Nitrogen loss and its health risk in paddy fields under different drainage managements

Subsurface drainage is a prerequisite for year-round crop production in a large area of northern Iran^, s paddy fields. Minimizing environmental and health issues related to nitrogen (N) losses through subsurface drainage systems provides suitable condition for sustainable agriculture in these fields. A field study was conducted to evaluate nitrogen loss and its health risk in the conventional and subsurface-drained paddy fields. Ammonium, nitrate, and total N concentrations of subsurface drainage effluents, surface runoff, and leachates were monitored during three successive rice-canola-rice growing seasons from July 2011 to August 2012. Different components of N balance and health risk of nitrate leaching to groundwater were also investigated. Ammonium in drainage effluents collected during the experimental period ranged from approximately zero to 1.72 mg L^?1, while nitrate fluctuated from 0.5 to 28.6 mg L^?1. Average nitrate concentration in leachates of subsurface-drained area was 7.7–81.4 % higher than that in subsurface drainage effluents, while it was 126.8 % higher than that in surface runoff for the conventional field. Subsurface drainage provided a better utilization of soil N through providing winter cropping and reduced the potential for non-carcinogenic risks of nitrate leaching to groundwater. The results are encouraging for producers engaged in rice-canola production in the study area with respect to the environment and human health quality.     

Study on the water and nitrogen balance in paddy fields with irrigation and drainage dual-purpose channel mode using the tank model

Paddy and Water Environment - In South China’s paddy irrigation area, irrigation and drainage dual-purpose channel mode (IDDCM) is applied to conserve farmland resources in rice cultivation...     

Surface and subsurface losses of N and P from salt-affected rice paddy fields of Saemangeum reclaimed land in South Korea

The present study was carried out to evaluate nutrient losses that occur during the course of agricultural activity from rice paddy fields of reclaimed tidal flat. For this study, we chose a salt-affected rice paddy field located in the Saemangeum reclaimed tidal area, which is located on the western South Korean coasts. The plot size was 1,000 m² (40 m × 25 m) with three replicates. The soil belonged to the Gwanghwal series, i.e., it was of the coarse silty, mixed, mesic type of Typic Haplaquents (saline alluvial soil). The input quantities of nitrogen and phosphorus (as chemical fertilizer) into the experimental rice paddy field were 200 kg N ha⁻¹ and 51 kg P₂O₅ ha⁻¹ per annum, and the respective input quantities of each due to precipitation were 9.3–12.9 kg N ha⁻¹ and 0.4–0.7 kg P ha⁻¹ per annum. In terms of irrigation water, these input quantities were 4.5–8.2 kg N ha⁻¹ and 0.3–0.9 kg P ha⁻¹ per annum, respectively. Losses of these nutrients due to surface runoff were 22.5–38.1 kg N ha⁻¹ and 0.7–2.2 kg P ha⁻¹ for the year 2003, and 26.8–29.6 kg N ha⁻¹ and 1.6–1.9 kg P ha⁻¹ for the year 2004, respectively. Losses of these nutrients due to subsurface infiltration during the irrigation period were 0.44–0.67 kg N ha⁻¹ and 0.03–0.04 kg P ha⁻¹ for the year 2003, and 0.15–0.16 kg N ha⁻¹ and 0.05–0.06 kg P ha⁻¹ for 2004. When losses of nitrogen and phosphorus were compared to the amount of nutrients supplied by chemical fertilizers, it was found that 11.3–19.1% of nitrogen and 0.5–1.7% of phosphorus were lost via surface runoff, whereas subsurface losses accounted to 0.2–0.8% for nitrogen and only 0.02–0.04% for phosphorus during the 2-year study period.     

Endogenous arabinoxylans variability in refined wheat flour and its relationship with quality traits

Arabinoxylans (AXs) are the major dietary fiber (DF) component in wheat and their consumption has been associated with several health benefits. Genetic improvement of the AX in refined wheat flour could be a good solution to improve the DF daily consumption while maintaining the flour desirable quality. In this study, 193 common wheat lines were analyzed for their AX content in refined flour and end-use quality. Wide variation in both the total arabinoxylan (TOT-AX) (10.8–16.5 mg/g) and water-extractable arabinoxylan (WE-AX) (3.2–7.6 mg/g) was identified and, in both cases, the genotype had the greatest impact on the observed phenotypes. Variation in the endogenous AX fractions appeared to have a moderate effect on wheat quality. The WE-AX, specifically, were positively correlated with gluten strength (r = 0.11 to 0.32) and bread loaf volume (r = 0.16), whereas the TOT-AX were negatively correlated with dough extensibility (r = −0.11) and bread making quality (r = −0.11). Overall, results of this study show that the genetic improvement of grain AX is feasible and that the AXs present in refined flour do not dramatically alter wheat quality indicating that it is possible to select varieties with high AX endosperm content end desired end-use quality.     

