Genotypic differences in growth,yield and nutrient accumulation of spring wheat cultivars in response to long-term soil fertility regimes

Determining genotypic responses to soil fertility may assist selection of cultivars that can be adapted to varied soil fertility regimes, and such selection under field conditions is still limited. A two-year field experiment was conducted in long-term field trials to investigate wheat genotype effects on early growth, yield and nutrient accumulation as affected by varied long-term soil fertility managements and nitrogen (N) fertilization. Results show that the early growth, grain yield and nutrient accumulation of spring wheat plants were strongly affected by soil fertility managements and genotypes. Early shoot and root biomass of singly grown plants and leaf canopy growth under standard growth density was associated with subsequent grain yield of plants under standard growth density across the gradient in soil fertility levels. Taifun and Thasos had stable higher yield and N and phosphorus (P) uptake across varied soil fertility regimes compared with other genotypes. Økilde, however, increased yield by 8–34% and N and P accumulation by 1–22% only when grown in the high organic manure treatment compared with other genotypes, indicating that it is more adapted to high organic fertility regimes. Therefore, the different responses and adaptations of genotypes to soil fertility regimes should be included during selection of cultivars.     

在富营养土壤斑块中根增值对玉米养分吸收和生长的贡献

Root proliferation can be stimulated in a heterogeneous nutrient patch; however, the functions of the root proliferation in the nutrient-rich soil patches are not fully understood. In the present study, a two-year field experiment was conducted to examine the comparative effects of localized application of ammonium and phosphorus (P) at early or late stages on root growth, nutrient uptake, and biomass of maize (Zea mays L.) on a calcareous soil in an intensive farming system. Localized supply of ammonium and P had a more evident effect on shoot and root growth, and especially stimulated fine root development at the early seedling stage, with most of the maize roots being allocated to the nutrient-rich patch in the topsoil. Although localized ammonium and P supply at the late stage also enhanced the fine root growth, the plant roots in the patch accounted for a low proportion of the whole maize roots in the topsoil at the flowering stage. Compared with the early stage, fine root length in the short-lived nutrient patch decreased by 44%-62% and the shoot dry weight was not different between heterogeneous and homogeneous nutrient supply at the late growth stage. Localized supply of ammonium and P significantly increased N and P accumulation by maize at 35 and 47 days after sowing (DAS); however, no significant difference was found among the treatments at 82 DAS and the later growth stages. The increased nutrient uptake and plant growth was related to the higher proportion of root length in the localized nutrient-enriched patch. The results indicated that root proliferation in nutrient patches contributed more to maize growth and nutrient uptake at the early than late stages.     

Comparison of root and root hair growth in solution and soil culture

Aerated solution culture is frequently used for studying plant growth. Few comparisons have been made of root growth in solution with that found in soil. The objective of this study was to compare root growth and root hair development in these two mediums. Corn (Zea mays L.) grown in aerated solution at two temperatures (18 and 25°C) and three P concentrations (2, 10, and 500 μmol L^‐1) was compared with that in three soils, Raub (Aquic Argiudoll) and two Chalmers (Typic Haplaquoll) silt loams, in a controlled climate chamber over 21d. Corn plant weight and root growth were similar in solution culture and Raub soil when grown at an air and soil temperature of 18°C. At 25°C both yield and root growth were greater in Raub soil, even though P uptake by corn was 7‐fold greater in solution culture. The same difference was found when corn grown at 25°C in solution culture at 3 different P concentrations was compared with that grown in Chalmers soil at two P levels. Percentage of total root length with root hairs, root length and density and consequently root surface area, were all greater in the Chalmers soil than in solution culture. An increase in soil P, resulted in a decrease in root hair growth. No such relationship was found in solution culture. Although the recovery and measurement of plant roots and root hairs is more convenient in solution culture, results from this study indicate that the usefulness of solution culture for determining those factors which control root growth and root hair development in soil is limited.     

Yearly variation of root distribution with depth in relation to nutrient uptake and corn yield

Abstract

Root length and root distribution in the soil profile is important in determining the amount of nutrients and water taken up by the plant. Data about year to year variation of corn (Zea mays L.) root growth and its relation to nutrient uptake are limited. An evaluation of the importance of root system size and distribution on P and K uptake and corn yield was made from samples taken annually from a long‐term fertility experiment on Raub silt loam, fine silty, mixed, mesic Aquic Argiudolls. Root density varied with soil depth among years, whereas P and K fertilizer treatment had no measureable influence on total root length. Ear leaf P concentration was highly correlated with the amount of roots in the 0 to 15 cm layer which contained most of the available P. Since P was not appreciably limiting corn yield, no significant relation was found between yield and P content of the ear leaf. Yields on K deficient plots were positively correlated with root density in the topsoil. Correlations of root densities in the deeper soil layers with both yield and ear leaf nutrient concentration became increasingly smaller with depth in the soil profile. The results indicate that root length plus root distribution in the soil may influence year to year variation in yield particularily on soils having low available nutrient levels. This variation in root growth may be responsible for differences among years in the response of crops to applied P and/or K.     

