【作者】 朱琳；

【导师】 李世清；

【作者基本信息】 西北农林科技大学 ， 植物营养学， 2009， 硕士

【摘要】 玉米（Zea mays）是黄土高原主要粮食作物之一。因玉米光合效率高,生长期与降水季节分布吻合性好;同时该区光照充足,热量适中,大气湿度低,昼夜温差大,呼吸损失少,有利于光合产物积累,其高产稳产性优于小麦和糜谷,玉米实际单产平均4800 kg.hm^-2左右,居于黄土高原禾谷类作物单产之首。但目前实际产量与潜力产量仍然存在较大差距,问题之一是缺乏适宜于本区的高产栽培体系及对不同栽培体系玉米养分吸收利用及管理的认识。本试验以黄土高原春玉米单作体系为对象,以理解不同栽培模式春玉米对养分吸收、累积及转运规律为重点,通过田间实验,不同栽培模式对春玉米对养分累积及养分效率的影响。研究结果对基于春玉米需肥规律,在设计高产栽培模式中,充分考虑养分管理,从而显著提高春玉米养分效率具有一定科学及应用价值。研究获得以下主要结论:1.不同栽培处理春玉米冠层生物量及籽粒产量显著不同,表现为补充灌溉>地膜覆盖>雨养>秸秆覆盖。方差分析表明,补充灌溉及地膜覆盖总生物量和籽粒产量均显著高于雨养处理,补充灌溉与地膜覆盖处理间差异不显著。说明在黄土旱塬地区,通过补充灌溉或者地膜覆盖能显著提高玉米产量。秸秆覆盖由于降低了土壤温度,对玉米生长并没有起到明显促进作用。2.土壤剖面NO₃^--N累积量虽然因栽培模式不同有所差异,但远不及随生育期变化显著,说明玉米对土壤NO₃^--N的吸收利用是控制玉米生长期土壤剖面NO₃^--N累积量变化的主要因子。与其它几种栽培模式相比,地膜覆盖由于对土壤水分,特别是对土壤温度的增加效应,在一定程度上可提高土壤剖面NO₃^--N累积量。由于玉米播种时施用基肥和种肥,且玉米苗期对土壤氮素消耗有限,因而土壤剖面NO₃^--N累积在玉米V6期仍然较高;尽管在拔节和抽雄期追施氮肥,但由于7⁹月玉米旺盛生长及对氮素的大量吸收利用,土壤剖面中NO₃^--N累积在V6～R2期急剧下降;从R2到R6,由于玉米对养分吸收逐渐减弱,由于土壤有机氮的矿化作用,土壤NO₃^--N累积量呈一定程度上升趋势。3.玉米不同器官养分含量及累积量显著不同,各官养分含量主要受生育期及品种控制,而累积量同时受栽培模式及生育期影响。从冠层不同器官养分累积量分配看,地膜覆盖及补充灌溉有利于促进养分,特别是氮、磷养分在籽粒中的累积,这显然与这两种栽培模式有利于促进氮磷从营养体向籽粒转移及有利于增加籽粒产量有关。在玉米营养生长期,叶片全氮含量较高,且比较稳定;R2～R6期,叶片全氮含量出现显著下降趋势。茎秆中氮含量以V12期最高,随生长发育显著降低。春玉米冠层氮素累积趋势与生物量累积基本一致。不同栽培模式氮素累积量显著不同,表现为补充灌溉>地膜覆盖>雨养>秸秆覆盖。不同栽培模式显著影响R6期籽粒中氮素含量,地膜覆盖及补充灌溉,特别是地膜覆盖,有利于增加籽粒氮素含量。从V6到V12期各栽培处理叶片磷含量表现为明显下降趋势,而V12到VT期表现为增加趋势,其中雨养处理增幅最为明显;从VT期至R2期变化不明显;从R2期开始到R6期,4种栽培处理均呈大幅下降趋势。随玉米生长发育,茎秆中磷含量均呈下降趋势。各栽培处理冠层磷素累积随生育期推进总体呈增加趋势,至成熟期累积量最大。茎叶中钾含量变化相似,但茎干中钾含量明显高于叶片,且各栽培处理间差异不大。春玉米植株钾积累量随生育期推进而增加,春玉米钾素在VT期以前分配到叶片和茎秆中较多,抽雄期后,钾素分配到茎秆中较多。各营养器官中氮、磷最终绝大部分转移到籽粒,在R6期籽粒中所占比例很高,而钾素最终大部分转移到茎秆中,其所占比例较高。4.栽培模式显著影响养分效率,对不同养分效率指标的影响有所不同,并且其影响程度与品种有关。不同栽培模式显著影响养分收获指数。地膜覆盖处理氮素收获指数先玉335和沈单10分别达0.684和0.661,显著高于雨养和秸秆覆盖栽培模式,表明在旱地玉米生产中,地膜覆盖可促进玉米营养器官氮素向籽粒转移;地膜覆盖后磷收获指数也有一定程度增加,与雨养栽培相比,先玉335及沈单10号地膜覆盖栽培磷收获指数有一定程度增加。地膜覆盖及补充灌溉对钾收获指数间基本没有差异。栽培模式对沈单10号养分生产效率的影响较对先玉335的影响突出。先玉335雨养栽培磷素生产效率显著高于其它栽培模式,氮、磷、钾养分生产效率在不同栽培模式间基本没有差异;但地膜覆盖栽培沈单10可显著增加氮、磷、钾养分生产效率,说明地膜覆盖有利于促进沈单10号吸收的养分转化为生物量。5.从提高养分效率及产量角度考虑,补充灌溉和地膜覆盖是较理想的黄土高原旱地玉米种植模式,但考虑到该地区水资源缺乏,地膜覆盖仍然是最佳的春玉米种植方式。更多还原

