Long-Term Effects of Straw and Manure on Crop Micronutrient Nutrition under a Wheat-Maize Cropping System

Management practices have significant effects on crop micronutrient contents. This study examined effects of applying chemical fertilizers of nitrogen (N), phosphorus (P), and potassium (K) (NPK), alone or supplemented with straw or manure, under a wheat-maize cropping system in a 18-year experiment, on the crops’ iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) contents throughout the crops’ development. The micronutrient contents of both wheat and maize were above critical values during vegetative development, but Zn contents of maize ear leaves were sub-sufficient under all treatments. The wheat grain Mn, Cu, and Zn contents were lower under fertilized treatments than in unfertilized controls. Nutrient balance calculations showed that NPK application alone or with straw resulted in deficits of the four micronutrients, but not application of NPK supplemented with manure. Hence, application of micronutrients, such as Zn, through organic or inorganic fertilizers is recommended for this cropping system.     

Alleviation of Multinutrient Deficiency for Productivity Enhancement of Rain-Fed Soybean and Finger Millet in the Semi-arid Region of India

Soil nutrient contents were determined in 802 surface soil samples (0–15 cm deep) collected from farmers' fields that support extensive cultivation of soybean (Glycine max L.) and finger millet (Eleusine coracana G.), spread across three districts, in the semi-arid regions of Karnataka, India. Following soil analysis, on-farm crop trials were conducted during 2005–2007 to study the crop response to the soil application of nitrogen (N), phosphorus (P), sulfur (S), boron (B), and zinc (Zn) fertilizers. Analyses of soil samples revealed that 4–83% fields were deficient in N, 34–65% in P, 83–93% in extractable S, 53–96% in B, and 34–88% of farmers' fields were deficient in Zn. On-farm trials conducted during the three rainy seasons (2005, 2006, and 2007) significantly (P ≤ 0.05) enhanced crop productivity indices such as yields of grain, stover, and total biomass in soybean and finger millet crops. Integrated management of deficient nutrients in finger millet and soybean crops significantly enhanced the grain and straw uptake of N, P, K, S, and Zn.     

秸秆还田对冬小麦产量和氮、磷、钾吸收利用的影响

【目的】陕西关中平原是我国典型的冬小麦—夏玉米轮作区,冬小麦播种前将上季收获后的玉米秸秆还田是当地普遍采用的作物秸秆管理方式。本研究以优化秸秆还田条件的小麦养分资源管理,实现作物增产和肥料增效为目标,通过2年的田间定位试验,探索关中地区玉米秸秆还田条件下,冬小麦高产高效的最佳养分管理措施。【方法】试验于2011年10月至2013年5月在陕西省周至县终南镇进行,供试冬小麦品种为周麦23,夏玉米品种为郑单958。采用裂区设计,主处理为玉米秸秆全量还田(S1)和秸秆不还田(S0),副处理为5个不同氮肥施用水平(N 0、84、168、252和336 kg/hm2),种植作物为冬小麦。通过不同氮水平的回归分析,研究了玉米秸秆还田对后茬冬小麦的籽粒产量、生物量和收获期地上部氮、磷、钾养分吸收利用的影响。【结果】与玉米秸秆不还田相比,秸秆还田对冬小麦籽粒产量和收获期地上部氮、磷、钾养分吸收量的影响均表现出低氮降低、高氮增加的趋势。第一年和第二年在施氮量分别低于N 153和187 kg/hm2时,秸秆还田处理小麦减产,相反则增产,并且增产量随着氮肥用量的增加而增大;生物量与产量趋势一致,前后两年玉米秸秆还田与不还田条件下,冬小麦生物量相等时的氮肥用量分别为N 190和202 kg/hm2。在产量构成要素中,同一氮水平时,秸秆还田对小麦穗粒数和千粒重没有明显影响,而每公顷穗数却表现为低氮降低、高氮增加的趋势,所以秸秆还田后穗数增加是小麦增产的主要原因。同时,在玉米秸秆还田条件下,小麦地上部氮、磷、钾吸收量增加时,第一年的氮肥用量分别高于N 275、123和213kg/hm2,第二年分别高于N 200、165和241 kg/hm2,但氮、磷、钾的收获指数不随施氮量的增加而递增。而且过量施氮也会造成小麦籽粒磷含量的降低。【结论】在综合同一施氮水平时,秸秆还田后的冬小麦籽粒产量和地上部氮、磷、钾养分吸收利用的变化,建议在陕西关中平原的冬小麦—夏玉米轮作区域,氮肥用量应控制在N 150~200kg/hm2,以保证在玉米秸秆还田条件下小麦的增产和氮、磷、钾养分资源的高效合理利用。     

Soil micronutrient availability to crops as affected by long-term inorganic and organic fertilizer applications

