Effect of Micronutrient-Based Integrated Use of Nutrients on Crop Productivity,Nutrient Uptake,and Soil Fertility in Greengram and Fingermillet Sequence Under Semi-arid Tropical Conditions

To identify the best combinations of micronutrient-based fertilization treatments in terms of crop yield and nutrient uptake, three field experiments with greengram?fingermillet as the test sequence with 12 treatments on micronutrient-based fertilization [with recommended nitrogen (N)?phosphorus (P)?potassium (K) fertilizer] were conducted during 2005 to 2007 in a semi-arid Alfisol at Bangalore. The effects of treatments on available soil and plant uptake of nutrients [N, P, K, sulfur (S), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), boron (B), and molybdenum (Mo)] and yield of crops were assessed based on standard analysis of variance procedure. Using the relationships of yield with soil and plant nutrient variables, regression models of yield through soil and plant variables were calibrated and effects of variables on crop yields were assessed. The models gave high and significant yield predictability in the range of 0.87 to 0.98 through different variables. The model of plant uptake through soil nutrients indicated that soil S, Fe, and Zn had significant positive effects, whereas soil N, K, B, and Mo had negative effects on plant nutrient status in greengram. Similarly, soil P, Mn, and Zn had significant positive effects, whereas soil N, K, and Fe had negative effects on plant uptake of nutrients in fingermillet. Based on a relative efficiency index (REI) criteria, T2 for plant uptake and T12 for maintaining soil nutrients were found to be superior in greengram, whereas T2 for plant uptake and T8 for maintaining soil nutrients were found to be superior in fingermillet over years based on REI. The combined REI over soil and plant nutrients for both crops indicated that application of T8 for greengram and T2 for fingermillet could be prescribed for attaining maximum plant uptake of nutrients and productivity of crops in sequence, apart from maintaining maximum soil fertility of nutrients under semi-arid Alfisols.     

Alfalfa Responses to Combined Use of Lime and Limiting Nutrients on an Acidic Soil

An on-farm field experiment was conducted on an acidic soil to investigate the effects of combined use of lime and deficient nutrients on herbage yield of alfalfa (Medicago sativa L.). Omitting lime and limiting nutrients led to elevated concentrations of aluminium (Al), iron (Fe), and manganese (Mn) in alfalfa leaves and stems and caused severe reductions in herbage yield of alfalfa. Combined use of lime (2 t ha^?1) and nutrients [phosphorus (P): 20 kg ha^?1, sulfur (S): 20 kg ha^?1, zinc (Zn): 4 kg ha^?1, and boron (B): 2 kg ha^?1] had the maximum increase in groundcover, root biomass, nodulation, leaf retention, leaf-to-stem ratio, herbage yield, crude protein, and nutrient composition of alfalfa. These beneficial effects were due to raised soil pH; improved calcium (Ca), P, S, Zn, and B nutrition; and reduced Al, Mn, and Fe toxicity. Aluminium and all the nutrients except copper (Cu) were more concentrated in alfalfa leaves than stems.

Aluminum concentration was about three times greater in the lower leaves than in upper leaves. Lower leaves also had much greater concentrations of Ca, Mg, K, S, Fe, Mn, Cu, and B compared with upper leaves. In contrast, P and Zn concentrations were greater in the upper leaves than in lower leaves. Results suggest that the combined use of lime and all the limiting nutrients may realize potential beneficial effects of alfalfa on acidic soils where more than one essential nutrient is deficient. This may increase growth potential, nitrogen contributions, and groundcover by alfalfa and reduce soil erosion and runoff.     

