大豆-柑桔间作磷的迁移与分配规律

A mini-plot field experiment was conducted on a loamy clay Oxisol to compare and evaluate P absorption and transfer in plant organs and P movement in soil profile at three P application depths under the soybean-citrus intercropping versus the monoculture using a ^32p tracer technique. Total P absorption （Pt） by soybean and P accumulation （Pa） in soybean organs decreased significantly （P 〈 0.05） under the intercropping in contrast to the monoculture. With intercropping, when ^32p was applied in topsoil （15 cm soil layer）, total ^32p absorption （^32pt） in soybeans was significantly lower （P 〈 0.05）, but when ^32p was applied to deeper soil layers （35 or 55 cm soil layer）, ^32pt in soybeans was significantly greater （P 〈 0.05）. The percentage of P in leaves to total P （Pa/Pt） and 32p in leaves to total ^32p （^32pa/^32pt） for soybean were ≥ 25% and those of root ≥ 12%. When P was applied ia topsoil and 55 cm soil layer, no significant differences were found between intercropping and monoculture for Pt of citrus. The P absorbed by citrus was transferred rapidly to the growing organs of aboveground during the experiment, and the speed of transferring to the growing organs slowed when P was applied to the deeper soil layers. In intercropping, P mobility was heightened in the soil profile, and P in deeper soil layers moved up to topsoil more rapidly.     

钙质土壤施用过磷酸钙21年后土壤无机磷分级和磷素有效性

A long-term (21-year) field experiment was performed to study the responses of soil inorganic P fractions and P availability to annual fertilizer P application in a calcareous soil on the Loess Plateau of China. Soil Olsen-P contents increased by 3.7, 5.2, 11.2 and 20.6 mg P kg^-1 after 21-year annual fertilizer P application at 20, 39, 59, and 79 kg P ha^-1, respectively. Long-term fertilizer P addition also increased soil total P and inorganic P (Pi) contents significantly. The contents of inorganic P fractions were in the order of Ca₁₀-P > Ca₈-P > Fe-P > Al-P > occluded P > Ca₂-P in the soil receiving annual fertilizer P application. Fertilizer P application increased Ca₈-P, Al-P and Ca₂-P contents as well as their percentages relative to Pi. Pi application increased Fe-P and occluded P contents but nor their percentages. Soil Ca₁₀-P content remained unchanged after fertilizer P application while its percentage relative to Pi declined with increasing fertilizer P rate. All Pi fractions but Ca₁₀-P were correlated with Olsen-P significantly. 90% of variations in Olsen-P could be explained by Pi fractions, and the direct contribution of Ca₈-P was predominant. Long-term annual superphosphate application would facilitate the accumulation of soil Ca₈-P, and thus improve soil P availability.     

不同氮源对中国稻田作物氮素营养的贡献

N availability is one of the most important factors limiting crop yield enhancement. The recovery of applications of ¹⁵N-labeled fertilizer and crop residues in a rice-wheat cropping system was determined for up to 6 consecutive growing seasons. The crop residues from the previous season were either incorporated or removed as two different treatments. Our results showed that 16. 55%-17.79% (17.17% on average) of the fertilizer N was recovered in the crop during the first growing season, suggesting that more than 80% of crop N was not directly from the N fertilizer. When ¹⁵N-labeled residues were applied, 12.01% was recovered in the crop in the first growing season. The average recoveries of fertilizer N and crop residue N in the soil after the first growing season were 33. 46% and 85. 64%, respectively. N from soil organic matter contributed approximately 83% of the N in the crop when ¹⁵N fertilizer was applied or 88% when crop residues were applied. There was a larger difference in the total ¹⁵N recovery in plant and soil between N applications in the forms of fertilizer and crop residues. Incorporation of crop residues following the ¹⁵N fertilizer application did not significantly promote ¹⁵N recovery in the crop or soil. On average, only additional 1.94% of N for the fertilizer-applied field or 5.97% of N for the crop residue-applied field was recovered by the crops during the 2nd and 3rd growing seasons. The total recoveries of ¹⁵N in crop and soil were approximately 64.38% for the fertilizer-applied field after 6 growing seasons and 79.11% for the crop residue-applied field after 5 growing seasons. Although fertilizer N appeared to be more readily available to crops than crop residue N, crop residue N replenished soil N pool, especially N from soil organic matter, much more than fertilizer N. Therefore, crop residue N was a better source for sustaining soil organic matter. Our results suggested that the long-term effect of fertilizer or crop residues on N recovery were different in the crop and soil. However, there was little difference between the practices of crop residue incorporation and residue removal following the N fertilizer application.     

