稻田复种轮作系统能流物流特征研究

稻田复种轮作是循环农业发展的重要措施,能量转化与物质循环是生态系统的基本功能之一,是农田生态系统最主要的研究内容之一。为探明稻田复种轮作这一耕作制度的优势,采用田间定位试验的方法,对稻田生态系统连作处理方式和轮作处理方式的能流与物流特征进行比较分析。研究结果表明:稻田复种轮作系统能提高农田生态系统的能量流动与物质循环。在能量流动方面,稻田轮作处理平均总初级生产力为74.37×1010 J-hm-2,比连作处理高31.35%;轮作系统能量总投入平均为9.42×1010 J-hm-2,比连作处理高4.90%;轮作系统的光能利用率平均为1.55%,比连作处理高31.36%;轮作处理辅助能量产投比平均为7.89,比连作处理高25.04%。在物质循环方面,轮作处理的N、P、K养分利用率明显高于连作处理,各个处理的N、P输出/输入均小于1,说明农田生态系统中N素、P素均有盈余,呈正平衡状态,有利于土壤N素、P素的良性循环;但是系统中K素的输入值小于系统内K素的输出,说明系统内存在严重的K素亏损。因此,在南方稻区,采用稻田复种轮作方式有利于提高系统的能流物流,从而使农田生态系统处于良性循环,对循环农业发展有良好的促进作用。

Characteristics of energy-nutrient flow of multiple cropping rotation systems in paddy field

Multiple cropping rotation system has been an important measure for development of recycling agriculture management. Energy conversion and material recycling have constituted the basic functions of ecosystems and the most important researches on farmland ecosystems. In order to investigate the advantages of multiple cropping rotation farming systems, a field experiment was carried out to analyze the characteristics of energy conversion and material recycling in continuous cropping and crop rotation systems in paddy ecosystems in Nanchang, Jiangxi Province. The results showed that multiple cropping rotation system improved energy conversion and material recycling in paddy ecosystems. In terms of energy conversion, average gross primary productivity, total energy investment, solar energy utilization and auxiliary energy output-input ratio of multiple cropping rotation treatments were respectively 31.35%, 4.90%, 31.36% and 25.04% higher than those of continuous cropping system. In terms of material recycling, K nutrient utilization was significantly higher than continuous cropping. N and P output/input of every treatment was less than 1, showing that N and P maintained a positive balance in paddy ecosystems. However, the smaller K input than output in paddy systems showed serious loss of K in the system. Thus multiple cropping rotation system improved energy conversion and material recycling in rice cultivation regions in South China. Multiple cropping rotation system not only induced a state of virtuous cycle in farmland ecosystems, also promoted the development of circular agriculture.