摘要：
【目的】通过定位试验,综合评价中国南方双季稻地区有机无机肥配施对水稻粒重与结实率的影响。【方法】从江西连续30年的定位试验稻田采样,比较施用化肥(NPK)、等养分条件下70%化肥配施30%有机肥(70F+30M)、50%化肥配施50%有机肥(50F+50M)、30%化肥配施70%有机肥(30F+70M)的稻穗不同部位粒重与结实率。有机肥早稻用紫云英,晚稻用腐熟猪粪；无机肥用尿素、过磷酸钙与氯化钾。采集的水稻品种为赣晚籼37号(926),把稻穗分为上、中、下三个部位,然后分别截取一次枝梗和二次枝梗上的籽粒测定粒重与结实率。【结果】1)与单施化肥相比,三个有机无机肥配施处理水稻的结实率均有提高,特别是稻穗中、下部的结实率均高于NPK处理,虽未达显著水平,但稻穗中、下部结实率的变异性远低于全施化肥处理；2)有机无机肥不同比例对粒重影响不同,50F+50M处理的粒重与NPK相比,显著增加了3.1%,而70F+30M和30F+70M处理差异不显著；3)将稻穗分为上、中、下三个部位,70F+30M和30F+70M处理不同穗位的粒重与NPK处理相比差异均不明显,但50F+50M处理穗上部与穗中部粒重分别增加了4.7%与3.8%,由于粒重变异系数较大,粒重增加不显著；4)与NPK处理相比,50F+50M处理稻穗上部的一次、二次枝梗粒重分别增加了4.8%与4.7%,稻穗中部的分别增加了3.0%与4.6%,但70F+30M和30F+70M处理稻穗上、中部不同枝梗的粒重与NPK处理相比无明显差异；5)有机无机肥配施处理稻穗上部各枝梗结实率与NPK处理无明显差异,但稻穗中、下部的一、二次枝梗结实率都大于NPK处理,其中二次枝梗结实率增加的幅度较大；有机无机配施穗中部与穗下部一次枝梗结实率变异系数小,但二次枝梗结实率的增加呈现不稳定状态。【结论】有机肥化肥的配施比例影响着水稻稻穗不同部位枝梗的实粒数和粒重。本试验条件下,50%化肥与50%有机肥配合最有利于增加稻穗中、上部一、二次枝梗的粒重,但对稻穗各部位粒重的增加不稳定；50%化肥配施50%有机肥配合还有利于增加稻穗中、下部二次枝梗的结实率。有机肥配施比例高于或低于50%时,养分供应滞后或超前,均未显现出优于单施化肥的效果,但是其结实率和粒重的稳定性,也在一定程度上体现了有机无机配施对水稻稻穗结实率和实粒重的良好作用。%[Objectives]The effects of long-term organic-inorganic fertilization on rice grain weight and seed-setting rate at different positions of rice spike were evaluated through the analysis of the samples from a long-term field experiment.[Methods]A field experiment with indica rice cultivar 926 as test material was conducted in Jiangxi Province, and the spike samples were collected from different parts after harvest. Four treatments i. e. mineral N, P and K (NPK), 70% chemical fertilizers plus 30% organic manure (70F+30M), 50% chemical fertilizers plus 50% organic manure ( 50 F+50 M ) , and 30% chemical fertilizers plus 70% organic manure ( 30 F+70 M ) were selected for the investigation from the 30-year long-term field experiment. All 4 treatments had the same rates of N, P , and K nutrients. The organic fertilizers were milk vetch and composted pig manure for early and late rice respectively, while the chemical fertilizers sources of N, P and K were urea, super-phosphate and potassium chloride respectively.[Results]1) The seed-setting rates in the three combination ratios of organic and chemical fertilizer treatments were increased, especially those in the middle and lower parts of an spike. Although the increments were not statistically significant, the coefficient of variation in the seed-setting rates was far lower than that in NPK treatment. 2) Different ratios of organic manure and the chemical fertilizers had different effects on the grain weight. The 50F+50M treatment significantly increased rice grain weight by 3. 1% compared with NPK treatment, but the 70F+30M treatment and 30F+70M treatment did not. 3) Dividing a spike into upper, middle and lower parts, the grain weights in the three parts of spike were not significantly increased in treatments of 70F+30M and 30F+70M, but was increased by 4. 7% and 3. 8% in the primary and secondary branch of rice spike in the treatment of 50F+50M, although not significant due to the high coefficient of variation. 4 ) Compared with treatment NPK, 50F+50M increased the rice grain weight by 4. 8% and 4. 7% in the primary and secondary branch of the upper parts, respectively, for the middle parts of spike by 3. 0% and 4. 6% respectively. However, treatments 70F+30M and 30F+70M had no significant difference with treatment NPK in rice grain weight in any branches of upper and middle parts of spike. 5 ) Organic-inorganic combined fertilization had no difference with NPK in seed-setting rate of different branches from upper parts of rice spike, but increased the set-setting rate in primary and secondary branches from middle and basal parts of rice spike, especially secondary branch of middle and basal parts of rice spike, but the use of organic fertilizer can’t improve the stability of the seed-setting rate in secondary branch of middle and basal parts of rice spike.[Conclusions]The ratio of organic and inorganic fertilizer has different effect on the seed weight and seed-setting rate in different parts and branches of a spike. In this experimental condition, 50% chemical fertilizer and 50% organic fertilizer shows significant increase in the seed weight in the primary and secondary branches of the middle and upper parts of a spike, which could be the main reason for the high yield. The 50% chemical fertilizer plus 50% organic fertilizer treatment is also good for the seed setting rate in the middle and basal parts of the secondary branches. So, 50 to 50 in organic and chemical nutrients should be recommended as a reasonable ratio.
