Rapid fertilization effect in soils after gully control and land reclamation in loess hilly and gully region of China

Land degradation is being widely recognized as a serious challenge in arid and semiarid environments worldwide and limited rapid development of agriculture. Although land reclamation and the newly-construction cultivated land have increased the area and agricultural mechanization of cultivated land, while its land fertility is low and poor physical structure and hydraulic conditions, which cannot meet the good quality and high yields of crops. Therefore, quickly and effectively fertilizing soil plays a vital role in the rapid development of agriculture in the region. However, the traditional soil fertilization systems and the technology of construction high-quality tillage layer are slow and the results are unremarkable. So, this study was conducted to investigate the potential for using additional organic amendments (woody peat, biochar, straw, etc.) to improve soil organic matter and nutrients, soil fertility, and plant growth in the newly-construction cultivated land on the loess plateau, China. The newly-construction cultivated lands are dammed land and terrace which from gully control and land reclamation project on the loess hilly and gully area, which is located in Kangping Village (36°44’N, 109°35’ E), Yan'an City, Shaanxi Province, China. The dam land has been selected study site. Field located experiments and laboratory analyses were combined. Three modes have been set in the experiment from 2016 to 2018: i) Recommended mode, ii) New mode, iii) Control mode. And the experiment was consisted of six treatments: woody peat (37.5 t/hm2) + bio-activator+ decomposed straw (A1), woody peat (37.5 t/hm2) + decomposed straw (A2); woody peat (15 t/hm2) + decomposed straw (B1), biochar (15 t/hm2) + decomposed straw (B2); decomposed straw (C1), control (C2). The results showed that: 1) Applying additional organic amendments (especially the woody peat) had great rapid effect on soil organic matter and readily oxidized carbon. Among them, when the wood peat was applied at 37.5 t/hm2, it undergoes a maize growth period. Compared with control (C2), the soil organic matter and readily oxidizable carbon of the tillage layer(0~15 cm)increased by 1.33 and 3.15 times, respectively. However, the organic matter could be quickly decomposed and consumption in the first year and second year during the maize growing period, especially adding the application of biological excitation regulators. In the third year, organic matter could be improved and protected. 2) For three consecutive years from 2016 to 2018, woody peat combined with bio-activator could increase corn grain yield, with the highest yield of maize grain yield in 2016 and 2017, 12 169 kg/hm2 and 14 396 kg/hm2, respectively. And the maize grain yield was 15 983 kg/hm2 in third year. Compared with the control for three consecutive years, the maize grain yield increased by 17.5%, 28.6% and 1.0%, respectively. 3) Biochar application could also increase the nutrient content of organic matter, total nitrogen, total potassium, and available phosphorus, but the content of readily oxidized carbon was significantly reduced, and the impacts on increasing grain yield of maize were lower than woody peat. In conclusion, additional woody peat can serve as a valuable amendment for the newly-constructed cultivated land in the loess plateau and other places of Northwest China by increasing soil organic and readily oxidizable carbon, improving soil fertility and promoting higher crop yields. Therefore, wood peat + bio-activator + decomposed straw + fertilizer is the best model for rapid construction of high-quality tillage layer in loess area. © 2019, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.