The Interactional Effects Of Different Alfalfa Sowing Amount And Plowing Time On Soil Fertility And Wheat Yield

Wheat-soybean rotation system is a common cropping system,this experiment aimed to study the interactional effcts of different alfalfa sowing amount and plowing time on the wheat dry matter accumulation,wheat yield and soil fertility,and clarified the best wheat-soybean rotation system for the region.This experiment was carried out in Yuanqu County,Yuncheng City,Shanxi Province,the tested wheat variety was Yannong 21.The experiment was designed with two factors,Factor 1 was the different longitudinal alfalfa sowing amount(ai:0.5?a2:1?a3:1.5 kg/mu),Factor 2 was the different horizontal alfalfa plowing time(bi:2016.9.10?b2:2016.9.20?b3:2016.9.30),which forming nine different experimental plots in the experimental field:M1(ai*bi)?M2(ai*b2)?M3(ai*b3)?M4(a2*bi)?M5(a2*b2)?M6(a2*b3)?M7(a3*bi)?M8(a3*b2)?M9(a3*b3).During different growth period,the rhizospheric soil nutrient contents(available nitrogen,available phosphorus and organic matter)and rhizosphere soil enzyme activity(urease,sucrase,alkaline phosphatase)were measured,and the wheat dry matter accumulation and wheat production were measured in wheat mature period.The results show:(1)For the soil nutrient content of the alfalfa soil,M8 treatment was more conducive to the increase of soil available nitrogen content,its soil nutrient content was relatively low under M4,M3,M6 treatments,and M8 treatment was 0.01%-39.14%higher than other treatments.The soil available phosphorus content showed the lowest treatment was M3,M7,M8,M9 treatments were more favorable to the accumulation of its content,and compared with other treatments,it could be as high as 0.34%-43.41%;soil organic matter content showed that the lowest treatment was M3,M8,M9 treatments were most beneficial to the accumulation of organic matter content,and it could be 1.96%-57.53%higher than other treatments.(2)For the enzyme activity of alfalfa soil,M1 and M3 treatments were relatively unfavorable to the increase of soil sucrase activity,but M8 treatment was more favorable to its activity improvement,and the rate of increase was 2.64%-61.52%;The treated soil phosphatase activity of Ml,M6,M7 treatments was lower,M9,M7,and M2 treatments were more favorable to the increasement of phosphatase enzyme activity,and the increase range was 1.16%to 17.20%;M1 and M5 treatments had poor effect on soil urease activity improvement.M8,M9 and M6 treatments were more conducive to increase soil urease activity and increased 3.45%-17.93%.(3)For the wheat dry matter accumulation and the wheat yield,the wheat dry matter accumulation of M2 treatment was lower than other treatments,and the lowest wheat yield was M1,but M8 treatmen was more beneficial both for the dry matter accumulation and wheat yield.Compared with other treatments,the growth ranges of the two indicators were 8.60%-34.79%and 0.03%-34.79%respectively.(4)For the soil nutrient content of wheat,the lowest available nitrogen content treatment was M1,M8 treatment was more conducive to the growth of available nitrogen content,and compared with other treatments,the growth range was 1.01%-14.87%.As for soil available phosphorus content,compared with other treatments,M3 treatment was the lowest one and the M7,M8 treatments were more beneficial for the increasement of soil available phosphorus,and the increase range was 0.83%-40.98%.The soil organic matter content of M1 and M3 treatments generally showed relatively low,the M9 treatment was more conducive to the growth of its content,compared with other treatments,the growth range was 2.03%-26.25%.(5)For the wheat soil enzyme activity,the alkline phosphatase activity of M4 was relatively low,M5 treatment was more conducive to the increase of alkline phosphatase activity,and increased from 1.52%to 11.38%.As for the soil urease activity,M5 was the lowest one and M7,M9 were relatively high,and the growth range was 4.35%-34.78%.The soil sucrase activity of M4 was the lowest,and the activity of M8 was the highest,and the growth range was 7.60%-44.71%.Above all,considering the results of soil fertility and yield structure,the experiment concluded that the treatments of M7,M8 and M9 were better than other treatments,expecially that the M8 and M9 treatments were the best,while M1,M2 and M3 were not beneficial for the promotion of soil fertility and wheat yield obviously.The results showed that increasing the alfalfa sowing amount properly and choosing the late period to return alfalfa back to test field were more beneficial to the increasement of soil fertility and wheat yield in this area.This experiment can provide parameter guidance for related research.