| Rice straw is an important renewable organic fertilizer.Reduction of fertilizer by rice straw returning is an important measure to achieve zero growth of total fertilizer in china.In order to fair use straw resources,to explore the effects of the different ways of rice straw returning on the growth of double cropping rice and physical and chemical properties of soil.Under the conditions of the same amount nutrient of nitrogen,phosphorus and potassium input,carried out 7years of location experiment,we studied the influence of straw returning full amount(SI+NPK),straw returning all burning ash(SB+NPK)and fertilization of chemical fertilizer(NPK)on double season rice yield,Plant C,N,P,K,Si nutritional properties and physical and chemical properties of soil.The main study results are as follows:1.Effects of rice straw different Incorporation ways on double cropping rice material productionUnder the conditions of the same amount nutrient of nitrogen,phosphorus and potassium input,the average of seven years′s early rice yield of SI+NPK was higher than that of SB+NPK、NPK by 2.75% and 5.97%,and the annual yield of early rice′tendency was straw returning higher than burning ash,burning ash than single N fertilization。The part of year′difference were significant。The yield of late rice,three conducts are high and low in these years,the average of seven years′s yield was basically equal。The average of seven years′s yield data shows,SI+NPK ′early rice of the effective panicle number and grains per panicle per unit area were higher than SB+NPK and NPK,higher than NPK by 0.66% 、 3.70%;Straw returning can increase the yield 。SI+NPK′late rice of the effective panicle number per unit area was significantly lower than NPK,decreasing amplitude was 5.54%,but grains per panicle was higher than it,increase by 6.95%;So Straw returning can′t reduce the yield of late rice 。 Correlation analysis indicated that,effect panicle number,grains per panicle were positive correlation with the yield,the early rice′correlation index were 0.996**、0.998**,the late rice′correlation index were all the same were 0.979*。In general,under the conditions of the same amount nutrient of nitrogen,phosphorus and potassium input,straw returning and added chemical fertilizer with it can increase the yield,keep the higher yield of late rice。With the same amount of N、P、K added,compared with NPK,SI + NPK can strong the dry matter production capacity of rice in the medium,thus can increase the dry matter of early rice,increased by 4.01%;The dry matter production capacity of late rice in the early stage were weakened,to the disadvantage of the late rice′accumulation of dry matter,decreasing amplitude was 5.13%;And SI + NPK can significantly improve the dry matter output rate and apparent transformation rate of stem and leaf,which was beneficial to thetransport of carbohydrate in stem and leaf,it also increase the photosynthetic product yield contribution。2.Effects of different methods of rice straw on the nutritional characteristics of double cropping riceCompared with NPK,SI+NPK reduced the treatment reduced the nitrogen content of vegetative organs at the tillering stage,maturing stage of early rice and the tillering stage,ear differentiation stage and ripening stage of late rice,and increased the nitrogen content of vegetative organs at early heading stage of early and heading stage of late rice;These promote the nitrogen in the vegetative organs was transported to the grain,improve the nitrogen use efficiency of early rice.SI+NPK can promote the transfer of phosphorus nutrition to grain in the stem and leaf organs of early rice,which is helpful to improve the phosphorus content in the middle and later periods of late rice。SI+NPK could replace the potassium which in the fertilizer to keep the potassium′content and accumulation of early rice,and improve the potassium content and accumulation of late rice in later period。Compared with NPK,SI+NPK、SB+NPK all improve the content of silicon in rice and the accumulation of every growth stages。SI+NPK could improve the apparent net carbon sequestration of early rice,compared with NPK,it increased 8.15%,increase the organic carbon content in the late maturing stage and the carbon accumulation in the middle and later periods。3.Effects of different methods of rice straw on soil physical and chemical propertiesCompared with SB+NPK and NPK,SI+NPK can significantly reduce soil bulk density,increase soil total porosity,porosity,field water holding capacity and maximum water holding capacity,balance soil water and gas conditions。SI+NPK could slow the soil acidification,compared with NPK,its PH was increased by 0.1;improve the soil organic matter,total nitrogen,effective silicon content to improve soil fertility。For the soil carbon fixation and rate,SI+NPK was higher than NPK、SB+NPK,Straw returning has a greater advantage in the carbon sequestration。... |
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