Starter fertilizer to spring barley and spring wheat in south-east Norway: Effects on growth and nutrient uptake

Abstract

Field experiments were carried out on three representative soils, to evaluate the effect of various starter fertilizers, together with different rates of band placed phosphorus (P), on nutrient uptake and yield of spring barley (Hordeum vulgare L.) and spring wheat (Triticum aestivum L.). The starter fertilizers were placed in the immediate vicinity of the seed, while the band placed P was placed at about 5 cm below the seeds and spaced at 25 cm between alternate seed rows. As starter fertilizer, monoammonium phosphate (MAP), calcium nitrate (CAN), ammonium nitrate (AN) and triple superphosphate (P20) were compared. In both species, effects of starter fertilizer on P uptake were most marked early in the growing season. At GS 13 application of 20 kg P ha^?1 as MAP increased the P uptake by 50% in barley and by 35% in wheat, compared to no seed-placed nutrients. For grain, the increase in P content was 8% for both species. The higher P uptake at GS 13 was supported by observations of higher plant vigour in the treatments with either P20 or MAP as starter fertilizer. The use of N only as starter fertilizer did not increase the vigour of the plants. Band placement of P also gave more vigorous plants in spring barley. The grain yield increased on the silty clay loam and on the silt soil when starter fertilizer was applied, especially with the use of MAP. Smaller and non-significant yield differences were found when starter fertilizer was used on the loam soil. No delay or reduction of emergence was observed with starter fertilizer. Therefore, on soils where root growth or nutrient uptake becomes limited during the first weeks after sowing, application of starter fertilizer is recommended in Norway for both spring barley and spring wheat. Crops grown on silty soils seem to have an especially high demand for easily available P given as starter fertilizer.     

Shoot and root biomass,phosphorus and nitrogen uptake of spring wheat grown in low phosphorus and moisture content conditions in a pot experiment

Abstract

A pot experiment was done in a greenhouse to investigate the effect of low phosphorus (P) and moisture content on growth and yield components of four spring wheat (Triticum aestivum L.) varieties. Days to emergence of seedlings were shortened, plant height, tiller number, and SPAD (Soil-Plant Analyses Development) index of the leaves were significantly (p?R²) values ranging from 0.72 to 0.90. The study underlines the strong relationship between moisture, P availability and uptake and provides more information on P nutrition during the vegetative stage of wheat in moisture and P deficient soils.     

玉米细根形成和土壤中无机磷分级平衡对缺磷的特异性响应

Plants have diverse strategies to cope with phosphorus (P) deficiency. To better understand how maize responds to P deficiency, a field experiment with two P levels, 0 and 100 kg P2O5 ha-1 (P0 and P100, respectively), was carried out as a part of a long-term Pfertilizer field trial. Plant and soil analyses showed that P-deficient maize reduced its growth rate, increased P use efficiency, and formed more thin roots with the diameter less than 0.6 mm at jointing and silking stages, compared to the plants treated with P100. Further, there were no differences in major inorganic P fractions (Ca 2 -P, Ca 8 -P, Al-P, Fe-P, occluded P and Ca 10 -P) between the rhizospheric and bulk soils at each harvest, even when soil Olsen-P was only 1.38 mg kg-1 . These results suggested that maize responded to P deficiency by reducing the internal P demand for growth and increasing P acquisition ability by favorable root morphological alteration at low carbon cost.     

Effect of one phosphorus rate placed in different soil volumes on p uptake and growth of wheat

Abstract

The volume of soil treated with P fertilizer affects P uptake by the crop. Earlier studies have shown that the stimulation of root growth in P‐fertilized soil was similar for both corn (Zea mays L.) and soybean (Glycine max L. Merr). The objective of this research was to determine the effect of fertilizer P placement on P uptake and shoot and root growth of spring wheat (Triticum vulgare L.). Wheat was grown for 34 days in Raub silt loam (Aquic Argiudolls) in a controlled climate chamber. One rate of phosphate per pot, 150 mg P per three kg of soil, was mixed with 2, 5, 10, 20, 40 and 100% of the soil in the pot. The P was equilibrated with moist soil for 5 days at 70°C followed by 21 days at 25° C before transplanting 8‐day‐old wheat plants into each 3 L pot. The P stimulation of root growth in the P‐treated soil was similar to that for corn and soybeans. The effect could be described by the equation y = x^0.7 where y is the fraction of the root system in the P‐fertilized soil where P is mixed with x fraction of the soil. The greatest P uptake and plant growth occurred when added P was mixed with 20% of the soil.     

