不同地力条件下不同养分水平对超级稻产量及养分利用率的影响

Effects of Different Nutrient Levels in Different Fertility Soils on Super Rice Yields and Nutrient Use Efficiency

在不同土壤养分条件下,对氮、磷、钾三大营养元素设置不同水平施用量,研究地力条件和养分水平对超级稻产量和养分利用率的影响。结果表明:随着施氮量的增加,产量呈现先升后降的趋势,平均以施180 kg/hm2产量最高。土壤氮素背景值与空白区产量呈正相关关系,R=0.8930,也就是说土壤氮含量高,不施氮肥水稻也能高产。氮素利用率与施氮水平呈极显著的负相关关系,与土壤背景氮呈单峰曲线关系。氮素收获指数随施氮水平的提高而下降,土壤氮含量对其并无影响。在土壤严重缺磷和钾素情况下,施磷钾有显著的增产效果,产量和施肥量有正相关关系,R分别为0.9841和0.9408,随着土壤磷素和钾素量的上升,施肥增产效果逐渐下降,在土壤含磷>10 mg/kg状态下甚至出现施磷减产的现象。磷钾肥农学利用率和表观利用率与其施用量呈极显著负相关,磷肥R分别为-0.9611和-0.9049,钾肥R分别为-0.9534和-0.9472,生理利用率受土壤背景值影响,与施用量的关系表观较复杂。磷肥农学利用率、表观利用率均与土壤背景磷含量呈单峰曲线关系,以土壤磷含量在少量缺乏的情况下,磷肥利用率最高。钾肥农学利用率与土壤含钾量的关系和磷肥相似,但其表观利用率却与土壤含钾量呈负相关关系。磷钾肥的收获指数与氮相似,随施肥水平的提高而下降,土壤磷钾含量对其并无影响。以上表明,超级稻生产在施肥措施中要考虑当地的土壤条件,尽量减少施用量,提高其利用效率,达到增产增效的目的。

Different NPK supply levels were applied in different fertility soils to study the effects of nutrient supply and soil fertility on super rice yields and the nutrient use efficiency.Experimental results can be summarized as follows：with the increase of N supply,super rice yields increased first,then decreased with peak occurring at N supply of 180 kg/ha.Positive correlation between nitrogen background value in soil and yield in blank plots was observed with R=0.893 0,that is,high yield can be harvested even with no application of N as long as the nitrogen background value in soil is high enough.As for nitrogen use efficiency,it demonstrated extremely significant negative correlation with N supply level and accorded to a single-peak curve with nitrogen background value in soil.The nitrogen harvest index decreases with the increase of N supply while soil nitrogen content doesn′t influence it.Under condition of severer deficiency of phosphorus and potassium,supply of P and K can significantly increase the yields with positive correlation between the supply level and yields,R=0.984 1 and R=0.940 8 for P and K,respectively.And with the increase of soil phosphorus and potassium contents,the yield-increasing effects decreased steadily and even reduced the yield when soil phosphorus content10 mg/kg.Significant negative correlation between the agronomic use efficiency and apparent utilization ratio of phosphorus and potassium and their application value can be observed with R=-0.961 1 and R=-0.904 9 for phosphorus,R=-0.953 4 and R=0.947 2 for potassium,respectively.Physiological use efficiency is determined by soil background value and has complicated relations with application value.Correlations between phosphorus agronomic use efficiency,apparent utilization ratio and phosphorus background value in soil accord to a one-peak curve with peak of phosphorus use efficiency occurring when there is slight deficiency of soil phosphorus content.Correlation between potassium agronomic use efficiency and soil potassium content is similar with that of phosphorus while negative correlation was observed between its apparent utilization ratio and soil potassium content.Harvest index of phosphorus and potassium is similar with that of nitrogen,decreasing with the increase of application value and soil phosphorus and potassium content has no effects.Based on the afore-mentioned results,it can be conclude that local soil fertility conditions should be considered in super rice production.To achieve high yields and high fertilizer use efficiency,efforts should be concentrated on decreasing fertilizer application value while increasing the use efficiency.