不同施肥处理对甘薯产量及土壤肥力与氮素利用的影响

Effects of Different Fertilization Treatments on Yield of Sweet Potato,Soil Fertility and Nitrogen Utilization

针对江西甘薯主产区化肥投入量大、养分施用不均衡及肥料利用率低等问题,以‘赣薯4号’为试验对象,设置不施肥(T1)、习惯施肥(T2)、配方施肥(T3)、配方施肥下有机肥氮替代化肥氮20%(T4)、配方施肥减氮20%(T5)5个处理,研究不同施肥方式对甘薯叶面积、产量、土壤肥力、养分吸收以及氮素利用率的影响。结果表明:配方施肥各处理(T3、T4、T5)较T2提高了甘薯叶面积指数,并在移栽后60 d达到峰值,T4、T5在甘薯生产后期(90~120d)保持较高的叶面积指数。配方施肥各处理提高了甘薯产量及其构成因素,其中T5的单株结薯数、块根产量最高,为T2的1.73倍和1.87倍;单个薯块质量、商品薯率以T3最高,其次为T4。与T2相比,配方施肥各处理改善了成熟期的土壤理化性质,有机质含量显著增加了117.57%~130.91%;速效钾含量增加了10.19%~20.37%;碱解氮含量增加了19.04%~27.38%、土壤pH提高了0.05~0.14。配方施肥各处理促进了甘薯对氮、磷、钾养分的吸收,其中块根氮、磷、钾吸收量以T5最高,分别较T2显著提高187.02%、87.62%、80.80%;茎叶氮、磷吸收量以T4最高,分别较T2提高55.98%、49.87%,茎叶钾吸收量以T5最高,较T2显著提高43.05%。T5的氮素总积累量、表观利用率、收获指数和偏生产力显著高于其他处理,分别为106.82 kg·hm^(-2)、62.83%、61.75%和380.02。综上所述,在本试验条件下,配方施肥减氮20%可显著提高甘薯产量、土壤肥力和氮素积累利用率。

Focus on the problems such as excessive input of chemical fertilizer,unbalanced nitrient and low utilization efficiency of fertilizer in the main sweet-potato-producing area in Jiangxi.With‘Ganshu No.4’as the material,five fertilization treatments,including no fertilization(T1),conventional fertilization(T2),formula fertilization(T3),replacement of chemical nitrogen with 20%organic fertilizer under formula fertilization(T4),and formula fertilization of reducing nitrogen by 20%(T5),were set up to study the effect of different fertilization on leaf area index,yield,soil fertility,nutrient absorption and nitrogen utilization of sweet potato.The results showed that compared with conventional fertilization(T2),the leaf area index of sweet potato could be improved under the formula fertilization treatments(T3,T4,T5),and the leaf area index peaked in 60 days after planting.The high leaf area index was maintained under T4 and T5 at the late stage of sweet potato production(90-120 d).the yield of sweet potato and its constituent element increased under each treatment of formula fertilizations.The greatest number of tubers per plant and highest yield of tuber were obtained in T5,which was 1.73 times and 1.87 times higher than that of T2,respectively.Under treatment T3,the mass of a single tuber and commodity rate were maximum,followed by T4.In contrast to T2,under each treatment of formula fertilization,soil physical and chemical properties were improved at maturity stage,the content of organic matter was significantly increased by 117.57%-130.91%,the content of available potassium was increased by 10.19%-20.37%,the content of alkali hydrolyzable nitrogen was improved by 19.04%-27.38%and value of soil pH was elevated 0.05-0.14.The absorption of nitrogen,phosphorus,and potassium nutrients in sweet potato were promoted under formula fertilization treatments.The highest level of absorption of nitrogen,phosphorus,and potassium in root tuber was shown in T5,which was remarkably increased by 187.02%,87.62%,and 80.80%compared with T2,respectively.The absorption of nitrogen and phosphorus in stems and leaves was the highest under T4 treatment,which was higher than T2 by 55.98%and 49.87%,respectively.The potassium absorption in stems and leaves was the greatest under T5 treatment,which was significantly higher than T2 by 43.05%.The level of total nitrogen accumulation,apparent utilization rate,harvest index and partial productivity were significantly higher in T5 than those in all the other treatments,which were 106.82 kg·hm^(-2),62.83%,61.75%and 380.02,respectively.In conclusion,formula fertilization with reducing nitrogen by 20%can significantly increase sweet potato yield,soil fertility and nitrogen accumulation and utilization.