| Machine transplanting rice has been widely used in our province since the beginning of this century,and now it has become the main way of rice production in our province.The majority of machine transplanting seedlings are blanket seedlings,which has the advantages of high efficiency and time saving.However,due to the high sowing density,short growth time and low elasticity of seedling age,the unfavorable factors such as weak seedling quality,low seedling rate and long green time are further amplified in the case of tense season,which in turn leads to further increase of sowing amount by some producers in the next year,forming a vicious circle of more seedlings and weaker seedlings,resulting in the increase of nitrogen application rate in Honda period,In particular,too much tillering fertilizer has seriously restricted the high yield potential of machine transplanted rice.Aiming at the problems of weak seedling and small elasticity of seedling age,the research and application of rice growth regulator(seedling strengthening agent for short)have been carried out in production,and certain results have been achieved.However,some producers excessively rely on the regulation of seedling strengthening agent and excessively prolong the seedling age,which has some hidden dangers for the recovery of seedling growth after planting.In view of the above problems in the production process of machine transplanted rice,the late maturing Medium Japonica Rice Nanjing 9108 was used as the test material in Xinnong rice wheat cooperative,Yaozhuang village,nanzha Town,Huai’an District,Huai’an City and Sihong rice culture center from 2018 to 2019.Experiments were carried out on comparison of seedling strengthening agents,sowing rate,fertilization in seedling stage,seedling age,number of seedlings planted in each hole,nitrogen application rate and tillering fertilizer application method.The seedling quality,tiller dynamics,leaf area coefficient,material production and distribution,yield and components,nitrogen absorption and utilization,rice quality and other traits of Nanjing 9108 were studied.In order to provide theoretical support and reference index for the formulation of green,high quality,high efficiency and high yield cultivation techniques of machine transplanted rice.The results are as follows:1.Comparative test of seedling strengthening agents:The results showed that:1)seedling height,stem base width,root number and other seedling qualities of rice treated with seedling strengthening agent were significantly better than those of CK treatment.There was no significant difference in seedling quality among different seedling strengthening agents;2)The yield of CK treatment was higher than that of CK treatment,with an average increase of 13.16%.The order of yield was seedling companion>seedling green>Jiewei>Longqi;3)There was no significant difference in leaf area coefficient between CK and CK at heading stage;4)Compared with CK treatment,the dry matter weight at heading stage and mature stage increased by 10.01%and 12.14%,and the seedling companion treatment was the largest;5)The plant nitrogen content was lower than that of CK treatment,and the nitrogen uptake,nitrogen grain production efficiency and nitrogen use efficiency were higher than that of CK treatment.Longqi treatment had the highest nitrogen uptake,and seedling companion treatment had the highest nitrogen production efficiency and nitrogen use efficiency.2.Experiment of Sowing rate:The results showed that:1)the seedling quality was significantly worse with the increase of seeding rate,the best was 75g,and the worst was 200g;2)The yield,panicle number,seed setting rate and 1000 grain weight were the highest under 75g treatment;3)The leaf area coefficient decreased significantly at heading stage,and it was the highest in 75g treatment;4)The plant dry matter weight decreased significantly at heading stage and mature stage,and the treatment of 75g was the largest;5)The plant nitrogen content rate increased significantly,but the plant nitrogen uptake,nitrogen grain production efficiency and nitrogen use efficiency decreased significantly.The plant nitrogen content rate was the highest in 200 g treatment,and the other three indexes nitrogen use efficiency were the highest in 75 g treatment.Combined with seedling quality and transplanting efficiency and other factors,under the condition of direct sowing of dry seeds,the appropriate sowing amount per plate was 120～125g.3.Experiment on fertilization in Seedling Stage:The results showed that:1)the seedling quality was significantly improved,and the treatment of Zhuang+twice fertilization was the best,and the treatment of no Zhuang+no fertilizer was the weakest;2)The yield,panicle number,grain number per panicle and 1000 grain weight were significantly increased in the treatment of Zhuang+2 times fertilization;3)There was no significant effect on leaf area coefficient;4)The treatment of Zhuang+2 times fertilizer increased the dry matter weight of plant significantly;5)The nitrogen content rate,nitrogen uptake,nitrogen grain production efficiency and nitrogen use efficiency were significantly increased,and the treatment of Zhuang+twice fertilization was the largest.4.Experiment of Seedling age:With the increase of seedling age:1)the seedling quality was significantly worse,the plant height,stem base width,root number and other indicators of 23 d treatment were the best,and the seedling quality of 38 d treatment was the worst;2)The yield and component factors decreased significantly,and the treatment of 23 d was the largest;3)The leaf area coefficient decreased significantly at heading stage;The dry weight of plant decreased significantly at heading stage and mature stage,and the treatment of 23 d was the largest;4)The nitrogen content of the plant increased significantly at the mature stage,with the highest at 38 d;The amount of nitrogen absorbed by plants decreased significantly at maturity stage,and reached the maximum at 23 d;Nitrogen grain production efficiency and nitrogen use efficiency decreased significantly,with the treatment of 23 d being the highest.5.Experiment on the number of seedlings