中国南方红壤上作物产量和土壤性质对长期施肥的响应

A 15-year fertilization experiment with different applications of inorganic N, P and K fertilizers and farmyard manure (M)was conducted to study the yield and soil responses to long-term fertilization at Qiyang, Hunan Province, China. Average grain yields of wheat and corn (1 672 and 5 111 kg ha^-1, respectively)for the treatment NPKM were significantly higher than those (405 and 310 kg ha^-1)of the unfertilized control and single inorganic fertilizer treatments. Compared with the corresponding initial values of the experiment, all treatments showed a yield decline of 9 to 111 kg ha^-1 year^-1 in wheat and 35 to 260 kg ha^-1 year^-1 in corn, respectively, and a significant pH decline of 0.07 to 0.12 pH year^-1, except for the treatments PK and NPKM. After long-term fertilization, the soil organic C, soil available P, exchangeable Ca²⁺ and Mg²⁺ and available Cu²⁺ and Zn²⁺ contents were higher in the treatment NPKM than in the treatments applied with inorganic fertilizer only. Compared to the treatment NPK, the treatment NPKM, where manure partially replaced inorganic N, had a positive impact on arresting the decline of soil pH. This improved grain yields of wheat and corn, suggesting that application of NPK fertilizer in combination with farmyard manure is important to maintain soil fertility and buffering capacity in red soil.     

黄绵土与淋溶土含水量与施肥方法对铵固定和肥料氮回收率的影响

Ammonium fixation and the effects of soil moisture and application methods on fertilizer N recovery were investigatedin two soils of Shaanxi Province, China, a Luvisol and an Entisol, through two experiments performed in the laboratoryand in a glass shelter, respectively, by using ammonium bicarbonate (NH4HCO3). The laboratory closed incubationbox experiment was conducted using the Luvisol to study NH fixation rate at soil moisture levels of 10.1%, 22.7% and 35.3% water filled pore space (WFPS). The fixed NH -N increased dramatically to 51% and 66%, 67% and 74%,and 82% and 85% 1, 2 and 36 h after fertilizer incorporation at moisture levels of 10.1% and 22.7% WFPS and 35.3% WFPS, respectively. The rapid NH fixation rates at all moisture levels could help prevent NH losses from ammonia volatilization. In the glass shelter pot experiment, N fertilizer was applied by either banding (in a concentrated strip)or incorporating (thoroughly mixing) with the Entisol and the Luvisol. An average of 74.2% of the added N fertilizerwas recovered 26 days after application to the Luvisol, while only 61.4% could be recovered from the Entisol, due tohigher NH fixation capacity of the Luvisol. The amount of fixed NH decreased with increasing WFPS. The amountof fixed NH in the incorporated fertilizer treatment was, oll average, 10% higher than that in the banded treatment.Higher NH fixation rates could prevent N loss and thus increase N recovery. The results from the Luvisol showed lowernitrogen recovery as soil moisture level increased, which could be explained by the fact that most of the fixed NH wasstill not released when the soil moisture level was low. When the fertilizer was incorporated into the soil, the recovery ofN increased, compared with the banded treatment, by an average of 26.2% in the Luvisol and 11.2% in the Entisol, whichimplied that when farmers applied fertilizer, it would be best to mix it well with the soil.     

