Alternate cotton-peanut intercropping:a new approach to increasing productivity and minimizing environmental impact

Recent publications have highlighted the development of an alternate cotton-peanut intercropping as a novel strat-egy to enhance agricultural productivity.In this article,we provide an overview of the progress made in the alternate cotton-peanut intercropping,specifically focusing on its yield benefits,environmental impacts,and the underlying mechanisms.In addition,we advocate for future investigations into the selection or development of appropriate crop varieties and agricultural equipment,pest management options,and the mechanisms of root-canopy interactions.This review is intended to provide a valuable reference for understanding and adopting an alternate intercropping system for sustainable cotton production.

Several Cotton Rotation and Intercropping Systems in Cotton Planting Area of Eastern Henan Province

In recent years,the area dedicated to cotton cultivation in eastern Henan Province has experienced a continuous decline.Developing efficient multi-cropping systems for cotton and increasing the multiple cropping index represent effective strategies to stabilize the cotton planting area and enhance the income of cotton farmers.This paper presents an overview of intercropping systems and the benefits associated with cotton rotation and intercropping practices.Specifically,it discusses the"early maturing cotton-wheat"rotation system,the"cotton-watermelon"intercropping system,the"cotton-Dutch bean"intercropping system,and the"early maturing cotton-peanut-garlic"intercropping system.

Highly-efficient Intercropping Mode and Selection of Suitable Peanut Varieties in Maize and Peanut Intercropping Systems

[Objective] The aim was to explore efficient maize and peanut intercrop-ping mode and select suitable peanut varieties of the mode in Yungui Plateau. [Method] In the test, 6 cropping methods were set by randomized block design. Yields and economic benefits were measured in mature stage with Excelland DPS. [Result] Compared with monoculture, maize and peanut intercropping systems took advantages and LER values were proved higher than 1. In the intercropping system with maize and Yun peanut No.3 at 2∶2, in particular, the value of LER was 1.40 and compound yield reached 9 036 kg/hm2; the net output values of maize kernel and fresh/dry peanut pod increased by 182.63% and 140.59%, compared with maize by monoculture. In addition, the output values of Yun peanut No.3 by monoculture and intercropping system increased by 5 069 and 3 272 yuan/hm2, respectively, than Yanshan conventional peanut varieties. [Conclusion] The efficient intercropping system with maize and peanut mode at 2∶2 mode in Yungui plateau and the Yun peanut No.3 exhibited higher yield and economic benefit advantages, compared with Yanshan conventional planting peanut varieties.

Influence of Fruit Tree Types and Arrangements on Yield, Quality and Economic Returns of Cotton of Intercropping System in Southern Xinjiang

[Objective] The aim was to provide a theoretical basis for stable and highly effective intercropping arrangements and scientific management measures by selecting apple, pear, peach, apricot, walnut, jujube and other fruit trees to study their influence on yield, fiber quality and economic returns of intercropped cotton in southern Xinjiang. [Method] Based on major cropping pattern in production, randomized block design was adopted to explore growth indicators, canopy micrometeorological indicators, yield and fiber quality in key growth stage. [Result] Shading has a significant effect on cotton canopy micro-environment and canopy diameter is proportional to shading effect. According to comparisons of the same tree type, the change of canopy micro-environment was as follows： under canopyouter canopymiddle points and peachpearapplewalnutjujube for comparisons among different tree types. Canopy diameter is directly proportional to the number of tree branch and boll weight reductions and shading is the main cause of yield reduction. The canopy expansion is the major cause of decline of light intensity, temperature and humidity of cotton canopy. [Conclusion] Fruit trees, which will promote cotton yield,quality and canopy-environment, are as follows： jujube walnut apple pear peach trees. In practice, trees, which are small in canopy or well trimmed, are popular in production, such as jujube trees, to improve cotton yield and fiber quality.