硼钼锌及互作对甘蓝型油菜籽粒产量的影响

A field experiment was conducted to study the effects of boron (B), molybdenum (Mo), zinc (Zn) and their interactions on seed yield and yield formation of rapeseed (Brassica napus L. var. Huashuang 4). Application of B fertilizer to a sandy soil increased the seed yield by 46.1% compared to the control and also created a considerably higher seed yield than the two treatments solely applying Mo and Zn fertilizers, which suggested that B was a main constraint for the seed yield of Huashuang 4 in this experiment. The effect of B fertilizer on the seed yield was attributed to an increase in the number of seeds per silique and siliques per plant. The combined application of B with Mo or Zn resulted in higher seed yield than the application of B, Mo or Zn alone, and the seed yield of the B+Mo+Zn treatment was the highest in all treatments, 68.1% above the control. Dry matter accumulation of seed followed a typical S-shaped curve and it was higher in plants supplied with B than in plants without B. A small but significant increase in the seed oil content and an improvement in the oil quality were also observed in all treatments compared with the control. These results suggested that optimal micronutrient application could provide both yield and quality advantages for rapeseed in poor soil.     

Influence of soil temperature and moisture on micronutrient supply,plant uptake,and biomass yield of wheat,pea, and canola

Abstract

Crop yield response to micronutrient fertilization is difficult to predict, particularly under unfavorable environmental conditions as these may alter both crop nutrient demand and the soil micronutrient supply to plant roots. The research objective was to evaluate the effect of various soil temperature and moisture conditions on crop growth response to added micronutrient copper (Cu), zinc (Zn), and boron (B) along with soil micronutrient supply and distribution among fractions. Brown and Dark Brown farm soils collected from southern Saskatchewan were used to grown wheat, pea and canola within controlled environment chambers. The biomass yields of all crops decreased under cold soil temperature and moisture stress (drought and saturated) conditions. Greater plant uptake of Cu, Zn, and B was associated with optimum (i.e., field capacity) soil moisture and warm temperature (23°C) growing conditions, compared to drought (i.e., 50% field capacity), saturated, and cold (5°C) temperature conditions. Environmental stress had the greatest impact on pea growth, reducing crop yield and micronutrient utilization efficiency more than 95%. Soil supplies of Cu and Zn were most negatively impacted by drought stress due to reduced mobility of these diffusion limited nutrients. The extractable micronutrients levels and chemical speciation fractions of Cu, Zn, and B indicating that bioavailability and micronutrient transformation were not affected during our short-term (i.e., six-weeks) study. However, it is suggested that assessments of micronutrient forms also be conducted on soil samples under actual moisture and temperature conditions as they exist in the experiment, as well as on dried, processed samples.     

Diagnosis of Secondary and Micronutrient Deficiencies and Their Management in Rainfed Agroecosystems: Case Study from Indian Semi‐arid Tropics

Rainfed agriculture in the semi‐arid tropical (SAT) regions of India is greatly influenced by water shortages caused by low, highly variable, and erratic rainfall. However, apart from water shortages, crop productivity in these regions is also affected by low fertility. Little effort has been devoted to diagnosing and managing the nutrient‐related problems in farmers' fields in the SAT regions of India. The ongoing integrated watershed management program by the International Crops Research Institute for the Semi‐arid Tropics and its partners provided the opportunity to diagnose the soil infertility‐related problems by soil testing, develop nutrient management protocols, and determine on‐farm crop responses to fertilization in the SAT zone of India. This article discusses examples from recent research on the diagnosis of multinutrient deficiencies and on‐farm crop responses to fertilization. Results of analyses of soil samples from farmers' fields in several districts of Andhra Pradesh, Karnataka, Tamil Nadu, Rajasthan, and Madhya Pradesh states and Junagarh district, Gujarat, showed that almost all farmers' fields had low organic carbon (C), low to moderate available phosphorus (P), and generally adequate extractable potassium (K). However, the widespread deficiencies of sulfur (S), boron (B), and zinc (Zn) were most revealing; their deficiencies varied with nutrient, district, and state. On‐farm trials conducted during three seasons (2002–2004) in three districts of Andhra Pradesh showed significant yield responses of maize, castor, groundnut, and mung bean to the applications of S, B, and Zn over farmer's input treatment, and the yield responses were larger when these nutrients were added along with nitrogen (N) and P. It is concluded that the deficiencies of nutrients such as S, B, and Zn are widespread and are holding back the potential of rainfed production systems. Clearly, nutrient deficiencies can be diagnosed by soil testing.     

