A Preliminary Study About ‘Tidy Field Technology’ On Growth,Development And Weed Control In Direct-Seeded Rice

Direct-seeded rice(DSR)is an important way to achieve light-simplified and mechanized in rice production as it saves both labor and cost and known to be an efficient crop establishment method.However,weeds are very crucial for successful production of rice through DSR technology.At present,the only way to eliminate weeds in DSR is by applying herbicides.For this purpose,the conventional herbicides are not always effective,and multiple applications of herbicides would increase the production costs and environmental burdens.The Tidy field technology(TFT)refers to the herbicide resistant rice being cultivated by conventional breeding technology.In TFT,variety of weeds can be eliminated by applying the broad-spectrum imazapic herbicide.Still the effect of TFT on weed control,rice growth and subsequence crop growth in DSR is not clear.The experiments were conducted during 2019 and 2020 at Huaqiao Town,Wuxue City of Hubei Province,China.Rice cultivars of conventional Huanghuazhan(V1)and herbicide-resistant Huanghuazhan(V2)were adopted under two different weeding management methods i.e.(i)broad-spectrum herbicide management(W1),and(ii)conventional herbicide management(W2)along with water spray on herbicide-resistant Huanghuazhan as control(CK).Total of five treatments were:V1W1,V1W2,V2W1(TFT),V2W2 and CK.The objectives of this study were(1)to explore the effects of TFT on the growth and grain yield of DSR;(2)to investigate the occurrence dynamics and control effect of weeds in DSR under different weed control treatments;(3)to comprehensive evaluation of the application of TFT based on the economic benefits and the growth and development of subsequent crops.The main results were as follows:(1)The highest of grain yield was observed in TFT,and the trend was the same in two years.The yield of V1W1 and V2W2 was significantly higher than that of V1W2 and CK,while the yield of V2W1 was the lowest,which was 0.By analysis the grain yield components,the higher yield of V1W1 and V2W2 was mainly due to the panicles per m~2increased by 12.6%,7.5%and 18.5%,17.3%in 2019 and 2020,respectively.Considering of the agronomic trait,the absorption and accumulation of N as well as production and distribution of dry biomass,the reason for the higher yield of V1W1 and V2W2 was that they had higher tiller number,leaf area index and total dry weight in the vegetative period.Meanwhile,stem and leaf N content of V1W1 and V2W2 were significantly higher than that of V1W2 and CK,which led to the higher biomass accumulation and its contribution rate to panicle biomass before and after flowering.(2)Higher grain yield of rice under TFT treatment was contributed by lower weed density.Compared with CK,the total plant number of weed control and dry weight control efficiency of V1W2 and V2W2 treatments were 66%-98%and 74%-100%in the whole growth period,respectively,while them were more than 95%in V1W1.Compared with V1W2 and V2W2,the higher weed control and yield of V1W1 was mainly attributed to broad-spectrum of imazapic,especially in M.vaginalis and C.difformis,the period of symbiotic competition with rice was reduced(3)TFT has highest economic benefit,while it has herbicide residue damage on subsequent crops.Compared with other treatments,higher net economic benefit in V1W1mainly resulted from not only reduced the cost of herbicide and labor cost of spraying herbicide,and also increased the yield of rice.However,compared with sprayed conventional herbicide or water,sprayed broad-spectrum herbicide imazapic significant inhibited growth and development of direct-seeded rapeseed,but had no significant effect on the subsequent wheat.In conclusion,TFT was a high yield and efficient weed control technology under DSR system,the lower herbicide input and higher weed control were the main reasons for its high grain yield and economic benefit of TFT.However,TFT has herbicide residue damage on subsequent crops to a certain degree.It may be an important research direction to solve herbicide residues by planting resistant crops,selecting safety interval period and soil bioremediation in the future.