Abstract:

The study aimed to explore the impact of the coupling of different cultivation and fertilization measures on the corn productivity of acidified soil in rocky desertification areas, providing a basis for the improvement of acidified soil and crop yield increase in rocky desertification areas. In 2023, a soil acidification improvement experiment was carried out in Muzhe Village, Xichou County, Wenshan Zhuang and Miao Autonomous Prefecture, Yunnan Province. The experiment included the following treatments: (1) fertilization measures: no fertilization (NK), chemical fertilizer (CK); (2) cultivation measures: intercropping of maize and soybean (INT); (3) coupling of cultivation and fertilization measures: technology integration (TI). There were 3 categories with 4 treatment measures in total to study the impact of the coupling of cultivation and fertilization measures on soil improvement, maize yield, maize nitrogen, dry matter accumulation and distribution, as well as the impact of environmental factors on maize yield. The results showed that at the harvest stage, the soil pH of TI, INT, NK and CK treatments were pH 6.12, 6.03, 6.02 and 5.97, respectively. The maize grain yields of TI, INT, CK and NK treatments were 10321.44, 9760.92, 8116.14 and 5732.18 kg/hm², respectively. The TI and INT significantly (P<0.05) increased the maize yield per unit area, while no fertilization significantly (P<0.05) decreased the maize yield. The proportion of grain nitrogen in above-ground nitrogen for INT, TI, and CK treatments was 50.25%, 50.91% and 57.39%, respectively. The proportion of grain dry matter in above-ground dry matter for INT, TI, and CK treatments was 49.19%, 51.40% and 54.13%, respectively. The trends of nitrogen distribution ratio and dry matter distribution ratio were the same for INT, TI, and CK treatments. The factors affecting crop yield were different at different growth stages of the crop. At the maize seedling stage, the factors affecting yield were nitrate nitrogen content, soil pH and ammonium nitrogen content, with explanatory degrees of 76.4%, 7.8% and 6.6%, respectively. At the vigorous vegetative growth stage of maize, the factors affecting yield were available phosphorus content and available potassium content, with explanatory degrees of 76.9% and 12.4%, respectively. At the reproductive growth stage of maize, the available potassium content, as a factor affecting yield, had an explanatory degree of 59.6%. The following conclusions could be drawn: (1) maize-soybean intercropping could increase the maize yield per unit area. The coupling of cultivation and fertilization measures could further increase the yield by increasing the proportion of dry matter distributed to grains, and could significantly increase the soil pH. (2) Intercropping would reduce the nitrogen transfer ratio of the above-ground vegetative organs of maize plants and weaken the contribution rate to grain nitrogen accumulation. Compared with intercropping, the coupling of cultivation and fertilization measures could increase the nitrogen transfer ratio of the above-ground vegetative organs of maize plants and the contribution rate to grain nitrogen accumulation. (3) Crops had different fertilizer requirements at different growth stages. Maize was sensitive to soil pH, ammonium nitrogen and nitrate nitrogen content at the seedling stage; it was sensitive to soil available phosphorus and available potassium content at the vigorous vegetative growth stage, and it was sensitive to soil available potassium content at the reproductive growth stage.

Key words: soil acidification, rocky desertification, cultivation measures, fertilization measures, maize, nitrogen utilization efficiency, intercropping of maize and soybean