To supplement human dietary nutrition, it is necessary to evaluate the effects of phosphorus (P) fertilizer application on grain and flour protein contents and especially on the bioavailability of ...zinc (Zn). A field experiment of winter wheat with six P application rates (0, 25, 50, 100, 200, 400 kg/ha) was conducted from 2013 to 2015. The grain yield increased with P application but was not further enhanced when P rates exceeded 50 kg/ha. As P application increased, the protein concentration in grain and standard flour and the viscosity of standard flour decreased. Phosphorus and phytic acid (PA) concentrations in grain and flours increased and then plateaued, whereas Zn concentration decreased and then plateaued as P application increased from 0 to 100 kg/ha. Estimated Zn bioavailability in grain and flours decreased as P application increased from 0 to 100 kg/ha and then plateaued. Estimated Zn bioavailability was greater in standard flour, bread flour, and refined flour than in grain or coarse flour. Phosphorus supply in the intensive cropping of wheat can be optimized to simultaneously obtain high grain yields, high grain and flour protein contents, and high Zn bioavailability.
Zinc (Zn) deficiency is a well-documented worldwide problem for crops and humans. Although phosphorus (P) fertilizer application achieves high grain yield in intensive agricultural systems, it can ...reduce Zn availability in cereal grains. Therefore, a quantitative evaluation of the P–Zn antagonism is needed. A global meta-analysis of 51 publications with wheat, maize, and rice was performed to quantitatively analyze the effect of P application on grain Zn concentration. Phosphorus application reduced grain Zn concentration by 16.6% for wheat, 20.2% for maize, and 0% for rice. Phosphorus application did not affect soil available Zn concentration but, averaged across the three crops, significantly decreased root Zn concentration by 9.94%; the reduction was associated with a reduction in colonization of roots by arbuscular mycorrhizal fungi. Phosphorus application did not affect shoot-to-root or grain-to-straw ratios of Zn concentration, indicating that Zn translocation and remobilization within the plant were not reduced by P application. Especially for wheat and maize, the P–Zn antagonism was explained by a “dilution effect” and the suppression of Zn uptake efficiency by roots rather than by a suppression of translocation and remobilization. In addition to partially explaining the cause of the P–Zn antagonism, this is the first study using meta-analysis method to quantitatively demonstrate a P–Zn antagonism for Zn concentration in wheat and maize. Biofortification for increasing the grain Zn concentration may benefit from an increased understanding of how P application affects rhizosphere and root processes.
Human deficiencies of iron (Fe) and zinc (Zn) are worldwide problems. Biofortification of wheat could reduce Fe and Zn deficiencies in societies that depend on wheat consumption. This study ...investigated the effects of foliar application of Fe with or without Zn on the concentrations of Fe and Zn in grain and especially in flour of three wheat cultivars. On average, grain Fe concentration was increased significantly from 29.5 mg kg−1 in the control to 37.8, 35.9, or 34.9 mg kg−1 by application of FeSO4, ferric citrate plus ZnSO4, or ferric citrate, respectively. As expected, grain Zn concentration was increased from 29.0 mg kg−1 in the control to 45.7 or 39.6 mg kg−1 by application of ferric citrate plus ZnSO4 or a complex of micronutrients. Although the Fe and Zn concentrations in flour were inherently lower than in bran and shorts made by experimental mill, the concentrations in flour were simultaneously increased from 10.4 to 12.4 mg kg−1 for Fe and from 11.8 to 17.4 mg kg−1 for Zn by application of ferric citrate plus ZnSO4. Importantly, Fe was peripherally localized within grain fractions and strictly limited to transport to endosperm, making it more difficult to increase the quantity of Fe in flour products by foliar Fe application, but the situation with Zn is promising because Zn is more readily transported to the endosperm than Fe. The current study increases the understanding of agronomic biofortification.
•Potassium application increased grain yield, but excessive application did not maintain the high yield increase rate.•Under recommended potassium treatments, potassium uptake requirements decreased ...with increasing grain yield.•Increasing potassium accumulation during post-anthesis growth stage is key to increasing grain yield.
Understanding grain yield response to potassium fertilizer supply and potassium uptake requirements is essential for devising optimized potassium fertilizer management policies in China. Currently, potassium fertilization is often ignored due to high natural levels of potassium in the soil. We conducted 836 on-farm experiments at 209 sites in China to quantify wheat (Triticum aestivum L.) grain yield response to potassium application rates, and evaluate potassium uptake requirements with increasing grain yield. Across all 209 sites, wheat grain yield increased by 70% from 3.3Mgha−1 at a control level to 5.6Mgha−1 for recommended potassium treatments (RKR, 102kgK2Oha−1). With 150% RKR treatments, no yield gains were achieved, while there was a notable decrease in potassium use efficiency. The potassium uptake requirements per Mg of grain (Kreq) increased from 21.1kg with RKR treatments to 21.9kg with 150% RKR treatments, which indicated that a luxury potassium uptake occurred under excessive potassium application. Under RKR treatments, Kreq decreased from 23.8kg with <4.5Mgha−1 to 20.2kg with >7.5Mgha−1, which was attributed to the increase of the harvest index (from 45.5% to 48.6%) and decline in grain potassium concentrations (from 4.7gkg−1 to 4.0gkg−1). When the grain yield was<7.5Mgha−1, potassium accumulation during post-anthesis was lower than that at pre-anthesis, by −78.5kgha−1 and −30.8kgha−1 with <6Mgha−1 and 6–7.5Mgha−1 yield ranges, respectively, but higher than that at pre-anthesis when the grain yield was >7.5Mgha−1 and by 18.2kgha−1. In summary, potassium fertilization can increase wheat grain yield in China and total potassium uptake requirements were shown to decrease with increasing grain yield. This suggests that potassium optimization must be taken into account in management decisions for high-yielding wheat production in China.