硒锌钼对黄土高原马铃薯和小白菜产量及营养元素与硒镉含量的影响

黄土高原旱地土壤微量元素硒锌钼潜在缺乏,不仅影响农作物产量,还降低农产品的矿物营养品质,研究施用硒锌钼肥料对该地区作物生长及可食部分营养元素含量的影响具有重要意义。通过田间试验,研究了硒锌钼肥单独土施、硒锌肥配施、硒锌钼肥配施对马铃薯和小白菜产量及营养元素和硒镉含量的影响。结果表明：硒肥提高了马铃薯块茎和小白菜叶片硒含量,分别由对照的0.02mg.kg-1和0.09mg.kg-1提高到1.51～2.15mg.kg-1和13.03～19.44mg.kg-1,钼肥提高了马铃薯块茎和小白菜叶片钼含量,分别由对照的0.43mg.kg-1和2.3mg.kg-1提高到1.03～1.16mg.kg-1和17.7～19.9mg.kg-1,单施与配施处理间无显著差异。锌肥土施或锌与硒、钼肥配合土施不但使小白菜叶片中的锌含量由对照的21.0mg.kg-1显著提高到48.1～68.4mg.kg-1,还使镉含量显著降低50%以上;施锌对马铃薯块茎的锌含量无显著影响。硒锌钼肥单施或配施均对马铃薯和小白菜产量及氮、磷、钾、硫、钙、镁、铁、锰、铜、硼含量无显著影响。因此,在黄土高原旱地,硒钼配合土施可同时提高马铃薯块茎的硒钼含量,硒锌钼配合土施可同时提高小白菜叶片的硒锌钼含量。     

RESPONSE OF ‘BURLAT’ SWEET CHERRY TREES TO POSTHARVEST SPRAYS OF NITROGEN,BORON AND ZINC

The aim of the study was to examine effects of postharvest sprays of nitrogen (N), boron (B), and zinc (Zn) on reproductive response of sweet cherry (Prunus avium L.) trees, fruit quality and plant nutrition. The experiment was conducted during 2007–2009 in central Poland on mature ‘Burlat’ sweet cherry trees/F12, grown on a coarse-textured soil with low level of organic matter, and optimal soil reaction. Soil status of phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), iron (Fe), manganese (Mn), Zn and copper (Cu) was optimal, whereas B – low. Sweet cherry trees were sprayed with boric acid-B, ethylenediaminetetraacetic acid (EDTA)-Zn, and urea-N at 30–40 d prior to initiation of leaf fall according to following schema: i) spray of N at a rate of 23 kg ha^?1; ii) spray of B and Zn at a dose of 1.1 kg ha^?1 and 0.5 kg ha^?1, respectively; and iii) spray of N, B and Zn at the same rates as in the above spray combinations. The trees sprayed with water served as the control. The results showed that fall spray treatments had no influence on cold damage of flower buds, plant N status and soluble solids concentration in fruit. Postharvest spray of N and combined spray of N, B and Zn injured leaves in the fall but did not cause defoliation. Sprays of B and Zn with or without N increased status of Zn and B in fall leaves, and B in flowers and midsummer leaves. Those sprays also improved fruit set and yield. In one out of two years of the study, fall sprays of N with or without B and Zn decreased mean fruit weight. The above results indicate that only leaf-applied B in the fall improved reproductive response of sweet cherry trees. It is concluded that under conditions of B shortage in a soil and/or plant tissues, postharvest B sprays can be recommended in sweet cherry orchards to improve reproductive growth of the trees.     

