密度和有机肥对苏北滩涂蓖麻群体生长及产量构成的影响

本研究于2013-2015年连续3年在江苏省大丰市金海农场沿海滩涂试验基地进行蓖麻种植密度和有机肥试验,探讨江苏沿海滩涂连续有机肥施用和种植密度对蓖麻群体生长和产量构成的影响。试验设高(18 000株·hm~(-2))、中(15 000株·hm~(-2))、低(12 000株·hm~(-2))3个种植密度与3个有机肥施肥水平(12 000 kg·hm~(-2)、6 000株·hm~(-2)和0 kg·hm~(-2))的田间小区互作试验。在蓖麻各生育期调查地上部干物质积累及其分配、叶面积指数、功能叶叶绿素含量、穗部性状及籽粒产量等指标。研究结果表明,连续3年施用有机肥可明显改善土壤养分状况,中密度下施用12 000 kg·hm~(-2)有机肥使开花期土壤全氮、有效磷、有效钾和有机质含量比不施有机肥处理分别升高47.37%、169.21%、54.65%和13.77%,达到显著水平(P0.05)。有机肥施用增加了中、低密度下蓖麻生长后期叶面积指数与功能叶叶绿素含量,对群体生长率产生了一定的促进作用,使得中密度群体地上部干物质积累量达到高密度水平。中密度群体增施有机肥还促进了干物质在花后生殖器官中所占比重,且单株有效穗数、单株粒数和百粒重随着有机肥施用量的增加而增加,有效补偿了密度降低带来的蓖麻群体产量降低,最终中密度处理下施用12 000 kg·hm~(-2)有机肥蓖麻获得最高产量(3 943.77 kg·hm~(-2)),与高密度群体差异不显著(P0.05)。由此可见,通过适当降低种植密度并增施有机肥能够有效合理地调控蓖麻群体生长,促进干物质的合理分配和转移,实现了保穗增重增产的目的。

Effect of organic fertilizer on growth and yield components of castor under different planting densities

A 3-year field experiment was conducted from 2013 to 2015 during summer castor growing seasons at the coastland of Jiangsu Province. The aim of the experiment was to analyse the effects of organic fertilizer and planting densities on popu-lation growth and yield components of castor. The interactive test of three planting densities 18000 plant·hm-2(D1), 15000 plant·hm-2(D2) and 12000 plant·hm-2(D3)] and three organic fertilizer application rates 12000 kg·hm-2(O1), 6000 kg·hm-2 (O2) and 0 kg·hm-2(O3)] were conducted with a castor cultivar of 'Zibi 8' as tested material. The investigated items included dry matter accumulation and distribution, leaf area index, chlorophyll content, spike characters and yield components. The results showed that the soil fertility could be improved significantly by using organic fertilizer for three years. With the appli-cation of organic fertilizer of 12000 kg·hm-2 under planting density of 15000 plant·hm-2(D2O1), the contents of soil total nitrogen, available phosphorus, available potassium and organic matter significantly increased by 47.37％, 169.21％, 54.65％ and 13.77％ respectively compared with that without organic fertilizer treatment (D2O3). Both leaf area index (LAI) and rela-tive content of chlorophyll at the late growth stage was maintained at a high level under planting densities of 15000 plant·hm-2 and 12000 plant·hm-2 with the application of organic fertilizer. Total dry matter production at filling and ripening stages under medium planting density (15000 plant·hm-2) plus 12000 kg·hm-2 organic fertilizer (D2O1) significantly improved to almost similar level to that under high planting density of 18000 plant·hm-2(D1O1). In addition, the distribution of dry matter in spike and crop growth rate (CGR) under planting density of 15000 plant·hm-2both improved after anthesis with the applica-tion of organic fertilizer. The effective panicles per plant, grain number per plant and 100-grain weight increased with the in-creased rate of organic fertilizer application, which effectively compensated for low spike number at lower planting density. In this study, the crop yield under medium density (15000 plant·hm-2) with 12000 kg·hm-2 organic fertilizer (D2O1) was 3943.77 kg·hm-2, which was similar to that under high planting density (D1O1). It was concluded that suitable planting den-sity in combination with the application of organic fertilizer effectively improved population growth and the reasonable dis-tribution of dry matter, delayed leaf senescence, increased dry matter accumulation and grain yield at mature stage of caster.