| Lime concretion black soil is widely distributed in low-lying areas along the HuaiRiver. The soil is easily flooded, and short of workable period, at the same time, theundeveloped agricultural machinery are also involved. All these factors result in lower cropyield and quality. Soil water logging is the most common agricultural disaster along theHuai River regions. The quantitative assessment of crops under waterlogged conditions issignificant because it helps to make corresponding management solutions in the dailyproduction practice. According to the area characteristics, this paper studies (i) the demandpattern and utility efficiency of N, P, and K by maize in different growth stages underflooded conditions;(ii) the maize response to flooding stress and quantitatively determinesthe expression and submergence tolerance threshold of maize under flooded conditions;and (iii) the effect of flooding submergence upon the nutrient absorption and output ofmaize. In order to enhance the ability of defense disasters along the Huai River inlow-lying land in the low-yield farmland. And implementation of cropland of the low yieldin corn lasts high yield ability and sustainable development. The main contents and resultsare as follows:Test was conducted in the lime concretion black soil of the Original soil column,setting six treatments, each treatment burying the corresponding root bag, and havingflooded in Six leaf stage and Huge bellbottom period, respectively. Nutrient content andbiomass of two root bags of maize stalk were measured each day during the flood, andoverall measurement was performed by uniform sampling after the flood. Besides, N, P,and K nutrient contents of the soil at the rhizosphere and root periphery were measuredevery day during the flood. Here are the conclusions:(1) Persistent flooding affects the distribution of N, P, K in soil at the rhizosphere androot periphery. For both two periods studied, the three nutrients contents in soil of theflooded area were all lower than those of control. N and K were enriched in the rhizosphere,while P was in deficit.(2) Significant impact of water-logging on maize growth was found. For the twostudied periods, biomass dropped substantially with the extension of submergence time,and the effect, according to the t-test, was significant or greatly significant. Absorption,accumulation and distribution of the nutrition elements (N, P, K) on the aerial andunderground parts of plant was severely inhibited. After removing water, the nutrient content on the aerial part of plant in different treatment was downward trended. These weremore sensitive in Six leaf stage than in Huge bellbottom period.(3) Under the waterlogged influence, for the two studied periods, the soluble sugarcontent and cumulative amount inside maize showed an upward trend. After removingwater, the maize soluble sugar content in different treatment gradually decreased.(4) Under the waterlogged condition, the Eh in the rhizosphere and root periphery isreduced, and it dropped substantially with the extension of submergence time. Significantrelationship between biomass and Eh values in the rhizosphere was observed.(5) The maize growth was significantly suppressed by water-logging with a lowerbiomass and subsequently, a decreased output. Besides, the decrease of output varied inproportion to the flooding time. Varied degree of influence was observed for differentperiods of submergence.(6) At Six leaf stage, a parabola relationship (R2=0.996**) could be fitted betweenbiomass and the flooded time. According to the equation, the time for biomass reduction tohalf of CK, i.e. submergence tolerance threshold, is three days. The result is completelyconsistent with the analysis between biomass and nitrogen content or its cumulant.Principal component analysis showed that, in five indicators of the impact of biomass,nitrogen is the major influence factor. |
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