Abstract: Abstract Aims Aiming at the problems of expanding saline and alkaline land area and decreasing yield of planted maize in Yinhuang Irrigation District of Ningxia, this study aimed to investigate the effects of vertical deep rotary tillage with organic fertilizer on the senescence characteristics and yield of maize leaves, and to provide a theoretical basis for delaying senescence and increasing the yield of maize in saline and alkaline land in this area. Methods A split-zone trial was conducted in Pingluo County, Ningxia from 2021 to 2022. Two types of tillage methods, conventional tillage (TF, tilling depth 25-30 cm) and vertical deep rotary tillage (DT, depth 40-45 cm), were set as the main zone, and four levels of organic fertilizer consumption, namely, 0 kg·hm-2 (M0), 7,500 kg·hm-2 (M1), 15,000 kg·hm-2 (M2) and 22,500 kg·hm-2 (M3), were set as the sub-zones. (M2), 7,500 kg·hm-2 (M1), 15,000 kg·hm-2 (M2) and 22,500 kg·hm-2 (M3) levels of organic fertilizer were used as sub-zones to analyze the yield and leaf senescence characteristics of maize in saline soil. Important findings (1) Corn yield was significantly increased when vertical deep rotary tillage was applied with 15000 kg·hm-2 organic fertilizer (M2 treatment), and the yield could be maximized by keeping the amount of organic fertilizer in the range of 14505~16710 kg·hm-2; under this treatment, the leaf area index (LAI), relative chlorophyll content The leaf area index (LAI) and relative chlorophyll content (SPAD) of maize were significantly increased under this treatment, and the onset of leaf senescence was delayed by 2.9~13.9 d. (2) Vertical deep rotary tillage with organic fertilizers decreased soil pH and EC, increased alkaline nitrogen (AN), effective phosphorus (AP), quick-acting potassium (AK) and organic matter (OM), significantly increased superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities and decreased proline (Pro) and malondialdehyde (MDA) contents, and significantly increased soluble sugar (SS) accumulation compared with other treatments. (MDA) and significantly increased soluble sugar (SS) content. The M2 treatment was the best, compared with the M3 treatment, where excessive organic fertilizer inputs increased soil pH and EC, reduced nutrients, decreased SOD, POD, CAT, SS, and Pro, and increased MDA accumulation, which inhibited maize growth and sustained yield improvement. (3) Pearson correlation analysis showed that maize yield was significantly or highly significantly positively correlated with LAI, SPAD, SOD, POD, CAT, Pro, and SS of leaves and AN, AK, and OM of soil, and significantly or highly significantly negatively correlated with MDA and EC. (4) The principal component analysis showed that the composite score under vertical deep rotary tillage with organic fertilizer treatment showed the trend of M2＞M3＞M1＞M0. In this study, vertical deep rotary tillage with 15000 kg·hm-2 organic fertilizer (M2) effectively improved saline soil environment, delayed leaf senescence, increased leaf antioxidant enzyme activities, and reduced MDA accumulation, which in turn increased maize yield.

Key words: Keywords Maize, Tillage practices, Organic fertilizer dosage, Leaf physiological properties, Soil chemical properties, Yield