【作者】 沈玉芳；

【导师】 李世清； 邵明安；

【作者基本信息】 西北农林科技大学 ， 植物营养学， 2007， 博士

【摘要】 水分和养分是限制作物生长发育的两个重要因子,但对于决定作物产量高低的首要因子是水还是肥并无一致结论。人们对水肥与产量之间的相互关系进行了大量研究,取得了重要进展。过去的研究主要集中在水肥在数量和时间的耦合方面,而对空间耦合(土层间的组合)研究资料相对较少。本试验针对黄土高原地区表层土壤干旱下层湿润特点,以冬小麦为指示作物,以土垫旱耕人为土(褐土)为供试土样,应用长期通气培养法,在阐明湿度和温度对0-90cm土壤剖面不同土层(每30cm为1土层)氮素矿化影响的基础上,采用隔层土柱试验,模拟土壤水分养分空间分布的几种状况,研究土柱不同部位水分、氮、磷空间组合对冬小麦生长发育、光合特性、养分分配利用及产量构成的影响。通过研究,获得以下主要结论:1.不同土层土壤有机氮的矿化累积量均随温度、水分含量升高而增加,各土层增幅的大小顺序为0-30cm>30-60cm>60-90cm,0-30cm土层矿化量远远大于其它土层,30-60cm土层矿化量虽然大于60-90cm土层,但差异有限;0-30cm土层可矿化氮是0-90cm土层可矿化氮的主体,其矿化氮占67.90%,30-60cm和60-90cm土层矿化氮占32.10%。0-30cm土层土壤氮素矿化量增加过程显著快于其它两层土壤,不同土层土壤氮素矿化过程不同,在培养期间0-30cm土层氮素矿化量与培养时间符合线性关系,而30-60cm和60-90cm土层符合对数函数;不同土层氮素矿化速率k与含水量w间为直线关系,相关系数r在0.93以上,0-30cm土层的k值对温度反映最为敏感,其次为30-60cm土层,以60-90cm土层反映最小。在较高温度培养条件下,随温度增加,土层越深,矿化速率增加越慢;温度和水分对不同土层土壤氮素矿化具有明显的正交互作用。对0-30cm土层,温度和水分对氮素矿化均表现出显著的正效应,随两因子同时增加,氮素矿化增加,但在高温情况下水分效果更加突出;而对30-60cm和60-90cm土层,虽然水分和温度对氮素矿化均表现出正效应,但温度效应比水分效果更加突出。0-30cm土层土壤有机氮矿化过程对温、湿度的反应比深层更为敏感,说明在生产实践中应根据不同土层土壤有机氮的含量和实际矿化过程来确定矿化所需的水热条件。2.叶绿素荧光参数对水分胁迫反应敏感,上干下湿(0-30cm土层干旱胁迫,30-90cm土层湿润)水分处理冬小麦叶片基础荧光(Fo)增大,而最大荧光(Fm)、可变荧光(Fv)、PSⅡ光化学效率(Fv/Fm)及PSⅡ潜在活性(Fv/Fo)等参数显著降低;氮、磷营养对叶绿素荧光参数也有一定影响,施肥总体可以调节水分胁迫对荧光参数的影响,氮磷配施较单施氮、单施磷有更强的调节能力;不同土层单施氮,各荧光参数间差异性不显著,而不同土层单施磷对各荧光参数的影响有一定规律,表现为0-90cm和0-30cm土层施肥比30-60cm和60-90cm土层施肥Fo减小,而Fm、Fv、Fv/Fm和Fv/Fo增大;在土柱整体湿润处理下,各土层氮磷配施处理间荧光参数差异显著;对土柱上干下湿处理,除Fv外,不同氮磷配施处理间其它参数差异性均达显著水平。3.上干下湿(0-30cm土层干旱胁迫,30-90cm土层湿润)的水分处理不同程度降低了小麦叶片SPAD值、净光合速率(Pn)和籽粒产量。两种水分处理下,氮磷配施处理对叶片SPAD值、净光合速率(Pn)和小麦产量的影响最为显著,其次是施磷处理,施氮处理影响不显著。从不同土层施肥处理看,对单施氮而言,在两种水分处理下,以0-90cm土层均匀施入叶片的SPAD值、Pn和小麦籽粒产量显著高于0-30cm、30-60cm和60-90cm土层施氮处理;对单施磷而言,在两水分条件下,0-90cm土层施磷处理小麦叶片的SPAD值、Pn和籽粒产量与0-30cm施肥处理间差异不显著;对氮磷配施而言,在整体湿润处理下,0-90cm土层氮磷配施处理小麦叶片的SPAD值、Pn和的小麦籽粒产量最高,与0-30cm土层施肥处理间差异不显著,但显著高于30-60cm和60-90cm土层施肥处理;对上干下湿处理,各土层施肥处理小麦叶片的SPAD值差异不显著,0-90cm土层氮磷配施处理小麦叶片Pn和小麦产量显著高于30-60cm土层施肥处理,30-60cm土层施肥处理显著高于60-90cm土层施肥处理和未施肥处理。4.上干下湿(0-30cm土层干旱胁迫,30-90cm土层湿润)水分处理显著影响抽穗期小麦旗叶面积和株高,与整体土层湿润相比二者分别降低7.03%和3.77%;上干下湿水分处理不同程度降低了小麦地上部和根系生物量及收获指数,但根冠比增加。单施磷小麦叶面积、旗叶面积和株高与氮磷配施间差异不显著,但前者有效分蘖数减少2.6个/柱,单施氮和CK叶面积、株高和有效分蘖数均极显著低于单施磷和氮磷配施处理。两种水分处理下,氮磷配施对小麦地上部生物量的影响最为显著,其次是施磷处理,施氮处理效果较差,而地下部生物量和根冠比在单施磷时最高。这与供试土壤各土层严重缺磷,而氮素供应相对丰富有关。0-90cm与0-30cm土层单施磷和氮磷配施处理间总叶面积、旗叶面积、株高以及有效分蘖数差异不显著,但均显著高于30-60cm和60-90cm土层相应施肥处理,不同层次单施氮处理间差异缺乏规律性。单施氮以均匀施入0-90cm土层地上部生物量和根系生物量最高,其次是施入30-60cm土层,施入0-30cm土层最低;单施磷以0-90cm土层施入地上部和根系生物量及根冠比与0-30cm土层施入差异较小,但均显著高于30-60cm和60-90cm土层施入;对氮磷配施而言,地上部和根系生物量从高到低依次是施入0-90cm、0-30cm、30-60cm、60-90cm土层施肥处理。由于土壤供氮充分,将氮肥集中施于0-30cm土层对生物量形成具有一定抑制作用,而均匀施入0-90cm土层有明显促进作用,在上层干旱胁迫时,这种趋势更加明显;在氮磷配施或者单施磷时,无论是上干下湿水分状况下,还是全土柱湿润下,0-30cm土层较充分的氮磷配合供应,有利于提高作物生物量。5.采用非破坏性、定点直接观察和研究植物根系的Minirhizotrons测定法,对不同土层水分、氮、磷组合对冬小麦根长、根表面积、根体积、根数、根系直径和根系生物量等指标的影响进行研究,并探讨根系特征与水分利用效率的关系。研究表明,根系直径主要分布在0.0000-0.5000mm之间,少部分分布在0.5000-1.0000mm之间,偶见直径大于1.0000mm根系,表现为0-30cm土层根系直径较大,30cm以下土层根系直径较小;根系直径受不同水肥处理影响较小。上干下湿(0-30cm土层干旱胁迫,30-90cm土层正常供水)水分组合小麦根长、根表面积、根体积和根数分别比整体湿润(0-90cm土层正常供水)分别增加18.9%、25.3%、29.8%和8.0%差异达显著或极显著水平。各处理小麦根系虽均在孕穗期达到高峰,灌浆初期开始衰退,但不同肥料处理小麦根系生长发育和分布规律不同:未施肥(CK)和单施氮小麦根长、根表面积、根体积和根数在孕穗期前一直有较快的增长速度,但总量较少,单施磷和氮磷配施小麦根长、根表面积、根体积和根数在拔节期前增长迅速,拔节后增长较慢,但数量较高。从不同土层施肥处理看,不同土层单施氮差异不显著;0-90cm土层单施磷显著高于0-30cm、30-60cm和60-90cm土层单施磷(P<0.05),对氮磷配施,0-90cm与0-30cm土层施肥处理间差异不显著,但均显著高于30-60cm和60-90cm土层施肥。