planted in each hole:The results showed that:1)the yield,plant dry matter weight,nitrogen uptake,nitrogen grain production efficiency and nitrogen use efficiency increased at first and then decreased with the increase of the number of seedlings per hole,and M5 treatment was the largest;2)The leaf area coefficient increased significantly at heading stage,and M7 treatment was the largest;3)The nitrogen content of plants decreased significantly at the mature stage,and M3 treatment was the largest.6.Experiment of nitrogen application rate:With the increase of nitrogen application rate:1)the yield first increased and then decreased,with the treatment of N20 being the largest,and the treatments of N25,N15 and no nitrogen application were the largest in panicles per mu,seed setting rate and 1000 grain weight,respectively;2)Leaf area coefficient and plant dry matter weight increased first and then decreased.N25 treatment was the largest in the former,and N20 treatment was the largest in the latter;3)The nitrogen content and nitrogen uptake increased significantly in N30 treatment;Nitrogen use efficiency increased first and then decreased,and N20 treatment was the largest7.Experiment of tillering fertilizer:With the increase of tillering fertilizer amount:1)the yield of strong seedling treatment decreased slowly,N1>N2>N3>N4;The yield of weak seedling treatment increased first and then decreased,N3>N4>N2>N1.The yield of strong seedling treatment was higher than that of weak seedling treatment,and the yield of strong seedling treatment increased by 13.66%on average.The yield of weak seedling treatment with the highest yield was less than that of strong seedling one-time fertilization treatment.The yield components of strong seedling treatment were higher than that of weak seedling treatment.Under strong and weak seedling treatment,the increase of yield depended on the increase of spikclets per panicle,seed setting rate and 1000 grain weight;2)The leaf area coefficient of strong seedling treatment decreased significantly at heading stage,and n1-1 treatment was the largest,weak seedling increased first and then decreased,and N2 treatment was the largest The leaf area coefficient of strong seedling treatment was higher than that of weak seedling treatment;3)The results showed that the dry matter weight of the strong seedlings decreased significantly at the mature stage,and the treatment N1 was the largest,the weak seedlings increased first and then decreased,and the treatment N3 was the largest.The dry matter weight of the strong seedlings was higher than that of the weak seedlings,and the average increase of the weak seedlings was 4.6 7%;4)The nitrogen content in mature plants of strong seedling and weak seedling treatment decreased significantly,and N4 treatment was the largest.The nitrogen content in strong seedling treatment was weak,and the average nitrogen content in mature plants increased by 3.47%;The nitrogen uptake of strong and weak seedlings increased significantly at mature stage,and N4 treatment was the largest.The nitrogen uptake of strong seedlings was weak,and the average nitrogen uptake of weak seedlings increased by 9.26%;The nitrogen grain production efficiency of strong and weak seedling treatment was the highest in N1 treatment;The nitrogen use efficiency of strong seedling treatment was the highest in N3 treatment,and that of weak seedling treatment was the highest in N2 treatment.With the increase of the amount of tillering fertilizer:1)the head rice rate of strong seedling treatment decreased significantly,with N1 treatment as the largest,weak seedling treatment increased first and then decreased,with N3 treatment as the largest,and the head rice rate of strong seedling treatment increased by 0.78%on average;2)The chalkiness rate and chalkiness degree of strong seedling treatment and weak seedling treatment decreased at first and then increased,and N2 treatment was the lowest.The chalkiness rate and chalkiness degree of strong seedling treatment and weak seedling treatment decreased by 3.92%and 10.58%respectively;3)The taste value of strong seedling treatment decreased significantly,and N1 treatment was the largest.The taste value of weak seedling treatment increased first and then decreased,and N2 treatment was the largest.The taste quality of strong seedling treatment was significantly better than that of weak seedling treatment;The amylose content of strong seedling treatment and weak seedling treatment decreased significantly,and n1-1 treatment was the largest.The amylose content of strong seedling treatment was weak,and the amylose content of weak seedling treatment increased by 0.39%;The protein content of strong seedling treatment and weak seedling treatment increased significantly,and N4 treatment was the largest.The protein content of strong seedling treatment was weak,and the protein content of weak seedling treatment increased by 2.53%;4)The peak viscosity,hot pulp viscosity,disintegration value and final viscosity of strong seedling treatment decreased significantly,and N1 treatment was the largest,weak seedling treatment increased first and then decreased,and N2 treatment was the largest.The disintegration value of strong seedling treatment increased by 6.07%;The recovery value and reduction value of strong seedling treatment increased significantly,and N1 treatment was the lowest,weak seedling treatment increased first and then decreased,and N2 treatment was the lowest.The recovery value and reduction value of weak seedling treatment decreased by 2.99%and 10.23%compared with strong seedling.There was a significant positive linear correlation between disintegration value and taste value,and a significant negative linear correlation between reduction value and taste value.The results showed that the yield of strong seedling rice was the highest when tillering fertilizer was applied once,and the main rice quality indexes were better than other treatments.Although multiple application of tiller fertilizer can moderately increase the yield of weak seedling rice,it also makes the main rice quality indicators worse. |
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