Improving crop productivity by optimizing straw returning patterns to delay senescence of wheat leaves

Climate change poses a significant risk to food security. Recent floods in Pakistan could serve as an example. In the current climate change scenario, there is a dire need to develop methods that increase crop productivity and reduce the threat of food insecurity in areas with low crop production. A detailed field experiment was conducted to check the effects of intercropping and straw mulching under conventional tillage (CT) and no tillage (NT) systems on soil health indicators and cotton productivity at the experimental area of Khwaja Fareed University of Engineering and Information Technology (KFUEIT), Rahim Yar Khan, Pakistan. The main plot treatments comprised CT and NT. The subplot treatments were sole cotton (C1), cotton + mung-bean intercropping (C2), cotton + mung-bean + straw mulching (C3) and cotton + straw mulching (C4) under CT, while sole cotton (N1), cotton + mung-bean intercropping (N2), cotton + mung-bean + straw mulching (N3) and cotton + straw mulching (N4) were the NT subplot treatments. Overall, NT increased plant height by 18.4 %, chlorophyll a and b contents by 28.2 and 21.1%, respectively, mean boll weight by 17.9%, and seed yield by 20.9% compared to CT (P < 0.05). The interaction of tillage and mulching increased plant height by 7.0% under CT and 21.8% under NT in comparison with no mulching. Similarly, straw mulching under NT increased chlorophyll a and b contents by 41.9 and 28.5%, respectively, mean boll weight by 26.9%, and cotton seed yield by 23.0% in comparison with no mulching under NT. Intercropping decreased crop yield without straw mulching but increased it under straw mulching. Further, straw mulching increased soil physicochemical properties under NT, which contributed to increasing crop productivity. We concluded that straw mulching under NT might be a promising practice for enhancing cotton yield, productivity, and soil health in low-productivity areas.

The field mulching could improve sustainability of spring maize production on the Loess Plateau

Effect of tillage practices on net carbon flux and economic parameters from farmland on the Loess Plateau in China

The present study investigated changes in endogenous hormones and protective enzyme activities in response to Psa (biovar 2) infection in resistant and susceptible accessions of Actinidia arguta. The resistant accession “Cuiyu” and susceptible accession “TL02062” were inoculated with Psa “R12.” The activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), phenylalanine ammonia-lyase (PAL), and polyphenol oxidase (PPO), as well as contents of salicylic acid (SA), jasmonic acid (JA), total phenolic, and lignin in plant stems at days 0 (CK), 2, 7, and 14 after inoculation were assessed. After inoculation, the activities of SOD, POD, PAL, and PPO in both resistant and susceptible accessions were significantly increased. The JA content in resistant accessions increased, while that in the susceptible accessions first decreased and then increased. The total phenolic contents of resistant accessions were higher than those of susceptible accessions. The SA content was positively correlated with the JA content and with PAL and POD activities. Lignin content was negatively correlated with the levels of SA, JA, and the activities of PAL and POD. The disease resistance of A. arguta is significant correlations with the levels of SA and JA, as well as the accumulation of polyphenolic compounds. This research indicates that SA and PAL play a pivotal role in regulating the defense responses of A. arguta against Psa infection. By comparing the differential physiological responses of resistant and susceptible accessions to Psa “R12,” this study provides novel theoretical insights into the physiological and biochemical mechanisms underlying disease resistance in A. arguta, offering valuable references for guiding disease-resistant breeding programs.

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 2years. 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.

To evaluate the effects of straw mulching and tillage on the soil water, soil temperature, and water use efficiency of maize (Zea mays L.), five straw mulching and tillage treatments were established: conventional tillage with no straw mulching (CK), conventional tillage with 1.0-fold straw mulching (CM1), no-tillage with 0.5-fold straw mulching (NM0.5), no-tillage with 1.0-fold straw mulching (NM1), and no-tillage with 1.5-fold straw mulching (NM1.5). Except for the soil water content in the 40 to 60 cm soil layer at the V3 stage, straw mulching improved the soil water content, had different effects on the soil temperature at different soil depths, and improved the water use efficiency by 7.24%. As the straw mulching quantity increased, the soil water content and water use efficiency increased, and soil temperature in the different soil layers and growth stages presented different trends. In addition to the soil water content at the V6 growth stage, no-tillage improved the soil water content, soil temperature, and water use efficiency compared with conventional tillage. Overall, NM1.5 had the best soil water conservation and temperature increasing effects, significantly improved the water use efficiency, and was the most appropriate straw mulching and tillage measure in the research area.

