Advanced Agrilytics, 751 E 400 S., Huntington, IN, 46750, USA.
Observatorio del Caribe Colombiano, Getsemaní, Calle del Guerrero #29-02, Cartagena de Indias, Colombia.
Plant Sci. 2018 Jul;272:301-308. doi: 10.1016/j.plantsci.2018.02.026. Epub 2018 Mar 15.
Improved P and K nutrition can enhance yield and persistence of alfalfa (Medicago sativa L.) grown on low fertility soils, but it is unknown if the improved agronomic performance is associated with greater taproot N and C reserves. Our objective was to use cluster analysis to determine how alfalfa plant persistence is altered by P and K fertilization, and determine if changes in specific taproot C and/or N reserves were associated with alfalfa plant death. Taproots were dug and plants counted in May and December of each year and taproots analyzed for P, K, starch, sugar, amino-N, and soluble protein. K-means clustering was used to create six clusters that were subsequently compared using two-sample t-tests. Low K in herbage and taproots was associated with low yield and poor persistence of the Low and Very Low clusters and taproots of these plants generally had low starch, protein, and amino-N concentrations. Plants died primarily between May and December. Plant persistence of the low yielding, P-deficient Medium cluster was high and associated with high starch concentrations. Low amino-N concentrations in taproots may provide an early indication of potential plant death because these were evident in poor-persisting Low and Very Low clusters early in the study.
改善 P 和 K 营养可以提高低肥力土壤上种植的紫花苜蓿（Medicago sativa L.）的产量和持久性，但尚不清楚改良的农艺性能是否与更大的主根 N 和 C 储量有关。我们的目的是使用聚类分析来确定 P 和 K 施肥如何改变苜蓿植物的持久性，并确定主根 C 和/或 N 储量的变化是否与苜蓿植物的死亡有关。每年 5 月和 12 月挖掘主根并计数植物，并分析主根的 P、K、淀粉、糖、氨基-N 和可溶性蛋白质。使用 K-均值聚类创建了六个聚类，然后使用两样本 t 检验对其进行比较。草料和主根中低 K 与低和极低聚类的低产量和较差的持久性有关，这些植物的主根通常淀粉、蛋白质和氨基-N 浓度较低。植物主要在 5 月至 12 月之间死亡。低产、缺 P 的中聚类的植物持久性高，与高淀粉浓度有关。主根中低氨基-N 浓度可能是潜在植物死亡的早期迹象，因为在研究早期，这种情况就出现在低产量、低持久性的低和极低聚类中。
