| The rice production in our country facing to the diversification of high-yield, high-quality, efficient, ecological and safe target diversified transformation of rice production is proposed to improve production efficiency, reduce labor costs, saving production requirements. It is an effective way to realize the goal of rice production using mechanized production methods and reasonable fertilizer application. The more previous studies on the characteristics of Rice Mechanized Production and the measures for the rational use of fertilizer were studied. However the role of potash fertilizer on the two is to be further explored. The effects of combined application of nitrogen (N) and potassium (K2O) at different growth stages on yield formation and Nitrogen. Potassium use efficiency (KUE) were investigated with hybrid rice F you 498 as material in 2014. For N fertilizer treatments, total N 180 kg/hm2, the ratio of basal, tillering, spikelet-promoting and spikelet-preserving N were 5:3:1:1 (N1),3:3:2:2 (N2),3:1:3:3 (N3) and NO (no N fertilizer applied) respectively. For K fertilizer treatments, total K2O 180 kg/hm2, the ratio of basal, tillering, spikelet-promoting and spikelet-preserving N were 10:0:0:0 (Ka),7:0:3:0 (Kb),3:0:7:0 (Kc) and K0 (no K fertilizer applied) respectively. In 2015, the study examined the effects of varying transplanting methods and potassium (K) application rates on yield formation. KUE, lodging resistance ability and grain yield of hybrid rice F you 498. The study was conducted as split-plot design with two rice transplanting methods (mechanized transplanting, T1; artificial transplanting, T2) and five K application rates (0 kg/hm2, K0; 60 kg/hm2, K1; 120 kg/hm2, K2; 180 kg/hm2, K3; 240 kg/hm2, K4) were arranged as main plot and split plot, respectively. The main study results are as follows:1 Effects of combined application of Nitrogen and Potassium at different growth stage on yield formation of hybrid-riceDifferent N and K application and the interaction had significant effects on the yield of rice:N1Ka, N2Kc and N3Kb obtained the highest yield with their corresponding N treatments,142.2kg/hm2,226.9 kg/hm2,222.7 kg/hm2, respectively, higher than the average, among which, N3K2 produced the maximum grains 10450.0 kg/hm. The total amount of floret, grain number and the actual yield of rice increased with the increase of the proportion of N fertilizer, while the weight of 1000-grain weight was the opposite. The effect of K fertilizer application on rice yield was mainly reflected in the number of effective panicle and total number of floret. In different N treatments, the number of effective panicle was the highest in Kc treatment. Increasing the proportion of K fertilizer could increase the yield of rice, and for N2 and N3 treatments, total spikelets were also enhanced with more K applied later. A moderate reduction of K proportion at earlier growth stage was beneficial for dry matter accumulation at elongation stage. For post-anthesis dry matter accumulation and its ratio, Ka at N1 and N2, and Kc at N3 were the optimal treatments respectively. Compared with Kb and Kc, Kl got the most advantageous Pn value of flag leaf after anthesis at N1, though its leaf area index (LAI) of top three leaves and SPAD values were lower than other treatments at and after anthesis. For N2 and N3, Ka could slow down the reduction of SPAD and Pn value, but Kb and Kc possessed more advantageous LAI of top three leaves, and obtained higher yield ultimately.2 Effects of combined application of Nitrogen and Potassium at different growth stage on Nitrogen,Potassium use efficiency of hybrid-rice F you 498The reasonable application of K fertilizer could not only guarantee the yield but also increase the utilization efficiency of nitrogen and potassium. N1Ka, N2Kc and N3Kb obtained the best fertilizer use efficiency respectively with their corresp onding N treatments. The retroposition of N fertilizer increased the yield of rice, total N accumulation and N contribution rate(NCR), N agronomic efficiency(NAE), N recovery efficiency (NRE) were increased. However, the increase of yield was le ss than that of total N uptake by the increment of N fertilizeR. The N treatment Kb, Kc treatment can improve the absorption of potassium in Rice. With the in-c rease of the proportion of N fertilizer 100 kg seed K absorption and K physiologi cal efficiency(KPE), total K uptake increased and then decreased.3 Effects of transplanting methods and potassium rates on grain yield and yield formation of hybrid-riceArtificial transplanting rice produced 3.21% more grains than mechanized transplanting rice, less spikelets per panicle and small sink size (total spikelets) were responsible for the lower yield of mechanized transplanting rice. An appropriate increase of K input enhanced 1000-grain weight and seed-setting rate, which was of assistance in yield promotion for mechanized transplanting rice, the K3 treatment produced more grains than others, thus 180 kg/hm2 was regarded as the optimal K application rate in this study. compared to artificial transplanting, SPAD values of flag leaf and top second leaf of mechanized transplanting was lower after heading stage, but the change was relatively steady. The LAI at full heading stage of mechanized transplanting was higher than that of artificial transplanting. However, the descend range of net photosynthetic rate of flag leaf during 10th day to 20th