不同处理小麦根系生物量均以0-30cm土层最高,平均占总根系生物量的67.2%,30-60cm和60-90cm土层分别占17.4%和15.4%,但施肥土层根系生物量相对增加,根系有在施肥土层聚积现象。总体看上干下湿水分处理小麦水分利用效率(WUE)有增加趋势,比整体湿润处理增加0.039mg/cm3水,施肥后小麦WUE均增加,以0-90cm土层施肥处理WUE最高。冬小麦的WUE与根长、根表面积、根体积、根数呈极显著正相关,相关系数r2分别为0.7992、0.7719、0.7243和0.7893(n=25),与根系总生物量相关性较弱,相关系数r2为0.2974,说明在影响WUE上根系形态特征比总生物量更加显著。6.小麦不同部位含氮、磷量表现为籽粒>根系>叶、穗余部>茎;氮、磷累积量表现为籽粒>>茎秆、叶>穗余部>根系。上干下湿水分处理使得小麦籽粒、穗余部含氮分别减少0.90%和2.40%,含磷量分别减少4.34%和12.99%,对其它器官氮、磷含量的影响不一。与整体湿润相比,上干下湿水分处理可降低小麦各器官氮、磷累积量,但对不同器官分配比例影响不大。与不施肥(CK)相比,氮磷配施小麦各器官含氮、磷量明显增加,单施氮时各部位含氮量均显著增加,但含磷量增幅较小;而单施磷时含磷量显著增加,含氮量略有降低;施肥后各器官氮、磷累积量虽然均增加,但在氮、磷、氮磷处理籽粒中氮、磷累积量所占比例减小;不同器官氮、磷累积量主要取决于生物量,而不是氮、磷含量。各土层根系氮、磷累积量除以0-30cm土层根系氮、磷累积量为最高这一般性特点外,施肥土层根系氮、磷累积量相对增加,与生物量的变化相一致。对单施氮处理,以0-90cm土层施肥各器官氮、磷累积量最高;而对单施磷和氮磷配施,均以0-90cm土层施肥处理籽粒及根系氮、磷累积量最高,其它器官高低不一。7.不同土层水肥处理的氮、磷肥利用率和农学效率差异显著,氮肥利用率高低在4.73%-41.19%之间,磷肥利用率高低在4.11%-13.58%之间,磷肥农学效率高于氮肥。单施氮整体湿润时氮肥利用率较上干下湿(0-30cm土层干旱胁迫,30-90cm土层湿润)低4.87%,而氮磷配施整体湿润时氮肥利用率较上干下湿高6.38%,差异均达显著水平;单施磷在两种水分处理下磷肥利用率差异较小,而氮磷配施在整体湿润时磷肥利用率较上干下湿增加5.01%(P<0.05)。上干下湿时氮磷配施氮肥利用率较单施氮高10.48%,磷肥利用率与单施磷处理相差仅为0.58%;整体湿润时氮磷配施氮肥利用率较单施氮高21.73%,磷肥利用率较单施磷处理高4.80%,说明0-30cm土层良好的水分条件有利于提高氮磷配施时氮、磷肥利用率。单施氮在两种水分处理下均以0-90cm土层施肥处理氮肥利用率最高;氮磷配施在整体湿润时0-90cm土层施肥与0-30cm土层施肥氮肥利用率显著高于30-60cm和60-90cm土层施肥处理;上干下湿时,0-90cm土层施肥处理的氮肥利用率显著高于其它土层施肥处理,分别比0-30cm、30-60cm和60-90cm土层施肥处理高9.5%、10.1%和20.2%;单施磷以0-90cm土层施入磷肥利用率最高,为8.55%,其次是0-30cm土层施肥处理,为7.93%;氮磷配施以0-30cm土层施肥磷肥利用率最高,显著高于其它土层施肥。单施氮或磷在上干下湿时氮、磷肥农学效率均高于整体湿润处理,但氮磷配施处理氮、磷肥农学效率均在整体湿润处理下较高;氮肥农学效率在单施氮和氮磷配施时均以0-90cm土层施肥最高;磷肥农学效率在上干下湿单施磷时以0-90cm土层施肥最高,其它则以0-30cm土层施肥处理最高。8.从水肥不同空间组合对光合、叶绿素荧光、根系分布、同化产物和养分分配、养分效率的影响等角度分析,无论对上干下湿水分分布,还是对整体湿润水分分布,保证0-30cm和0-90cm土层适量氮磷供应,不仅对产量形成和提高养分利用效率最为重要,而且有利于提高籽粒氮、磷含量及促进氮、磷养分向籽粒中的转移。但从生产实践角度出发,考虑到在石灰性土壤中肥料氮终产物以硝态氮为主,且容易移动,而磷肥不易在土壤中迁移这一特点,无论对整体湿润,还是最常见的上干下湿土壤水分分布状况,氮磷配施时,仍然以施入0-30cm土层较好。更多还原

【Abstract】 Water and nutrients are major factors limiting crop production, but which is more important to crop yield is unsure. Lots of researches on water and fertilizer coupling in quantity and time had been made and many important results had been acquired, but research on water and fertilizer spatial coupling (in different soil layer) are relatively insufficient. So a cylindrical pot experiment was conducted with Eum-Orthic Anthrosols (Cinnamon soils) under rain-preventing condition to study the effects of spatial coupling of water, nitrogen and phosphorus on photosynthetic characteristics and yield of winter wheat, with the basis on the characteristic of surface layer drought and substrate wetness of loess plateau. The pot consisted of three layers with each layer of 30cm depth and a 2cm layer of coarse sand between soil layers for obstructing water and nutrients exchange. Before that, a study was made of the influence of water condition and temperature on soil nitrogen mineralization of different layers with aerobic incubation experiments. The main results are shown as follows:1. Nitrogen mineralization accumulation quantity of all soil layers gained with the increase in temperature and water content, but the mineralizable nitrogen in the layer of 0-30cm was much greater than those in other soil layers. The