Effects of Different Intercropping Modes on Growth, Yields and Economic Benefit of Cassava and Peanut in Symbiotic Period

[Objective] This study was conducted to investigate effects of different intercropping modes on growth, yields and economic benefit of cassava and peanut in symbiotic period. [Method] With sole cropping of cassava （M1） and sole cropping of peanut （M2） as control groups, effects of intercropping of cassava with 1 row, 2 rows and 3 rows of peanut （M3, M4 and M5）on crop growth, yields and economic benefit were studied. [Result] Intercropping affected both growth and yields of cassava and peanut. Growth competition existed between cassava and peanut, and plant heights of cassava and peanut changed similarly. In late stages of intercropping, treatments M1, M2 and M5 showed higher plant heights under no nitrogen application, while treatment M3 and M4 exhibited higher plant heights under nitrogen application; intercropping improved leaf temperature, but no obvious law could be observed among different intercropping treatments; and intercropping improved total dry matter amount, which was the highest in M5 in root expanding stage and on the 30th day of the expanding stage, and the highest in M4 on the 60th day of the expanding stage. Intercropping reduced the yield of single plant, but improved the economic benefit of red upland soil; and under no nitrogen application and nitrogen application, cassava yields decreased by 25.35% and 14.55%, respectively, peanut yields decreased by 28.76% and 52.60%, respectively, while economic benefit increased by 72.90% and 56.82%, respectively. [Conclusion] Compared with sole cropping, interplanting cassava with 1 row, 2 rows or 3 rows of peanut could all improve economic benefit, and the economic benefit increased with number of rows of interplanted peanut increasing.

Research on Efficiency Improving Technology for Intercropping Sesame (Sesamum indicum) and Peanut (Arachis hypogaea)

[Objective] The research aimed to establish a optimized combination of intercropping and fertilization application technology of intercropping sesame （Sesamum indicum） and peanut（Arachis hypogaea）. [Method] Double factor randomized block design （2 fertilization methods and 5 ratios） was adopted, with 10 treatments, 3 repeats. There were a total of 30 plots, with plot area of 12.0 m2. Two fertilization methods included C1 [base fertilizer （540 g/plot compound fertilizer ＋ topdressing （90 g urea）] and C2 [all as base fertilizer （540 g/plot compound fertilizer）]. Five different proportions （sesame： peanut） were M1（2∶4）, M2（2∶6）, M3（1∶4）, monoculture sesame （CK1） and monoculture peanut （CK2）, respectively. [Result] Output value and land equivalent ratio （LER） of C1M2 treatment （6 lines peanut/2 lines sesame, base fertilizer 540 g/plot （compound fertilizer） ＋ （topdressing urea 90 g） were the highest of 22 378.68 yuan/hm2 and 1.56 respectively; sesame yield was 641.64 kg/hm2 and peanut yield was 2 506.67 kg/hm2. Output-input ratio was 4.94. The income was increased by 32.32% and 95.97% compared with only planting of peanuts and sesame. [Conclusion] The study provided a theoretical basis for finding the best intercropping combinations of sesame and peanut and rational application fertilizations.

Selection of Cotton Variety Suitable for Cottonwheat Intercropping in Rainy and Poor Sunshine Years

The year of 2013 is a typical rainy and poor sunshine year, and the monthly sunshine hours from May to October were all lower than the average, which from July to September was only 69.3%,71.1% and 56.2% of average, respectively. In cotton-wheat system 10 cotton varieties （lines） were planted to select the most suitable varieties for cotton-wheat system in rainy and poor sunshine years through investigating cotton growing traits in 2013. The results showed that in cotton-wheat system the vegetative growth of cotton was mainly from late June to middle July especially in rainy and poor sunshine years. And with the increase of the cotton growth period the peak of vegetative growth delayed, the ratio of the autumn bolls increased, and the ratio of pre-frost yield decreased. In all the varieties unginned cottonyield of Zhongmiansuo 50 with shorter growth period, higher rate of summer bolls and better fiber quality, seed yield reached 3 814.1 kg/hm2, higher than that of other varieties （lines） significantly, and the rate of pre-frost yield reached 83.4%, which was the most suitable variety for cotton-wheat system in rainy and poor sunshine years.

