施肥覆膜对旱地小麦产量形成及土壤有机碳组分的影响

Effects of fertilization and plastic film mulching on yield formation and soil carbon pool of dry land wheat

针对黄土高原旱地小麦化肥投入过量且养分供应不平衡问题,有必要探究当地冬小麦典型覆膜种植方式下监控定量施肥的增产效应及对土壤有机碳组分的影响.于2012-2016年通过大田试验,研究农户模式(FP)、监控施肥(MF)、垄膜沟播+监控施肥(RF)、全膜覆土穴播+监控施肥(FH)4种栽培模式对旱地冬小麦群体动态变化、干物质积累、产量形成及土壤有机碳组分的影响.结果显示:FH处理可显著改善旱地冬小麦的群体结构,基本苗、最大分蘖数和成穗数较传统农户模式分别提高24.8%、24.6%和31.3%(P <0.05),其干物质积累量增加主要在生育后期,成熟期干物质量较农户模式平均提高43.3%.不同处理籽粒产量与公顷穗数、千粒重均呈极显著正相关,相关系数分别为0.810^**、0.80^**,其中FH处理具有最高的公顷穗数和千粒重,较FP处理分别高36.7%和4.8%,进而籽粒产量提高了42.1%.连续4年监控施肥结合覆膜种植较农户模式可显著提高土壤总有机碳(TOC)含量,其中垄膜沟播种植更有利于土壤轻组有机碳(LFOC)活性组分的增加,而全膜覆土穴播则更有利于土壤重组有机碳(HFOC)稳定性组分的增加.覆膜种植较监控施肥处理总体上可显著提高颗粒态有机碳(POC)的含量,但不同处理间水溶性有机碳(SWOC)含量差异不显著.总体上,全膜覆土穴播结合监控施肥可以更好地构建小麦群体结构,提高干物质积累量和籽粒产量的形成,并且可通过增加生物还田量提高土壤稳定性有机碳及总有机碳的增加,更适合黄土高原旱地冬小麦高产高效生产及土壤质量的提升.

The goal of this study was to overcome the problems of excessive fertilizer input and nutrient supply imbalance in dryland wheat production of the Loess Plateau. The effects quantitative fertilization of wheat yield and the soil carbon pool needs to be studied under typical mulching modes. Through field experiments, variation in population dynamics, dry matter accumulation, yield formation, and changes in soil organic carbon of dry land winter wheat were studied in four modes: farmer practice(FP), monitored fertilization(MF), ridge-furrow with plastic film mulching system(RF), and flat soil surface with plastic film mulching and hole sowing(FH) from 2012 to 2016. The results showed that FH treatment significantly improved the population structure of wheat. Compared with FP treatment, the number of basic seedlings, maximum tillers and the spike of FH treatment increased by 24.8%, 24.6% and 31.3%(P< 0.05), respectively. The increase of dry matter accumulation was mainly reflected in the late growth stage, and the dry matter quality at maturity increased by an average of 43.3% compared with that of the farmer practice. The grain yield of different treatments was significantly positively correlated with the spike number and 1 000-grain weight, with the correlation coefficients of 0.810^** and 0.80^**. The FH treatment had the highest number of spikes and 1 000-grain weight, which was 36.7% and 4.8% higher than that of the FP treatment, respectively, and the grain yield increased by 42.1%. Monitoring fertilization combined with mulching could significantly increase soil total organic carbon(TOC) content compared with the FP treatment. The RF treatment was more beneficial to the increase of light organic carbon(LFOC) in soil organic carbon active components, whereas FH treatment was more beneficial to the increase of recombinant organic carbon(HFOC) in soil organic carbon stability components. Compared with the MF treatment, the filmmulching planting significantly increased the content of particulate organic carbon(POC), but the difference in water-soluble organic carbon(SWOC) content in different treatments was not significant. In summary, the monitored fertilization combined flat soil surface with plastic film mulching and hole sowing could better construct the wheat population structure, increase the dry matter accumulation and grain yield, and increase the soil stable organic carbon and total organic carbon by increasing the amount of biological return, which is more suitable for high-yield and high-efficiency production and soil quality improvement of winter wheat in the dryland of the Loess Plateau.