不同土种土壤氮素等养分与水稻基础产量的关系

Relations between soil nitrogen and other nutrients and rice basal yields in different soil local types

通过对不同土种土壤养分测定及不施氮肥空白区试验,分析不同土种土壤氮素等养分与水稻基础产量的关系,研究不同土种不施氮肥空白区每100 kg基础产量稻谷需氮量及土壤氮素当季利用率。结果表明:①水稻土类4个土种土壤有机质、全氮、碱解氮、速效钾含量及不施氮肥空白区水稻基础产量明显高于潮土类4个土种,速效磷含量两者较为接近;②同一土种不同农田土壤中全氮、有机质与碱解氮的含量相对稳定,空间变异相对较小;③8个土种土壤有机质含量与水稻基础产量均呈极显著正相关;④8个土种土壤有机质含量均对不施氮肥空白区水稻基础产量起关键作用,且极显著大于全氮、碱解氮、速效磷、速效钾所起的作用;⑤根据土壤养分测定及不施氮肥空白区试验结果,建立了不同土种不施氮肥空白区水稻基础产量模型,模拟值与实测值吻合度较高;⑥潮土类4个土种不施氮肥空白区每100 kg稻谷平均需氮量为1.48 kg,水稻土类4个土种则为1.69 kg;⑦潮土类4个土种土壤氮肥当季平均利用率为46.4%,而水稻土类4个土种土壤氮肥当季平均利用率为41.6%。

Soil nitrogen and other nutrients in different soil local types, with the plots without nitrogen application as controls, were measured in this study to investigate the relations between rice basal yields and soil nutrients, and to determine the nitrogen amounts required for 100 kg rice basal yield and the recovery of soil nitrogen in rice season. Results showed as follows： ① Organic matter, total nitrogen, alkali-hydrolyzable nitrogen, abailable potassium and rice basal yield in control plots were obviously higher in 4 soil local types of paddy soil than those in 4 soil local types of fluvo-aquic soil. But available phosphorous in paddy and fluvo-aquic soil was close; ② Total nitrogen, organic matter and alkali-hydrolyzable nitrogen in different fields of the same soil local type were relatively stable with less spatial variation. ③ Significant and positive correlation between rice basal yield and organic matter content was found in all 8 soil local types ; ④ Organic matter had greater effect on rice basal yield than other available nutrients tested in this study; ⑤ Based on the results, we developed models to simulate rice basal yields in fifferent soil local types and the models could satisfactorily fit the observed values; ⑥ The average amount of nitrogen required for 100 kg basal yield was 1.48 kg in fluvo-aquic soil and 1.69 kg in paddy soil; ⑦ The average recovery of soil nitrogen in rice season was 46.4% and 41.6% in fluvo-aquic ,soil and paddy soil, respectively.