mineralizable nitrogen of the 0-30cm soil layer was the major part, accounting for 67.90% of the total, and the value of both 30-60cm and 60-90cm soil layers was 32.10%. Mineralization quantity of 0-30cm soil layer increased faster than another two soil layers. Every soil layer had different mineralization process under different water contents, that is to say, mineralization process of 0-30cm soil layer could be expressed with linear equation, and 30-60cm and 60-90cm soil layers with logarithm equation in incubation time. The relations of soil nitrogen mineralization rate (k) with water content (w) could be expressed by the linear equation, and the correlation coefficient was above 0.93. It was found that k of 0-30cm soil layer was most sensitive to temperature, and then of 30-60cm, and of 60-90cm the least. As a whole, nitrogen mineralization rate of deeper soil layer increased slowly with the temperature under the higher incubation temperature. These results suggested that temperature and water content had interactive effects on nitrogen mineralization quantity and rate. To 0-30cm, both temperature and water content had remarkable positive effect, but moisture is more evident under the higher incubation temperature. But to 30-60cm and 60-90cm, temperature exerted more evident effect. Temperature, moisture content and incubation time had also remarkable linear correlation (p< 0.0001). From the results, we found that mineralization process of 0-30cm soil layer was more sensitive to temperature and water content, which means that nitrogen mineralization process is determined by such factors as temperature, moisture and soil layer.2. The kinetic parameters of chlorophyll fluorescence of winter wheat were sensitive to water stress. The basic fluorescence(Fo) of wheat leaves increased under the water condition of 0-30cm soil-dry and 30-90cm soil-wet (D), while the maximal fluorescence(Fm), the variable fluorescence(Fv), the photochemical efficiency(Fv/Fm) and potential activites(Fv/Fo) of PSII decreased remarkably. Nitrogen and phosphorus nutrient could weaken the effect of water stress on fluorescence parameters; and the effect of NP treatments (mixing nitrogen and phosphorus) was better than P treatment (applying phosphorus). Comparing layer treatments with the same fertilizer, we found that the difference of fluorescence parameters with N applying in different layers was unapparent, that Fo with P applying layer of 0-90cm and 0-30cm were lowered than of 30-60cm and 60-90cm, but Fm, Fv, Fv/Fm and Fv/Fo was higher; that the difference of fluorescence parameters with NP applying in different layers was remarkable.3. SPAD and the net photosynthetic rate (Pn) of leaf and yield of wheat were inconsistently lower under the water condition of 0-30cm soil-dry and 30-90cm soil-wet (D) than of 0-90cm soil-wet (W). Under each water treatment, compared to fertilizer treatments at the same layer, it showed that SPAD, Pn and yield of NP treatments were maximal, followed by P treatment, then was N treatment (applying nitrogen). Compared to layer treatments with the same fertilizer, it was found that SPAD, Pn and yield with nitrogen