Biochemical and microbial properties of rhizospheres under maize/ peanut intercropping

Maize/peanut intercropping system shows the significant yield advantage. Soil microbes play major roles in soil nutrient cycling and were affected by intercropping plants. This experiment was carried out to evaluate the changing of rhizosphere microbial community composition, and the relationship between microbial community and soil enzymatic activities, soil nutrients in maize/peanut intercropping system under the following three treatments： maize （Zea mays L.） and peanut （Arachis hypogaea L.） were intercropped without any separation （NS）, by half separation （HS） using a nylon net （50 μm） and complete separation （CS） by using a plastic sheet, respectively. The soil microbial communities were assessed by phospholipid fatty acid （PLFA）. We found that soil available nutrients （available nitrogen （Avail N） and available phosphorus （Avail P）） and enzymatic activities （soil urase and phosphomonoesterase） in both crops were improved in NS and HS treatments as compared to CS. Both bacterial and fungal biomasses in both crops were increased in NS followed by HS. Furthermore, Gram-positive bacteria （G＋） in maize soils were significant higher in NS and HS than CS, while the Gram-negative （G-） was significant higher in peanut soil. The ratio of normal saturated to monounsaturated PLFAs was significantly higher in rhizosphere of peanut under CS treatment than in any other treatments, which is an indicator of nutrient stress. Redundancy analysis and cluster analysis of PLFA showed rhizospheric microbial community of NS and HS of both plants tended to be consistent. The urase and Avail N were higher in NS and HS of both plants and positively correlated with bacteria, fungi （F） and total PLFAs, while negatively correlated with G＋/G- and NS/MS. The findings suggest that belowground interactions in maize/peanut intercropping system play important roles in changing the soil microbial composition and the dominant microbial species, which was closely related with the improving of soil available nutrients （N and P） and enzymatic activities.

Timing and splitting of nitrogen fertilizer supply to increase crop yield and efficiency of nitrogen utilization in a wheat–peanut relay intercropping system in China

Agronomically optimizing the timing and rates of nitrogen(N) fertilizer application can increase crop yield and decrease N loss to the environment. Wheat(Triticum aestivum L.)–peanut(Arachis hypogaea L.) relay intercropping systems are a mainstay of economic and food security in China. We performed a field experiment to investigate the effects of N fertilizer on N recovery efficiency, crop yield, and N loss rate in wheat–peanut relay intercropping systems in the Huang-Huai-Hai Plain, China during 2015–2017. The N was applied on the day before sowing, the jointing stage(G30) or the booting stage(G40) of winter wheat, and the anthesis stage(R1) of peanut in the following percentage splits: 50-50-0-0(N1), 35-35-0-30(N2), and 35-0-35-30(N3), using 300 kg N ha-1, with 0 kg N ha-1(N0) as control. ^(15)N-labeled(20.14 atom %) urea was used to trace the fate of N in microplots. The yields of wheat and peanut increased by 12.4% and 15.4% under the N2 and N3 treatments, relative to those under the N1 treatment. The ^(15)N recovery efficiencies( ^(15)NRE) were 64.9% and 58.1% for treatments N2 and N3, significantly greater than that for the N1 treatment(45.3%). The potential N loss rates for the treatments N2 and N3 were23.7% and 7.0%, significantly lower than that for treatment N1(30.1%). Withholding N supply until the booting stage(N3) did not reduce the wheat grain yield; however, it increased the N content derived from ^(15)N-labeled urea in peanuts, promoted the distribution of ^(15)N to pods, and ultimately increased pod yields in comparison with those obtained by topdressing N at jointing stage(N2). In comparison with N2, the N uptake and N recovery efficiency(NRE) of N3 was increased by 12.0% and 24.1%,respectively, while the apparent N loss decreased by 16.7%. In conclusion, applying N fertilizer with three splits and delaying topdressing fertilization until G40 of winter wheat increased total grain yields and NRE and reduced N loss. This practice could be an environment-friendly N management strategy for wheat–peanut relay intercropping systems in China.

