稻草覆盖对马铃薯土壤养分释放及养分平衡的影响

    Effects of straw mulching on nutrient release and nutrient balance in potato soil

    • 摘要:
      目的  探索马铃薯种植过程中稻草覆盖还田模式下稻草N、P、K释放和土壤N、P、K养分平衡的特征。
      方法  采用盆栽试验的方法,对稻草覆盖还田后的腐解速率及养分释放状况进行研究。
      结果  稻草覆盖还田82 d后,其C、P含量变化较小,K含量降低93.96%,而N含量却提高了49.22%;覆盖稻草可为土壤提供大量养分且以K居多,每覆盖还田100 kg稻草可为马铃薯生长提供N 0.42 kg、P 0.14 kg(P2O5)和K 1.70 kg(K2O);稻草腐解率为70.87%;各养分累积释放率表现为:K>C>P>N,C、N和P累积释放率分别为71.89%、56.85%和68.75%,K累积释放率最高,为98.22%。覆盖稻草和施用钾肥对土壤K平衡影响较大,不施钾肥和稻草土壤的K亏缺达163.80 kg/hm2,覆盖稻草或施用钾肥均可有效降低土壤钾素亏缺量,稻草与钾肥配合施用可使土壤K收支平衡,甚至盈余。
      结论  在稻草覆盖还田情况下,可适当减少钾肥用量,以降低生产成本,缓解我国钾肥资源匮乏的困境。

       

      Abstract:
      Objective  To study the characteristics of nitrogen(N), phosphorus(P) and potassium (K) nutrient release and soil N, P, K nutrient balance under straw mulching pattern during potato planting process.
      Method  We studied the decomposition rate and nutrient release status of mulching straw using pot experiment.
      Result  Straw carbon (C) and P contents changed slightly after mulching for 82 days, while K content decreased by 93.96%, and N content increased by 49.22%. The mulching straw provided a large amount of nutrients (especially K) with 100 kg mulching straw contributing 0.42 kg N, 0.14 kg P (P2O5), and 1.70 kg K (K2O) to soil used for potato growth. Straw decomposition rate was 70.87%. The nutrient accumulative release rates were performed as: K (98.22%) > C (71.89%) > P (68.75%) > N (56.85%). Straw mulching and K fertilization largely affected soil K balance. The K deficient amount was 163.80 kg/hm 2 without straw mulching and K fertilizer application. K deficient amount was effectively reduced by straw mulching and K fertilization, and even K had surplus with combined application of straw and K fertilizer.
      Conclusion  The straw mulching pattern can reduce K fertilizer application amount and production cost, and relieve the dilemma of K fertilizer resource deficiency in China.

       

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