Widespread malnutrition of zinc (Zn), iodine (I), iron (Fe) and selenium (Se), known as hidden hunger, represents a predominant cause of several health complications in human populations where rice (
...Oryza sativa
L.) is the major staple food. Therefore, increasing concentrations of these micronutrients in rice grain represents a sustainable solution to hidden hunger. This study aimed at enhancing concentration of Zn, I, Fe and Se in rice grains by agronomic biofortification. We evaluated effects of foliar application of Zn, I, Fe and Se on grain yield and grain concentration of these micronutrients in rice grown at 21 field sites during 2015 to 2017 in Brazil, China, India, Pakistan and Thailand. Experimental treatments were: (i) local control (LC); (ii) foliar Zn; (iii) foliar I; and (iv) foliar micronutrient cocktail (i.e., Zn + I + Fe + Se). Foliar-applied Zn, I, Fe or Se did not affect rice grain yield. However, brown rice Zn increased with foliar Zn and micronutrient cocktail treatments at all except three field sites. On average, brown rice Zn increased from 21.4 mg kg
–1
to 28.1 mg kg
–1
with the application of Zn alone and to 26.8 mg kg
–1
with the micronutrient cocktail solution. Brown rice I showed particular enhancements and increased from 11 μg kg
–1
to 204 μg kg
–1
with the application of I alone and to 181 μg kg
–1
with the cocktail. Grain Se also responded very positively to foliar spray of micronutrients and increased from 95 to 380 μg kg
–1
. By contrast, grain Fe was increased by the same cocktail spray at only two sites. There was no relationship between soil extractable concentrations of these micronutrients with their grain concentrations. The results demonstrate that irrespective of the rice cultivars used and the diverse soil conditions existing in five major rice-producing countries, the foliar application of the micronutrient cocktail solution was highly effective in increasing grain Zn, I and Se. Adoption of this agronomic practice in the target countries would contribute significantly to the daily micronutrient intake and alleviation of micronutrient malnutrition in human populations.
Microbes associated with phosphorus (P) cycling are intrinsic to soil P transformation and availability for plant use but are also influenced by the application of P fertilizer. Nevertheless, the ...variability in soil P in the field means that integrative analyses of soil P cycling, microbial composition, and microbial functional genes related to P cycling remain very challenging. In the present study in the North China Plain, we subjected the bacterial and fungal communities to amplicon sequencing analysis and characterized the alkaline phosphatase
(
encoding bacterial alkaline phosphatase in a long-term field experiment (10 years) with six mineral P fertilization rates up to 200 kg P ha
. Long-term P fertilization increased soil available P, inorganic P, and total P, while soil organic P increased until the applied P rate reached 25 kg ha
and then decreased. The fungal alpha-diversity decreased as P rate increased, while there were no significant effects on bacterial alpha-diversity. Community compositions of bacteria and fungi were significantly affected by P rates at order and family levels. The number of keystone taxa decreased from 10 to 3 OTUs under increasing P rates from 0 to 200 kg ha
. The gene copy numbers of the biomarker of the alkaline phosphatase
was higher at moderate P rates (25 and 50 kg ha
) than at low (0 and 12.5 kg ha
) and high (100 and 200 kg ha
) rates of P fertilization, and was positively correlated with soil organic P concentration. One of the keystone taxa named BacOTU3771 belonging to Xanthomonadales was positively correlated with potential functional genes encoding enzymes such as glycerophosphoryl diester phosphodiesterase, acid phosphatase and negatively correlated with guinoprotein glucose dehydrogenase. Altogether, the results show the systematic effect of P gradient fertilization on P forms, the microbial community structure, keystone taxa, and functional genes associated with P cycling and highlight the potential of moderate rates of P fertilization to maintain microbial community composition, specific taxa, and levels of functional genes to achieve and sustain soil health.