Amino acid composition of coagulable protein from tubers of 34 potato varieties and its relationship with protein content

Summary Samples of coagulable protein, from tubers of 34 varieties ofSolanum tuberosum, were analysed for amino acids. The coagulable protein was rich in most of the essential amino acids. The essential amino acid index ranged from 86 to 93. Methionine was the first limiting essential amino acid. Its content in coagulable protein was considerably higher than values reported in literature. Lysine content was very high, which makes the protein a valuable component for mixed feed. Arginine was the second limiting amino acid. The varietal differences in amino acid composition were small. There was no correlation between protein content and content of most of the essential amino acids. Breeding for increased protein content in potato may be expected to have little effect on the nutritional value of the protein. Selection can be directed to content of coagulable protein.

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Zusammenfassung Aus Knollen von 34 Sorten vonSolanum tuberosum mit grossen Unterschieden im Proteingehalt wurden Muster von koagulier-barem Protein hergestellt. Die Proteinmuster wurden auf Aminos?uren analysiert. Methionin und Cystin wurden mittels einer Methode von Moore (1963) (Tabelle 1) getrennt bestimmt. Das koagulierbare Protein weist hohe Gehalte bei den meisten essentiellen Aminos?uren auf (Tabelle 2). Der Index der essentiellen Aminos?uren (EAAI) reichte von 86 bis 93, was für ein Pflanzenprotein hoch ist. Methionin was die erste begrenzende essentielle Aminos?ure (Tabelle 3), aber sein Gehalt war bedeutend h?her als in der Literatur aufgeführt. Der Lysingehalt war sehr hoch, was das Protein zu einem wertvollen Bestandteil für Mischfutter macht. Arginin war die zweite begrenzende Aminos?ure. Zwischen Arginin- und dem Proteingehalt wurde eine signifikant negative Korrelation (r=−0,589) festgestellt. Dies ist wichtig. wenn das Protein im Futter für Geflügel, das einen hohen Argininbedarf hat, verwendet wird. Die sortenbedingten Unterschiede in der Zusammensetzung der Aminos?ure waren relativ klein (Tabelle 2). Es gab keine Korrelation zwischen Proteingehalt und dem Gehalt an den meisten essentiellen Aminos?uren (Tabelle 4). Der Züchtung auf erh?hten Proteingehalt in Kartoffeln wird nur wenig Einfluss auf den N?hrwert des Proteins haben. So kann die Auslese auf den Gehalt an koagulierendem Protein ausgerichtet werden.

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Résumé Dans le but d'étudier les protéines coagulables on a préparé des échantillons avec 34 variétés deSolanum tuberosum ayant de grandes différences dans leur teneur en protéines. A partir de ceux-ci on a effectué l'analyse des acides aminés. La méthionine et la cystine ont été évalués sèparément par la méthode de Moore (1963) (tableau 1). Les protéines coagulables avaient une teneur élevée pour la plupart des acides aminés indispensables (tableau 2). Leur index se situait entre 86 et 93, ce qui est élevé pour des protéines de plantes. La méthionine a été le premier acide aminé indispensable limitant (tableau 3) mais sa teneur était considérablement plus élevée que celle donnée dans la littérature. La teneur en lysine était très haute, faisant de ces protéines un constituant valable pour les aliments composés. L'arginine a été le second acide aminé limitant. Une corrélation négative (r=−0,589) entre l'arginine et le taux de protéines s'est avérée significative. On doit en tenir compte lorsque ces protéines sont utilisées comme aliments destinés aux volailles, qui nécessitent un taux élevé d'arginine. Les différences variétales en acides aminés ont été relativement faibles (tableau 2). Il n'existe pas de corrélation entre la teneur des protéines et la plupart des acides aminés indispensables (tableau 4). L'hybridation dans le but d'augmenter le taux de protéines dans les pommes de terre peut être considéré comme n'ayant que peu d'effet sur la valeur nutritionnelle de ces protéines. Aussi, la sélection peut être orientée vers l'amélioration de la teneur en protéines coagulables.

     

锰对茶树生长发育及茶叶品质关系的研究进展

本文介绍锰元素与茶树生长发育的关系:不同类型茶园土壤锰含量以及锰在茶树体内分布规律;锰对茶叶产量、品质和光合作用的影响;茶树缺锰和锰毒症状,以及茶树生长过程中锰对茶树吸收利用锌、铁、磷等元素的影响,为更深入研究茶树锰营养提供参考。     

Grain number and its relationship with dry matter, N and P in the spikes at heading in response to N×P fertilization in barley

The aim of this work was to study the effects of nitrogen (N) and phosphorus (P) deficiencies and their interaction on spike N, P and biomass around flowering in barley (Hordeum vulgare spp. distichum L.) and its relationship with grain number and grain yield. Two experiments were carried out with microcrops grown in 200 l containers using malting barley (cv. Quilmes Palomar). Treatments were a factorial combination of two levels of N and two or three levels of P fertilization. Dry matter partitioning to spikes was not or only slightly affected by nutrient deficiencies. Then, the effects on spike biomass were similar to those on total aboveground dry matter. Although partitioning of N to the spike in N fertilized treatments was lower than in N stressed ones, spike N content was higher in the N fertilized.