Heat stress due to climate change irreparably affects all physiological and biochemical processes of plants, such as photosynthesis, respiration, and hormonal metabolism, decreasing growth and development and reducing yield and quality traits. It is, therefore, imperative to be acquainted with stress-related physiological responses of plants to cope with heat stress, which is predicted to continue to increase due to climate change. The goals of this study were to compare abscisic acid (ABA), jasmonic acid (JA), and salicylic acid (SA) contents and chlorophyll content (SPAD) and maximum quantum efficiency of PSII ( F v /F m ) values in Phaseolus species under heat-stress and non-stress conditions. Eight heat-tolerant and two heat-sensitive bean genotypes, including common bean ( P. vulgaris L.), tepary bean ( P. acutifolius A. Gray), runner bean ( P. coccineus L.), and lima bean ( P. lunatus L.), were grown in the greenhouse. ABA, JA, and SA significantly varied among Phaseolus species and between heat-tolerant and heat-sensitive bean genotypes. ABA, JA, and SA contents were higher under heat-stress conditions than under non-stress conditions, suggesting that these stress-related hormones played a crucial role in survival strategy. In contrast, chlorophyll content and maximum quantum efficiency of PSII values were higher under non-stress conditions. Under non-stress conditions, the heat-tolerant genotypes commonly had lower JA and SA contents than the heat-sensitive genotypes, indicating that the heat-tolerant genotypes had a superior stress threshold. The lower JA and SA contents might be evaluated as selection criteria to discriminate heat-tolerant and heat-sensitive genotypes without exposure to heat stress. Additionally, path analysis was conducted to determine the direct and indirect effects of biochemical and physiological traits on chlorophyll content. The analysis revealed that the fold change in SA had the most significant positive direct effect on chlorophyll content, while the fold change in total phytohormones exhibited a strong negative direct effect. Indirect effects highlighted the complex interactions among phytohormones, particularly the antagonistic influence of ABA over SA. Besides, heat-tolerant genotypes had acquired unique adaptive characteristics to cope with heat stress, probably during the evolutionary process before domestication.

We examined the correlation between changes of root morphology and endogenous hormones in intercropping systems of wheat and faba bean under different phosphorus levels by hydroponics. Compared with monocropping wheat (MW), the intercropping of wheat and faba bean (W∥F) significantly increased root length of wheat, reduced root average diameter of wheat, and increased root surface area under the condition of 1/2P (low P) level. At the conventional phosphorus level, intercropping significantly reduced root average diameter of wheat, and increased root length and root surface area. Compared with monocropping faba bean (MF), W∥F significantly promoted the growth of faba bean root and increased root surface area of faba bean. At the level of 1/2P, intercropping significantly increased the content of auxin (IAA), abscisic acid (ABA), sali-cylic acid (SA) and jasmonic acid (JA). At the conventional phosphorus level, intercropping could significantly increase the content of IAA, ABA and JA in wheat root, while no significant difference in the SA content of wheat root between monocropping and intercropping wheat was found. Intercropping could increase the content of ABA and SA in faba bean roots, but did not affect IAA and JA contents of faba bean roots. There was no significant correlation between the contents of endogenous hormones (IAA, ABA, SA and JA) and root morphology (root length, root average diameter and root surface area) of wheat and faba bean roots in wheat or faba bean monocropping system. In wheat and faba bean intercropping system, there was a positive correlation between IAA contents of wheat and faba bean and their root length and root surface area. W∥F enhanced IAA of wheat and faba bean root, which was an important factor driving the change of root morphology in the intercropping system of wheat and faba bean.

Straw mulching is more important than no tillage in yield improvement on the Chinese Loess Plateau

The resistance of the jujube (Ziziphus jujuba) to the devastating insect pest Apolygus lucorum (Hemiptera, Insecta) involves the jasmonic acid signaling pathway

In the hilly areas of southern China, uplands and paddies are located adjacent to each other. Using rice straw as mulch for upland soil may improve crop production and partially replace chemical fertilizers, which may mitigate N2O emissions. A field experiment was conducted to investigate the potential of rice straw mulching for mitigating N2O emissions and increasing crop production. The treatments included no mulching (CK), 5000kgha-1 of straw mulching (SM5), and 10,000kgha-1 of straw mulching (SM10). Moreover, all the treatments received equivalent amounts of nitrogen, phosphorus, and potassium from chemical fertilizers plus rice straw. Relative to CK, cumulative N2O emissions decreased by 23.1 and 33.5% with SM5 and SM10, respectively. Significant positive correlations were observed between N2O fluxes and soil water-filled pore space (WPFS) (r 2 = 0.495, P < 0.05) and between seasonal cumulative N2O fluxes and the chemical N fertilization rate (r 2 = 0.814, P < 0.05). These findings indicate that soil WPFS was the key environmental factor in N2O emissions and that the substitution of chemical nitrogen fertilizer with rice straw was the main driver of N2O mitigation. Relative to CK, the maize yield increased by 16.5 and 29.6% with SM5 and SM10, respectively, which can be attributed primarily to the increases in soil moisture. The chemical fertilizer input could be decreased and N2O emissions could be mitigated through straw mulching, while achieving improved crop yield. This management strategy has great potential, and this study provides an important reference for low-carbon agriculture.