Widespread Deficiencies of Sulfur,Boron, and Zinc in Indian Semi-Arid Tropical Soils: On-Farm Crop Responses

On-farm studies were conducted during 2002–2004 to determine fertility status, including sulfur (S) and micronutrients, and crop response to fertilization on farmers' fields in the semi-arid zone of India. Nine hundred-twenty four soil samples taken from farmers' fields, spread in the three districts of Andhra Pradesh (India), were analyzed for soil chemical fertility parameters. Results showed that samples were low in organic carbon (C), total nitrogen (N), and low to moderate in extractable phosphorus (P), but adequate in available potassium (K). Analyses of soil samples for extractable S and micronutrients was most revealing and showed that 73–95% of the farmers' fields were deficient in S, 70–100% in boron (B), and 62–94% in zinc (Zn). On-farm trials conducted during three seasons (2002–2004) showed significant yield responses of maize, castor, groundnut, and mung bean to the applications of S, B, and Zn. The yield responses were larger when S, Zn, and B were applied along with N and P. Applications of S, B and Zn also significantly increased the uptake of N, P, K, S, B, and Zn in the crop biomass. Results show widespread deficiencies of S, B, and Zn under dryland agricultural conditions; results also show that the nutrient deficiencies can be diagnosed by soil testing. It was concluded that the drylands in the semi-arid regions of India were not only thirsty (water shortage), but also hungry (nutrient deficiencies).     

Effect of zinc application on the dry matter yield uptake and distribution of zinc and other micronutrients in cocoa (Theobroma cacao. L.)

Abstract

The effects of application of zinc fertilizer on dry matter yield, uptake and distribution of zinc and other nutrients by Amazon and Amelonado cocoa cultivars grown in a soil of low zinc content in the greenhouse were investigated.

There was a differential response to zinc fertilization by the two cocoa cultivars. Maximum dry matter yields of Amazon and Amelonado were attained with 10 ppm Zn and 50 ppm Zn, respectively. Under similar experimental conditions Amelonado seedlings expressed zinc deficiency symptoms whereas Amazon did not.

Zinc concentrations in the leaves, stem and roots of both cuitivars did not give a good index of the zinc status of the crops. This was because of the existence of the “Piper‐Steenbjerg”; effect in that nil zinc rates often gave higher leaf concentration of the zinc than next higher rate. In general, the relative content of zinc followed the pattern; leaves > roots > stem with the Amazon cultivar containing more zinc than the Amelonado.

The distribution of absorbed Cu in the leaves, stem and roots did not differ in both varieties. Whereas Fe uptake was mostly concentrated in the roots, Mn absorbed was largely concentrated in the leaves of both varieties and only Mn uptake in the leaves of Amazon consistently increased with Zn application.

The differences in the uptake and distribution of nutrients between the two cocoa cultivars was attributed to differences in their ability to extract nutrients from the soil and in their requirements for metabolic processes.     

Effect of Glyphosate and Zinc Application on Yield,Soil Fertility,Yield Components,and Nutritional Status of Soybean

Glyphosate is a widely used nonselective herbicide for the control of agricultural weeds. It is being increasingly used in glyphosate resistant genetically modified plants. However, there are few studies on its effects on the nutritional status of soybean, particularly on the uptake of zinc (Zn). Two experiments were conducted under field conditions in a Typic Quartzipsamment and an Orthic Ferralsol to investigate the effect of glyphosate application × Zn interaction on soil fertility, yield components, seed yield (SY), shoot dry weight (SDW) yield, and nutritional status of soybean. The five Zn rates 0, 3, 6, 9, and 12 kg ha^?1 were used in two soybean varieties [BRS 133 (conventional—NGM) and its essentially derived transgenic line BRS 245RR (GM), which was divided into: with (+Gly) and without (–Gly) glyphosate application. Only the P (phosphorus) and Zn available concentrations in the soil were impacted by Zn rates. However, the available P concentration only decreased in the soil planted with GM soybean. Mehlich 1 and diethylenetriaminepenta acetic acid–triethanolamine (DTPA–TEA), 7.3 extractants were effective to determine the available Zn. In the two crop sites, the number of pods per plant (NPP) and the SDW yield were affected by the interaction varieties × Zn. SY was influenced by the application of the herbicide, reducing a potential phytotoxic effect with the use of high rates. Regarding the nutrients, only the foliar calcium (Ca), boron (B), iron (Fe), and manganese (Mn) concentrations were negatively affected by glyphosate, and in the case of Zn, the difference occurred only between the varieties BRS 133 and BRS 245RR.     