Fate of Fertilizer Nitrogen Applied to Crops Grown on Fluvo-Aquic Soil in Huang-Huai-Hai Plain

The fate of urea-and ammonium bicarbonate(ABC)-nitrogen (N) applied by prevailing traditional techniques to winter wheat (Triticum aestivum L.)or maize (Zea mays L.)grown in the fields of Fluvo-aquic soil was investigated using ^15N tracer-micro-plot technique.Results show that:(1) at maturity of wheat,N recovery in plants and N losses of urea and ABC applied at seeding in autumn were 31-39%,and 34-46%,respextively,while the corresponding figures for side-banding at 10 cm depth in early spring were 51-57%,and 5-12%;surface-broadcast of urea followed by irrigation at early spring was as efficient as the side-banding in improving N recovery in plants and reducing N loss,however,such techuique was found less satisfactory with ABC.(2)At the maturity of maize,N recovery in the plants and N loss of urea and ABC sidebanded at seedling stage or prior to tasseling ranged from 23% to 57%,and 9% to 26%,respectively.(3) Either in Wheat or in maize experiment,the majority of residual fertilizer N in soil profile (0-60cm) was in the form of biologically immobilized organic N,however,the contribution of ammonium fixation by clay minerals increased markedly nwith depth in soil profile.(4) Though the proportion of residual fertilizer N was generally highest in the top 20 cm soil layer,considerable reaidual N (nostly 6-11% of the N applied)was found in 60-100 cm soil layers.     

灌溉施用氮肥后氮素在土壤中的转化及淋失状况: 土柱模拟研究

A soil column method was used to compare the effect of drip fertigation (the application of fertilizer through drip irrigation systems, DFI) on the leaching loss and transformation of urea-N in soil with that of surface fertilization combined with flood irrigation (SFI), and to study the leaching loss and transformation of three kinds of nitrogen fertilizers (nitrate fertilizer, ammonium fertilizer, and urea fertilizer) in two contrasting soils after the fertigation. In comparison to SFI, DFI decreased leaching loss of urea-N from the soil and increased the mineral N (NH₄⁺-N + NO₃^--N) in the soil. The N leached from a clay loam soil ranged from 5.7% to 9.6% of the total N added as fertilizer, whereas for a sandy loam soil they ranged between 16.2% and 30.4%. Leaching losses of mineral N were higher when nitrate fertilizer was used compared to urea or ammonium fertilizer. Compared to the control (without urea addition), on the first day when soils were fertigated with urea, there were increases in NH₄⁺-N in the soils. This confirmed the rapid hydrolysis of urea in soil during fertigation. NH₄⁺-N in soils reached a peak about 5 days after fertigation, and due to nitrification it began to decrease at day 10. After applying NH₄⁺-N fertilizer and urea and during the incubation period, the mineral nitrogen in the soil decreased. This may be related to the occurrence of NH₄⁺-N fixation or volatilization in the soil during the fertigation process.     

根－土界面区域磷酸盐的分布和移动: Ⅱ. 土壤水分含量和磷酸盐施用量的影响

The phosphate in the soil-root interface zone under various soil water contents and application rates of phosphate was still of depletion distribution which could be described by a power function in the form of C/Co= ax^b(C/Co is the relative content of fertilized phosphate in a distance from the root surface x, a and b are the regression constants). The depletion rate of phosphate in soil near the root surface was higher and the depletion range was narrower under lower soil moisture. On the contrary, at higher soil water content the depletion range was wider, generally. The application rate of phosphate led to the greater depletion intensity of phosphorus was higher in the heavier texture soils. In general, the depletion intensity in the soils, which decreased with increasing clay content or increasing buffering power of soil, decreased in the order as loessal soil and black lou soil > lou soil > yellow cinnamon soil when 50 or 100 mg of phosphorus were applied in the form of KH₂PO₄. This result indicated that the phosphate distribution and its movement in the soil-root interface zone closely related with the buffering capacity of soil.     