Maize/peanut intercropping increases photosynthetic characteristics, 13C-photosynthate distribution, and grain yield of summer maize

Intercropping is used widely by smallholder farmers in developing countries to increase land productivity and profitability. We conducted a maize/peanut intercropping experiment in the 2015 and 2016 growing seasons in Shandong, China. Treatments included sole maize (SM), sole peanut (SP), and an intercrop consisting of four rows of maize and six rows of peanut (IM and IP). The results showed that the intercropping system had yield advantages based on the land equivalent ratio (LER) values of 1.15 and 1.16 in the two years, respectively. Averaged over the two years, the yield of maize in the intercropping was increased by 61.05% compared to that in SM, while the pod yield of peanut was decreased by 31.80% compared to SP. Maize was the superior competitor when intercropped with peanut, and its productivity dominated the yield of the intercropping system in our study. The increased yield was due to a higher kernel number per ear (KNE). Intercropping increased the light transmission ratio (LTR) of the ear layer in the maize canopy, the active photosynthetic duration (APD), and the harvest index (HI) compared to SM. In addition, intercropping promoted the ratio of dry matter accumulation after silking and the distribution of 13C-photosynthates to grain compared to SM. In conclusion, maize/peanut intercropping demonstrated the potential to improve the light condition of maize, achieving enhanced photosynthetic characteristics that improved female spike differentiation, reduced barrenness, and increased KNE. Moreover, dry matter accumulation and 13C-photosynthates distribution to grain of intercropped maize were improved, and a higher grain yield was ultimately obtained.

The importance of aboveground and belowground interspecific interactions in determining crop growth and advantages of peanut/maize intercropping

Intercropping of maize(Zea mays L.) and peanut(Arachis hypogaea L.) often results in greater yields than the respective sole crops. However, there is limited knowledge of aboveground and belowground interspecific interactions between maize and peanut in field. A two-year field experiment was conducted to investigate the effects of interspecific interactions on plant growth and grain yield for a peanut/maize intercropping system under different nitrogen(N) and phosphorus(P) levels. The method of root separation was employed to differentiate belowground from aboveground interspecific interactions. We observed that the global interspecific interaction effect on the shoot biomass of the intercropping system decreased with the coexistence period, and belowground interaction contributed more than aboveground interaction to advantages of the intercropping in terms of shoot biomass and grain yield. There was a positive effect from aboveground and belowground interspecific interactions on crop plant growth in the intercropping system, except that aboveground interaction had a negative effect on peanut during the late coexistence period. The advantage of intercropping on grain came mainly from increased maize yield(means 95%) due to aboveground interspecific competition for light and belowground interaction(61%–72% vs. 28%–39% in fertilizer treatments). There was a negative effect on grain yield from aboveground interaction for peanut, but belowground interspecific interaction positively affected peanut grain yield.The supply of N, P, or N + P increased grain yield of intercropped maize and the contribution from aboveground interspecific interaction. Our study suggests that the advantages of peanut/maize intercropping for yield mainly comes from aboveground interspecific competition for maize and belowground interspecific facilitation for peanut, and their respective yield can be enhanced by N and P. These findings are important for managing the intercropping system and optimizing the benefits from using this system.

The Effects of Peanut Intercropping with Different Gramineous Species and Their Intercropping Model on Iron Nutrition of Peanut

The effects of peanut intercropped with five different gramineous species with different phyto-siderophore release rate on iron nutrition of peanut were studied in field experiment. The rate of phyto-siderophore release of five gramineous species was as following: barley>oats>wheat>>maize>sorghum. The results showed that intercropping of peanut with five gramineous species could improve iron nutrition of peanut respectively. This indicated that root exudates, especially for phytosiderophore of gramineous plants played an important role in improvement of iron nutrition of peanut. Although phytosiderophore release rates of maize and sorghum were lower than those of barley, oats and wheat, the five gramineous species had the same effects on iron improvement of peanut. The less phytosiderophore release of maize was enough to improve iron nutrition of peanut in intercropping system. For every intercropping system, intercropping model I ( the ratio of gramineous plants : peanut : gramineous plants was 2 : 3:2) was much better in improvement of iron nutrition of peanut than that of intercropping model I (the ratio of gramineous plants : peanut: gramineous plants was 2: 6:2). This led to have greater rhizosphere effect of gramineous plants on iron nutrition of peanut in intercropping model I than intercropping model I .