Alleviation of Multinutrient Deficiency for Productivity Enhancement of Rain-Fed Soybean and Finger Millet in the Semi-arid Region of India

Soil nutrient contents were determined in 802 surface soil samples (0–15 cm deep) collected from farmers' fields that support extensive cultivation of soybean (Glycine max L.) and finger millet (Eleusine coracana G.), spread across three districts, in the semi-arid regions of Karnataka, India. Following soil analysis, on-farm crop trials were conducted during 2005–2007 to study the crop response to the soil application of nitrogen (N), phosphorus (P), sulfur (S), boron (B), and zinc (Zn) fertilizers. Analyses of soil samples revealed that 4–83% fields were deficient in N, 34–65% in P, 83–93% in extractable S, 53–96% in B, and 34–88% of farmers' fields were deficient in Zn. On-farm trials conducted during the three rainy seasons (2005, 2006, and 2007) significantly (P ≤ 0.05) enhanced crop productivity indices such as yields of grain, stover, and total biomass in soybean and finger millet crops. Integrated management of deficient nutrients in finger millet and soybean crops significantly enhanced the grain and straw uptake of N, P, K, S, and Zn.     

Optimum Nutrient Rate and Nutritional Constraints in Tuber Crops Growing in Ultisol of India with Special Emphasis on Tannia

Tuber crops are generally grown in marginal lands with low native soil fertility. In India, laterite soils (acidic Ultisols) are the major soils for tropical tuber crops and are poor in innate fertility. Among tropical tuber crops, some have adapted to poor soils, such as cassava, whereas others such as tannia (Xanthosoma sagittifolium L.) cannot establish well in these soils and may manifest nutritional disorders, which ultimately result in the complete devastation of the crop. Therefore, we investigated the effects from a preliminary rate trial (PRT) and nutrient-omission pot trial (NOPT) using maize as a test crop and a NOPT with tannia to determine the optimum nutrient rate and limiting nutrients, as well as nutritional problems affecting the growth and yield of tannia. Each experiment was laid out in a complete randomized design with three replications and was conducted for both garden and paddy soils. The PRT revealed that the optimum nutrient requirements for the soils were different, with garden soils requiring nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), boron (B), zinc (Zn), and molybdenum (Mo) at 200, 60, 160, 70, 60, 50, 4, 8, and 0.8 kg ha^?1, respectively, and paddy soil requiring twice these rates. The NOPT indicated that in addition to N, P, K, B, and Mo in both garden and paddy soils, Ca and Zn in paddy soils and S in garden soils were the constraining nutrients. The NOPT carried out with tannia indicated that the main nutritional problem was subsoil acidity-induced multinutrient deficiencies involving K, Ca, and Mg.     

Interactive effect of boron and zinc on growth and metabolism of mustard

Abstract

Mustard (Brassica campestris L.) cv. T9 was grown in refined sand at three levels of boron (B), deficient (0.0033 ppm), normal (0.33 ppm), and excess (3.3 ppm), each at three levels of zinc (Zn), low (0.00065 ppm) adequate (0.065 ppm), and high (6.5 ppm). The B deficiency effects were accentuated by low zinc viz., the decreased biomass, B and Zn concentrations in leaves and seeds and the activity of carbonic anhydrase and accumulation of reducing sugars and stimulated activities of peroxidase, ribonuclease, and acid phosphatase in B deficient leaves were aggravated further. Synergism was also observed between the two nutrients when both B and Zn were in excess together as excess B accelerated the effects of high Zn by lowering further the reduced biomass, economic yield, and carbonic anhydrase activity and raised further the increased concentration of B and Zn in leaves and seeds, reducing sugars and activity of peroxidase obtained in excess Zn. In mustard, additive effects of high Zn and low B was reflected when high Zn increased the reduced biomass, seed yield, leaf B, and decreased the stimulated activities of peroxidase, ribonuclease, acid phosphatase, and high concentration of non‐reducing sugars to some extent in low B.     

