Effects Of Different Mulching Methods On Growth And Nutrient Absorption Of Rice And Barley Plants

Pot experiments were conducted by with the soil from a long-term different aerobic rice cultivation experimental station to study soil available nutrient,crop growth,nutrient absorption and nutrient use efficiency under different cultivation conditions in rice-barley rotation system from 2005 to 2007.In order to provide a theoretical basis for further popularization of rice aerobic cultivation,the effects of different N forms on rice growth, nutrient absorption,nitrogen use efficiency,and soil fertility status under non-flooded cultivation were studied as well.1.According to mensurating soil available nutrient content,the results showed that:(1) different rice cultivation modes significantly affected soil nitrogen form in rice season,soil NH₄⁺ content in waterlogged cultivation treatment(W) was higher than in aerobic cultivation at all rice growth stages;(2) in barley reason,different cultivation modes had no effects on NH₄⁺ content in soil;NO₃^--N content in WB(barley cultivated after water-logged rice) was the lowest during the whole growth stage,and NO₃^--N content in BB(barley cultivated after rice bare),PFB(Barley cultivated after rice covered with plastic film) and SMB(Barley cultivated after rice covered with straw mulching) was 5.26%,4.23%and 18.04%higher than that in WB, respectively,at the tillering stage;(3) in rice season,soil available P content in W treatment was the highest during the whole growth stage.There were no significant differences among all four treatments;(4) at the whole rice-barley stage,soil available K content was the highest in SMB treatment and the lowest in WB treatment.2.Waterlogged cultivation(W) was beneficial to rice growth,and its yields were 26-47% and 7-31%higher than aerobic cultivation treatment in 2006 and 2007,respectively.The yield composition factors of waterlogged cultivation(W) were better than those of aerobic cultivation,with higher grains per spike,seed bearing rate and thousand seed weight.There were no significant differences in rice yield between SM and W treatment.Aerobic rice cultivations were beneficial to the aftercrop barley growth,and its barley yields were 5～17% and 12～29%higher than W treatment in 2005 and 2006,respectively;The yield composition factors of barley cultivated after rice cultivated in aerobic soil were better than those of waterlogged cultivation(WB).In all aerobic rice cultivation treatments,tiUering occurred before winter in SMB treatment earlier than others,with higher grains per spike and thousand seed weight.3.N,P and K accumulation in W were the highest at whole rice growth stage,and N accumulation at maturing stage were 22.59%,18.79%and 42.48%higher than in aerobic cultivation rice straw mulching covered(SM),aerobic cultivation with plast film mulching covered(PF) and aerobic cultivation with without any mulching(B),respectively.Compared to other treatments,above-ground N accumulation in SMB was the highest at the whole growth stage,and P and K accumulation at tillering stage.In rice growth season,N accumulation and NT in W were the highest at later stage,while NTE was the highest occurred in SM;In barley season,NT and NTE were the highest in SMB,and the lowest in WB;(4) NPE,NUPE and NUTE in rice season were the highest occured in W,but NHI was the highest occured in SMB; NPE,NUPE and NHI in barley season were the highest occured in SMB,and the lowest occured in WB.4.In order to study the effects of different N forms(ammonium,as A;nitrate,as N; ammonium and nitrification inhibitor,as A+DCD) on growth and nutrient absorption of rice plants under non-flooded cultivation at tillering and booting stage,a pot experiment with different form N fertilization was conducted in green house.The results showed that:(1) At tillering and booting stage,biomass,number of tillers and area of newly expanded leaves of rice plants under A and A+DCD treatments were higher than that under N treatment;(2) The highest net photosynthetic rate occurred in rice plants under A+DCD treatment,and the lowest net photosynthetic rate occurred in rice plants under N treatment;(3) Proportion of potassium distributing in leaves of rice plants under A and A+DCD treatments was higher than that under N treatment,while proportion of potassium distributing in stems of rice plants under N treatments was higher.