To explore the effects of crop rotation combined with reduced fertilization on crop yield and soil nutrients in the rotation system, and to optimize fertilizer application in rotation system of burclover(Medicago polymorpha)-rice(Oryza sativa),this study adopted the double-factor completely randomized design, and set up five treatments, including "continuous cropping rice(high fertilizer)" "burclover(no fertilizer) + rice(middle fertilizer)" "burclover(fertilizer) + rice(middle fertilizer)" "burclover(no fertilizer) + rice(low fertilizer)",and "burclover(fertilizer) + rice(low fertilizer)". The results showed that there were significant differences in yield and soil nutrients with the reduced fertilizer in rotation system. The highest rice yield in the treatment of “burclover(fertilizer) + rice(low fertilizer)” was higher than the other treatments in the same year, with organic matter significantly increased by 14.81%~38.13%,soil pH reduced by 2.34%~5.03%,and soil nitrogen content significantly increased by 0.80%~35.66%(P<0.05). Thus, reducing fertilizer application in crop rotation can effectively improve yield and soil nutrients in crop rotation systems.
香蕉枯萎病在全球香蕉种植区广泛分布,给香蕉产业带来了严重打击,其防控技术研究成为香蕉生产领域关注的热点,目前的防控措施主要有种植抗病品种、化学防治、生物防治、轮作.香蕉枯萎病作为一种土传真菌病害,蕉地土壤管理贯穿整个防控过程.文章重点介绍了近年来通过向土壤施用抗菌剂、添加生物菌剂、科学施肥以及轮作对香蕉枯萎病防控效果的研究进展,以期为香蕉枯萎病综合防控的深入研究提供参考.抗菌剂多菌灵对香蕉枯萎病菌的抑制率达到82.9%,解淀粉芽孢菌将香蕉枯萎病的发病率降至15%以下,生物菌肥将香蕉枯萎病的发病率降至10%以下,香蕉与甘蔗、韭菜、辣椒轮作将香蕉枯萎病的发病率降至5%以下,四种方法对香蕉枯萎病的防控均表现出良好效果.
[目的]探究国内主栽西番莲品种的成花坐果特性及与温度、光照强度等气象因子的关系,明确其优势坐果枝蔓和节位以及影响成花坐果的关键气象因素和主要影响时段.[方法]以国内主栽西番莲品种'台农1号'为研究对象,采用单因素随机区组法,调查不同节位、不同枝蔓的花芽分化率、花芽退化率及坐果率,并分析不同生长季各级枝蔓的成花坐果特性及与温光等气象因子的相关关系.[结果](1)'台农1号'西番莲夏秋季平均花芽分化率为77.2%,平均花芽退化率为41.4%,平均坐果率为36.5%,整体表现为花芽分化多退化也多,坐果率较低.不同节位间呈现基部节位花芽分化少,端部节位花芽退化多的特征;其中,4~7节位花芽分化数较多且坐果率稳定,为优势坐果节位.二级蔓的花芽分化基数较大,且坐果数较多;基部1~3节位着生的一级蔓和二级蔓的花芽性状优于第3节位之后着生的枝蔓.(2)相关关系分析结果显示,在开花前20~35 d日最高温度和日平均温度与单株花芽分化率和花芽退化率均呈显著负相关;其次,开花当日最高温度和平均温度分别高于36.19℃和26.24℃时坐果率随温度升高而下降,且开花后5~20 d的日最高温度与一级蔓和二级蔓坐果率均呈显著负相关.进一步分析表明,花芽形成期最高温/最低温34.2/20.4℃~36.7/23.4℃条件下,不利于二级蔓和三级蔓花芽形成;而越接近花芽分化后期,日平均光照强度为4.00~4.79 klx,光照强度越大则二级蔓和三级蔓的花芽分化率和退化率越高,而低温加弱光条件下花芽分化则受到抑制.此外,日平均相对湿度与二级蔓成花坐果性状呈负相关关系.[结论]'台农1号'西番莲优势坐果节位为4~7节位,优势坐果枝蔓为二级蔓,且花前20~35 d和开花当天及花后5~20d的高温分别是限制其花芽形成和坐果的最主要气象因素.