Effect of potato legume intercropping composite system on carbon and nitrogen transfer characteristics and yield

Abstract: In order to investigate the effect of potato-legume intercropping on the activity of key enzymes of carbon and nitrogen transfer and yield of potato, and then to determine the suitable planting pattern of potato, to mitigate the barriers of potato succession, and to provide a reference for the cultivation of crops with high yields and high land utilisation in semi-arid areas of southern Ningxia. The experiment was carried out from May 2020 to September 2021 in Haiyuan County, Ningxia. A randomised block experiment design was adopted, and five treatments were set up, namely, potato monoculture (IP), soybean monoculture (IS), faba bean monoculture (IB), intercropping of potato and soybean (PS), and intercropping of potato and faba bean (PB), in which the potato leaves were tested for the effects of sucrose phosphosynthesis enzyme (SPS), sucrose synthase (SS), nitrate The results of the two-year study showed that intercropping potato with legume crops can significantly increase the activities of carbon and nitrogen transfer-related enzymes in potato leaves, increase the yield of the population and improve the land utilisation rate, with the best performance in the intercropping of potato with soybean (PS) treatment. 2020, compared with the intercropping of potato alone (IP), the intercropping of potato with soybean (PB) can significantly increase the activities of carbon and nitrogen transfer-related enzymes, increase the yield of the population and improve the land utilisation rate. Compared with potato monocropping (IP), the SS, SPS, GS, NR activity, soluble sugar and soluble protein contents of PS and PB treatments increased by 5.87% to 20.39%, 10.47% to 16.75%, 12.53% to 18.06%, 13.59% to 38.01%, 5.84% to 7.81%, 6.27% to 17.14% and 1.32% to 9.68%, 5.19% to 10.27%, 3.28% to 9.86%, 8.35% to 27.05%, 1.47% to 4.61% and 5.62% to 10.07%, and the performance in 2021 was consistent with that in 2020. Correlation analysis showed that each index of soluble sugar, soluble protein, SS, SPS, GS, and NR was highly significant and positively correlated with yield, and there was a highly significant positive correlation between the key enzymes of carbon metabolism, SS, SPS, and the enzymes related to nitrogen metabolism, GS and NR. Principal component analysis showed that intercropping between potato and legume crops mainly promoted yield formation by increasing soluble sugar, SPS, GS, and NR. The land equivalent ratio (LER) in both intercropping systems was greater than 1, with intercropping yield advantages, and intercropping between potato and soybean was optimal. In conclusion, in the semi-arid zone of southern Ningxia, in order to improve the barriers to continuous cropping, improve land utilisation and enhance yield, potato cultivation can adopt intercropping between potato and legume crops, with potato intercropped with soybean (PS) as the best treatment.
Keywords: Potato; Legumes; Intercropping; Carbon and nitrogen transfer characteristics; Land equivalence ratio; Crops