连续种植蔬菜对潮土磷素水平的影响

Soil P status, inorganic P fractions, and P sorption properties were studied using sandy fluvo-aquic horticultural soils, which are high in organic matter content for vegetable production in comparison with a soil used for grain crop production in Zhengzhou, Henan Province, China. P fractions, Olsen-P, and OM were determined at different depths in the soil profile and sorption isotherm experiments were performed. Most P in excess of plant requirements accumulated in the topsoil and decreased with soil depth. Total P, inorganic P, and OM concentrations increased with continued horticultural use. Olsen-P concentrations in the 0-20 cm depth of horticultural soils were 9 to 25 times higher than those of the grain crop soil. A linear transformation of the Langmuir equation showed that the P adsorption maximum (491.3 mg P kg^-1) and the maximum phosphate buffering capacity (162.1 L kg^-1) for 80-100 cm were greater in the grain crop soil than the horticultural soils. Thus, the most immediate concern with excess P were in areas where heavy P fertilizer was used for vegetable crops and where soil P sorption capacities were low due to sandy soils and high organic matter content.     

不同N水平紫色土上不同水稻品种吸收N、K的动力学

A pot experiment was conducted to study the effect of nitrogen fertilizer on nitrogen and potassium uptake by four rice cultivars. Results showed that the quadratic parabola relationship between biomass of rice and nitrogen levels was observed, with the maximum biomass at the nitrogen level of 150 mg kg^-1. The rates of nitrogen and potassium uptake by the four rice cultivars depended on growth stage and rice cultivar with the maximum rate of N in Shanyou-63 and maximum rate of K in Kaiyou-5 (hybrid rice), respectively. The kinetics of nitrogen and potasssium uptake by rice plant could be quantitatively described by the following equations: y = a + blogt, y = ab + t^1/2 and y = ae^-bt. The b value in the equations was correlated significantly to the rates of nitrogen and potassium uptake (N_R and K_R, r = 0.901^**~0.990^**), suggesting that the b value could be used to distinguish the index of nitrogen and potassium uptake capacity of rice. The maximum values of nitrogen uptake by plant (b value) and apparent recovery of fertilizer nitrogen were observed in Shanyou-63, and the minimum value in Eryou-6078. However, the capacity of potassium uptake (b value) by Kaiyou-5 ranked first and that by Shanyou-63 second. There was a significant linear relationship between nitrogen level and nitrogen uptake by rice, but a quadratic parabola relationship was found between nitrogen level and patassium uptake by rice. The application of nitrogen fertilizer decreased the ratios of potassium to nitrogen uptake by rice plant. The greatest reduction in the ratio was observed at high nitrogen level, and the least reduction was found in Kaiyou-5 and Shanyou-63 due to their greater ability to absorb potassium.     

栽培模式及施肥对玉米和大豆根际土壤磷素有效性的影响

栽培模式及施肥管理对作物吸收利用土壤磷素的影响较大,本研究为探明玉米/大豆套作系统作物根系交互作用下根际土壤无机磷组分动态变化特征,利用盆栽试验测定了玉米/大豆套作(M/S)、玉米单作(MM)和大豆单作(SS)3种栽培模式以及不施肥(CK)、施氮钾肥(NK)和施氮磷钾肥(NPK)3种施肥处理下玉米和大豆地上部生物量及吸磷量和根际与非根际土壤速效磷、无机磷组分含量,以期为优化玉米/大豆套作系统磷素管理提供理论依据。研究结果表明同一施肥水平下,套作玉米的籽粒产量显著高于单作玉米;施磷显著提高了单作玉米籽粒产量,而对套作玉米籽粒产量影响不大。无论施肥与否,套作大豆秸秆及籽粒产量均高于单作大豆。所有施肥处理均表现为套作模式下单株作物地上部磷积累量显著高于单作模式。玉米成熟期,CK、NK处理下套作玉米根际土壤速效磷含量分别比单作玉米高54.2%和71.8%;大豆始花期,NPK处理下套作大豆根际土壤速效磷含量比单作大豆高19.8%。大豆成熟期,NK、NPK处理下套作大豆根际土壤速效磷含量分别比单作大豆高23.8%和108.0%。无论是单作还是套作模式,玉米根际土壤Al-P含量在3个施肥处理下均低于非根际土壤。CK和NK处理下单作玉米根际土壤Al-P含量分别是套作玉米的1.19倍和1.22倍;NPK处理下单作玉米根际土壤Fe-P含量是套作玉米的1.21倍。在CK、NK和NPK施肥处理下,单作大豆根际土Al-P含量分别是套作大豆1.12倍、1.30倍和1.25倍,单作大豆非根际土Al-P含量分别是套作大豆的1.22倍、1.30倍和1.06倍。CK、NK处理下单作大豆根际土壤Fe-P含量分别是套作大豆的1.47倍和1.12倍。研究得出结论,低磷条件下,与单作相比,玉米/大豆套作更有利于作物对土壤Al-P、Fe-P的活化吸收。     

