Agriculture in rainfed dry areas is often challenged by inadequate water and nutrient supplies. Summerfallowing has been used to conserve rainwater and promote the release of nitrogen via the N mineralization of soil organic matter. However, summerfallowing leaves land without any crops planted for one entire growing season, creating lost production opportunity. Additionally, summerfallowing has serious environmental consequences. It is unknown whether alternative systems can be developed to retain the beneficial features of summerfallowing with little or no environmental impact. Here, we show that diversifying cropping systems with pulse crops can enhance soil water conservation, improve soil N availability, and increase system productivity. A 3-yr cropping sequence study, repeated for five cycles in Saskatchewan from 2005 to 2011, shows that both pulse-and summerfallow-based systems enhances soil N availability, but the pulse system employs biological fixation of atmospheric N 2 , whereas the summerfallow-system relies on 'mining' soil N with depleting soil organic matter. In a 3-yr cropping cycle, the pulse system increased total grain production by 35.5%, improved protein yield by 50.9%, and enhanced fertilizer-N use efficiency by 33.0% over the summerfallow system. Diversifying cropping systems with pulses can serve as an effective alternative to summerfallowing in rainfed dry areas.

Water shortage threatens agricultural sustainability in many arid and semiarid areas of the world. It is unknown whether improved water conservation practices can be developed to alleviate this issue while increasing crop productivity. In this study, we developed a "double mulching" system, i.e., plastic film coupled with straw mulch, integrated together with intensified strip intercropping. We determined (i) the responses of soil evaporation and moisture conservation to the integrated double mulching system and (ii) the change of soil temperature during key plant growth stages under the integrated systems. Experiments were carried out in northwest China in 2009 to 2011. Results show that wheat-maize strip intercropping in combination with plastic film and straw covering on the soil surface increased soil moisture (mm) by an average of 3.8 % before sowing, 5.3 % during the wheat and maize co-growth period, 4.4 % after wheat harvest, and 4.9 % after maize harvest, compared to conventional practice (control). The double mulching decreased total evapotranspiration of the two intercrops by an average of 4.6 % (P < 0.05), compared to control. An added feature was that the double mulching system decreased soil temperature in the top 10-cm depth by 1.26 to 1.31 °C in the strips of the cool-season wheat, and by 1.31 to 1.51 °C in the strips of the warm-season maize through the 2 years. Soil temperature of maize strips higher as 1.25 to 1.94 °C than that of wheat strips in the top 10-cm soil depth under intercropping with the double mulching system; especially higher as 1.58 to 2.11 °C under intercropping with the conventional tillage; this allows the two intercrops to grow in a well "collaborative" status under the double mulching system during their co-growth period. The improvement of soil moisture and the optimization of soil temperature for the two intercrops allow us to conclude that wheat-maize intensification with the double mulching system can be used as an effective farming model in alleviating water shortage issues experiencing in water shortage areas.

Nearly 90% of the 390 million ha of grasslands in northern China are degraded. ‘Grazing exclusion’ has been implemented as a nature‐based solution to rejuvenate degraded grasslands, but the effectiveness of the rejuvenation processes is uncertain. Here, we investigated the effects of grazing exclusion on aboveground plant community traits, soil physiochemical and biological properties, and the mechanisms responsible for enhanced grassland rejuvenation. A meta‐analysis across various studies was used to assess the effectiveness. On average, grazing exclusion improved vegetation coverage by 18.5 percentage points and increased aboveground biomass by 1.13 t ha−1 and root biomass by 1.27 t ha−1, which represent an increase of 84%, 246%, and 31%, respectively, compared with continuous grazing practices. Grazing exclusion reduced soil bulk density by 13.7% and increased soil water content by 68.9%. Grasslands under grazing exclusion increased soil organic carbon (SOC) in the 0‐ to 15‐cm depth by 3.95 (±0.35 Std err) t ha−1 and total soil N, available N, and total soil P in the 0‐ to 40‐cm depth by 2.39 (±0.14), 0.83 (±0.37), and 1.96 (±0.44) t ha−1, respectively, compared with continuous grazing; these values represent an increase of 31%, 25%, 23%, and 14%, respectively. Prolonging the duration (years) of grazing practices enlarged the differences in SOC and soil N content between grazing exclusion and continuous grazing. Grazing exclusion has improved plant community traits and enhanced soil physiochemical and biological properties of degraded grasslands, and thus, this ‘nature‐based’ approach can serve as an effective means to rejuvenate degraded grasslands.

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Diverse crop rotations enable the best use of residual soil water and nutrients, thus decreasing necessary production inputs. Here, we determined the effect of cropping sequences on soil residual water and nutrients and the performance of subsequent wheat (Triticum aestivum L.). Nine rotation systems were evaluated at Swift Current, SK, and Brooks, AB, from 2010 to 2014. Pea (P, Pisum sativum L.) and lentil (L, Lens culinaris Medik.) as preceding crops before wheat (W) or the rotation systems with pea (P-P-P-W) or lentil (L-L-L-W) included more than once in the 4-yr rotations had the highest residual soil water and N in the 30-90 cm depth and continuous wheat (W-W-W-W) had the lowest. Preceding pea and lentil increased the grain yield of the subsequent wheat by 26% and 18%, respectively, as compared with continuous wheat. Variance partitioning of redundancy analysis revealed that soil residual water and residual N explained 12.4%-42.7% (average 30%) of the yield variation observed in the subsequent wheat, with the rest of the rotational benefits unexplainable by soil residual water and residual nutrients. Investigation of the factors other than soil water and nutrients that contribute to the succeeding wheat yield may further enhance the rotational effect.

Food security has been a significant issue for the livelihood of smallholder family farms in highly populated regions and countries. Industrialized farming in more developed countries has increased global food supply to meet the demand, but the excessive use of synthetic fertilizers and pesticides has negative environmental impacts. Finding sustainable ways to grow more food with a smaller environmental footprint is critical. We developed an integrated cropping system that incorporates four key components: 1) intensified cropping through relay planting or intercropping, 2) within-field strip rotation, 3) soil mulching with available means, such as crop straw, and 4) no-till or reduced tillage. Sixteen field experiments, conducted with a wide range of crop inputs over 12 consecutive years (2006 to 2017), showed that the integrated system with intercropping generates significant synergies—increasing annual crop yields by 15.6 to 49.9% and farm net returns by 39.2% and decreasing the environmental footprint by 17.3%—when compared with traditional monoculture cropping. We conclude that smallholder farmers can achieve the dual goals of growing more food and lowering the environmental footprint by adopting integrated farming systems.

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