【作者】 何园球；

【导师】 沈其荣；

【作者基本信息】 南京农业大学 ， 植物营养学， 2003， 博士

【摘要】 我国红壤地区以低山丘陵和岗地为主，一些高榜田和水源不充足的地方进行常规淹水种稻十分困难。由于降雨分布不均，季节性干旱非常严重，一方面影响作物的正常发育，同时很难使被络合的磷酸根离子释放出来，从而限制作物对土壤水分和养分的吸收，降低水分和养分的利用率；此外，从长远来说，南方缺水的压力依然存在。近年来采用水稻旱作能获得几乎与传统水稻相同的产量，而节水60％～100％，这为南方丘陵地区种植水稻提供了一个很好的替代耕作制度。但是红壤本来就缺磷，水稻旱作后其土壤磷素营养就成为限制旱作水稻产量的因子之一。因此，研究水稻旱作条件卜水分对土壤磷素形态转化及其有效性不仅能揭示红壤水磷交互作用，更能为南方丘陵地区推广水稻旱作提供合理的水磷调控理论和管理措施，这对充分发挥这类资源的巨大潜力，促进红壤丘陵、特别是低丘岗地区大农业发展均有十分重要的意义。 针对上述问题于2001-2002年进行了田间试验、盆栽试验和培育试验，旨在探索水分和磷素对旱作水稻生理特性、生物量和产量、水分利用率、全素含量和吸收量以及红壤磷素的有效性、形态与转化的影响。主要结论如下： 1、通过大田实验研究了水磷对旱作水稻生理特性的影响。结果表明，水磷对旱作水稻叶面积有极显著的影响，且交互作用明显，在中磷中水条件下旱作水稻叶片生长最快；对旱作水稻叶片的光合有效辐射有极显著的影响，且交互作用明显，其值随施磷量和土壤含水量的增加而增加；对净光合速率有显著的影响，但二者间的交互作用不明显，其值随含水量的增加而轻微增加，不同施磷量以低磷和中磷时最高；对气孔导度和蒸腾速率没有显著的影响，但二者间的交互作用显著，不同水分状况以高水＞低水＞中水，其值随施磷量的增加而增加。这表明水分对水稻叶片的净光合有效辐射、净光合速率影响很小；水稻旱作时蒸腾作用弱，有利于节约水分。水稻叶片的蒸腾作用与土壤含水量的高低有关，高水条件蒸腾作用最大。施磷量对水稻叶片的净光合有效辐射、净光合速率和气孔导度有一定的影响，中高水状况下有利于水稻干物质的积累和产量的形成，增施磷肥有利于增加水稻叶片的蒸腾作用。 2、通过盆栽和大田实验研究了水磷对旱作水稻产量的影响。水磷对旱作水稻生物量和产量有极显著的影响，且二者间的交互作用明显，影响程度以籽粒＞茎＞根。土壤含水量为饱和持水量的60％时明显降低旱作水稻生物量和产量，而80％和100％时几乎没有影响，同时，旱作水稻生物量和产量均随施磷量的增加而增加。这说明控制土壤水分为饱和持水量的80％时就能完全满足旱作水稻的生长，但要求获得较高的产量时必须注意磷肥的投入，或者采取一些调控措施提高土壤磷的利用率。 3、通过盆栽和大田实验研究了水磷对旱作水稻全磷含量和吸收量的影响。结果表明，水磷对大田旱作水稻全磷含量和吸收量的影响不显著；对盆栽而言，水不显著磷则显著；但二者间的交互作用明显，因而其差异主要体现为水和磷的复合效应。旱作水稻全磷含量随着土壤含水量的增加在盆栽条件下下降，籽粒中则以中水时最高，大田中有轻微的上升，籽粒中含量则下降；旱作水稻全磷含量随着施磷量的增加而增加；全磷平均含量盆栽以茎＞籽粒＞根；大田则以籽粒＞茎＞根。在中磷条件下，水分对旱作水稻磷素吸收的影响盆栽条件下以中水＞高水＞低水；大田条件下，根茎中全磷含量随着土壤含水量的下降而下降，籽粒中则相反，吸磷量以中水＞高水＞低水。在中水条件下，随着水稻旱作条件下水磷对土壤一植株磷素营养的影响施磷量的增加水稻全磷吸收量增加，但无磷与低磷间增加的幅度最大，不同施磷量间幅度较小。旱作水稻各部分全磷平均吸收量以籽粒>茎>根。上述说明，早作水稻生育前期要保持较好的水分状况，中后期对水分的要求较低，要控制水分;磷肥可作基肥全部施入，以满足茎杆前期和中期的发育，使更多的磷转移到水稻籽粒中并获得更高的产量。同时，要注意秸杆还田，使大部分磷保留在土壤中。 4、通过盆栽、大田和模拟实验探讨了水磷对红壤全磷、有机磷和有效磷的影响。水磷各自对红壤全磷和有机磷的影响不显著，对土壤有效磷的影响显著，但二者间有明显的交互作用。栽种水稻 (培育)后，总体来说土壤有机磷含量上升，全磷和有效磷含量下降。在中磷条件下，随着土壤含水量的卜降，盆栽土壤全磷和有机磷含量上升，有效磷下降;大田土壤有机磷含量上升，有效磷含量前期上升，后期下降，全磷含量则基本不变;培育土壤有机磷和有效磷含量以中水时含量最高。在中水条件下，随着施磷量的增加，盆栽土壤全磷和有效磷含量增加，有机磷含量则基本不变;大田十壤全磷含量卜降，有机磷和有效磷含量则上升;培育土壤施磷量为无磷和低磷时，有效磷含量的平均值人幅度降低，而中磷和高磷时则大幅度上升。盆栽与大田和培育实验相比，水磷二者对土壤有机磷和有效磷的影响不显著，其作用主要体现在三者的交互上;大田土壤全磷、有机磷和有效磷含量要高得多，水分对红壤有效磷的影响较大，对有机磷次之，对全磷影响较小，这种影响主要体现在磷的含掣.不.}变化方向两更多还原