applying layer of 0-90cm were maximal, but the results were ruleless when nitrogen was applied in layer of 0-30cm, 30-60cm and 60-90cm; that, under W condition, yield with phosphorus applying layer of 0-30cm was highest; under D condition, yield with phosphorus applying layer of 0-90cm were highest; both SPAD and Pn with phosphorus applying layer of 0-90cm were highest, followed by 0-30cm; that under W or D treatment, yield, SPAD and Pn with nitrogen and phosphorus applying layer of 0-90cm were highest, of 0-30cm, 30-60cm and 60-90cm presented downtrend.4. Compared with 0-90cm soil-wet (W), leaf area and plant height of heading stage decreased by 7.03% and 3.77% separately under the water condition of 0-30cm soil-dry and 30-90cm soil-wet (D). The above-ground biomass, root biomass and HI were inconsistently lower, but ratio of root to shoot (R/S) higher under the condition of D. Comparing fertilizer treatments at the same layer, it showed that the effective tillers were reduced by 2.6(n/pot) of P treatment than NP treatments; that the difference of the leaf area and plant height was not significant between P treatment and NP treatments; that leaf area, plant height and fertile tillers of N treatment and CK were markedly lower than P treatment and NP treatments. Under each water treatment, above-ground biomass of NP treatments was maximal, followed by P treatment, then was N treatment, but root biomass and R/S were maximal at the treatment of P, due to P deficiency and N enrichment in the soil. Comparing layer treatments with the same fertilizer, we found that leaf area, plant height and fertile tillers of P and NP applying layer of 0-90cm and 0-30cm were remarkably higher than of 30-60cm and 60-90cm; but the rule was not obvious at the treatment of N applying in different layer. Above-ground biomass and root biomass of N applying layer of 0-90cm was maximal, of 0-30cm was lowest. Above-ground biomass, root biomass and R/S of P applying layer of 0-90cm and 0-30cm were markedly higher than of 30-60cm and 60-90cm; and above-ground biomass and root biomass of NP applying layer of 0-90cm was maximal, followed by 0-30cm, 30-60cm and 60-90cm orderly. Because the soil was full of nitrogen, applying N in layer of 0-30cm was inhibitory to biomass, but of 0-90cm was stimulative, which was more obvious under the condition of D. The biomass of crop would be higher mixing nitrogen and phosphorus in layer of 0-30cm, regardless of the condition of D and W.5. Minirhizotrons is one of the new study methods, which has the merit of non-destructive and the fixed-point visual observation. The experiment dealt with the effects of spatial coupling of water, nitrogen and phosphorus on root character of different soil layers at different growth stages using minirhizotrons, and discussed the relation of root characteristics with water use efficiency (WUE). The root character indexes mainly included root length, root seeming area, root volume area, root number, root diameter and root biomass of winter wheat. The results showed that a majority of root diameters was between 0.0000mm and 0.5000mm and a little was beyond 0.5000mm. The diameters of root in 