Millet/peanut intercropping at a moderate N rate increases crop productivity and N use efficiency,as well as economic benefits,under rain-fed conditions

Cereal and legume intercropping has been widely adopted to increase crop productivity in sustainable farming systems worldwide.Among different intercropping combinations,millet and peanut intercropping can be adapted to most waterlimited areas.However,there are few studies on the differences in yield characteristics and nitrogen use efficiency between millet/peanut intercropping and monocultures under different nitrogen (N) application rates.The objective of this study was to determine the yield advantages and economic benefits,as well as the appropriate N application rate,of millet/peanut intercropping.A two-yearfield experiment was conducted with three cropping patterns (monoculture millet,monoculture peanut and millet/peanut intercropping) and four N rates (0,75,150 and 225 kg ha^(-1)).The results showed that the land equivalent ratio (LER) and net effect (NE) of the intercropping system reached their highest levels at the N input of 150 kg ha^(-1)in 2018 and 2019 (1.04 for LER,0.347 Mg ha^(-1)for NE,averaged across two years).Millet was the dominant crop in the intercropping system (aggressivity of millet and peanut (Amp)>0,competitive ratio of millet and peanut (CRmp)>1),and millet yields achieved their highest values at N inputs of 225 kg ha^(-1)for monoculture and 150 kg ha^(-1)for intercropping.NUE reached its highest levels with N inputs of 150 kg ha^(-1)for all planting patterns over the two years.Intercropping combined with an N input of 150 kg ha^(-1)achieved the highest net income of 2 791 USD ha^(-1),with a benefit-cost ratio of 1.56,averaged over the two years.From the perspective of economics and agricultural sustainable development,millet/peanut intercropping at 150 kg N ha^(-1)seems to be a promising alternative to millet or peanut monoculture.

Competitiveness and Profitability of Intercropping Sunflower with Peanut under Different Irrigation Water Levels and Potassium Fertilizer Rates

A two-year study was carried out at Ismailia Agricultural Research Station, Egypt during 2016 and 2017 summer seasons to evaluate competitive effects of intercropping sunflower and peanut under different drip irrigation water amounts and K fertilizer rates for increasing farmer profitability. Three irrigation amounts (70%, 100% and 120% ETo), three K fertilizer levels (57, 86 and 114 K2O kg/ha) and four intercropping patterns of sunflower and peanut (different spatial arrangements) were implemented. The experimental design was strip split plot with three replications. The results showed that there were no significant differences between 100% and 120% ETo on most of yield traits of the intercrops. The highest K fertilizer level had the highest values of most yield traits of the intercrops. The highest values of peanut and sunflower traits were obtained from intercropping sunflower with peanut, where peanut seeds were sown on both sides of all the raised beds, sunflower seeds were sown on one row above the raised beds and the following bed was left without intercropping (P1). Thus, to attain the highest yield of intercrops and water equivalent ratio (WER), the lowest competitive pressure and the highest farmer profitability, 120% ETo, 114 K2O kg/ha and P1 intercropping pattern should be implemented. This research found that the result of competitiveness was consistent with the result of profitability.

Effects of Nitrogen Fertilizer on Rhizosphere Microbial Populations under Cotton Intercropped with Red Date in Arid Desert Oasis of Southern Xinjiang

[Objective]This study aimed to determine the number of microorganisms of cotton rhizosphere in a soil at various amounts of applied nitrogen fertilizer in a red date-cotton intercropping system. [Method] In the field experiment, nitrogen fer-tilizer was applied at 0, 150, 300, 450, 600, and 750 kg/hm2, respectively. The dy-namic changes of the populations of bacteria, fungi and actinomycetes at the rhizo-sphere of cotton intercropped with red date were investigated. [Result] Microbial populations significantly increased at nitrogen fertilizer of 300 and 450 kg/hm2 during bud, flowering and bol opening periods. The numbers of bacteria and actinomycetes were higher during flowering and bol opening stages than at bud stage. The num-ber of fungi slightly changed during the entire growth period. Appropriate amount of nitrogen fertilizer （300 to 600 kg/hm2） was favorable to the survival of the microor-ganisms in the soil under the intercropping system. [Conclusion] The study provides a guideline for screening and determining the optimum amount of applied nitrogen fertilizer.