八宝景天–柑橘间作降低柑橘根际土壤镉含量以减少对镉的吸收

  【目的】  超富集植物与经济作物间作是实现重金属污染农田边生产边修复的有效措施。为此,研究八宝景天 (Hylotelephium spectabile) 和柑橘间作对柑橘重金属吸收累积的影响,为柑橘生产提供安全、经济有效的栽培措施。  【方法】  以早熟和晚熟柑橘、八宝景天为试材进行盆栽试验,以全Cd含量为0.92 mg/kg的污染土壤和0.06 mg/kg的清洁土壤为供试土壤。分别设置早熟和晚熟柑橘单作、八宝景天单作、早熟和晚熟柑橘–八宝景天间作和柑橘–八宝景天限制性间作,共7个处理,限制性间作采用半透膜根际袋将八宝景天和柑橘根系分开。在植株生长74天 (7月) 和218天 (12月)时采样,调查植株生物量和Cd含量,分别测定根际土壤全Cd和有效态Cd含量。  【结果】  与柑橘单作相比,与八宝景天间作柑橘的叶片Cd含量降低了26.7%,与清洁土壤种植的柑橘叶片Cd含量 (0.011 mg/kg) 相近。间作条件下,柑橘根际土壤中全Cd含量由0.92 mg/kg降低至0.75 mg/kg,有效态Cd含量由单作处理的0.82 mg/kg降低至0.78 mg/kg,低于柑橘单作处理;柑橘–八宝景天间作柑橘根际土壤中全Cd的减少量是柑橘–八宝景天限制性间作柑橘根际土壤全Cd减少量 (6.52%) 的2.83倍。柑橘–八宝景天间作中八宝景天对土壤Cd的年提取量、年去除率分别达1.40 mg/pot、3.34%,与其单作 (1.50 mg/pot、3.73%) 相比,去除效率降低了10.6%,其主要原因是间作降低了八宝景天的生物量。  【结论】  尽管柑橘–八宝景天间作影响八宝景天对镉的去除效率,但显著降低了柑橘根际全Cd和有效态Cd含量,进而将柑橘叶片Cd含量降低到与清洁土壤下近似的水平,实现了边修复边安全生产的目标,因此,柑橘–八宝景天间作可作为中低度Cd污染农田土壤修复的重要生物措施。     

不同种植模式对作物根系固土拉力特性的影响

玉米大豆间作体系对土壤流失的影响研究多集中在地上部,而鲜有研究报道玉米大豆间作根系特征对固土拉力特性的影响。采用田间径流小区试验,研究了坡耕地条件下玉米大豆间作(MD)、玉米单作(MM)、大豆单作(DD)和裸地(CK)的生物量和根系固土拉力。结果表明:MD处理的玉米根系密度较MM处理增加了19.64%,10—20cm土层深度范围内MD处理与MM和CK处理间差异显著(p0.05),MD处理较MM和CK处理分别高出了4.25%和4.84%,在0—10cm范围内,MD处理较MM和CK处理分别提高了2.49%和15.85%,在20—30cm范围内,MD处理较MM和CK处理分别提高了1.56%和6.25%。MD处理的地上部分鲜重生物量较MM处理增加了2.46%,干重生物量较MM处理增加了7.31%,地下部分鲜重生物量较MM处理增加了5.06%,干重生物量较MM处理增加了3.17%。在0—30cm土层范围内,能有效保持土壤水分,提高土壤含水率。MD处理较MM处理、DD处理和CK处理不论在玉米样方还是在大豆样方其固土能力均强,在施加相同荷载情况下,间作处理比单作处理土壤样方的位移偏移量较单作处理时偏移量小。     

