Wheat-maize Intercropping Research Articles

High productivity of wheat intercropped with maize is associated with plant architectural responses

Mixed cultivation of crops often results in increased production per unit land area, but the underlying mechanisms are poorly understood. Plants in intercrops grow differently from plants in single crops; however, no study has shown the association between plant plastic responses and the yield advantage. Here, we assessed the productivity of wheat-maize intercropping as compared to sole wheat and sole maize, and the associated differences in wheat shoot and leaf traits. In two field experiments, intercrop wheat and maize were both grown in alternating strips consisting of six rows of wheat and two rows of maize. The traits of wheat plants in border rows of the strips were compared to the traits of plants in the inner rows as well as those in sole wheat. Leaf development, chlorophyll concentration and azimuth, as well as the final leaf and ear sizes, tiller dynamics of wheat and yield components of both crops were determined. The relative densities of wheat and maize in the intercrop were 0.33 and 0.67, respectively, but the corresponding relative yields compared to the respective monocultures were 0.46 for wheat and 0.77 for maize. Compared to wheat plants in the inner rows of the intercrop strips as well as in the monoculture, border-row wheat plants in the intercrop strips had (a) more tillers owing to increased tiller production and survival, and thus more ears, (b) larger top leaves on the main stem and tillers, (c) higher chlorophyll concentration in leaves, (d) greater number of kernels per ear and (e) smaller thousand-grain weight. Grain yield per metre row length of border-row wheat was 141% higher than the sole wheat, and was 176% higher than the inner-row wheat. The results demonstrate the importance of plasticity in architectural traits for yield advantage in multispecies cropping systems.

Greenhouse gas emissions and stocks of soil carbon and nitrogen from a 20-year fertilised wheat-maize intercropping system: A model approach

Accurate modelling of agricultural management impacts on greenhouse gas emissions and the cycling of carbon and nitrogen is complicated due to interactions between various processes and the disturbance caused by field management. In this study, a process-based model, the Soil-Plant-Atmosphere Continuum System (SPACSYS), was used to simulate the effects of different fertilisation regimes on crop yields, the dynamics of soil organic carbon (SOC) and total nitrogen (SN) stocks from 1990 to 2010, and soil CO2 (2007–2010) and N2O (2007–2008) emissions based on a long-term fertilisation experiment with a winter-wheat (Triticum Aestivum L.) and summer-maize (Zea mays L.) intercropping system in Eutric Cambisol (FAO) soil in southern China. Three fertilisation treatments were 1) unfertilised (Control), 2) chemical nitrogen, phosphorus and potassium (NPK), and 3) NPK plus pig manure (NPKM). Statistical analyses indicated that the SPACSYS model can reasonably simulate the yields of wheat and maize, the evolution of SOC and SN stocks and soil CO2 and N2O emissions. The simulations showed that the NPKM treatment had the highest values of crop yields, SOC and SN stocks, and soil CO2 and N2O emissions were the lowest from the Control treatment. Furthermore, the simulated results showed that manure amendment along with chemical fertiliser applications led to both C (1017 ± 470 kg C ha−1 yr−1) and N gains (91.7 ± 15.1 kg N ha−1 yr−1) in the plant-soil system, while the Control treatment caused a slight loss in C and N. In conclusion, the SPACSYS model can accurately simulate the processes of C and N as affected by various fertilisation treatments in the red soil. Furthermore, application of chemical fertilisers plus manure could be a suitable management for ensuring crop yield and sustaining soil fertility in the red soil region, but the ratio of chemical fertilisers to manure should be optimized to reduce C and N losses to the environment.

Water use and crop coefficient of the wheat–maize strip intercropping system for an arid region in northwestern China