The damage risk evaluation of Aphis gossypii on wheat by host shift and fitness comparison in wheat and cotton

Aphids are considered as one of the key pests for wheat production worldwide. Major aphid species that infest wheat in China include Sitobion avenae, Rhopalosiphum padi, Schizaphis graminum and Metopolophium dirhodum. However, during our wheat field survey in Wenshang County of Shangdong＇Province, China, we observed that Aphis gossypii can feed on wheat. The damage risk of A. gossypii on wheat was assessed using host shift method. A population of A. gossypii collected from a wheat field in 2015 and another population reared on cotton under laboratory conditions for a decade without exposure to insecticides were used in the study. The results of host shift demonstrated that the A. gossypfi colony from wheat has not yet developed wheat specialization. Moreover, the assessment of A. gossypii fitness on wheat and cotton showed that fecundity and net reproductive rate of A. gossypii population fed on wheat was significantly higher comparing to the population fed on cotton, whether the initial host of A. gossypii population was wheat or cotton. This study raises a warning that the cotton aphid has potential to establish well on wheat and it may cause significant effects under specific circumstances. Therefore, future studies are required to evaluate the effects of A. gossypfi on wheat production.

盐碱地花生棉花等幅间作对花生光合特性及产量效益的影响

为充分利用盐碱地土地及温光热资源,明确盐碱地花生/棉花等幅间作种植模式下,不同垄行位置对花生光合产物积累和光合特性的影响,提高盐碱地农业生产综合效益,在田间条件下,采用花生/棉花6∶4等幅间作周年轮作高效种植模式,研究花生带不同垄行位置对其光合产物积累、光照强度、叶绿素荧光特性等的影响及产量和效益的变化。结果表明:(1)盐碱地花生/棉花等幅间作种植模式较花生单作可显著增加花生主茎高、侧枝长、功能叶片非光化学荧光淬灭系数(NPQ),显著降低生物量、相对叶绿素含量(SPAD)、叶面积系数(LAI)、净光合速率(P_(n))、蒸腾速率(T_(r)),产量明显降低;间作棉花果枝数、单株铃数、铃重和产量均明显提高,间作系统综合经济效益显著提高。(2)间作系统中花生带两边垄行(IP1、IP3)、单作花生和单作棉花的冠层光照强度峰值均出现在12:00,但中间垄行(IP2)花生冠层辐射强度峰值滞后到14:00,且间作花生带两边垄行冠层光照度显著低于花生单作处理。(3)间作系统中,花生花针期后垄行位置对光合效率的影响显著,中间垄行SPAD、LAI和NPQ值均显著高于两边垄行,而两边垄行间无明显差异;但P_(n)、气孔导度(G_(s))和T_(r)受试点和垄行位置影响显著,其中东营市试点花生各生育期的各垄行位置间均无显著差异,而高唐县试点间作花生功能叶P_(n)、G_(s)和T_(r)均显著低于单作处理,且间作处理的IP2垄行显著高于IP1、IP3两边垄行。(4)两试点间作棉花和花生产量低于其单作处理,但综合效益较传统植棉收益分别提高11.94%(东营)和27.08%(高唐),间作系统土地当量比大于1.02。

