Effects Of Rice Varieties On Different Type Soils Basic Nitrogen Supply In Paddy Soil And Its Mechanism

To elucidate the physiological basis of different types rice absorbing and using soilbasic nitrogen, choose 11 different genotype rice varieties that are extensively cultivated inJiangsu Province recent years, and research the differences of different genotype ricegrowth and yield components without nitrogen fertilizer application in different soil. Futher,using 19 different rice varieties as materials, effects of basic nitrogen(N) supply capacity ofdifferent texture soils on rice yield in Jiangsu Province were studied at 195 experimentplots in 11 counties. The main results were summarized as follows:1. The differences of different genotype rice growth and yield components withoutnitrogen fertilizer application in different soil were studied under 3 types soil in potexperiment. The results showed that different rice varieties have great difference in growthduration. The rice varieties tiller numbers of cyan mud soil was the highest in three kinds ofsoil, and that of silt was lowest. The more original soil-fertility rising, the bigger range oftiller numbers increasing.Seen from the overall, the rice varieties with long growth duration absorbs morenitrogen and accumulates more dry matters, so that its basic yield is more, variety and soilhave significantly interaction to the basic yield. From silt to yellow mud soil then to cyanmud soil, the panicle number per 667m², the grain number per panicle and total storagecapacity (grains per 667m²) are appearing rising trend along with the original soil-fertility.However, the seed setting rate and 1000 grains weight are appearing descending trend alongwith the original soil-fertility. Variety and soil have significantly interaction to the paniclenumber per 667m², the grain number per panicle and the seed setting rate; but have nointeraction to 1000 grains weight. Different rice varieties have dear difference ofaboveground total dry matters. Seen from the overall, the total dry matters appears the trendof hybrid Late Japonica＞Indica＞conventional Late Japonica＞hybrid Medium Japonica＞conventional Medium Japonica. The rice varieties growth duration positively correlatedsignificantly with its dry matter accumulation (R² of Japonica and Indica respectively are 0.5839^** and 0.6587^**). The entire growth duration positively correlated significantly withthe aboveground total plant nitrogen accumulation (R² of Japonica and Indica respectivelyare 0.5839^** and 0.6587^**).2. The effect of basic nitrogen supply capacity (BNC) of different texture soils onpotential rice yield (PRY) in Jiangsu Province were studied at 195 experiment plots in 11counties with 19 different rice varieties. Results showed that basic rice yield (BRY), whichis rice yield without nitrogen application during whole growth stage, was significantlycorrelated to PRY. BRY of clay soil was the highest in three kinds of soil, and BRY ofsandy soil was lowest. BRY was positively correlated to BNC significantly, even the vauleof BRY and BNC was widely changed with soil type. While got the same BRY, BNC ofclay soil was higher than that of loam soil and sandy soil. N requirement for 100 kg grainyield of BRY of Japonica rice was higher than that of Indica rice. BNC were linearpositively correlated with alkaline hydrolysable N in all experimental plots, but coefficientof determination(R²) is lower than 0.4000.3. Five types of rice were cultivated in three types of soils solution to investigatedifferences of response of the basic amounts of soil nitrogen supply to different rice types.Results showed that the basic amounts of soil nitrogen supply (on the average) of Indicarice was 25.6% more than that of Japonica rice. Compared with conventional indica andJaponica rice, the basic amounts of soil nitrogen supply of hybrid Indica and Japonica ricewas 19.5% and 32.5% higher. N utilization efficiency for soil (NUEs) improve significantlywith the increase of the basic soil nutrient. Gains N utilization efficiency for soil nitrogen(Ng/Ns) was highest among all types, Ng/Ns of Indica rice was higher than that of Japonicarice, but that of other types was not significantly different. The increased range of NUEsand N-requirement for 100 kg gain of Japonica rice was higher than that of Indica rice.