Tillage and mulch effects on soil physical environment, root growth, nutrient uptake and yield of maize and wheat on an Alfisol in north-west India

Field experiments were conducted for 6 years on a silty clay loam to study the effect of soil management on soil physical properties, root growth, nutrient uptake and yield of rainfed maize (Zea mays L.) and wheat (Triticum aestivum L.) grown in a sequence. Treatments were: no-tillage (NT), NT+pine needle mulch at a rate of 10 t ha⁻¹ (NT+M), conventional tillage (CT), CT+pine needle mulch at a rate of 10 t ha⁻¹ (CT+M) and deep tillage (DT). The soil is classified as a Typic Hapludalf and has compact sub-surface layers. The NT treatment increased the bulk density of the surface layer but this problem was not observed in the no-tilled treatment having mulch at the surface (NT+M). The CT+M and NT+M treatments favourably moderated the hydro-theregime resulting in greater root growth, nutrient uptake and grain yields of maize and wheat. The DT treatment, imposed only once, at the beginning of the study, also enhanced root growth and grain yields. The yields were similar to the mulched treatments for maize and somewhat less than the mulched treatments for wheat. Mulched treatments generally showed significantly greater total uptake of N, P and K than corresponding unmulched ones. Since NT+M was comparable to CT for maize and superior for wheat, the latter is preferable since it does not require ellaborate tillage.     

不同水分条件下分层施磷对冬小麦根系分布及产量的影响

研究不同水分条件下分层施磷对冬小麦根长分布、水分利用效率(water use efficiency,WUE)及产量的影响,旨在找出旱地农业最佳水肥处理方式。试验设不施磷(CK)、表施磷(surface P,SP)、深施磷(deep P,DP)和侧深施磷(deep-band P,DBP)4种处理,每个施磷水平下设补充灌溉(W1)和干旱(整个生育期无补充灌溉)(W2)2种水分处理。结果表明,施磷位置及补充灌溉显著(P0.05)影响冬小麦孕穗期根长分布、WUE及产量,同时会改变根系空间分布。干旱胁迫使冬小麦0~30 cm土层根长密度下降,降低17.5%,却促进了30 cm以下土层根长发育,增加13.3%,促进对土壤水分和磷素的吸收,从而提高产量。无论灌溉与否,施磷处理0~30 cm土层根长密度、吸磷量、WUE及产量均显著高于CK(P0.05)。施磷位置对冬小麦WUE和产量的影响随土壤水分而异,无补充灌溉时,与磷肥表施相比,磷肥深施显著增加WUE和产量(P0.05),分别平均增加28.5%和16.0%,且深层根长(30~100 cm)与吸磷量、WUE和产量的变化趋势一致;而在补充灌溉时,与磷肥表施相比,磷肥深施却显著降低WUE(P0.05),平均降低13.3%,且深层根长与WUE、产量的关系缺乏规律性。该试验结果表明,土壤水分供应不足时,磷肥深施有利于促进冬小麦深层土壤根系生长发育,提高对土壤水分吸收利用能力,从而利于形成高产。该研究可为理解作物生长及产量对水分养分空间耦合的响应提供理论依据。     

Early nitrogen deficiency favors high nitrogen recovery efficiency by improving deeper soil root growth and reducing nitrogen loss in wheat

ABSTRACT

A two-year field and micro-plot ¹⁵N-labelled experiment was conducted under two levels of N application rate (240 and 180 kg N ha^–1) with three basal N application stages [seeding (L0), four-leaf stage (L4), and six-leaf stage (L6)] to investigate the effects of reducing basal N application amount and postponing basal N fertilization period on wheat growth and N use efficiency (NUE). No significant differences were observed in grain yield, root growth and root morphology between the N180L4 and N240L0 treatments, while the root-shoot ratio of N180L4 was significantly improved. Postponing basal N application period increased the residual basal ¹⁵N in soil and reduced basal ¹⁵N loss, and N180L4 treatment favored the highest ¹⁵N recovery efficiency (NRE), mainly due to reduced ¹⁵N loss. Grain yield and basal NRE were significantly positively correlated with root dry weight in deeper soil layers (40–60 cm), and the contribution of root growth to improved grain yield and NRE increased with the downward distribution of the roots. Therefore, postponing the basal N fertilization period under N deficiency promotes deeper root growth during the post-jointing period and increases basal N uptake, as well as reducing basal N loss and increasing grain yield and NUE.     

