The Effect Of Different Collocation Of Intrarow Spacing With Row Spacing On Growth And Development Of Rice

The effect of collocation of intrarow spacing and row spacing on growth and yield of rice werestudied, with taking the production and the climatic conditions of middle Jilin Province regions as thefoundation. Using Song-122, the experiments were carried out at experimental base of Jilin AgriculturalUniversity in 2005.There were three row spacing designs: 30cm equal row, 50cm-20cm width-narrowrow, 70cm-20cm width-narrow row. Adjusting intrarow according to planting density (10bunches/m²,17bunches/m² and 24bunches/m²), so there were 9 treatments. The treatment was named as rowspacing-density. After transplanting rice seedlings in the field, and waiting to turn green rice ofseedlings, sample plants were marked card and investigated morphological characters every 2 weeks;Chlorophyll content was measured every 2 weeks too. In rice main growth period, the dry matteraccumulation all rice organs were measured. Net photosynthetic rate (Pn), stomatal conductance (Gs),intercellular CO₂concentration (Ci) and transpiration rate were measured at grain filling stage. Afterharvest, yield was measured and yield components were analyzed. The results showed:Under low planting density (10bunches/m²), there was beneficial to achieve a large number oftillers of single plant by enlarging space in row (i.e. adopting width-narrow row), but the number oftillers of the population was reduced. Under high planting density (24bunches/m²), when the rowspacing was 50cm-20cm, the number of tillers of single plant was reduced, but the number of tillers ofthe population was not reduced, it even increased; but when the row spacing was 70cm-20cm, thenumber of tillers of single plant and the population both reduced. Under moderate planting density(17bunches/m²), there were adequate tillers of single plant and the population by enlarging space inrow befittingly (50cm-20cm). But when the row spacing was 70cm-20cm, the increase of the number oftillers was inhibited significantly. Under any planting density, the leaf area of single plant and LAI (leafarea index) of the population were reduced. But there was a trend that leaf area and LAI increasedslowly and reduced slowly, the max. LAI was more optimization when adopting width-narrow rowcollocation.Only the 30-10, 50-17 and 70-10 treatments showed the trend that dry matter accumulation ofsingle plant and population was increased after heading period. In 70-17 treatment, dry matteraccumulation of single plant and population was reduced. In 50-10 treatment, dry matter accumulation of single plant was increased, but the population's was reduced. 30-24,50-24 and 70-24 dry matteraccumulation of single plant was reduced, but the population's was increased. Viewing the Relationshipbetween biological yield and economic yield, dry matter accumulation of 30-10,50-17,70-10,50-24,70-24,30-24 would help to promote the yield of rice, but the panicles of the population of 70-10,30-10,70-24 were less than CK, meaning the dry matter of these treatments were distribution invegetative organs, it could not transfer to reproductive organs after heading, so the dry matteraccumulated at earlier stage was waste.The different collocation of intrarow spacing and row spacing had no effect on the content ofchlorophyll in rice growth duration. Under low and moderate planting density, the rate of netPhotosynthesis was heightened by adopting width-narrow row, but there was no significant difference. Italso could reduce transpiration rate, and there was significant difference. The different collocation ofintrarow spacing and row spacing would help to promote the photosynthesis ability of rice afterheading.When the width-narrow row spacing was 50cm-20cm, the theoretical yield and actual productionwere higher than CK (30-17) under moderate and high planting density. But when the width-narrow rowspacing was 70cm-20cm, the theoretical yield and actual production were reduced significantly. Byadopting width-narrow row collocation, the panicle length, the weight of thousand grain, settingpercentage and number of grains per ear were increased. These would help for yield formation of singlepanicle. In 70cm-20cm width-narrow row spacing treatments, the number of panicles in unit area wasreduced significantly, and it was the main reason of the yield decreased. In 50cm-20 width-narrow rowspacing treatments, the number of panicles in unit area was reduced slightly, but the difference was notsignificant, growth status of single panicle was well, so the yield of the population was even increased.