施氮量对玉米/大豆套作系统土壤微生物数量及土壤酶活性的影响

为揭示玉米/大豆套作体系下土壤氮素转换的调控机理和根际微生态效应,以种植模式为主因素[设玉米单作(MM)、大豆单作(SS)和玉米/大豆套作(IMS)3种处理],以玉米、大豆施氮总量(玉米、大豆施氮比例为3∶1)为副因素[设不施氮(NN,0 kg?hm~(-2))、减量施氮(RN,180 kg?hm~(-2))和常量施氮(CN,240 kg?hm~(-2))3个处理],研究了玉米/大豆套作系统下不同施氮量对作物根际土壤微生物数量及土壤酶活性的影响。结果表明:与相应单作相比,套作下玉米根际土壤真菌、放线菌数量分别提高25.37%和8.79%;套作大豆根际土壤真菌、放线菌、固氮菌数量高于单作大豆;套作玉米根际土壤蛋白酶、脲酶活性和套作大豆根际土壤蛋白酶活性均显著升高。各施氮水平间,减量施氮下玉米、大豆根际土壤真菌数量较常量施氮和不施氮均有所提高;施氮提高了玉米、大豆根际土壤放线菌数量;大豆根际土壤固氮菌数量以减量施氮最高,比不施氮和常量施氮高17.78%和5.67%;玉米根际土壤蛋白酶活性、脲酶活性和大豆根际土壤脲酶活性均以减量施氮为最高。适宜的施氮量不仅能增加玉米/大豆套作土壤中真菌、放线菌、固氮菌的数量,还能提高土壤蛋白酶、脲酶活性,调节土壤氮素的转化,促进玉米/大豆对土壤中氮素的吸收,实现节能增效。     

辽西北沙地苹果-花生间作系统土壤养分空间分布特征及间作效应

[目的] 研究辽西北沙地农林复合系统土壤养分的空间分布及其效应,从土壤养分角度探讨果农间作系统中果树和农作物对土壤养分的相互作用关系,为该区农林复合系统的可持续经营提供科学合理的依据。[方法] 以苹果与花生间作、花生单作、苹果单作为研究对象,对0-60 cm土层深度,0-300 cm水平距离范围内土壤养分含量进行测定和分析。[结果] 沙地间作系统中土壤有机质、速效钾极缺乏,全氮、碱解氮很缺乏,全磷缺乏,有效磷含量中等;间作系统在水平方向上,苹果树和花生植株对总养分有机质、氮、磷的竞争激烈位点位于果树带区,对有效养分氮、磷、钾的竞争激烈位点位于近果树作物区;在垂直方向上,各养分总体表现出了表聚性,间作系统对有机质、有效磷的竞争主要位于深土层,对全磷、速效钾的竞争主要位于表土层,对全氮、碱解氮表现为合作效应,表土层效应更高;与苹果单作、花生单作相比较,间作系统速效钾和有效磷含量呈现负效应。[结论] 沙地苹果-花生间作系统土壤养分贫瘠,应在果树带区施用有机肥、磷肥,作物区施入钾肥,以减轻养分竞争,提高养分效应。     

不同磷水平下玉米-大豆间作对红壤无机磷组分及有效磷的影响

通过2年盆栽试验，探讨不同磷水平下玉米–大豆间作根际土壤无机磷组分、土壤有效磷含量及作物磷吸收的差异，明确土壤无机磷组分、土壤有效磷与作物磷吸收之间的相互关系。试验设置玉米单作、大豆单作、玉米–大豆间作3种种植方式以及3个P2O5施用水平(0、50、100 mg/kg，分别记作P0、P50、P100)，共9个处理。结果表明：与单作相比，2018年和2019年在P0、P50和P100水平下，间作显著提高玉米和大豆的籽粒产量，并显著提高玉米和大豆植株的磷素吸收量。与常规施磷水平(P100)下的单作处理相比，玉米–大豆间作在磷肥减少50%(P50)的条件下，并未降低玉米和大豆的磷吸收量与籽粒产量。3个磷水平下，间作提高了玉米和大豆根际土壤有效磷含量，而降低了根际土壤总无机磷以及Fe-P、Al-P、Ca-P、O-P的含量；同时适当增施磷肥显著提高了玉米和大豆根际土壤总无机磷及各无机磷组分的含量。本试验条件下，间作促进土壤中Fe-P、Al-P、Ca-P和O-P的活化(尤其是Fe-P)，是低磷胁迫下间作土壤有效磷含量与作物磷吸收量增加的重要原因。玉米–大豆间作具有节约磷肥、维持作物产量及根际土壤有...     

