A suitable rotational conservation tillage system ameliorates soil physical properties and wheat yield: An 11-year in-situ study in a semi-arid agroecosystem

摘要

With the changing global climate, dryland agriculture faces major challenges related to soil water scarcity and soil erosion, threatening global food safety and sustainability. Conservation tillage rotation is considered to be an effective method that can better alleviate these threats if the plowing method is retained and incorporated into the popular no-tillage and subsoiling rotation systems. With this in mind, a long-term (2007-2018), plowing-based conservation rotational tillage experiment was established in an extraordinarily semi-arid region in Heyang Country, Shaanxi Province, China. Four treatments were applied: (1) a three-year rotation where the first year was no-tillage, the second year rotated via alternate plowing, and the third year was subsoiling tillage (NPS); (2) a two-year rotation alternating annual subsoiling tillage with plowing (SP); (3) a two-year rotation alternating annual plowing tillage with no-tillage (PN); and (4) continuous annual plowing (P). After the 11-year experiment, three rotational systems (NPS, SP, and PN) had significantly ameliorated soil bulk density (BD), porosity, and water-stable aggregates (WSA). Especially when compared to the P treatment, the SP rotation significantly reduced mean BD (5.19 %) and increased porosity (5.69 %) at 0-60 cm soil depth. This happened with higher amounts of water-stable macro-aggregates (26.92 %), and may have a synergetic relationship between the WSA of 2-5 and 0.25-2 mm at 30-40 cm soil depth. Also this significantly enhanced the average soil water storage (0-200 cm) under wet rainfall patterns (500.50 mm), and even occurred in extremely dry (391.37 mm) and wet (566.26 mm) years; as well significantly promoted the average water use efficiency (7.25 %) and yield (8.37 %), respectively. Overall, the SP rotation is a suitable agricultural tillage scenario for ameliorating soil bulk density, porosity, water-stable aggregates, water use and storage, yields, and profits that meet the variable climate of dryland farming ecosystem in the future.