0-30cm soil layer were bigger than in other soil layers. And water and fertilizer had less effect on root diameter. There was a remarkable difference of different root character indexes between different water treatments. And compared with 0-90cm soil-wet (W), root length, root seeming area, root volume and root number increased by 18.9%, 25.3%, 29.8% and 8.0% separately under the water condition of 0-30cm soil-dry and 30-90cm soil-wet (D). The rule of root growth and distributing were different between different fertilizer treatments, although growth momentums of all wheat roots arrived at the zenith at the booming stage and started to decline at the filling stage. Root length, root seeming area, root volume and root number of N treatment and CK were less, but had faster growth rate all along. Root length, root seeming area, root volume and root number of P treatment and NP treatments were higher, but had lower growth rate after the jointing stage. Comparing layer treatments with the same fertilizer, we found that there was no significant difference of root character indexes between the treatment of N applying in different layer, that all root character indexes were significant higher at the treatment of P applying in 0-90cm than 0-30cm, 30-60cm and 60-90cm soil layer, that significantly higher at the treatment of NP applying in 0-90cm and 0-30cm than 30-60cm and 60-90cm soil layer. On the whole, root biomass of 0-30cm soil layer was highest, accounting for 67.2% of 0-90cm soil layer averagely. And those of 30-60cm and 60-90cm accounted for 17.4% and 15.4% separately. But root growth increased relatively at the fertilizer layer. Compared with W, WUE of wheat increased by 0.039mg/cm3 under the water condition of D. Fertilizer treatments could improve WUE, and WUE of 0-90cm fertilization was highest. Correlation analysis showed that WUE and root length, root seeming area, root volume and root number were remarkable positive correlation and correlation coefficient(r2) was 0.7992, 0.7719, 0.7243 and 0.7893(n=25), that WUE and root biomass were lower correlation and r2 was only 0.2974. It showed that root character indexes had more remarkable effect on WUE than root biomass.6. Nitrogen and phosphorus content of grain was highest, followed by root, then was leaf and rachis and hull (RH), and stem was lowest. Nitrogen and phosphorus uptake of grain was highest, followed by stem and leaf, then was RH, and root was lowest. Nitrogen content of grain and RH decreased by 0.90% and 2.40% separately under the water condition of 0-30cm soil-dry and 30-90cm soil-wet (D), and phosphorus content decreased by 4.34% and 12.99% separately. Compared with the water condition of 0-90cm soil-wet(W), nitrogen and phosphorus uptakes decreased under D, but distribution proportion changed little. Compared with CK, both nitrogen and phosphorus content of plant components of NP treatments increased. Nitrogen content of N treatment increased remarkably, but phosphorus content increased little. Nitrogen and phosphorus uptake increased with fertilizer treatments, but distribution proportion of grain decreased. Nitrogen and phosphorus uptake of different