施磷对玉米吸磷量、产量和土壤磷含量的影响及其相关性

为了给玉米磷高效利用提供理论依据, 在低磷土壤(Olsen-P 4.9 mg·kg^-1)上, 通过田间试验, 研究了施磷0(T₀)、50 kg(P₂O₅)·hm^-2(T₁)、100 kg(P₂O₅)·hm^-2(T₂)、200 kg(P₂O₅)·hm^-2(T₃)、1 000 kg(P₂O₅)·hm^-2(T₄)对两个玉米品种"鲁单9002" (LD9002)、"先玉335"(XY335)的产量、磷素吸收利用及根际磷动态变化的影响。结果表明: 两玉米品种根际土、非根际土速效磷含量在不同生育时期都表现为T12O₅)·hm^-2的T₃处理非根际土转化为根际土土壤磷的量最大, 同时玉米生物量、产量、磷转移量也达到最高, 而施磷1 000 kg(P₂O₅)·hm^-2处理玉米生物量、产量与中磷水平相比没有显著增加, 但植株吸磷量较高。XY335的花后磷转移量小于LD9002。相关分析表明, LD9002根际土、非根际土速效磷含量与茎、叶吸磷量之间显著相关, 以播种后79 d与茎、叶磷浓度、吸磷量、生物量、产量之间的相关系数最高; 而XY335根际土、非根际土速效磷含量与茎、叶磷浓度之间显著相关, 在播种后47 d期间与茎、叶磷浓度、吸磷量、生物量、产量之间的相关性最好。因此, 在低磷土壤上, LD9002和XY335分别在播种后79 d和47 d时是植株对磷的敏感期, 可以通过测试根际土、非根际土速效磷含量来反映土壤的供磷状况; LD9002在79 d时最大吸磷量需要的根际土、非根际土速效磷含量分别为54.95 mg·kg^-1、32.99 mg·kg^-1, XY335品种在47 d时最大吸磷量需要的根际土、非根际土速效磷含量分别为51.24 mg·kg^-1、35.35 mg·kg^-1; 施磷量1 000 kg(P₂O₅)·hm^-2处理两品种玉米产量、生物量、磷积累量与施磷量100~200 kg(P₂O₅)·hm^-2处理没有显著差异。

Effect of phosphorus application on soil available phosphorus and maize phosphorus uptake and yield

To simultaneously enhance maize yield and phosphorus fertilizer efficiency, the effects of phosphorus application on maize phosphorus uptake and utilization, yield, and the dynamic changes of rhizosphere phosphorus were studied in a field experiment. The study was conducted in low soil phosphorus (Olsen-P 4.9 mg·kg^-1) condition at Henan Province with two maize varieties - "Ludan 9002" (LD9002) and "Xianyu 335" (XY335). The application rates of the P fertilizers were 0 (T₀), 50 kg(P₂O₅)·hm^-2 (T₁) ,100 kg(P₂O₅)·hm^-2 (T₂), 200 kg(P₂O₅)·hm^-2 (T₃) and 1 000 kg(P₂O₅)·hm^-2 (T₄), respectively. The results showed that the order of available phosphorus contents in rhizosphere and non-rhizosphere soils of the two maize varieties at different growth stages was T₁ < T₂ < T₃ < T₄. The highest phosphorus transformation rate from non-rhizosphere to rhizosphere soils was at 61 d after maize planting under 200 kg(P₂O₅)·hm^-2 (T₃). Also treatment T₃ had the highest biomass, grain yield and phosphorus transformation rate. Under 1 000 kg(P₂O₅)·hm^-2 phosphorus fertilizer application (T₄), no significant increase was noted in biomass and grain yield compared to intermediate phosphorus level. However, maize phosphorus uptake was much higher under treatment T. Phosphorus transformation rate of XY335 after flowering was lower than that of LD9002, suggesting higher phosphorus use efficiency by LD9002. Correlation analysis showed significant relationships among available phosphorus contents of rhizosphere and non-rhizosphere soils and phosphorus accumulation in stems and leaves of LD9002, especially at 79 d after planting. Also significant relationships were noted among available phosphorus content of rhizosphere and non-rhizosphere soils and those of stems and leaves of XY335, especially at 47 d after planting. This suggested that 79 d and 47 d after planting were key phosphorus demand periods after planting in LD9002 and XY335, respectively. Available phosphorus content of rhizosphere and non-rhizosphere soils reflected the capacity of the soils to release phosphorus. Suitable phosphorus concentration of rhizosphere and non-rhizosphere soils for the highest phosphorus uptake were respectively 54.95 mg·kg^-1 and 32.99 mg·kg^-1 at 79 d after planting LD9002. The corresponding values for XY335 were respectively 51.24 mg·kg^-1 and 35.35 mg·kg^-1 at 47 d after planting. When phosphorus application rate increased to 1 000 kg(P₂O₅)·hm ^-2, no significant difference existed in terms of yield, biomass and phosphorus uptake compared with those under phosphorus application rate of 100~200 kg(P₂O₅)·hm^-2.