【Abstract】 It is difficult to cultivate paddy rice in conventional waterlogged condition in a high position of field or a place where water resource is deficient, due to the terrain of red soil regions being mainly low hill and hillock in the south China. Here, seasonal drought is very serious because of the uneven distribution of the rainfall. The popularly accepted cultivation of paddy rice variety in aerobic soil condition is very useful in development of rice cultivation in the low hill area of southern part of China. Almost the same yield of rice grain could be obtained in aerobic as in waterlogged cultivation and furthermore 60%~100% of irrigated water can be saved. However, phosphorus availability is becoming a more serious problem since the shift of waterlogged to aerobic. Therefore, it is of great importance to investigate the effect of soil water content on the transformation of soil phosphorus in this new rice cultivation system. In this paper, we are trying to clarify the interaction between soil water and phosphorus and its effect on phosphorus nutrition of rice plant and thus, provide an appropriate way to manage the water and phosphorus in the system of rice cultivation in aerobic soil condition in the red soil area.Field, pot and incubation experiments were conducted to study the effect of soil water and phosphorus (P) supply on paddy rice cultivated in aerobic soil. The results obtained were as follows.1. The results in the field experiment indicated that soil water and P had remarkable effect on the leaves’ area and the interaction of soil moisture and P was significant. Rice leaf emergency was the fastest at moderate water (80% of saturated water content, SWC) and moderate P (26.5kg/hm2). There was also a remarkably interactive effect of water and phosphorus on the valid radiation of photosynthesis (VRP) and the VRP values were enhanced with the increase of P application rates and soil moistures.Net photosynthesis velocity (NPV) was also affected but interaction was small. No significant effect was found in the air vent conducting degree (AVCD) and rising velocity (RS), but the interaction was distinct. The transpiration of paddy rice cultivated in aerobic soil was slight, which was useful for saving water. The greatest transpiration took place when the soil moisture was high. To some extent, P application in soil had effect on NPVR, NPV and AVCD. Moderate or high moisture regime could produce higher dry matter of paddy rice and increasing yield and enhancement of P application rates could improve the transpiration of rice leaves.2. Soil water and P application had an interactive effect on rice biomass and grain yield, the biggest effect being in grains followed by shoots and roots. When soil moisture was 60% of SWC, biomass and grain yield of the rice were significantly reduced. No difference of the biomass and grain yield was found when soil moisture was at 80% and 100% of SWC. The biomass and grain yield of rice cultivated in aerobic soil increased with the increase of P application rates. More P fertilization should be done in aerobic cultivation to get good yield of rice grain than in waterlogged cultivation.3. Soil moisture had no significant effect on phosphorus uptake while phosphorus application had asignificant effect. In pot experiment, phosphorus uptake in grain was the largest at soil moisture of 80% of SWC but the average of total phosphorus uptake was in the order of shoots > grains > roots; in field experiment, the order was grains > shoots > roots. In field experiment, amount of phosphorus uptake by the rice plant was ordered by moderate moisture > high moisture > low moisture. When moisture was at 80% of SWC, phosphorus uptake by the rice plant increased with the increase of P application rates. It was important to maintain a good soil moisture condition if rice is to be cultivated in aerobic soil.4. Soil moisture and P had no significant effect on total P (TP) and organic P (OP) in soil but on available P (AP). After planting (or incubating) paddy rice, soil OP content i更多还原