作物栽培科学的新发展——从作物化控到物化栽培工程

本文概述了作物化控的兴起、发展动态和大田作物化控的成就与局限性 ;分析了作物物化栽培产生的背景、意义及研究方向 。

农作物化控栽培工程技术的发展与中国农业现代化前景

人均耕地不足是我国种植业最根本的资源制约,农业技术的最大课题就是寻求耕地不足的技术替代。化控栽培工程是化控措施与传统技术相互配合而诱变出的新的技术组合,对作物生长发育可以进行外部条件加内部激素水平的双重调控,从而为农业栽培展示了夺取更高单产的极大可能。80年代以来,我国在农作物化学控制工程技术研究和应用领域已取得多项进展。本文讨论了化控在修饰良种、革新传统栽培技术和建立定向诱导的模式栽培等方面的意义,指出化控栽培工程在实现多熟复种制的高产稳产上具有不可替代的重要功能。并提出了加强作物化控栽培的理论与方法研究的必要性及其要点。

Soil Biological Changes for a Natural Forest and Two Plantations in Subtropical China

Conversion of natural forests into pure plantation forests is a common management practice in subtropical China.To evaluate the effects of forest conversion on soil fertility, microbe numbers and enzyme activities in topsoils (0-10 cm)were quantified in two 33-year-old monoculture plantations of Castanopsis kawakamii Hayata (CK) and Cunninghamia lanceolata Lamb. (Chinese fir) (CF), and compared to a neighboring relict natural C. kawakamii forest (NF), in Sanming,Fujian. Five soil samples were collected once each in January, April, July, September and November in 2000 in each forest for laboratory analysis. Over the sampling year, there were significant differences for bacteria, fungi and actinomycetes between forests and between seasons (P ＜ 0.05). The largest bacteria and fungi populations were in NF, while CF contained the greatest number of actinomycetes. There were also significant differences (P ＜ 0.05) with microbial respiration for forests and seasons. Additionally, compared with NF, urease and acid phosphatase were significantly lower (P ＜ 0.05)in CK and CF. Also, the correlations of soil hydrolysable N and available P to soil microbial and enzymatic activities were highly significant (P ＜ 0.01). Thus, to alter the traditional Chinese fir monoculture so as to mimic the natural forest conditions, managing mixed stands of Chinese fir and broadleaf trees or conducting crop rotation of conifers and broadleaf trees as well as minimizing forest disturbances like clear-cutting, slash burning and soil preparing, could be utilized.

Historical Evolution of Mariculture in China During Past 40 Years and Its Impacts on Eco-environment

The rapid development of mariculture in China in recent decades has satisfied people's demand of seafood, and has made a great contribution to economic development. However, mariculture has also caused some negative impacts on the eco-environment. By statistically analyzing national data(as well as data for four main provinces) regarding the mariculture area and cultivation species in China since reform and opening up, the historical evolution of mariculture during the past 40 years was analyzed, the driving factors related to policy, market and technology innovation were discussed, and the potential impacts of mariculture on the coastal eco-environment were also illustrated. The statistical results indicated that the maricultural area increased radically during the past 40 years, from 1979(116.47 × 10~3 ha) to 2012(2205.65 × 10~3 ha), with an increase of nearly 20-fold. Shandong Province represented the fastest-growing region, with an increase of 31-fold. Moreover, the cultivated species had gradually become diversified. Initially, shellfish and algae were major species, and then it developed to various species including fish, and currently shellfish and crustaceans were the major species. The development of mariculture was driven by government policies, market economy and technology innovation. Rapid development of mariculture also caused significantly adverse impacts on the eco-environment of the coastal regions. For example, the sea reclamation for mariculture decreased the area and function of coastal wetlands and the contaminants originating from mariculture destroyed the coastal aquatic environment. Fortunately, the implementation of ‘13 th Five-Year Fisheries Planning' is expected to help both improve the seafood quality and reduce the contamination in coastal aquatic environment. This current study will provide reference for management and structure adjustment of mariculture in the future.

