| Under the new situation of sharp decline in agricultural labor force,mechanization and light-simplified cultivation have received increasing attention.Direct-seeding rice,as a kind of rice cultivation method,has developed rapidly in suitable areas because of its time-saving and labor-saving.However,the problem of fertilization and labor still restricts the development of direct-seeding rice.At present,in response to the problem of fertilization and labor for transplanted rice,our laboratory has coordinated the nitrogen release peaks of slow and controlled release fertilizers and formulated a variety of new slow-mix fertilizers with nitrogen release cycles that are more consistent with the law of rice fertilizer requirements.The"machine-transplanted rice slow-mixing one-time fertilization technology"is used to achieve the effect of"one-time fertilization and lifetime fertilizer"for machine-transplanted rice.With the rapid development of multi-functional direct seeding machines such as the synchronous ditching and ridge fertilization of rice,such as direct seeding machines for direct seeding of rice and other multi-functional direct seeding machines,one-time fertilization technology for direct seeding of rice machines has become possible.In this study,according to the fertilizer requirement law of direct-seeded rice,combined with the nutrient release characteristics of different slow and controlled-release fertilizers,a special slow-mix fertilizer formula that can meet the nutrient requirements of direct-seeded rice was sought to realize the one-time fertilization technology of direct-seeded rice,which is helpful to promote direct seeding.Mechanization of rice and light and simplified production are of great significance.This experiment was carried out in the Baima Teaching and Research Experimental Base of Nanjing Agricultural University,Jiangsu Province in 2020.The conventional split fertilization（CK）and no nitrogen fertilizer（N0）were set as controls.Four kinds of slow and controlled release nitrogen sources were selected:sulfur-coated urea（SCU）,urease inhibitor（AHA）,urea formaldehyde（UF）,resin-coated urea（PCU）,design different combinations of plans,and study the effects of a single slow and controlled release fertilizer and its different combinations on rice yield,nitrogen absorption and utilization and quality Influence,explore the best fertilizer composition scheme suitable for direct-broadcasting one-time fertilization technology.The main findings are as follows:1.Differences in nitrogen release laws of different slow-and controlled-release fertilizers and combinationsThere are significant differences in the nitrogen release law among different slow-and controlled-release fertilizers and combinations.The nitrogen release law of a single slow and controlled release fertilizer is not in line with the law of direct-seeded rice.SCU,AHA and UF are released explosively in the early stage,and the AHA fertilizer has a longer effect;PCU nitrogen shows the later release.The slow and controlled-release fertilizers released in the early and late stages are mixed in two or three groups according to a certain ratio,and the performance is similar to the compound formula.The nitrogen release during the whole growth period is more consistent with the nitrogen demand law of rice.In the combination,AHA+UF+PCU has an obvious peak of nitrogen release during the panicle differentiation-heading stage,which is more in line with the law of direct-seeded rice.2.The combination of different slow and controlled-release fertilizers is more conducive to stabilizing the yield of direct-seeded riceCompared with CK,a single slow-release fertilizer showed a significant yield reduction trend,mainly due to the significant reduction in total spikelets.Compared with CK,the formula of AHA participation showed a stable yield trend in the combination plan.Among them,AHA+UF+PCU had the most significant increase in yield,which was an increase of 5.8%compared with CK,mainly because its later release was more in line with the needs of direct seeding rice.Fertilizer law shows high dry matter accumulation after panicle differentiation,stabilizes the effective panicle number,total spikelets,seed setting rate,and 1000-grain weight,while increasing the number of grains per panicle.Most of the other formulas show a certain yield reduction trend.3.The combination of different slow and controlled-release fertilizers improved the nitrogen recovery efficiency of direct-seeded rice.Compared with CK,a single slow and controlled-release fertilizer reduces the efficiency of nitrogen recovery.Among them,SCU and UF reach significant levels.The main reason is that the nitrogen released from the fertilizer during the period from direct seeding to sugar weaning cannot be absorbed and utilized by the rice.Loss of nitrogen.In the combination,compared with CK,the combination plan involving AHA increased the nitrogen absorption and nitrogen content of the plant from the heading stage to the maturity stage,thereby increasing the nitrogen recovery and utilization rate.Compared with CK,it increased by 11.3%and 11.6%,respectively and Percentage points and 15.0 percentage points,the rest of the combination plan and CK are not significantly different.Compare d with CK,the compound formula significantly improved the nitrogen fertilizer recovery efficiency by 10.4%and 13.0%respectively.4.Different slow and controlled-release fertilizers can improve the appearance,processing and taste quality of rice after being combinedIn a single controlled release fertilizer,SCU,AHA,and UF significantly improved the appearance quality compared with CK,and obtained similar processing,nutrition and taste quality;PCU significantly reduced the appearance quality and ta ste quality compared with CK.Compared with CK,the two or two groups,the three or three groups and the compound formula have significantly improved the appearance and processing quality,slightly reduced the nutritional quality,and improved the eating quality.Based on the above results,the combination of AHA+UF+PCU significantly increased the yield and nitrogen utilization efficiency of direct-seeded rice,while improving the quality of rice.Therefore,this study believes that the combination of AHA+UF+PCU is the most suitable one-time fertilization technology for direct seeding.Good slow fertilizer formula. |