Relay strip intercropping of spring wheat and maize is practiced on a large scale in arid regions of northwestern China. In this study, a field experiment was carried out during 2012 and 2013 growing seasons to examine water use and crop coefficient of this system in an arid environment. The experiment comprised three treatments: sole-cropped wheat, sole-cropped maize, and wheat–maize intercropping. The grain yields of both intercropped wheat and maize were enhanced by intercropping. The gross economic profit for wheat–maize intercropping was 16.4% lower than that of sole maize and 95.4% higher than that of sole wheat. The overall land use efficiency was improved by intercropping. The time course of leaf area index in intercropping had the similar trends to those in sole crops with relatively low values, which never exceeded 3.0m2m−2 throughout both growing seasons. Compared to weighted means of the sole-cropping systems, wheat–maize intercropping used 26% and 24% more water in 2012 and 2013, respectively. The water-use efficiency of intercropping was nearly the same as the weighted means of the sole crops. Due to the incomplete groundcover in intercropping plots, more water was consumed as soil evaporation. Averaged over two seasons, the ratio of soil evaporation to actual evapotranspiration was 33.4, 20.7 and 24.1% for intercropping system, sole-cropped wheat and sole-cropped maize, respectively. Crop coefficient (Kc) of sole-cropped wheat was 0.19±0.02, 1.05±0.07, and 0.42±0.09 at the initial, mid and late season in two seasons, respectively. Kc value of the sole-cropped maize was 0.22±0.03, 1.10±0.06 and 0.60±0.02 at the initial, mid and late season, respectively. The Kc values of the wheat–maize intercropping system varied in 0.21±0.03, 0.89±0.05, and 0.78±0.06 at the initial, middle and late wheat growing season, and in 0.85±0.03 and 0.61±0.01 at the middle and late maize growing season, respectively. Therefore, longer growing season and incomplete ground cover are the main factors that resulted in higher water use for wheat–maize intercropping compared to sole crops. Results of this study can help to improve the irrigation efficiency for the wheat–maize strip intercropping system.

Less carbon emissions of wheat–maize intercropping under reduced tillage in arid areas

Intercropping is used to increase grain production in many areas of the world. However, this increasing crop yield costs large amounts of water used by intercropped plants. In addition, intercropping usually requires higher inputs that induce greenhouse gas emissions. Actually, it is unknown whether intercropping can be effective in water-limited arid areas. Here, we measured crop yield, water consumption, soil respiration, and carbon emissions of wheat–maize intercropping under different tillage and crop residue management options. A field experiment was conducted at Wuwei in northwest China in 2011 and 2012. Our results show that wheat–maize intercropping increased grain yield by 61 % in 2011 and 63 % in 2012 compared with the average yield of monoculture crops. The intercropping under reduced tillage with stubble mulching yielded 15.9 t ha−1 in 2011 and 15.5 t ha−1 in 2012, an increase of 7.8 % in 2011 and 8.1 % in 2012, compared to conventional tillage. Wheat–maize intercropping had carbon emission of 2,400 kg C ha−1 during the growing season, about 7 % less than monoculture maize, of 2,580 kg C ha−1. Reduced tillage decreased C emission over conventional tillage by 6.7 % for the intercropping, 5.9 % for monoculture maize, and 7.1 % for monoculture wheat. Compared to monoculture maize, wheat–maize intercropping used more water but emitted 3.4 kg C per hectare per millimeter of water used, which was 23 % lower than monoculture maize. Overall, our findings show that maize–wheat intercropping with reduced tillage coupled with stubble mulching can be used to increase grain production while effectively lower carbon emissions in arid areas.

Effect of combined nitrogen and phosphorus fertilizer application of wheat-maize intercropping system

针对内蒙古河套灌区农业面源污染的现状, 本研究以内蒙古河套灌区常规作物小麦和玉米为供试材料, 采取 "3414" 部分实施方案, 对氮、磷肥的施用效应及养分交互作用进行了研究, 探讨进一步削减当地农业生产过程中的肥料用量的施肥技术。结果表明: 小麦/玉米套作条件下, 作物产量与氮、磷肥施用量之间满足二次型回归模型, 氮肥、磷肥及氮磷交互效应对产量产生显著影响, 氮磷交互作用>氮>磷。在施肥水平较低时, 氮、磷肥表现出较好的协同促进作用, 在达到产量的极限值后, 则表现为无效及拮抗作用; 中氮中磷处理能够较好地满足作物生长发育过程中对氮和磷的需求, 提高作物对氮、磷的利用率。但随着施肥量的进一步增加, 作物植株吸肥量也随之增加, 施肥效益降低, 肥料利用率持续下降。通过对氮、磷单因素及二因素肥料效应的分析, 对施肥水平做进一步优化, 得出小麦最佳施氮量为167.67~196.61 kg·hm^-2, 最佳施磷量为130.43~186.64 kg·hm^-2; 玉米最佳施氮量为222.10~299.14 kg·hm^-2, 最佳施磷量为156.14~188.00 kg·hm^-2。这将为进一步削减氮、磷配施量, 改善当地土壤养分平衡, 减轻农业面源污染提供一定的指导作用。