Number of grains was positively associated with spike N and P content as well as spike dry matter at heading in both experiments. Number of grains per unit of spike dry matter at heading in N fertilized microcrops tended to be higher than in N stressed ones, though this effect was not associated with N fertilization effects on N concentration in spikes.

Combining these results with others from the literature from wheat crops, we found a strong relationship between number of grains and spike N content at flowering, but this relationship does not seem to be better than that with spike biomass, judged by the regression coefficients. This indicates that the early application of N may induce a higher number of grains than that predicted by increased spike dry weight at flowering, but this additional effect is not universally related to differences in spike N concentration.     

60%环·敌可湿性粉剂防除蔗地杂草药效试验

对60 %环·敌可湿性粉剂进行了田间小区药效试验 ,结果表明该药剂防除蔗地杂草效果优良。每667m2 施药100 -225克防效达90 %以上。在杂草充分萌芽后5叶期左右施药能有效防除一年生单、双子叶杂草 ,对甘蔗相对安全。但不同甘蔗品种对其敏感性有差异。推荐使用剂量为每667m2 施100-160克     

Inheritance of the concentration of water-soluble carbohydrates and its relationship with the concentrations of fibre and crude protein in herbage of cocksfoot (Dactylis glomerata L.)

The concentration of water‐soluble carbohydrates (WSC) of cocksfoot is lower than that of other temperate grasses. Increasing the WSC concentration in cocksfoot is important in increasing its digestibility and preference by ruminants. The genetic variation in mono‐ and disaccharides, fructans and total WSC concentrations and their inter‐relationships with crude protein (CP) and fibre concentrations of cocksfoot (Dactylis glomerata L.) at the vegetative growth stage in half‐sib cross populations were assessed in two experiments conducted under spaced planting and sward conditions. There was a wide range in the means for concentrations of fructan, WSC and neutral‐detergent fibre (NDF) in parents and progeny whereas there was a narrow range of the means for concentrations of mono‐ and disaccharides, CP and acid‐detergent fibre (ADF). Mean concentrations of mono‐ and disaccharides showed the smallest range. Mean squares of entries in parents and progenies were significant for mono‐ and disaccharides, fructan and total WSC concentrations in all populations. The entry × year interactions for fructan and total WSC concentrations were significant in the parents and the half‐sib progeny. However, the entry × year interactions for mono‐ and disaccharide concentrations in progeny were not significant. Concentration of WSC was under genetic control as mean squares of the concentration values were significant and variance components for all traits were significantly larger than zero. There were negative genetic correlations between WSC and ADF and NDF concentrations. Narrow‐sense heritabilities (h_n) estimated from variance components of progeny for total WSC concentrations were 0·59 and 0·53 in sward and spaced planting conditions respectively. The h_n of fructan and WSC concentrations were similar in both sward and spaced planting conditions, whereas that of mono‐ and disaccharide concentrations varied from 0·20 to 0·69. It was found that the genetic variation of the total WSC concentration in cocksfoot depended mainly on genetic variation in fructan concentration. These results suggested that the forage quality of cocksfoot at the vegetative growth stage was influenced by an additive gene effect and could be improved genetically by recurrent selection.     

New insight into puroindoline function inferred from their subcellular localization in developing hard and soft near-isogenic endosperm and their relationship with polymer size of storage proteins

Wheat endosperm texture is correlated with one major locus, Ha, located on the short arm of chromosome 5D, which comprises several genes among which are two puroindoline genes, Pina and Pinb. In this study, we used two near-isogenic lines, the hard-textured line lacking Pina and the soft-textured line containing both Pina and Pinb wild-type genes. Hard and soft endosperms were observed at four kernel developmental stages, from 180 °Cd to 750 °Cd. Puroindolines were located within protein bodies at the onset of prolamin accumulation by transmission electron microscopy and immunolabelling. Ab initio modeling showed a closer structural relationship between puroindolines and 2S storage proteins from dicots than between puroindolines and other cysteine-rich wheat proteins, i.e. LTP and amylase inhibitors. Compared to the soft line, storage protein polymers in the hard line exhibited higher molecular mass (increase of from 6 to 93%) and polydispersity indices (increase of from 26 to 63%) over the course of the 4-year experiment. This suggests that puroindolines might impact the aggregation of storage proteins. Finally, these data pave the way for investigation of the role of protein–protein interactions in the texture of wheat endosperm.