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Purpose: On a global scale, water resources are under intense stress due to climate change. It is, therefore, crucial to understand how in situ water harvesting techniques and the addition of soil organic amendments such as biochar affect soil properties and productivity of alfalfa (Medicago sativa L.) to inform wider adoption by farmers. Methods: To contribute to this research area, an experiment was conducted at the Anjiagou Catchment experimental station during the 2020 to 2021 alfalfa growing seasons. The experimental design was a split-plot design with three replications. The main treatment was maize straw biochar, and the sub-treatment was ridge-furrow rainwater harvesting. The biochar treatments were 30 t ha−1 and 0 t ha−1, and the rainwater harvesting methods were flat planting (FP), tied-ridging (TR), and open-ridging (OR). Results: In 2020, soil temperature in the TR treatment decreased by 6.54 and by 4.08% for the OR treatment compared with the FP. In 2021, soil temperature decreased by 3.87 and 0.87% in the TR and OR, respectively, compared with the FP. In general, the integration of rainwater harvesting systems and maize straw biochar amendment significantly (p < 0.05) increased alfalfa fodder yield during the 2-year growing seasons investigated. Mean soil desiccation increased by 55.16% in the no-biochar–amended treatment compared to 52.58% for the biochar-amended soils. Overall, the highest net economic benefit throughout the 2 years of alfalfa cultivation was recorded in the TR and OR treatments with maize straw biochar addition. Conclusion: In both experimental years, ridge-furrow rainwater harvesting-planting with maize straw biochar produced the highest alfalfa fodder yield than the FP treatment and the no-biochar–amended soil. An important contribution of this work to smallholder forage farming is the evidence demonstrating the positive effects of maize straw biochar in ridge-furrow rainwater harvesting system on alfalfa fodder yield, water productivity, and economic benefit in rain-fed agriculture. [ABSTRACT FROM AUTHOR]

Background. Loss of organic matter and mineral nutrients to soil erosion in rain- fed agriculture is a serious problem globally, especially in China’s Loess Plateau. As a result, increasing rainwater usage efficiency by tied-ridge-furrow rainwater harvesting with biochar is expected to improve agricultural productivity. Nonetheless, with limited knowledge on tied-ridge-furrow rainwater harvesting with biochar, small-scale farmers face the challenge of adoption, thus, the rationale for this study. Materials and methods. A field experiment was conducted to determine the influence of open-ridging (OR) and tied-ridging (TR) with bio-degradable film on ridges and biochar in furrows on runoff, sediment losses, soil moisture, fodder yield, and water use efficiency (WUE) on sloped land, using flat planting (FP) without ridges and furrows as control, during alfalfa-growing year (2020). Results. Runoff in flat planting (30%), open ridging (45%), and tied ridging (52%) were decreased with biochar to the extent where sediment was decreased in flat planting (33%), open ridging (43%), and tied ridging (44%) as well. The mean runoff efficiency was lower in flat planting (31%), open ridging (45%), and tied ridging (50%) in biochar plots compared to no-biochar plots. In biochar and no-biochar plots, soil temperature on ridges of TR was higher than that on OR, which was higher than FP during alfalfa growing season. Soil temperature in furrows during alfalfa growing season in biochar and no-biochar plots were in the order FP > OR > TR. Mean soil water storage for FP, OR, and TR, in biochar plots was higher than in no-biochar plots. This indicates biochar has a beneficial impact on open riding. Total annual net fodder yield (NFY) was significantly (p = 0.00) higher in treatments in the order TR > OR > FP. Tied ridging had a significant effect on actual fodder yield (AFY) in biochar plots, while open ridging significantly affected AFY in no-biochar plots. Annual total mean NFY and AFY increased by 8% and 11% in biochar plots compared to no-biochar plots. In biochar and no-biochar plots, water use efficiency was in the order TR > OR > FP. Conclusively, water use efficiency was significantly higher (p = 0.01) in biochar plots compared to no-biochar plots. Conclusion. When crop production is threatened by soil erosion and drought, mulched tied-ridge with biochar is beneficial to crop growth in rain-fed agriculture, according to this research. Smallholder farmers should be trained on applying this technique for water-saving to mitigate runoff, soil erosion, sediment losses, and improve food security in semiarid areas. [ABSTRACT FROM AUTHOR]

Soil desiccation is a major challenge faced by subsistence farmers growing alfalfa (Medicago sativa L) in consecutive cultivation in semiarid regions. We hypothesized that alfalfa fodder yield would increase with the length of growing season, growing degree-days, and rainfall. A field experiment was conducted on alfalfa production from 2012 to 2016 to 1) determine the response of fodder yield to rainfall, the length of growing season, and accumulated growing degree day (AGDD) in different growing-cutting stage (GCS)s; 2) obtain the suitable mulching material and the optimum ridge width for ridges with manually compacted soil (MCS), mulched with bio-degradable film (BF), and plastic film (PF). There were 10 treatments (3 ridge widths × 3 ridge-mulching materials + flat planting (FP) as control) with three replications laid in a randomized block design. The ratio of the first GCS to the second GCS in fodder yield ranged from 1.10 to 4.55, which was similar to the ratio of the first GCS to the third GCS in fodder yield ranged from 1.14 to 4.59, although rainfall, the length of growing season, and AGDD were different during the two or three GCSs. The highest fodder yield was obtained from the first GCS in one year and reached the highest level in the second growing year, and maintained a similar level in the subsequent years, although rainfall, the length of growing season, and AGDD varied during the five year periods. Fodder yield was affected by both the rainfall in the GCS and the available soil moisture prior to the GCS. Compared to FP, the increase of evapotranspiration for MCS, BF, and PF was 11, 61, and 63 mm, respectively. Fodder yield for BF and PF increased by 28% and 33%, respectively. Fodder yield for MCS maintained the same level as that for FP. Evapotranspiration increased and fodder yield decreased as ridge width increased. The optimum ridge width for MCS, BF, and PF was 29, 39, and 37 cm, respectively, across five years. Future study should focus on alfalfa-crop rotation to mitigate soil desiccation after alfalfa consecutively production. • High rainfall, growing season length and temperature did not mean high alfalfa fodder yield. • Soil moisture prior to growing-cutting stage and rainfall in the stage had impact on alfalfa fodder yield. • Rainfall had higher effects on alfalfa fodder yield than actual evapotranspiration. • Highest fodder yield was obtained in first growing-cutting stage and reached highest level in second stand year. • Optimum ridge width for ridge compacted with soil, biodegradable and plastic film was 29, 39 and 37 cm, respectively. [ABSTRACT FROM AUTHOR]