Relationships among soil respiration, soil temperature and dry matter accumulation for wheat-maize intercropping in an arid environment

Liu, S. B., Chai, Q. and Huang, G. B. 2013. Relationships among soil respiration, soil temperature and dry matter accumulation for wheat-maize intercropping in an arid environment. Can. J. Plant Sci. 93: 715-724. Spring wheat (Triticum aestivum L.) intercropped with maize (Zea mays L.) offers an opportunity to boost grain production in short-season areas, but little is known about the sustainability of the intercropping system. This study, conducted at an arid irrigation site in 2009 and 2010, determined water consumption and soil respiration (Rs) characteristics and their relationships to soil temperature (Ts) and above-ground dry matter (DM) accumulation for wheat/maize (W/M) intercropping compared with sole wheat and sole maize. The W/M intercropping had a co-growth period of 70-80 d, allowing the two intercropped species to complete their life cycles. Maximum DM rate for the wheat in the W/M system was significantly greater than that for sole wheat (57 vs. 51 g d-1), which occurred at around 72 to 77 ...

Relationships among soil respiration, soil temperature and dry matter accumulation for wheat-maize intercropping in an arid environment

Liu, S. B., Chai, Q. and Huang, G. B. 2013. Relationships among soil respiration, soil temperature and dry matter accumulation for wheat-maize intercropping in an arid environment. Can. J. Plant Sci. 93: 715–724. Spring wheat (Triticum aestivum L.) intercropped with maize (Zea mays L.) offers an opportunity to boost grain production in short-season areas, but little is known about the sustainability of the intercropping system. This study, conducted at an arid irrigation site in 2009 and 2010, determined water consumption and soil respiration (Rs) characteristics and their relationships to soil temperature (Ts) and above-ground dry matter (DM) accumulation for wheat/maize (W/M) intercropping compared with sole wheat and sole maize. The W/M intercropping had a co-growth period of 70-80 d, allowing the two intercropped species to complete their life cycles. Maximum DM rate for the wheat in the W/M system was significantly greater than that for sole wheat (57 vs. 51 g d−1), which occurred at around 72 to 77 d after sowing (DAS), whereas the maximum DM rate for the maize in the W/M system was between 31.6 and 44.9 g m−2 d−1, or 30 to 43% lower than that of sole maize. The ercroppedhe umulation of a thetime to reach maximum DM was 96 DAS in 2009 and 80 DAS in 2010 for sole maize, and the corresponding time for the intercropped maize was delayed by 6 to 10 d. Soil respiration and DM was a curvilinear relationship; with the increase in DM accumulation, Rs increased, reached a peak at the early flowering stage for wheat and at the silking stage for maize, and then declined. Soil respiration increased linearly with increases in soil temperature during the growth period for both sole and intercropping, suggesting that farming practices aimed at reducing soil temperature will be effective in reducing carbon emissions. Evapotranspiration during the co-growth period averaged 44.1 mm for sole wheat and 48.5 mm for the intercropped wheat and 57.0 mm for sole maize and 48.0 mm for the intercropped maize, but soil water status had little or no effect on Rs. Wheat/maize intercropping had greater grain yield with lower soil respiration over the corresponding sole plantings, and it can serve as a sustainable cropping system for arid irrigation areas.

Water utilization in alternative irrigation under wheat-maize intercropping system in oasis areas

A field experiment was carried out to investigate the effect of alternative irrigation on water consumption, yield and water use efficiency (WUE) under wheat-maize intercropping in the oasis region of Shiyang River Basin, Gansu Province. The results indicate that evaporation for alternative irrigated intercropping system (AI) decreases by 44.0 mm compared to conventional irrigated intercropping system (CI). Water consumption under AI also increases by 15.4 mm while yield and WUE are respectively enhanced by 13.92% and 9.21% compared to CI. All these results show that alternative irrigation is an effective and practicable way to improve yield and WUE of wheat-maize intercropping. Although evaporation and water consumption in alternative irrigated intercropping system increase with increasing irrigation quota, overall WUE actually decreases.