【Abstract】 Maize is a major grain crop on the Loess Plateau. It yields much more and with high stability than other major crops such as wheat and Mi which probably attributes to its high photosynthesis efficiency as well as accumulation of photosyntherate. The average yield is 4800 kg.hm-2; and can maintain the Despite the availability of modern hybrids and better agronomic practices, there existed large gaps between attainable yield of maize grown with recommended practices and potential productivity on the Loess Plateau. A field experiment was conducted for 2 years in Changwu, Shaanxi (35.2°N and 107.8°E). The field cultivation practices tested were: supplementary irrigating (SI), rain-fed (RF), plastic film mulching (FM), corn straw mulching (SM). The objective of this study were: (i) to validate of the Hybrid-Maize model in the maize production system and simulate the potential productivity of maize on the Loess Plateau, (ii) to determine the most important management yield-limiting factor(s) on maize grain production. The main results were showed as follow:1. Plant biomass and yield formation of spring maize differed notably according to cultivation practices. Both shoot biomass and grain yield were significantly higher in supplementary irrigation and film mulching treatments than those in rain-fed treatment; there was no significant difference between those in two former treatments. However, straw mulching decreased the crop grain yield, likely because of reduction of the soil temperature.2. Accumulation of nitrate nitrogen in the soil profile varied according to the cultivation practices, though even more dramatically among plant growth stages, indicating dominant effect of nitrogen absorption by the plants with the growth process. Film mulching improved the soil moisture and especially thermal conditions, and hence promoted the accumulation of nitrate nitrogen. Nitrate nitrogen in the soil profile maintained at high level at the crop growth stage R6, likely because of the low rate of absorption of the base and seed fertilizer by the crop seedlings. However, nitrate nitrogen was decreased remarkably from V6 to R2 stage when the vigorously growing plants consumed large amount of nitrogen in spite of the additional manure applications at V10 and VT stages. And then it accumulated gradually in the soil profile at the late grow stages, e.g. from R2 to R6, likely because of slow nitrogen absorption by the plant and mineralization organic nitrogenous in the soil.3. Nutrient content and accumulation in plant organs were significantly different from each other. The content was affected by plant growth stage and crop variety, while the accumulation differed according to practices patterns as well as plant growth stages. Nutrient accumulation, especially for N and P, in the grain seeds were increased in film mulching and supplementary irrigation, indicating a promotion of nutrient transportation from vegetative organs to the seeds.Total N content in leaf was stable and rather higher at vegetative stage than the others; and it was significantly decreased from R2 to R6. In the stem, N content peaked at growth stage V12, and declined dramatically after that. Shoot N accumulation was in consistent with the dry matter evolving. Plant N accumulation in different cultivation practices varied, ranked as follows: supplementary irrigation > film mulching > rain-fed > straw mulching. Irrigation, especially mulching increased the N content in the grain seed compared to rain-fed treatment. P content in leaf declined notably from the crop growth stage V6 to V12, increased from V12 to VT especially in the rain-fed treatment, changed rarely from VT to R3, and then declined dramatically until physiological mature. In the stem, P content was decreased with the crop growth progress under all the practice patterns. On the contrary, shoot P accumulation increased with the plant growing and peaked at the R6 stage.Patterns of K content in different growth stages were similar in the leaf and stem. And, K content was significantly higher in the stem than in the leaf, however no such difference was observed among the cultivation practices. K accumulation in the crop plants increased with plant growth process; distribution of K was rather more in the leaf than the stem at stages before VT, while it was right reversed that after.Both N and P in the vegetative organs was finally mobilized to the grain seeds, making the highest P content in it at the R6 stage. While K was transported to the stem in which the content was highest at R6 stage4. Nutrient use efficiencies varied significantly among cultivation practices, and the variance was also different according to crop variety. N harvest index was significantly higher in film mulching (0.0684 for maize variety Pioneer 335 and 0.6661 for variety Shendan 10) than in rain-fed and straw mulching treatment, indicating the improvement of N transportation from vegetative organs to the economic grain yield. Similarly, film mulching also enhanced the P harvest index in both the varieties compared to the rain-fed treatment. However, K harvest index was rather stable among all of the practices treatment.Effect of cultivation practices on the nutrient productive efficiency was much more notable in variety Xianyu 10 than Pioneer 335. P productivity efficiency was significantly higher in the rain-fed treatment than the others for maize variety Pioneer 335, while the productivity efficiency of both N and K was quite the same among all the treatment. However, in variety Shendan 10, N, P, K productivity efficiencies were significantly increased compared to the rain-fed treatment, indicating enhancement of convention of plant absorbed nutrient into plant biomass dry matter.5. These results show that both supplementary irrigation and film mulching practices were benefit for high yield in spring maize on the Loess Plateau. However, film mulching would be preferred with the consideration of shortage of available water resource in the area.更多还原