基于微根管技术的玉米根系生长监测

为了研究玉米根系生长规律,该文利用固城农业气象试验站内设置的大型根剖面系统,采用微根管观测法,对试验地上玉米主要生育期的根系生长动态进行定期直接跟踪监测,并以方形整段标本法作为参照标准,对试验数据采用MATLAB软件辅助图像处理和现代统计方法进行分析。结果表明：微根管法与方形整段标本法对得出的根长密度随深度增加呈递减型有较好的一致性,两者相关系数达到0.83以上,通过0.05的显著性检验;由观测数据建立的回归方程能较好地反映土壤中玉米根系生长规律,进一步表明微根管法是一种破坏性较小、可准确定位跟踪植物根系在土壤中生长动态变化的先进技术,对植物根系生长研究有较好的推广应用价值。     

水磷互作对黑垆土春小麦生长及产量的影响

在温室条件下进行了黑垆土水磷互作对春小麦生长及产量影响的研究。结果表明,水分和磷素对春小麦苗期与抽穗期内株高和叶面积皆有一定影响,但交互作用的表现不同;适宜的水分与磷素配合既满足了春小麦物质生产过程中对水分和营养元素的需求,又促进了春小麦生长发育,提高了生物产量、经济产量及水分生产效率,从而可以达到以水促磷和以磷促水的目的;而缺水高磷组合或高水低磷组合均不利于春小麦生长发育,其产量与水分生产效率也较低。     

南佛罗里达州温室条件下番茄生长和养分吸收模型的验证

The Soil and Water Assessment Tool(SWAT) has been widely used throughout the world to model crop growth and nutrient uptake in various types of soils.A greenhouse experiment was performed to validate the process equations embedded in SWAT for describing the growth and nutrient uptake of tomatoes in south Florida.The scaled growth curve of greenhouse-grown tomatoes was in close agreement with the theoretical model for field conditions,with the scaling factors being the maximum canopy height and the potential heat units.Similarly,the scaled leaf area index(LAI) growth curve and the scaled root depth curve for greenhousegrown tomatoes agreed with the SWAT functions,with the scaling factors being the maximum LAI and maximum root depth.The greenhouse experiment confirmed that the growth of biomass is a linear function of the intercepted photosynthetically active radiation.The fractions of nutrients in the plant biomass under greenhouse conditions were found to be on the order of 60% of those fractions observed in the field.Values of the initial P distribution(0.2 mg kg -1),initial ratio of mineral stable P to mineral active P(50:1),and initial ratio of humic N to humic P(2.4:1) were determined from soil measurements and can be used for field simulations.The conventional saturation-excess model for soil-water percolation was used to predict the movement of water in the top 10 cm of the greenhouse containers and the results agreed well with measurements.     

长期定位试验中氮肥与磷肥有机肥联合施用通过刺激根的生长增加玉米产量和养分吸收

Imbalanced application of nitrogen (N) and phosphorus (P) fertilizers can result in reduced crop yield, low nutrient use efficiency, and high loss of nutrients and soil nitrate nitrogen (NO₃^--N) accumulation decreases when N is applied with P and/or manure; however, the effect of applications of N with P and/or manure on root growth and distribution in the soil profile is not fully understood. The aim of this study was to investigate the combined effects of different N and P fertilizer application rates with or without manure on maize (Zea mays L.) yield, N uptake, root growth, apparent N surplus, Olsen-P concentration, and mineral N (Nmin) accumulation in a fluvo-aquic calcareous soil from a long-term (28-year) experiment. The experiment comprised twelve combinations of chemical N and P fertilizers, either with or without chicken manure, as treatments in four replicates. The yield of maize grain was 82% higher, the N uptake 100% higher, and the Nmin accumulation 39% lower in the treatments with combined N and P in comparison to N fertilizer only. The maize root length density in the 30--60 cm layer was three times greater in the treatments with N and P fertilizers than with N fertilizer only. Manure addition increased maize yield by 50% and N uptake by 43%, and reduced Nmin (mostly NO₃^--N) accumulation in the soil by 46%. The long-term application of manure and P fertilizer resulted in significant increases in soil Olsen-P concentration when no N fertilizer was applied. Manure application reduced the apparent N surplus for all treatments. These results suggest that combined N and P fertilizer applications could enhance maize grain yield and nutrient uptake via stimulating root growth, leading to reduced accumulation of potentially leachable NO₃^--N in soil, and manure application was a practical way to improve degraded soils in China and the rest of the world.     

