| Rice cultivation is one of the most effective ways to improve and utilize low-lying saline-alkali land in Ningxia Plain.Due to climate and environmental changes,the amount of water from the Yellow River has decreased year by year,and the amount of water allocated to agriculture in Ningxia has also decreased.Planting new water-saving and salt-tolerant rice varieties and optimizing reasonable irrigation quota distribution methods are one of the effective ways to solve the contradiction between water and rice in Ningxia Plain.Therefore,this experiment carried out the effect of different irrigation quota distribution methods on the yield of different saline-alkali tolerant rice varieties.The experiment adopted a two-factor split-plot experiment.The main plot was four irrigation quota distribution methods,and the subplot was three saline-alkali tolerant rice varieties.By measuring the physical and chemical properties of paddy soil and the changes of rice growth and yield,the law of salt vertical migration in saline-alkali paddy field was preliminarily found out,and the response of rice root growth and yield change to salt vertical migration was analyzed.The suitable irrigation quota allocation method was put forward for different saline-alkali tolerant rice varieties.The research results provide scientific and technological support for rice planting in saline-alkali land of Ningxia Plain under the new situation,and are of great significance to the ecological protection and high-quality development of the Yellow River Basin in Ningxia.The main conclusions of this experiment are as follows:1、Different irrigation quota allocation methods can effectively reduce the pH and total salt of topsoil in saline-alkali paddy fields,and increase the contents of organic matter,alkali-hydrolyzed nitrogen,available phosphorus and available potassium.After harvest,the soil pH and total salt content of each treatment decreased by 1.70%and 8.25%on average compared with that before planting.The contents of organic matter,available nitrogen,available phosphorus and available potassium in each treatment increased by 10.15%,2.30%,12.20%and 1.65%on average.Among them,W1 has the best effect.2、The law of salt transport in saline-alkali paddy soil under different irrigation quota distribution methods was preliminarily found out.The soil salinity of 0-140 cm in saline-alkali paddy field increased first,then decreased sharply,then tended to be relatively stable and finally increased slightly with the growth period.Among them,W1 had the smallest salt variation(maximum 5.08 ds/m,minimum 3.87 ds/m).The soil salinity in each growth period of saline-alkali paddy field decreased first,then increased and then decreased slightly with the increase of soil depth.Among them,W1 had the largest salt variation(maximum 4.26 ds/m,minimum 3.13 ds/m).3、The effects of different irrigation quota allocation methods on the growth of salt-tolerant rice were different.W2 significantly promoted the growth of rice roots,W1 significantly promoted the growth of rice shoots and improved the photosynthetic performance of rice.Under the W2 treatment,the average root length,root area and root volume of different varieties of saline-alkali tolerant rice were 31.22 cm,73.31 cm2 and 1.33 cm3,respectively.The root growth of Ningjing 56 was the best.Under W1 treatment,the average seedling emergence rate,leaf area index and net photosynthetic rate of different varieties of saline-alkali tolerant rice were 68.30%,8.20 and 16.77 μmol/m-2/s,respectively.The photosynthetic performance of Jiesan was the best.(4)Under different irrigation quota allocation methods,the average yield of rice was 537.30 kg·666.7 m-2,of which W1 had the highest yield of 610.40 kg · 666.7 m-2.The order of yield of three saline-alkali tolerant rice under W1 treatment was:Jiesan(688.91 kg·666.7 m-2)>Ningjing 56(613.42 kg·666.7 m-2)>YC813(528.92 kg·666.7 m-2).5、In summary,the study found that W1(pre-emergence irrigation 220 m3/666.7m2,seedling stage 70 m3/666.7m2,tillering stage 120 m3/666.7m2,jointing stage 140 m3/666.7m2,heading stage 90 m3/666.7m2,filling stage 60 m3/666.7m2)is suitable for the high-yield irrigation quota allocation method of rice in the saline-alkali land of Ningxia Plain.Jiesan is a saline-alkali rice variety suitable for the above irrigation quota allocation method. |
PDF Full Text Request