheat heads (Gs59).     

Response of soybean to foliar‐applied boron and magnesium and soil‐applied boron 1

Annual plants may partition carbon (C) preferentially to reproductive structures slowing root elongation and subsequent nutrient uptake. Although foliar applications of nitrogen (N), phosphorus (P), potassium (K), and sulfur (S) supplement uptake by roots, soybean [Glycine max (L.) Merr.] yield increases have not been found in most studies. Experiments were designed to determine if foliar applications of boron (B), magnesium (Mg), or B+Mg would increase soybean yield and if soybean would respond to B applied to the soil several weeks prior to planting. Foliar B or Mg applied separately four times during reproductive growth did not affect soybean yield. However, four foliar applications of B+Mg increased soybean yield 12% at Mt. Vernon and 4% at Columbia over a three‐year period. Two foliar applications of B+Mg during the late reproductive stages increased soybean yield 8% over a two‐year period. The yield increase from foliar B+Mg treatment resulted from an increased number of pods on the main stem (18%) and branches (44%). A 2.8 kg/ha B application to soil eight weeks prior to planting increased soybean yield 11% during the first year and 13% the second year but had no effect on soybean yield by the third year after application. When results from the first two years were combined, 2.8 kg/ha B applied to soil increased the number of pods per branch by 17% and the number of branch pods per plant by 39%. Foliar applications of B+Mg increased soybean yield in four of six site‐years in the three‐year experiments at two locations.     

Foliar application of molybdenum in common beans. I. Nitrogenase and reductase activities in a soil of high fertility

Although common bean (Phaseolus vulgaris L.) has a good potential for N₂ fixation, poor nodulation following inoculation, principally under field conditions, has led to increased nitrogen (N) fertilizer use in this crop. In the face of the negative environmental effects of N fertilizer, alternative methods have been studied to minimize the amount to be applied. In this sense, foliar application of molybdenum (Mo) has been cited as a promising method. Several papers show that high bean yields (1,500–2,500 kg ha^‐1), may be obtained in the southeasten region of Brazil, when there is an application of N as side dressing or Mo spray 25 days after plant emergence. A field experiment was carried out to verify the effect of Mo foliar application on nitrogenase and nitrate reductase activities and on bean yield. Treatments included Rhizobium inoculation (with and without), foliar application of Mo (0 and 40 g ha^‐1), N at planting (0 and 20 kg ha^‐1) and N applied as side dressing (0 and 30 kg ha^‐1). Molybdenum and N as side dressing were used 25 days after plant emergence. Molybdenum increased greatly the nitrogenase activity and extended the period of high nitrate reductase activity, with a consequent increase in total shoot N. Increase of nitrogenase activity did not depend on inoculation, showing that soil native rhizobia may increase in effectiveness when appropriately handled. Bean yield did not differ significantly when fertilized with either Mo or N as side dressing.     

Effects of Selcote® ultra and sodium selenate (laboratory versus commercial grade) on selenium concentration in feed crops

Field studies were conducted at two locations in P.E.I., Canada on cereals and forages on the effect of soil applications of Selcote® Ultra and on a comparison of sodium selenate (laboratory versus commercial grade) on selenium (Se) concentration in plant tissue. Soil at both locations was sandy loam in texture and the soil pH ranged from 5.8 to 6.0. The data showed that 5 g Se ha^‐1 added as Selcote® Ultra was adequate to raise the Se level in the first two cuts of forage tissue above the minimum required level of 100 ug kg^‐1. For cereals, 10 g Se was necessary to achieve the same level. The residual effect of 10 g Se ha^‐1 from Selcote® Ultra added in the first year maintained plant Se at >100 μg kg^‐1 in the second year in the first cut of alfalfa at one location and ryegrass at both locations. A comparison of selenate‐Se (laboratory vs commercial grade) showed that both sources at similar levels of Se fertilization were equally effective in enriching barley grain with Se with no significant differences. Addition of 10 g Se ha^‐1 rate was necessary to ensure adequate Se (>100 ug kg^‐1) concentration in the ensuing graia Increasing rates of Se increased the Se levels in grain. Selenium concentrations were much higher in the barley boot stage vegetative tissue than in the grain. Results of this study showed that only 5 g Se ha^‐1, as Selcote® Ultra, is needed to maintain adequate Se in forages. The laboratory and commercially available selenate‐Se sources were equally effective in raising Se in barley.     

Effects of foliar fertilization on yield,protein, oil and elemental composition of two soybean varieties

Abstract

The effects of foliar fertilization on the yield and seed composition of two soybean (Glycine max L. Merrill) varieties were investigated under mid‐Missouri conditions over a 2‐year period. The foliar fertilizer treatments consisted of (i) 80–8–24–4 (NPKS) kg/ha, (ii) 40–4–12–2 (NPKS) kg/ha, and (in) control (no foliar treatment) with the optimum proportion of N:P:K:S in the solution 10:1:3:0.5 respectively. Nutrient sources were urea, potassium polyphosphate, and potassium sulfate. Water solutions of fertilizers (pH 6.9) containing 0.1% Tween 80 (v/v) were sprayed on the plants using a CO₂ ‐ pressurized back‐pack sprayer. Foliar fertilizer was split between four equal applications during the seed filling period. The variety Mitchell at the higher rate and the variety Williams at the lower fertilizer application rate produced slight, though statistically insignificant, yield increases. At the higher rate of application, the seed protein contents of both varieties increased, while the oil contents decreased. The concentrations of P and K in the seeds were not affected by foliar fertilization, but at the higher rate, there was a small decrease in S content of Williams variety.     

The Effect of MSW Compost on Metal Uptake and Yield Of Wheat,Barley and Canola in Less Productive Farming Soils of Alberta

Experiments were started in May 1998 at two sites to measure various crop responses to a mixed municipal solid waste-biosolids cocompost (named Nutri Plus) and examine the fate of certain metals associated with Nutri Plus compost. There were six treatments: Check, 50, 100, and 200 T compost/ha, NPKS (75 kg nitrogen (N) /ha, 20 kg phosphorus (P)/ha, 45 kg potassium (K) and 18 kg sulphur (S)/ha), PK (20 kg P, 45 kg K/ha), and three crops: canola (Brassica rapa cv. ‘Hysyn 110’), wheat (Triticum aestivum L. cv. ‘Roblin’) and barley (Hordeum vulgare L. cv. ‘Lacombe’). Each treatment was replicated four times and was in a complete randomized block design. In the compost treatments, 20 kg P and 45 kg K were applied due to low concentration of these two nutrients in the compost. Soil and plant samples were analyzed for nutrient content such as N, P and K. In addition, plant samples and soil samples after the compost application were also analyzed for elemental content of As, B, Cr, Co, Cu, Zn Se, Mo, Cd, Hg and Pb. The research results show that the compost slightly increased heavy metal concentrations in the soil but did not cause any phytoxicity to crops. Yield from 100 and 200 T/ha application was higher with the compost than with NPKS treatment. However, the yield of the 50 T/ha application was similar to that of NPKS treatment. Comparing the two sites, the compost apparently was more beneficial at Site 1 than at Site 2 in the year of application. This is likely due to the lower indigenous soil fertility and poor soil physical properties at Site 1. The N content in cereal grains was similar among the compost treatments but lower than the Check and NPKS treatments due to the diluting effect of higher yield. The oil content in canola seed was similar among all treatments. The results suggest that Nutri Plus compost applications generated positive yield responses in all three crops. Crop yield increased as the application rate increased. Heavy metal loading was not an immediate problem with the compost application, although it will limit total compost application over time to the same soil