Effects Of Water Regulation On Productivity And Water Use Of Lycium Barbarum Intercropping With Sainfoin In Gansu Yellow River Irrigation District

Aiming at the problems of serious continuous cropping obstacles,low productivity and water use under the traditional planting mode of Lycium barbarum in Gansu Yellow River irrigation district,exploring scientific and reasonable planting mode and water regulation mode has become one of the key contents of local L.barbarum industry research.In this paper,L.barbarum and Sainfoin were studied,three water treatments were prepared,namely:full irrigation:75%⁸5%?W1?,light water deficit:65%⁷5%?W2?and moderate water deficit:55%⁶5%?W3?,Further,three planting modes were set up,namely:L.barbarum monoculture?DG?,Sainfoin monoculture?DH?and L.barbarum intercropping with Sainfoin?JZ?.The effects of water regulation and intercropping on the soil environment,crop growth,photosynthesis,yield and water use efficiency were researched,The correlation of water use efficiency between leaves and farmland was analyzed,and the suitable water regulation mode and planting mode for high yield and high efficiency of local L.barbarum and Sainfoin were obtained.The main conclusions show that:?1?With an increase in the water deficit degree,the average water content of0-120 cm soil layer in each treatment showed a decreasing trend;Compared with the corresponding monoculture,L.barbarum intercropping with Sainfoin was observed to decrease the soil water content in the 0-120 cm soil layer by 2.93%⁵.30%under the conditions of W2 and W3.With an increase of depth,the soil water content of each treatment showed a trend of increasing first and then decreasing,and the maximum value was obtained at 60 cm or 80 cm;Compared with L.barbarum monoculture,intercropping increased the moisture content in the 0-60 cm soil layer in July and August under the condition of W3.With an increase in the water deficit degree,the total water consumption of L.barbarum intercropping with Sainfoin showed a decreasing trend.Within the 0-60 cm each soil layer,slight water deficit was beneficial to increase the organic matter content of L.barbarum monoculture and intercropping.Compared with L.barbarum monoculture,intercropping was observed to increase the organic matter in the 0-20 cm soil layer by 14.88%³2.95%and decrease the ammonium nitrogen by 2.53%⁶.38%.Compared with the corresponding monoculture,intercropping reduced the nitrate nitrogen content of each soil layer by0-60 cm under the condition of W2.?2?With an increase in the water deficit degree,the growth of plant height and ground diameter of L.barbarum showed a trend of increasing first and then decreasing,while the growth of North-South/East-West crown showed a decreasing trend.Under the same water treatment,intercropping had no significant effect on the growth of ground diameter and crown diameter of L.barbarum,but intercropping was observed to significantly increase the growth of plant height of L.barbarum by24.21%under the condition of W2.With the deepening of water deficit,the plant height of Sainfoin decreased gradually,and intercropping was lower than that of monoculture under the same water conditions.With an increase of cutting times,the crude protein content of Sainfoin was observed to increase by 3.21%²9.54%,acid detergent fiber and neutral detergent fiber content was observed to decrease by11.52%²1.21%and 11.51%¹4.75%in turn.Under the condition of W1,the quality of the second crop of Sainfoin was better in the intercropping mode,and compared with Sainfoin monoculture,intercropping increased the crude protein content by2.21%and decreased the acid detergent fiber and neutral detergent fiber contents by2.43%,0.72%respectively.?3?With an increase in the water deficit degree,the chlorophyll content of Sainfoin monoculture and intercropping showed a decreasing trend,the chlorophyll content of L.barbarum monoculture and intercropping was the highest under the conditions of W1 and W2,respectively.Under the conditions of W2 and W3,intercropping was observed to increased the chlorophyll content of L.barbarum by8.95%and 5.27%in turn.With the deepening of water deficit,the daily mean values of net photosynthetic rate and transpiration rate showed a decreasing trend.Under the condition of W3,the daily mean values of L.barbarum leaves water use efficiency was the highest,and intercropping increased significantly by 2.81%compared with L.barbarum monoculture.Under the condition of W1,the daily mean values of leaves water use efficiency of Sainfoin intercropping was the highest,and intercropping increased significantly by 23.98%compared with Sainfoin monoculture.?4?Under the condition of W2,the yield of dried fruit and water use efficiency of L.barbarum monoculture were the highest(2546.80 kg·hm^-2,4.87kg·hm^-2·mm^-1).With an increase in the water deficit degree,the total yield and system water use efficiency of Sainfoin monoculture and L.barbarum intercropping with Sainfoin showed a decreasing trend.Under the condition of W1,intercropping increased significantly the dry fruit yield of L.barbarum by 9.69%Compared with L.barbarum monoculture;There was no significant difference in hay yield between Sainfoin intercropping and monocropping.Due to the difference of yield between L.barbarum and Sainfoin,the overall performance of water use efficiency was as follows:L.barbarum intercropping with Sainfoin>Sainfoin monoculture>L.barbarum monoculture,and Compared with the average WUE of the corresponding monoculture,the intercropping system increased by 80.86%¹09.66%under the same water regulation.?5?Based on the correlation analysis of water use efficiency of L.barbarum and Sainfoin at different scales,it was found that there was no significant water use efficiency correlation between leaves and farmland of L.barbarum,and there was a significant positive water use efficiency correlation between leaves and farmland of Sainfoin.Comprehensively,the results showed that light water deficit?soil moisture was maintained at 65%⁷5%of the field capacity?was conducive to high yield and water use efficiency of L.barbarum monoculture;Under sufficient irrigation?soil moisture was maintained at 75%⁸5%of the field capacity?,L.barbarum intercropping with Sainfoin can improve the yield of L.barbarum,forage quality and system water use efficiency.