Effect Of Long-term Fertilizer Experiment On Yield Of Wheat And Rice And On Fertility Of Purple Soil

Based on the long-term ferti1izer experiments in the national monitoring base of purple soilfertility and fertilizer benefit at Southwest Agriculture University, an investigaion had beencarried out to deal with the effects Of diffirent fertilizer treatment on wheat and rice yield, thechange of fertilizer benefit and the evolution of sqil fertility in the wheat-rice crop rotation froml 999.09 to 2000.09. The method of fieId experiment and indoor chemical anaIysis was used in theresearch. The resuIts were as follows:1. AppIying either the chemical fertifizer (N, P K) or the organic ferti1izer could 1ead to theremarkable increase of wheat yeild in 2000. The increasing yield of wl1eat were 8.6kg. l8.7kg,6.6kg per kilograrn N, P2O5. K2O. respectiveIy. Tl1ere was 20% increase of yield in the treatmentof organic fertiIizer compared to CK treatment and 10W20% increase of yieId in the treatment ofboth chemical and organic fertiIizer compared to the treatment of only chemical fertiIizer. Theincrease of wheat yie1d ranked as M+NPK>NPKvNmK>PK, the treatment of both organic andproper chemical fertilizer was the best way tbr l1igh and stable yieId of wheat in purpIe soil. TheresuIt was simiIano that in three years ago.2. The resuIt of Iocated test during l992--2000 showed that f wheat yield is lowest in thepIots of no fertilizer appIied to wheat, which account for 50% of that in the plots of applyingcompleted fertilizef, but the yearly yield kept within 1 .3-1 .4Uhm', it didn't went down as the test'sIasting. It showed that the soiI productivity of neutral purpIe soil was stabIe and lasing, but pooLNo N or P fertiIizer was applied to wheat, the wheat yield went down year by year From the sixthyear of the tesL the wheat yield was near to that in CK plotS. and ithen kept within t.4-l .5t/hm2.With the treatment of only nitrogen, its fertilizer effect decreased year by year, reduced from 9.4kgto 0.7kg; with the application of nitrogen. phosphorus and potassium fertiIizer. the effect ofnitrogen fertilizer was about 8.0kg; The fertiIizer effect of phosphonJs and potassium trended upyear by year; The fertilizer effect of phosphorus increased from 3.2kg to l8.7kg, In nearIy fiveyears. POtassium fertilizer had nothing tO do with the yield of wheat, rarely effect on increase ofrice yieId. From the sixth year of tI1e test, tl1e yieId of wheat and rice increased obviously with theapplication of potassium fertilizer, about 6.5 -- 7.4kg on wheat and 7.5 -- l 1 .0kg on rice. With theappIication of NPK+M, the wheat yieId went up to the highest. but averaged only 3.0t/I1m2. Shortof sunshine, (there were about 350 hours sunIight during the time of wheat growth) is the mainfactor of low wheat yield. So, in Chongqing area with long foggy and short sunlight, the winterpIants should be considered in .order to improve the nutrient utiliZaion efficiency and soilproductivity.3. In 2000, the use of different fertiIizer ratio led to the increasing order of rice. which wasthe same as that in yearly test resuIt; The l1ighest yieId of rice was due to the application of4colnpleted tbrtiIizer, the second was NP and NK, the third was onIy nitrogen fertiIizer's treatment,the non-use of fertilizer brought the lowest rice yield. With the method of substraction, the riceyie1d increased by l.7kg. l3.6kg. 106kg per a N.P2O5. K2O. respectively. The yieId of riceincreased by l8% with the app1ication of organic feI'ti1lzer compared to that with no fertilizerappIied to rice. The treatment of StaIks back to fields is better than that witl1 the appIication ofdung for rice yield.4. From l992 to 2000. the rice yield is greatly affected by the Climate. For example, due tothe climate was unusal in l993, the rice yield reduced to the Iowest, averaged onIy 4.0t/hm2 in alltreatments. Main cIimate factor in other years of test was almost the same as that in 30--year-average (l95 l -- l980), the average of rice yieId was about 6.or7.0t/hm2 in all tr...