A long-term (1999–2007) field experiment was conducted to investigate the effects of three nitrogen (N) fertilization rates (0, 130, and 300 kg N/ha) on micronutrient density in wheat grain and its ...milling fractions. At maturity, grains were harvested and fractionated into flour, shorts, and bran for micronutrient and N analysis. N fertilization increased iron (Fe), zinc (Zn), and copper (Cu) density in wheat grain compared to the control. Increase of N application rate from 130 to 300 kg N/ha, however, did not further increase the three micronutrient densities in grain. Micronutrient concentrations were usually highest in the bran and lowest in the flour. High N application increased Zn and Cu densities in all three milling fractions and increased Fe concentration in shorts and bran but not in flour. N application did not affect the manganese (Mn) concentration in grain. N fertilization changed the proportions of Fe and Cu in flour and bran but did not affect the distribution of Zn. Because N fertilization increased micronutrient accumulation in wheat grain, proper management of N fertilization has the potential to enhance the nutritional quality of this important food.
•Wheat yield gaps and population development in NCP were significantly affected by sowing and N management.•Early sowing and optimal seeding density produced more pre-winter stems and spike ...number.•Excessive inputs of N rate and early dressing N fertilizer decreased percentage of productive tillers.•Integrated crop-N management significantly increased wheat yield, spike number and NUE compared with farmers practice.
It is essential to identify the main components that limit crop yield to achieve high crop yields. We collected data from 156 experimental field plots over six crop seasons to determine the degree to which wheat yield is limited by spike number and to further understand the effects of different sowing dates, seeding rates, and nitrogen (N) management on population development and yield. High yields in plots (>8.5tha−1) were attributable to increased spike numbers associated with elevated pre-winter stem numbers and higher percentage of productive stems. An early sowing date with a seeding rate of 350seedsm−2 significantly produced higher spike numbers than a late sowing date with a seeding rate of 540seedsm−2. High basal N fertilizer rate and dressing N at the regreening stage, typical of farmers’ N practices, markedly decreased productive stem percentage compared to an optimal basal N rate and N dressing at the stem-elongation stage. A dressing N rate of 120kgNha−1at stem-elongation stage increased spike number compared to applications of 0 or 60kgNha−1. Based on our results, we designed an integrated crop-N management (ICM-N) for generating high yields and high N use efficiency. The ICM-N strategy increased grain yield by 33% (p<0.05) while using a 27% lower N fertilizer rate led to an 87% increase in N use efficiency over three crop seasons compared to a standard farmers’ management strategy.
Root is important in acquiring nutrients from soils. Developing marker-assisted selection for wheat root traits can help wheat breeders to select roots desirable for efficient acquisition of ...nutrients. A recombinant inbred line (RIL) population derived from wheat varieties Xiaoyan 54 and Jing 411 was used to detect QTLs for maximum root length and root dry weight (RDW) under control, low nitrogen and low phosphorus conditions in hydrophobic culture (HC). We totally detected 17 QTLs for the investigated root traits located at 13 loci on 11 chromosomes. These loci differentially expressed under different nutrient supplying levels. The RILs simultaneously harboring positive alleles or negative alleles of the most significant three QTLs for RDW,
, and
, were selected for soil column culture (SC) trial to verify the effects of these QTLs under soil conditions. The RILs pyramiding the positive alleles not only had significantly higher shoot dry weight, RDW, nitrogen and phosphorus uptake in all the three treatments of the HC trial, but also had significantly higher RDW distribution in both the top- and sub-soils in the SC trial than those pyramiding the negative alleles. These results suggested that QTL analysis based on hydroponic culture can provide useful information for molecular design of wheat with large and deep root system.
The relationships between grain yields and whole-plant accumulation of micronutrients such as zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu) in maize (Zea mays L.) were investigated by studying ...their reciprocal internal efficiencies (RIEs, g of micronutrient requirement in plant dry matter per Mg of grain). Field experiments were conducted from 2008 to 2011 in North China to evaluate RIEs and shoot micronutrient accumulation dynamics during different growth stages under different yield and nitrogen (N) levels. Fe, Mn and Cu RIEs (average 64.4, 18.1 and 5.3 g, respectively) were less affected by the yield and N levels. ZnRIE increased by 15% with an increased N supply but decreased from 36.3 to 18.0 g with increasing yield. The effect of cultivars on ZnRIE was similar to that of yield ranges. The substantial decrease in ZnRIE may be attributed to an increased Zn harvest index (from 41% to 60%) and decreased Zn concentrations in straw (a 56% decrease) and grain (decreased from 16.9 to 12.2 mg kg-1) rather than greater shoot Zn accumulation. Shoot Fe, Mn and Cu accumulation at maturity tended to increase but the proportions of pre-silking shoot Fe, Cu and Zn accumulation consistently decreased (from 95% to 59%, 90% to 71% and 91% to 66%, respectively). The decrease indicated the high reproductive-stage demands for Fe, Zn and Cu with the increasing yields. Optimized N supply achieved the highest yield and tended to increase grain concentrations of micronutrients compared to no or lower N supply. Excessive N supply did not result in any increases in yield or micronutrient nutrition for shoot or grain. These results indicate that optimized N management may be an economical method of improving micronutrient concentrations in maize grain with higher grain yield.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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