Technology Of Phosphate And Potassium Annual Operation In Wheat-rice Rotation Under High Yield Condition

In the form of a field experiment, a wheat-rice rotation was conducted to study how to use limited P and K fertilizer most efficiently in one year, in sandy and black soil,and the tested crops were wheat and rice. The effect of different ratios of P,K fertilizer distributed to wheat and rice in one year on the yield component factors,yield,nutriment aborption, nutriment production efficiency and nutrient balance was determined on the premise that the total sum of P（K） fertilizer during the cycle of the rotation kept invariable.Concludingly,it would provide basis for setting up agreeable P,K distribution techonology and sustaining high yiled,steady yield and low nutrition consumption for wheat and rice.The study on wheat and rice biomass and economic yields showed that:crops biomass and economic yields could be raised by increasing propotions of P applied to wheat and K applied to rice.Aboveground biomass was gradually rising and that of both wheat and rice increased remakably between jointing stage and booting stage.During rotation, the treatment with the highest biomass of wheat and rice in maturity was T5（ratio of P,K allocation in wheat-crop:70％-30％ratio of P,K allocation in rice-crop:30％-70％）, and that with the lowest biomass was T2（no P in wheat-crop no K in rice-crop）.The average biomass of all wheat–crops and rice-crops in mature stage was respectively12907.2kg hm^-2,23329.5kg hm^-2. In wintering stage, jointing stage and booting stage, the wheat biomass of T5was almost the highest,and that of T2was quite low.For wheat and rice economic yields of single season and the total crop yield of the whole cycle of rotation,T5was averagely beyond the other treatments and T2was averagely the lowest treatment.The average yield of rotation cycles of T5was15386.9kg hm^-2,3percent higher than T1（P,K equally distributed to wheat and rice）. The average yield of rotation cycles of T2was14172.4kg hm^-2,5.3percent lower than T1. The wheat and rice average yields of single season and the average yield of the whole rotation cycle of T4（ratio of P,K allocation in wheat-crop:30％-70％ratio of P,K allocation in rice-crop:70％-30％） were0.5percent higher than T1,2.6percent lower than T1and4.4percent lower than T1.Based on significant difference analysis,correlation analysis and path analysis of wheat,rice yield component factors,raising the proportion of P fertilizer applied to wheat helped to increase wheat effective ears numbers. Wheat effective ears numbers and weights of1000grains were both correlated positively strikingly with wheat yields,and weights of1000grains were also correlated positively significantly with effective ears numbers.The coefficient of direct effect of wheat effective ears on wheat yields was0.848.The coefficient of indirect effect of weights of1000grains through effective ears numbers on wheat yields was0.332. Raising the proportion of K fertilizer applied to rice helped to increase rice kernel numbers. Rice weights of1000grains and yields had extremely remakeable correlation,meanwhile kernel numbers and weights of1000grains had significant correlation. The coefficient of direct effect of rice effective ears on rice yields was1.060. The coefficient of indirect effect of kernel numbers through weights of1000grains on rice yields was0.590.The study on nutrient content and nutrient aborption of wheat（reaped in2010） and rice（reaped in2009） showed that:during wheat and rice growing,crops nutrient content generally descended and accumulative nutrient aborption generally ascended. The treatment with the highest wheat accumulative N,P,K aborption in maturity was T5（ratio of P,K allocation in wheat-crop:70％-30％）,and its N,P,K aborption amounts were respectively200.77kg hm^-2、22.51kg hm^-2、71.05kg hm^-2. The key stage of wheat accumulative N,P,K aborption was the same,and it was between the jointing stage and booting stage.In the course of this stage,the proportions of wheat N,P,K aborption in total accumulative N,P,K aborption were respectively21.7％～43.5％、22.3％～52.4％、14.5％～40.8％. Between the booting stage and mature stage,a section of plant K discharged from wheat.The amounts of wheat nutrient aborption in each growing stage had no significant relation to fertilizer proportin. Except rice accumulative P,K aborption in booting stage, the treatment with the highest rice accumulative N,P,K aborption in maturity was still T5（ratio of P,K allocation in wheat-crop:70％-30％）. The key stage of rice accumulative N,P,K aborption was as well between the jointing stage and booting stage,and the proportions of rice N,P,K aborption in total accumulative N,P,K aborption were respectively21.7％～43.5％、22.3％～52.4％、14.5％～40.8％.The study of the total nutrient aborption demanded by crops producing100kg seeds and nutrient production efficiency revealed that: The treatment with the highest N aborption needed when producing100kg wheat or rice seeds was T2（no P in wheat-crops no K in rice-crops）.Its N production efficiency was correspondingly the lowest,and the average N production efficiency of wheat-crops and rice-crops was respectively29.97kg kg^-1、31.15kg kg^-1. The treatment with the highest P aborption needed when producing100kg wheat seeds was T3（ratio of P,K allocation in wheat-crop:100％-0％）.T2was also the highest K aborption needed when producing 100kg wheat seeds.The wheat P,K production efficiency of T5was the highest,but its N production efficiency was fairly low.In rice-crops,T5had low P,K production efficiency,but high N production efficiency.The study of nutrition balance during rotation cycleⅠrevealed that: After one rotation cycle, soil N and K losses occurred in the treatments T1^T5and the amounts were respectively17～73kg/hm²，234～273kg/hm². Soil P was something of surplus and its surplus was26～34kg/hm². Soil N and K losses of T5were the most serious,and its P surplus was the lowest. Soil N loss of T2（no P in wheat-crops） and T3（no P in rice-crops） were both at the medium level,and their soil K loss were both low. P surplus of T2was high,but that of T3was at a low level. Soil N loss of T1（P,K equally distributed to wheat and rice） was the lowest,and its P surplus and K loss was respectively the most and fairly low.The study on on crops economical benefits in rotation cycle Ⅰ showed that,wheat gains,rice gains and the total cycle gains of T5were all the highest,and they were respectively14042.6yuan、23877.4yuan�'�37920yuan.In addition, wheat,rice and the total cycle VCRs were as well the highest, and they were respectively13.0、16.9、15.2.Adopting T5（ratio of P,K allocation in wheat-crop:70％-30％）,peasant annual earnings would be1545yuan/hm²higher than T1（P,K equally distributed to wheat and rice）.