day after heading stage was greater in mechanized transplanting. Applying K fertilizer could stabilize SPAD values of flag leaf after heading stage and the changes of the net photosynthetic rate after full heading stage, when compared with no K fertilizer. LAI of mechanized transplanting and artificial transplanting increased with the increase of K application rate at first, then showed a downward trend. The largest LAI of mechanized transplanting and artificial transplanting were obtained in K3 treatment and K2 treatment, respectively. The dry matter weight of mechanized transplanting was higher than that of artificial transplanting at jointing stage and full heading stage, whereas it was higher in artificial transplanting at maturity stage. With the increase of K application rate, the dry matter weight in different organs increased firstly and then decreased at different stages, and the effect of K level on stem-sheath (tillering capacity) and leaf at different stages in mechanized transplanting was greater than that in artificial transplanting. In terms of dry matter accumulation, mechanized transplanting had more advantage in it before jointing stage while artificial transplanting showed more superior after full heading stage. Moreover, too high or too low potassium application rate is not conducive to dry matter transportation of stem-sheath and leaf in the later period of rice. Dry matter transformation amount and rate of stem-sheath in mechanized transplanting and artificial transplanting are the highest when the K application rate is 180kg/hm2. However, the amount and rate of leaf dry matter transformation were the highest when the K application rate are 120 kg/hm2 and 180kg/hm2 in mechanized transplanting and artificial transplanting, respectively.4 Effects of transplanting methods and potassium rates on Potassium use efficiency of hybrid-riceCompared with artificial transplanting rice, mechanized transplanting rice in different organs of NK uptake is significantly higher in jointing period. However no obvious differences were found in NK uptake at full heading period and maturity. In every stage difference of planting patterns for NK uptake first increase and decrease with increase K application. For N absorption, mechanical transplanting rice maximum N uptake is higher than theoretical K application rate at every stages. Nevertheless mechanical transplanting rice maximum K uptake is lower than theoretical K application rate at each period. Machined-transplanting rice of K transport is significantly higher than hand panting rice and difference planting patterns show no obvious difference in N transportation. And high or low K application rate are not conductive to NK transport. K Transformation of stem-sheath reached peak,when K application is 120kg/hm2. While K application rate is 180kg/hm2, K transformation amount of artificial transplanting rice is maximum. For the different K application levels, with increase K application that potassium contribution efficiency (KCE) and K uptake utilization efficiency show firstly increasing then decreasing. In machined transplanted rice potassium agronomic efficiency (KAE), KCE and potassium physical efficiency (KPE) are significantly higher than artificial transplanting rice. Compared with machined transplanting rice that KUE of hand planting rice is significant higher. However KCE and KUE firstly increased then decreased with increasing K application.5 Effects of transplanting methods and potassium rates on lodging resistance of hybrid-riceThe plant height and length of basal internodes of artificial transplanting rice were higher than those of mechanized transplanting rice, while the former still obtained significantly greater lodging resistance ability than the latter. The significantly greater basal internode thickness, dry matter substantial degree, stem-sheath density, K content and cellulose content of artificial transplanting rice may probably played key roles in gaining a better ability of keeping away from lodging than mechanized transplanting rice. Within varied K rates treatments, basal internode thickness, dry matter substantial degree, stem-sheath density, culm type index and cellulose content of rice plants reached their highest level in 120 kg/hm2 or 180 kg/hm2 for artificial transplanting and 180 kg/hm2 or 240 kg/hm2 for mechanized transplanting, in addition, The lodging index of mechanized transplanting rice was smallest with 120 kg/hm2 K fertilizer input, while artificial transplanting rice got the greatest lodging resistance ability when K application rate reached 240 kg/hm2. To sum up, mechanized transplanting rice could maintain a higher lodging resistance ability with a less K fertilizer input compared with artificial transplanting rice. In conclusion,120 kg/hm2 was the optimal K application rate for mechanized transplanting rice, which could reduce the lodging risk efficiently as well as promote grain yield to the highest level. As for the artificial transplanting rice, the optimal K rate should increase to 180 kg/hm2?240 kg/hm2 to realize the growth of grain yield and lodging resistance ability simultaneously. In consideration of less K fertilizer input, mechanized transplanting rice would acquire greater advantages in production efficiency and cost with further improvement in grain yield in comparison with artificial transplanting rice. |
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