Chemical Variation in Essential Oils of Salvia Officmalis L, Ecotypes Cultivated in Albania

Salvia officinalis L. was cultivated in different geographic locations of Albania. Sage plants originated from imported seeds and wild Albanian plants. Around 30 chemical compounds were identified in the essential oils of all cultivated sage plants; the latter were found to be very rich in camphen, fl-thujone, a-pinene, eucaliptol, rich to moderate in β-pinene and camphor, and less rich in a-thujone and limonene. Sharp differences in chemical composition patterns and content of individual chemical compounds were noticed between and within cultivation sites. Cultivated sage was poorer in α-thujone versus wild plants. Cultivated sage, of Albanian wild plants origin, was the richest in α-thujone （18.45%） versus imported seeds sage. β-thujone over-dominated α-thujone in all cultivated sage plants. Volatile characters of cultivated sage were indicative of the species but not of the geographic origin of plant material. Variation in essential oils composition and chemical compounds＇ content （biosynthetic pathways） in cultivated sage is related more to the genetic background than the environmental factors. If cultivating sage in Albania, then wild local ecotypes would be best to use as α-thujone is maintained at satisfactory levels, local natural base is preserved, unnecessary hybridization with imported seeds sage is prevented, and are more resistant and cost effective.

种衣剂处理对水稻发芽率质量指标的影响研究

正 近年种子包衣作为作物物化栽培的重要手段已在我国一些主要农作物种子上推广应用。进行种子包衣,种衣剂的选用是关键。种衣剂是一类根据作物或其它植物种子、种苗的生理特性,以农药、肥料、激素等为活性成分,成膜剂、乳化剂等为非活性成分加工而成的种子处理剂。不同农作物有与之相配备的种衣剂。大田结果证明:种子包衣后,种衣剂中活性成分可促控幼苗生长,防控苗期病虫害。

Short-Term Responses of Nitrous Oxide Emissions and Concentration Profiles to Fertilization and Irrigation in Greenhouse Vegetable Cultivation

In vegetable cultivation, the majority of N2O emissions occur after fertilization; it is therefore important to understand any factors contributing to this process. An experiment was conducted to investigate short-term N2O dynamics following topdressing in a greenhouse vegetable field in South China. During two topdressing processes, three different urea-N treatments with irrigation were conducted in May and June in a tomato （Lycopersicum esculentum） cultivation. The N2O fluxes, soil concentration profiles and soil environments at the 0-60 cm depths at 10 cm intervals were measured both immediately prior to and 5 days after topdressing. The N2O fluxes before topdressing ranged from 6.7=1=2.1 to 55.0-4-28.8 μg N m-2 h-1; even higher numbers were recorded in highly fertilized plots. The NO3-N accumulation in the soil caused by vegetable cultivation during the 5 years prior to the start of the experiment, resulted in high background N2O fluxes. One day after topdressing （1 DAT） in May and June, N2O fluxes increased, which coincided with sharp increases in soil N2O concentrations at depths of 2.5 and 15 cm and in NOa-N and NH4＋-N contents at depths of 0-20 cm. From 1 to 5 DAT, fluctuations in the N2O fluxes did not harmonize with the N2O concentrations at a depth of 2.5 cm, which was attributed to different gas diffusion rates at depths of 0-10cm. These results suggested that surface soil N and environmental conditions were crucial for determining the short-term N2O ebullitions during topdressing in greenhouse vegetable cultivation.

Effect of Intensive Greenhouse Vegetable Cultivation on Selenium Availability in Soil

Soil properties dramatically change after long-term greenhouse vegetable cultivation, which further affects soil selenium （Se） nutritional status and plant Se uptake. An evaluation of Se availability after long-term greenhouse vegetable cultivation （CVC） can help in better understanding its influential factors under GVC conditions and will also facilitate further regulation of soil Se nutrition in GVC systems. Two typical GVC bases were chosen： one with clayey and acidic soil in Nanjing, southern China, and the other with sandy alkaline soil in Shouguang, northern China. Twenty-seven surface soil samples at the Nanjing base and 61 surface soil samples at the Shouguang base were collected according to cultivation duration and cultivation intensity. Soil properties including soil available Se （PO4^3--Se） and total Se （T-Se） were analyzed. The results showed that soil PO4^3--Se was significantly and negatively correlated with soil Olsen-P, available K （A-K）, and electrical conductivity （EC） at the Nanjing base. At the Shouguang base, however, no significant correlation was found between soil PO4^3--Se and Olsen-P and EC, and soil PO4^3--Se increased with increasing soil organic matter （OM）. Intensively utilized greenhouse vegetable cultivation caused significant changes in soil properties and further affected soil Se availability. Due to different management practices, the dominant factors affecting Se availability varied between the two GVC bases. At the Nanjing base, the dominant influential factor on soil Se availability was soil nutritional status, especially Olsen-P and A-K status. At the Shouguang base, where organic fertilizers were applied at high rates, soil OM was the dominant influential factor.