Impact of Postharvest Sprays of Nitrogen,Boron and Zinc on Nutrition,Reproductive Response and Fruit Quality of ‘Schattenmorelle’ Tart Cherries

The aim of the study was to examine effects of fall sprays of nitrogen (N), boron (B) and zinc (Zn) on nutrition, reproductive response, and fruit quality of tart cherry (Prunus cerasus L.). The experiment was conducted during 2008–2010 in Poland on mature ‘Schattenmorelle’ sour cherry trees, planted at a spacing of 4.0 × 1.5 m on a coarse-textured soil with low level of organic matter, and adequate reaction and availabilities of macro- and micronutrients. Tart cherries were sprayed with boric acid-B, ethylenediaminetetraacetic acid (EDTA)-Zn, and urea-N at 40–50 d prior to initiation of leaf fall according to following schema: (i) spray of N at a rate of 23 kg ha^?1; (ii) spray of B and Zn at doses of 1.1 kg ha^?1 and 0.5 kg ha^?1, respectively; and (iii) spray of N, B, and Zn at the same rates as in the above spray combinations. The trees sprayed with water were served as the control. The results showed that postharvest spray treatments had no effect on defoliation, cold damage of flower buds, fruit set, yielding, plant N status, mean fruit weight, and soluble solids concentration in fruit. Postharvest sprays of B and Zn with or without N enhanced status of Zn and B in fall leaves, and B in flowers but had no impact on levels of the above micronutrients in summer leaves. Leaf-absorbed B was withdrawn in the fall, whereas Zn was immobile. It is concluded that postharvest B sprays can be recommended to increase B status in flowers of tart cherry, whereas fall sprays of urea-N and Zn are not able to improve plant nutrition of those nutrients the following season.     

Comparison of DTPA and resin extractable soil Zn to plant Zn uptake

Abstract

Extraction of soil zinc with routine chemical extractants does not always reflect differences in Zn availability as detected by plant uptake. This study was undertaken to explore and compare the use of an ion exchange resin and diethylenetriaminepentaacetic acid (DTPA) for extracting soil Zn as related to plant Zn uptake. Beans were grown in 1989 following differential cropping with corn and beans or fallow in 1988 on a Portneuf silt loam near Kimberly, Idaho. Two Zn fertilizer treatments were imposed across previous cropping treatments. A batch method for determining resin extractable soil Zn was established.

Both plant Zn concentration and Zn uptake by beans in 1989 were significantly higher in Zn fertilized than unfertilized treatments regardless of previous crop; and higher in plots previously cropped with corn than beans or fallow, regardless of Zn treatment. DTPA and resin extractable soil Zn were significantly higher in Zn fertilized plots compared to unfertilized plots but did not differ between previous cropping treatments. Resin and DTPA extractable soil Zn concentrations were positively correlated. Resin extracted soil Zn correlated better with plant Zn concentration and Zn uptake throughout the growing season than DTPA extracted soil Zn, particularly in plots that had been fallowed or previously cropped with corn. Resin may be extracting labile soil Zn not extracted with DTPA and, therefore, be better simulating plant uptake. Both extraction methods correlated better with Zn uptake when evaluated within cropping treatments, emphasizing the need to consider previous crop when calibrating soil tests.     

硼钼锌配合对甘蓝型油菜产量和品质的影响

通过水泥池小区试验,研究了B、Mo、Zn配合对甘蓝型油菜双低品种华双4号产量和品质的影响。结果表明,B、Mo、Zn配合产量最高,比对照增产20.7%;两种微量元素配合时,以BMo配合最佳,其产量与BMoZn配合差异不显著,BZn或MoZn配合仅比对照略有增产。BMoZn配合的每角粒数居各处理首位,每株角果数居第二,BMo配合的每株角果数和千粒重处于各处理首位。试验还表明,凡有配施硼的处理,即:BMo、BZn和BMoZn,有利于提高华双4号菜籽的含油量;凡配施锌的处理,即:MoZn、BZn和BMoZn,有利于提高华双4号菜籽的蛋白质含量。微量元素的各种配合均可降低华双4号菜籽的硫甙、芥酸含量;BZn配合具有最高的油酸含量,较低的棕榈酸、硬脂酸、亚油酸和亚麻酸含量,对改善华双4号菜籽的脂肪酸组分配比最为有利。对于双高(高硫甙、高芥酸)油菜,只考虑提高其产量及含油量,以BMo配合较好;而对优质的双低(低硫甙、低芥酸)油菜,其饼粕所含的蛋白质可以直接作为动物饲料,因此在提高其产量、含油量,改善油分品质的同时,还要兼顾其蛋白质含量,则以BMoZn配合效果最好。     