This paper analyzes the relationship between runoff, soil erosion, sediment particles, and natural rainfall characteristics on sloping farmland in the red soil region of southern China. The surface runoff and soil loss data were measured on runoff plots during 66 natural rainfall events from 2015 to 2018 in Jiangxi Province. The results show that the maximum 30-min rainfall intensity (I30) is positively related to the runoff depth, soil erosion modulus, and sediment mean weight diameter (MWD). With the increase in I30 during rainfall, the coarse sand content increases, and the fine sand content decreases. The average annual runoff of slope tillage, hedgerows with slope tillage, straw mulching with conventional tillage, and contour tillage decreased by 32.56%, 65.87%, 83.99%, and 87.30%, respectively, compared with that of bare land. Soil and water conservation measures can significantly reduce slope runoff. The flow-reduction effect of contour tillage and straw mulching with conventional tillage increases as I30 increases, and the flow-reduction effect of hedgerows with slope tillage first increases and then decreases as I30 increases. The coefficients of variation and standard deviations of the flow-reduction effects of different soil and water conservation measures decrease with increasing I30. The average annual soil erosion moduli of slope tillage, hedgerows with slope tillage, contour tillage, and straw mulching with conventional tillage decreased by 59.33%, 91.29%, 97.17%, and 98.45%, respectively, compared with that of bare land. Soil and water conservation measures can significantly reduce the sediment yield on slopes. The flow-reduction effects of hedgerows with slope tillage, contour tillage, and straw mulching with conventional tillage all increase with I30, and their coefficients of variation and standard deviations decrease with I30. The average single rainfall erosion sediment MWD of decreased by 5.91%, 8.33%, 9.69%, and 13.32%, respectively, compared with that of bare land. Straw mulching with conventional tillage can significantly reduce the MWD of erosion sediment, effectively reduce the content of coarse sand, and increase the content of fine sand. Straw mulching with conventional tillage is a very good soil and water conservation measure for sloping farmland. It not only has the best effect on reducing flow and sediment, but also can effectively intercept coarse sand and reduce the MWD of erosion sediment.

Straw and plastic mulching have been widely used in northwest China because of their ability to improve water use efficiency and increase grain yields. However, the dynamic changes of soil carbon (C) and nitrogen (N) under continuous straw and plastic mulching is rarely mentioned. A field experiment was conducted over four consecutive wheat (Triticum aestivum L.)-maize (Zea mays L.) rotation cycles in Northwest China to determine dynamic changes in soil C and N under three treatments: CK (traditional non-mulched), PM (transparent plastic mulching), and SM (straw mulching). Over the four wheat–maize cycles, soil organic carbon (SOC) in SM increased by 18% in the 0–0.2 m soil layer, while in PM SOC decreased by 15%, and in CK SOC changed little. Total N under CK and SM remained basically unchanged over time, but declined over time under PM. The overall microbial biomass carbon (MBC) and nitrogen (MBN) under SM increased by 32% and 17%, respectively, after four rotation cycles compared with significant decreases of 29% and 22% under PM and little change under CK. SM reduced soil temperature and increased soil water content, while PM increased both ST and water relation to the CK. Both SM and PM treatments increased grain yield and reduced nitrate N leaching. In the long run, straw mulching can improve SOC, MBC, MBN, and wheat–maize yield, and should be the recommended mulching practice for sustainable wheat–maize production in dryland areas in response to the potential challenges of climate change to dryland agriculture.

Abstract. This study investigated the response mechanisms of maize leaf photosynthetic characteristics to straw mulching and tillage measures in the black soil region of northeast China. Five treatments were established based on tillage and the average straw mulch yield from prior years (6500 kg ha-1): conventional tillage with no straw mulching (CK), conventional tillage with 1.0-fold (6500 kg ha-1) mulching (CM1), no tillage with 0.5-fold (3250 kg ha-1) mulching (NM0.5), no tillage with 1.0-fold (6500 kg ha-1) mulching (NM1), and no tillage with 1.5-fold (9750 kg ha-1) mulching (NM1.5). The net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, and light response curves of maize leaves were determined and compared between the treatments with different straw mulching amounts and farming methods and between different growth stages. The photosynthetic capacity of maize leaves was greater under NM1.5 than under the other treatments except at the V6 growth stage, and the increase in yield was the most obvious effect. The photosynthetic capacity of maize leaves can be improved by increasing the quantity of straw mulch. The photosynthesis of maize was affected by nonstomatal factors at different growth stages, and straw mulching reduced the negative effects of nonstomatal factors on the photosynthesis of maize leaves. Based on a light response model of the photosynthetic rate, the maximum net photosynthetic rate, light saturation point, and apparent quantum efficiency increased as the straw mulch quantity increased, and the magnitude of the increase was greatest between the 1.0-fold and 0.5-fold straw mulching treatments. This finding indicated that straw mulching can increase the adaptability of maize to strong light and improve the efficiency of maize under weak light; moreover, the NM1.5 treatment led to the greatest improvement in the light response characteristics of maize leaves. Keywords: Photosynthetic characteristic, Photosynthetic light response curve, Straw mulching, Tillage measure.

Effects of tillage and straw mulching on the crop productivity and hydrothermal resource utilization in a winter wheat-summer maize rotation system