Potatoes (Solanum tuberosum) are the most important noncereal crop in the world. Increasing potato production is critical for future global food security. China is the world’s largest potato producer, and potato productivity is constrained by water scarcity and poor fertilizer use efficiency (NUE_F). Recently, autumn film mulched ridge microfurrow rainwater harvesting (ARF) tillage has been successfully applied in potato production in dryland farming in Northwest China. However, the effects of ARF on the use efficiency (NUE_F) of applied nitrogen (N), phosphorus (P), and potassium (K) nutrients in potatoes have not been systematically studied. A 3-year, consecutive field trial with four treatments, including moldboard planting without fertilizer application (control, CK), spring and autumn film mulched ridge microfurrow rainwater harvesting planting (SRF and ARF), and standard film mulched ridge-furrow planting (FRF), was conducted during 2018–2020. ARF greatly increased the water levels in the 0–200 cm soil profile at potato harvest compared to SRF, FRF, and CK. ARF and SRF significantly increased the levels of soil organic carbon (SOC), total and available NPK (TN, TP, TK and AN, AP, AK) compared to FRF and CK, with ARF being the most efficient at increasing the levels of the AN, AP, and AK. ARF significantly improved the soil water and nutrient activity and contributed the most to potato tuber and biomass yield and hence the NUE_F. Under ARF, significant and positive associations were observed between the soil fertility traits, soil water storage (SWS), potato tuber yield, biomass yield, and NUE_F. Soil fertility traits and the SWS were positively correlated with potato tuber and biomass yield. The SWS, potato tuber, and biomass yield positively correlated with the partial factor productivity (PFP) and the recovery efficiency (RE) of the applied NPK nutrients. Increased nutrient levels and their combination increased the NUEF and NUEF’s components. The TN and AN contributed more significantly to the PEP and agronomic efficiency (AE) of the applied NPK nutrients; the TP was significantly positively correlated with the AE (AE_N, AE_P, and AE_K), while the AP was correlated with PEP (PFP_N, PFP_P, and PFP_K) and RE (RE_N, RE_P, and RE_K); the TK was significantly positively correlated with the PFP and RE of the applied PK nutrients, while the AK was significantly positively correlated with the PE_P, AE, and RE of the applied K nutrients. Therefore, ARF results in a synchronous increase in yield and NUE_F and is the most efficient planting system for potato production in dryland farming.

Film mulched ridge-furrow tillage (FMRF) with straw incorporation (S) can efficiently improve rain-fed maize yield and water use efficiency (WUE). The key mechanisms were investigated via a 3-year consecutive FMRF and S interactive experiments [CP (conventional planting, Control), CP_S, FMRF, FMRF_S] from 2014 to 2016. In comparison with CP, FMRF_S increased the temperature by 1.8°C to 4.8°C and the soil water content of 0–200 cm soil profile (W₂₀₀) by 98.0 mm to 106.7 mm from the seedling to tasseling stage, and decreased the temperature by 1.1°C to 3.7°C from flowering to maturity. The concentrations of soil organic carbon (SOC), soil total and available nitrogen, phosphorus and potassium (TN, TP, TK and AN, AP, AK) were also remarkable increased by 5.9% to 55.1% (P < 0.05) for FMRF_S, respectively. FMRF_S considerably mitigated the effects of the frequent water and heat stress and fertility deficit and led to a higher maize yield (27.0% to 40.0%), improved WUE (1.4-folds to 2.0-folds). The W₂₀₀, SOC, TN, TP, AN and AP significant contribute to maize yield. Therefore, FMRF_S not only enhanced the soil fertility but also maintained soil water balance, thus causing a significant increase in maize yield and WUE.

Commercial humic fertilizers (humates) can be used to improve carbon sequestration. In this study, a 3-year field trial (2016–2018) employed four treatments to investigate the mechanism by which humate increases carbon sequestration in fluvo-aquic soils: (1) blank: bare soil with no agricultural treatment; (2) control: standard film mulch (FM) ridge-furrow tillage (which acts as CK); (3) humate: FM tillage plus humate; and (4) straw: FM tillage plus straw. The three treatments strongly affected the soil carbon sequestration, with the humate and straw treatments more significant than the blank treatment. Moreover, the ≥2.0-mm macroaggregate fraction, >1-mm soil aggregate-associated carbon, weight mean diameter (MWD) and geometric mean diameter (GMD), and microbial biomass nitrogen (MBN) values for the straw and humate treatments were all significantly increased (p < 0.05), increasing the carbon sequestration by 1.9 and 0.9 Mg C ha⁻¹y⁻¹ compared to the control, respectively. Carbon sequestration was significantly associated with >1.0-mm aggregate-associated C, MWD, GMD, MBN, and organic C input. Humate and straw synergistically regulate the soil and microbial processes and greatly increase the straw C return to soil while efficiently increasing the macroaggregate fraction and stability, macroaggregate-associated carbon, and physical protection of aggregates, thereby increasing the carbon sequestration. Therefore, humate may be a novel economical alternative to straw to efficiently increase the carbon sequestration in dry fluvo-aquic soils.