Boron and zinc deficiencies and toxicities and their interactions with other nutrients in soybean roots,leaves, and seeds

In many parts of the world, soils deficient and/or toxic in micronutrients reduce potential soybean (Glycine max) yields. The objective of our study was to grow plants in low to high concentrations of boron (B) and zinc (Zn) to determine how B and Zn deficiencies and toxicities affect soybean growth and interact with other essential nutrients in roots, leaves, and seeds. We found that B significantly affected levels of all essential nutrients except manganese and iron, while Zn significantly affected all essential nutrients in at least one plant tissue tested. Some of the physiological responses and nutrient interactions were cultivar-dependent. This study showed how deficiencies and toxicities of B and Zn affect plant growth and how B and Zn fertility interacts with many of the other essential nutrients.     

土施和喷施锌肥对冬小麦子粒锌含量及生物有效性的影响

为揭示潜在性缺锌土壤上不同施锌方式对小麦子粒锌含量及其生物有效性的影响,选用5个冬小麦品种进行了土施和喷施锌肥的田间裂区试验。结果表明,供试土壤条件下,不同施锌方式对小麦产量均无明显影响,但是在一定施锌方式下小麦子粒锌含量大幅度提高。与对照相比,土施、喷施及土施+喷施锌肥提高小麦子粒锌含量幅度分别为-6.1%、64%和83%,提高小麦子粒锌携出量幅度分别为-3.6%、69%和83%。3个施锌处理降低子粒中植酸含量的幅度分别为-2.4%、7.2%和1.5%,降低植酸与锌摩尔比的幅度分别为-25%、41%和44%,且不同品种之间也存在一定差异;虽然植酸与锌的摩尔比有所下降,但仍高于20。此外,单独土施锌肥虽可大幅度提高耕层土壤有效锌含量,但对子粒锌含量及生物有效性的影响很小。总之,在小麦生长后期喷施锌肥是提高潜在性缺锌土壤上小麦子粒锌含量和生物有效性较为经济的方式,对改善小麦锌营养品质有较好作用。     

黄土和塿土中Fe, Mn, Cu和Zn向植物根部移动的机理

The pot experiments were conducted in the artificial climate laboratories to determine the relative importance of mass flow and diffusion in supplying Fe, Mn, Cu and Zn to wheat, soybean and maize plants growing in loessal soil and lou soil. It was found that the calculated relative contribution of mass flow of iron, manganese, copper and zinc to plant uptake varied from 5% to more than 100%, depending on the crop species and soil types as well as plant growth stage, soil moisture, atmosphere humidity, etc. The results also showed that the major transportation mechanisms of these micronutrients in soil-root system varied with the crop and its growth, climate and soil, significantly. In general, mass flow was more important for Cu and Zn and diffusion was more significant for Fe and Mn at the seedling stage.     

Effect of single and combined applications of zinc with iron and boron on the contents of “Deveci” pear trees

This research was conducted to correct the ion of zinc (Zn) deficiencies and to examine the efficiency of foliar Zn application on pear groves along with iron and boron. The treatments consisted of control, soil and foliar applications. Every foliar applied Zn elevated considerably Zn contents of the leaves. But, increases in fruit Zn contents were rather limited as compared to Zn contents of the leaves. It is thought that accumulation of Zn in the fruits was due to movement of Zn from the leaves well-supplied with Zn to the fruits. Therefore, foliar application of Zn should be conducted at least four times at the rate of 0.1% to increase Zn contents in the fruits in terms of human's daily Zn intake. Foliar applications of Zn alone and combined Zn + Fe, Zn + B and Zn + Fe + B applications significantly increased Zn, Fe and B concentrations, respectively, in the pear trees, as well.