plant components lied mainly on biomass, not on nitrogen and phosphorus content. Root nitrogen and phosphorus uptake of 0-30cm soil layer were highest, and increased relatively at the fertilization layers. Nitrogen and phosphorus uptake of different plant components with fertilizer applying in the layer of 0-90cm was highest when only nitrogen applied. Nitrogen and phosphorus uptake of grain and root with fertilizer applying in the layer of 0-90cm was highest when only phosphorus or nitrogen and phosphorus applied.7. There was bigger difference between nitrogen utilization rate(NUR) and phosphorus utilization rate (PUR) of wheat of different treatments. NUR and PUR were in the range of 4.73%-41.19% and 4.11%-13.58% separately. Phosphorus agronomy efficiency (PAE) was higher than nitrogen agronomy efficiency (NAE). Compared with the water condition of 0-30cm soil-dry and 30-90cm soil-wet (D), NUR decreased by 4.87% under the water condition of 0-90cm soil-wet (W) when only nitrogen applied. But NUR increased by 6.38% when nitrogen and phosphorus mixed. There was no significant difference of PUR between W and D when only phosphorus applied, and remarkable difference when nitrogen and phosphorus mixed. PUR under W increased by 5.01% when nitrogen and phosphorus applied mixed. There was a difference of NUR and PUR between different fertilizer treatments. NUR of NP treatments was higher than N treatment under D, and NUR increased by 10.48%. But the difference of PUR between NP treatments and P treatment was only 0.58% under D. The difference of NUR and PUR was higher under W than D. NUR and PUR increased by 21.73% and 4.80% separately. It showed that better water condition of 0-30cm soil layer could improve NUR and PUR of NP treatments. NUR was highest whether nitrogen or nitrogen and phosphorus applying layer of 0-90cm under two water conditions. PUR was 8.55% when only phosphorus applying layer of 0-90cm, and it was higher than phosphorus applying in other layers. But PUR was highest when nitrogen and phosphorus applying at the same time in the layer of 0-30cm. NAE and PAE were higher under D than W when only nitrogen or phosphorus applied, but it was contrary when nitrogen and phosphorus mixed. NAE was highest when nitrogen or nitrogen and phosphorus applied in the layer of 0-90cm. PAE was highest when phosphorus applied in the layer of 0-90cm under D and nitrogen and phosphorus applied in the layer of 0-30cm under W.8. From the point of view of the effect of water and fertilizer spatial coupling on photosynthesis, chlorophyll fluorescence, root distribution, assimilation matter and nutrient distribution and nutrient efficiency, enough effective nitrogen and phosphorus supplying of 0-30cm and 0-90cm soil layer was very important to crop growth regardless of the condition of D and W. It was not only very important to increase yield and nutrient efficiency, but also advantageous to increase nitrogen and phosphorus content and transfer nutrient to grain. Practically, fertilizer should be applied in the layer of 0-30cm when mixed nitrogen and phosphorus, because NO3--N move easily in calcareous soil and phosphorus slow.更多还原