广东省甜玉米/大豆间作模式的效益分析

过田间试验, 研究了甜玉米/大豆间作对甜玉米产量、主要农艺指标、养分利用率和光能利用率的影响。结果表明, 甜玉米/大豆间作模式的土地当量比大于1(1.07), 说明甜玉米/大豆间作具有一定的产量优势;与单作相比, 间作甜玉米千粒重提高17.88%, 差异显著; 甜玉米/大豆间作群体经济效益提高24.08%, 养分利用率提高54.09%, 两指标的差异达到极显著水平; 生长后期, 间作对甜玉米光能利用体现出一定的正效应, 播后55 d间作甜玉米光能利用率较单作增加28.44%。甜玉米/大豆间作不仅可改善作物群体结构, 提高自然资源利用率, 而且可减少化肥施用量, 具有显著的经济和环境效益。     

不同根构型玉米品种间作对根系分布、养分积累和产量的影响

为探讨不同根构型玉米间作模式下的根系形态分布、养分积累和产量变化,本研究设置大田和盆栽试验,以2个不同根构型的玉米（Zea mays L.）品种金赛501(JS501,根紧凑型）和漯玉16（LY16,根平展型）为材料,研究了玉米间作和单作下根系形态、空间分布、养分积累和产量的变化特征。结果表明,间作下玉米群体根总长度、根总表面积和根总体积分别比单作增加10.28%、19.55%、15.95%,但根平均直径无明显变化。在0～20 cm土层中,间作的玉米根总长度、总表面积和总体积平均比单作高15.27%、21.82%和9.44%;在20～40 cm土层则比单作高12.95%、9.18%和20.31%。间作使根紧凑型品种（JS501）根系横向分布扩大了15 cm,群体根系纵向分布较单作平均加深10 cm,并使40～60 cm土层根长密度平均增加26.03%。间作显著提高了群体根系活力和养分积累量,根系活力比单作平均提高27.83%,植株氮、磷和钾积累量平均比单作提高18.27%、14.79%和15.75%。同时,间作提高了干物质和籽粒产量,比单作提高11.03%和15.36%,且土地当量比大...     

种植方式对玉米大豆套作体系中作物产量、养分吸收和种间竞争的影响

为探寻玉米-大豆套作体系下作物间的资源竞争关系,揭示玉米-大豆套作系统的增产机理,本研究以玉米-大豆套作系统(简称玉豆套作)为对象,通过2 a大田定位试验,研究了玉豆套作带状连作(A1)、玉豆套作带状轮作(A2)、玉豆套作等行距种植(A3)、玉米单作(A4)、大豆单作(A5)5种种植方式对玉米、大豆的产量、养分吸收及种间竞争能力的影响。结果表明,与单作和等行距种植相比,带状种植的玉米产量降低、大豆产量显著增加,A2的大豆产量分别比A5和A3高25.5%和89.2%。与带状连作相比,带状轮作促进玉米增产和对N、P、K的吸收,玉米籽粒产量及植株N、P、K的吸收总量分别提高7.5%、18.5%、9.1%、14.1%。与大豆单作相比,带状套作显著增加了大豆的经济系数和养分收获指数,A2的经济系数和植株N、P、K收获指数分别增加40.9%、11.9%、20.6%、39.9%。带状种植方式下,玉米对N、P、K的竞争力弱于大豆(Ams0,CRms1),但带状轮作提高了玉米的种间竞争力和营养竞争比率。玉米-大豆套作体系下,相对带状连作和等行距种植,带状轮作种植有利于玉米与大豆间的和谐共生,促进了玉米、大豆对养分的吸收,提高了系统的产量和土地当量比率(LER)。