不同供Zn量对三种小麦基因型幼苗生长和养分吸收的影响

采用溶液培养方法,研究了不同供Zn量(0、0.5、104、0.mg/L,分别用Zn0、Zn0.5、Zn10、Zn40表示)对三种亲缘关系很远的半冬性小麦基因型郑麦9023、陕512、西农979幼苗生长发育及Zn、Fe、Mn吸收的影响,以期为筛选耐高锌的小麦基因型提供理论依据。结果表明,不供Zn时小麦幼苗未出现缺Zn症状;Zn0.5对小麦的正常生长影响较小。三种基因型小麦的幼苗在过量供Zn(Zn10、Zn40)时均受到严重伤害:抑制小麦分蘖、根系及地上部生长,叶片叶绿素SPAD值显著降低,小麦植株尤其是根部的耐性指数降低;施入的Zn的转运率显著降低,却大大提高了小麦植株尤其是根部的Zn含量和吸收量,但Zn10时幼苗体内Zn含量和吸收量大于Zn40,且Zn10比Zn40更能在根部积累Zn。Zn与Fe的吸收在根部似乎表现为互助作用,而地上部表现为颉颃作用;Zn与Mn之间表现出强烈的颉颃作用。过量供Zn时以西农979耐性指数最大,Zn转运率最高,植株体内的Fe、Mn含量也高。总之,供Zn量为通常配方的51～0倍时对小麦幼苗的生长尚无明显影响;1002～00和4008～00倍时则能对小麦幼苗造成严重伤害,三种供试小麦基因型中以西农979对过量Zn毒害的耐性最强。     

Effect of varied soil nitrogen supply on growth and nutrient uptake of young Norway spruce plants grown in a shaded environment

To understand the effect of increased soil N supply on tree growth and nutrient uptake, three-year-old Norway spruce seedlings were grown in pots on low-nutrient mineral forest soil supplemented with N in mineral or organic form. Outdoor shaded growth conditions were used, to test the hypothesis that shaded plants are particularly susceptible to high soil N supply. Plants were harvested eleven months after planting. Shoot growth was not affected by the N supply, but N concentrations in needles and roots were increased in plants supplied with mineral N (150 or 300 mg N [kg soil]^—1). Root growth was drastically reduced and root/shoot ratios were decreased in plants with higher N uptake. A high supply of mineral N to soil also decreased the concentrations of other essential elements (P, K) in the needles and thus had effects on plant growth which may impair the stress resistance of trees. Organic N in the form of keratin (150 mg N [kg soil]^—1) did not influence plant growth significantly. The adverse effects of high mineral N supply were particularly pronounced under shaded conditions in comparison to results from other experiments using higher light intensity and temperature conditions.     

Nodulation and root growth increase in lower soil layers of water‐limited faba bean intercropped with wheat

Below‐ground niche complementarity in legume–cereal intercrops may improve resource use efficiency and root adaptability to environmental constraints. However, the effect of water limitation on legume rooting and nodulation patterns in intercropping is poorly understood. To advance our knowledge of mechanisms involved in water‐limitation response, faba bean (Vicia faba L.) and wheat (Triticum aestivum L.) were grown as mono‐ and intercrops in soil‐filled plexiglass rhizoboxes under water sufficiency (80% of water‐holding capacity) and water limitation (30% of water‐holding capacity). We examined whether intercropping facilitates below‐ground niche complementarity under water limitation via interspecific root stratification coupled with modified nodulation patterns. While no significant treatment effects were measured in intercropped wheat growth parameters, water limitation induced a decrease in shoot and root biomass of monocropped wheat. Likewise, shoot biomass and height, and root length of monocropped faba bean significantly decreased under water limitation. Conversely, water limitation stimulated root biomass of intercropped faba bean in the lower soil layer (15–30 cm soil depth). Similarly, total nodule number of faba bean roots as well as nodule number in the lower soil layer increased under intercropping regardless of water availability. Under water limitation, intercropping also led to a significant increased nodule biomass (48%) in the lower soil layer as compared to monocropping. The enhanced nodulation in the lower soil layer and the associated increase in root and shoot growth provides evidence for a shift in niche occupancy when intercropped with wheat, which improves water‐limited faba bean performance.