等带宽间作模式下不同玉米花生行比对花生光合特性和系统产量的影响

【目的】明确相同带宽条件下不同玉米花生种植行比对花生光合特性和系统产量的影响,为构建适宜行比的玉米花生带状间作模式提供理论参考和技术支持。【方法】以玉米花生带状间作系统为对象,设置玉米单作,花生单作,玉米花生间作(3.6 m的总带宽,行比分别为2∶6、4∶4、6∶2),研究不同行比对间作花生干物质积累、叶面积指数、叶片光合参数、产量构成和玉米花生系统产量的影响。【结果】3种间作模式的干物质量和叶面积指数均小于单作,其中2∶6种植模式在花生生育后期的叶面积指数较4∶4和6∶2分别提高30.07%和44.19%,等带宽间作体系下相对较少的玉米行比可以增加间作花生的叶绿素含量和光合速率,保持花生叶片较高的光合能力,从而获得产量优势。间作显著降低了玉米的穗数、穗粒数和百粒重以及花生的单株饱果数和百果重,系统产量以2行玉米6行花生的种植模式最高,为13749.9 kg/hm^(2),3种间作模式的土地当量比均大于1,且综合产量均显著高于单作玉米和单作花生。【结论】在玉米花生等带宽间作模式下,花生行比的增加缓解了玉米的荫蔽效应,改善了花生的光合能力,同时提高土地利用率,实现稳粮增油、均衡生产。

不同玉米Ⅱ花生模式对花生产量及氮和钙养分吸收的影响

为明确不同的玉米||花生模式对花生干物质积累、产量形成及氮、钙养分吸收的影响,探究最佳的间作模式,设置5种种植方式,即玉米单作(SM)、花生单作(SP)、玉米||花生行比3:4(IMP1)、3:6(IMP2)、6:8(IMP3)。2018-2019两年试验结果表明:间作的玉米产量和花生产量均低于单作,但三种间作模式的土地当量比均大于1,且IMP2最高。对于间作体系总产量而言,IMP1和IMP2无显著差异,但显著高于IMP3,较IMP3分别提高4.69%~4.70%和5.04%~5.97%。间作花生群体干物质、氮素和钙素积累量在花生结荚期后显著低于单作。在三种不同的间作模式中,IMP2的群体干物质、氮素和钙素积累量显著高于IMP1和IMP3模式,成熟期IMP2的花生群体干物质较IMP1、IMP3分别提高40.07%~47.16%和25.24%~25.72%;群体氮积累量分别提高33.63%~43.28%和26.58%~29.34%;群体钙积累量分别提高33.48%~49.06%和34.25%~38.97%。IMP2和IMP3的中垄(MR)花生群体干物质、氮素和钙素积累量均高于东垄(ER)和西垄(WR),但差异不显著。综合以上分析可得,玉米花生间作行比3:6具有明显的间作优势。

冬小麦-夏玉米Ⅱ夏花生周年种植的农田温室气体排放及碳足迹评价

为探究冬小麦-夏玉米Ⅱ夏花生周年种植模式对农田温室气体排放及碳足迹的影响,设置冬小麦-夏玉米、冬小麦-夏花生、冬小麦-夏玉米Ⅱ夏花生3种轮作种植方式;其中夏玉米Ⅱ夏花生间作设置3∶4,3∶6和6∶8三种行比。通过大田试验研究了周年农田温室气体排放和碳足迹特征。结果表明,夏玉米Ⅱ夏花生种植模式能够减少农田温室气体的排放,与玉米单作相比,土壤CO_(2)和N_(2)O的平均排放通量降幅分别为10.24%~18.75%和10.78%~23.93%、排放总量降幅分别为8.30%~19.12%和14.09%~26.81%。间作减少了后茬冬小麦(轮作模式下)的温室气体排放,间作处理的后茬冬小麦较玉米单作处理的后茬冬小麦土壤CO_(2)排放通量减少3.79%、排放总量减少3.84%;土壤N_(2)O排放通量减少16.80%、排放总量减少17.66%;土壤CH_(4)排放总量呈现“汇”现象。此外,单作玉米生产过程中碳足迹主要来源是氮肥,占总排放的49.13%;单作花生生产过程中碳足迹主要来源是氮肥和地膜,分别占总排放的23.77%和26.06%;间作模式下碳足迹主要来源是氮肥、柴油和地膜,分别占总排放的31.50%、16.74%、17.92%。间作模式增加了后茬小麦碳排放效率、降低了全球增温潜势和温室气体排放强度。综上,冬小麦-夏玉米Ⅱ夏花生(间作玉米花生行比3:6)周年种植模式能够减少农田碳排放与作物生产过程中的碳足迹,具有良好的生态效益。