有机肥与覆盖方式对滩涂围垦农田水盐与作物产量的影响

Dynamics of soil water, salt and crop growth under farmyard manure and mulching in coastal tidal flat soil of northern Jiangsu Province

针对土壤盐碱障碍因子普遍存在于新围垦滩涂农田并严重抑制作物生长的问题,设置了有机肥(鸡粪堆肥)、薄膜覆盖、秸秆覆盖及有机肥+薄膜覆盖、有机肥+秸秆覆盖组合措施,研究其对土壤水盐的调控作用与对作物生长的促进效应。结果表明:各调控均有利于滩涂围垦农田土壤水盐环境的改善、作物的生长,并整体表现出组合措施优于单项措施、秸秆覆盖优于薄膜覆盖的趋势。其中,有机肥+秸秆覆盖组合措施为调控措施中的优化处理,表现在土壤含水量高、土壤电导率与pH值低,作物产量高,增产率达100%以上。单施有机肥虽能增加土壤含水量、降低土壤pH值,但其土壤电导率升高了11.56%,产生了一定的次生盐渍化风险,与覆盖措施的组合能有效控制土壤盐分的表聚,使其显著低于对照,从而保证了有机肥的持续使用。该研究表明,有机肥与覆盖传统农艺措施的有效组合可较好地调控滩涂围垦农田土壤水盐,促进作物增产,该研究为苏北滩涂新垦农田盐碱障碍因子的消减及作物增产提供了一种新途径,也为当地有机肥及秸秆资源的可持续利用提供了依据。

Soil salinity, a typical characteristic of reclaimed coastal tidal flat soil, restrains soil quality improvement and crop growth seriously in coastal area of northern Jiangsu Province. Careful soil management is important for the soil salt elimination and crop promotion. Farmyard manure （FYM） and mulch applications, which affect soil properties and plant significantly, are regarded as an effective improvement pattern of saline land. As a conventional management in the study region, FYM and mulch are used for the amendment of the new reclaimed tidal flat regularly, but little is known about their effects on crop growth and the dynamic of soil water and salt. A study was conducted on a typical coastal tidal flat saline land to evaluate the effects of FYM, polyethylene film mulch （PM）, straw mulch （SM）, FYM combined with PM （FYM ＋ PM）, FYM combined with SM （FYM ＋ SM） on soil water, soil salinity and crop growth in 2011 and 2012. CK represented no FYM and mulch application and served as a control. Dynamic of soil properties were observed, such as soil water content, electric conductivity （EC） and pH, and the growing indicators of maize and barley, including plant height, stem diameter, leaf area index, biomass and yield. The experiment, laid out in a randomized complete block design with three replications, was studied in Huanghaiyuan Farm, which specialized in the agricultural utilization for coastal tidal flat. Results of three continuous crop cultivations indicated that, soil water and salt fluctuated strongly and were affected by all of the treatments. Compared to the CK, all of the treatments increased soil water content, although with a quantitative difference. Soil salt, indicated by soil electric conductivity, was controlled well by PM and SM, with the relative decreasing percent of 23.91 %,28.57 %,70.28 % and 27.17 %,40.00 %,49.51 % respectively after the three harvest time. However, FYM and mulch had weak effects on soil pH. FYM application had a risk of secondary salinization because of the increased soil salt content caused by the high salt content of chicken manure; however, the increasing trend was controlled when FYM application was combined with mulch management. Growth of maize and barley were promoted significantly with high growth index and yield and kept in the order of FYM ＋ SM FYM ＋ PM FYM SM PM CK. It was considered that FYM＋SM was the best treatment for salinity elimination and crop promotion of the reclaimed coastal tidal flat saline land, due to the higher soil water content, lower soil electric conductivity and pH and the better plant performance under FYM＋SM. Yield of maize and barley were increased significantly by FYM＋SM more than 100 %, and reached the average yield of the desalted soil, which reclaimed for a long time in the study area. Therefore, the new cultivation pattern of FYM＋SM is recommend for soil quality and productivity improvement of the reclaimed coastal tidal flat saline land and the sustainable utilization of FYM, crop straw in the coastal area of northern Jiangsu Province.