长期不同施肥对水稻干物质和磷素积累与转运的影响

【目的】磷是制约黄壤生产力的重要限制因子,提高作物的磷效率是农业科学研究的热点之一。探讨不同施肥模式对水稻干物质和磷素积累与转运的影响,为黄壤稻田合理施用磷肥提供理论依据。【方法】依托22年的黄壤(水田)长期定位试验,选取其中6种施肥模式:不施肥(CK);不施磷肥(NK);平衡施用化肥(NPK);单施有机肥(M);1/2有机肥替代1/2 NP (0.5 MNP);有机肥化肥配施(MNPK)。除CK和MNPK外,NK、NPK、M、1/2 MN处理为等氮量165 kg/hm^2,施磷量依次为P2O5 0、82.5、79.4、81.0 kg/hm^2,MNPK施N330 kg/hm^2、P2O5 161.9 kg/hm^2。于水稻分蘖期、开花期及成熟期,采集水稻植株样品,分析比较各处理水稻产量、干物质和磷素积累与转移特征、磷肥吸收利用效率的差异。【结果】水稻产量、干物质和磷素积累量大小顺序均表现为MNPK> M> 0.5 MNP> NPK> CK> NK。磷素积累快速增长开始(t1)和结束(t2)时间均较干物质积累提前2~8 d和5~20 d,且磷素积累快速增长持续时间(Δt)也较干物质缩短了4~12 d,表明磷素快速吸收较干物质早,且持续时间短。处理NK、NPK、0.5 MNP、MNPK干物质最大增长速率(Vm)出现时间(t0)以及t1、t2分别比CK和M处理滞后5~10 d、1~4 d、6~16 d,Δt延长了1~14 d。各处理干物质和磷素积累的Vm均表现为M、MNPK> 0.5 MNP、CK> NPK> NK。水稻籽粒干物质积累量主要来源于花后干物质积累,磷素积累量则主要来源于花前磷素积累向籽粒的转运,各处理花后干物质积累率为29.5%~43.4%,施用化肥各处理显著高于CK和M处理,各处理花前磷素积累率为60.5%~85.6%,大小为CK> NPK、M> NK、0.5 MNP、MNPK。与NPK处理相比,M和0.5 MNP处理磷肥吸收效率、磷肥偏生产力、磷肥利用率分别显著提高了0.43kg/kg、48.9 kg/kg、40.8个百分点和0.26 kg/kg、32.2 kg/kg、25.3个百分点。【结论】黄壤地区水稻栽培中长期缺磷不利于花后干物质的积累,也不利于花前磷素的积累,严重制约水稻产量和磷吸收量的提高。在氮磷钾投入平衡前提下,长期单施有机肥可促进花前干物质和磷素的积累及其向籽粒的转运,但不利于花后干物质和磷素的积累,长期单施化肥可延长干物质和磷素积累的快速增长持续时间,但最大增长速率较小,而长期有机无机配施均较有利于促进水稻花前和花后干物质和磷素的积累,水稻产量和磷肥利用率均较高,是最合理的施肥方式。

Effect of long-term fertilization patterns on dry matter and phosphorus accumulation and translocation in rice

【Objectives】Phosphorus (P) is often deficient in yellow soil, improving P efficiency in crop production is greatly concerned in researches. The effects of fertilization patterns on the dry matter and P accumulation and translocation in rice were compared in this paper, aiming to setup rational P fertilization in yellow paddy soil.【Methods】The study was based on a successive 22-years’ field experiment in the yellow paddy soil. Six treatments were chosen from the experiment, they were blank CK, NK, NPK, manure alone (M), 0.5 MNP and MNPK. Except CK and MNPK, NK, NPK, M and 1/2 MNP had the same N input of 165 kg/hm2, and P₂O₅ input of 82.5, 79.4 and 81.0 kg/hm2 in turn. MNPK treatment had N and P₂O₅ input of 331 and 161.9 kg/hm2. Rice aboveground parts were sampled at tillering, flowering and maturity stages, the grain yield, dry matter and P contents were measured. P accumulation and transfer characteristics, P uptake and utilization efficiency were calculated.【Results】Rice yield, dry matter and P accumulation ranked as follows: MNPK > M > 0.5 MNP > NPK > CK > NK. Compared with dry matter accumulation, the start time ( t₁) and the end time (t₂) of P accumulation during fast-accumulation period advanced 2–8 d and 5–20 d, and the duration (Δt) of P accumulation in fast-accumulation period was shortened by 4–12 d, which indicated that the P accumulation was faster than dry matter and lasted for a shorter time. In contrast to the CK and M treatments, the t₀ [days of the maximum dry matter accumulation rate (V_m) occurred], t₁, t₂ of dry matter accumulation in the treatments with chemical fertilizer application (NK, NPK, 0.5 MNP, MNPK) lagged 5–10 d, 1–4 d, 6–16 d, respectively. The Δt of dry matter and P accumulation also prolonged 1–14 d and 1–15 d, respectively. The V_m of dry matter and P accumulation ranked as M, MNPK > 0.5 MNP, CK > NPK > NK. Dry matter and P accumulation amount of rice grain were mainly derived by post-anthesis period dry matter accumulation and pre-anthesis period P translocation, respectively. The post-anthesis period dry matter accumulation rate of each treatment was 29.5%–43.4%, and the treatments with chemical fertilizer had significantly better effect than that of CK and M treatment. The pre-anthesis period P accumulation rate of treatments was 60.5%–85.6%, and the order was CK > NPK, M > NK, 0.5 MNP, MNPK. Compared with the NPK treatment, 0.5 MNP and M treatments significantly increased the P absorption efficiency, P partial factor productivity and P utilization efficiency by 0.43 kg/kg, 48.9 kg/kg, 40.8 percentage points and 0.26 kg/kg, 32.2 kg/kg, 25.3 percentage points, respectively.【Conclusions】Long-term P deficiency was not conducive to dry matter accumulation in post-anthesis period and P accumulation in pre-anthesis period, which seriously restricts the improvement of rice yield and phosphorus uptake. Long-term solely application of organic manure could promote the dry matter and P accumulation and transport in pre-anthesis period, but restricted those in post-anthesis period. Long-term solely application of chemical fertilizer could prolong the Δt of dry matter and P accumulation, but the V_m was small. Long-term integrated fertilization with organic manure and chemical fertilizers could promote the dry matter and P accumulation both in pre-anthesis period and after-anthesis period, leading to high grain yield and P use efficiency, which is the best fertilization pattern in yellow paddy soil.