Micronutrient status in soils and crops can be affected by different fertilization practices during a long-term field experiment. This paper investigated the effects of different fertilization treatments on total and DTPA-extractable micronutrients in soils and micronutrients in crops after 16 year fertilization experiments in Fengqiu County, Henan Province, China. The treatments of the long-term experiment included combinations of various rates of N, P and K in addition to two rates of organic fertilizer (OF) treatments. Winter wheat and summer maize were planted annually. Soil macro- and micronutrients along with pH and organic matter (OM) were analyzed. Grains and above ground parts of both crops in the final year were harvested and analyzed for Cu, Zn, Fe and Mn. The results showed that soil Cu, Zn, Fe and Mn concentrations did not change among the different treatments to a significant level, except for a slight decrease of soil Zn in the CK (no fertilizer application) compared to the OF treatment. The DTPA-extractable soil Zn, Fe and Mn concentrations increased from 0.41 to 1.08 mg kg⁻¹, from 10.3 to 17.7 mg kg⁻¹, and from 9.7 to 11.8 mg kg⁻¹, respectively, with increasing soil OM content, thus showing the importance of soil OM in micronutrient availability for crops. The NPK treatment also had higher DTPA-extractable micronutrient concentrations in soil. Deficiency of N or P resulted in a low yield but high micronutrient concentrations in crops except Cu in maize stalks. Higher available soil P significantly decreased crop micronutrients, possibly because of their precipitation as metal phosphates. Maize stalks contained higher concentrations of micronutrients than those of wheat straw, whereas wheat grain had higher micronutrients than those of corn grain. The transfer coefficients (TCs) of micronutrients from straw to grain were significantly different between winter wheat (1.63–2.52 for Cu; 2.31–3.82 for Zn; no change for Fe; 0.55–0.84 for Mn) and summer maize (0.24–0.50 for Cu; 0.50–1.21 for Zn; 0.02–0.04 for Fe; 0.07–0.10 for Mn). In conclusion, application of organic matter significantly increased the DTPA-extractable concentrations of Zn, Fe and Mn compared to the CK, grain and vegetative tissue in the CK and NK had higher micronutrient concentrations than those in other treatments.     

低土壤肥力下秸秆还田和施钾对作物产量及土壤钾素平衡的影响

为了研究我国华北平原低肥力土壤条件下秸秆还田和施钾肥对作物产量和钾素平衡的影响,于2008年10月～2011年10月在中国农业科学院高新技术园区国家测土施肥中心实验室试验基地（河北省廊坊市）,通过3年6季的定位试验,比较了施钾与秸秆还田的增产效应、钾素吸收利用和作物土壤系统的钾素平衡状况。结果表明:在氮、磷肥充足的情况下,施用钾肥（NPK）、秸秆还田（NP+St）和秸秆还田配施钾肥（NPK+St）,均有明显的增产效应,表现为NPK+StNPKNP+StNP;不同施钾措施在夏玉米上的增产效果优于冬小麦;同一作物秸秆还田结合施钾肥的增产效果最好,降低了年度间的产量变异系数,在获得高产的同时,年际间产量稳定,有利于稳产;施钾肥和秸秆还田可显著提高小麦和玉米的钾素吸收总量; NPK+St、NPK、NP+St处理的钾素表观平衡系数分别为1.26,0.42,0.92。秸秆还田和施钾肥有利于钾素的收支平衡,减轻作物对土壤钾素的消耗,缓解土壤钾素肥力下降的程度,可维持土壤钾素肥力的稳定。     

低土壤肥力下施钾和秸秆还田对作物产量及土壤钾素平衡的影响

为了研究我国华北平原低肥力土壤条件下秸秆还田和施钾肥对作物产量和钾素平衡的影响,于2008年10月～2011年10月在中国农业科学院高新技术园区国家测土施肥中心实验室试验基地(河北省廊坊市),通过3年6季的定位试验,比较了施钾与秸秆还田的增产效应、钾素吸收利用和作物-土壤系统的钾素平衡状况。结果表明:在氮、磷肥充足的情况下,施用钾肥(NPK)、秸秆还田(NP+St)和秸秆还田配施钾肥(NPK+St),均有明显的增产效应,表现为NPK+St>NPK>NP+St>NP;不同施钾措施在夏玉米上的增产效果优于冬小麦;同一作物秸秆还田结合施钾肥的增产效果最好,降低了年度间的产量变异系数,在获得高产的同时,年际间产量稳定,有利于稳产;施钾肥和秸秆还田可显著提高小麦和玉米的钾素吸收总量;NPK+St、NPK、NP+St处理的钾素表观平衡系数分别为1.26、0.42、0.92。秸秆还田和施钾肥有利于钾素的收支平衡,减轻作物对土壤钾素的消耗,缓解土壤钾素肥力下降的程度,可维持土壤钾素肥力的稳定。     

Productivity and nutrient use efficiency of maize,sorghum, and cotton in the West African Dry Savanna

Sustainable agricultural practices are needed to improve food security and support livelihoods in West Africa, where soil nutrient deficiencies and rainfed production systems prevail. The objective of this study was to assess the productivity and nitrogen (N) and phosphorus (P) use efficiencies of three dominant crops (maize, sorghum, and cotton) under different soil management strategies in the dry savanna of northern Benin. Data were collected for each crop in experiments with (1) an un‐amended soil as control, (2) a low use of external inputs, (3) an integrated soil–crop management practice, and (4) a high mineral fertilizer use, as treatments. Data were collected through researcher‐managed and farmer‐managed on‐farm trials in 2014 and 2015, and analyzed using linear robust mixed effects model and Pearson's correlation. Above‐ground biomass accumulation did not differ significantly among the control, integrated soil–crop management practice, and high mineral fertilizer use up to 30, 50, and 60 d after planting for maize, cotton, and sorghum, respectively. Thereafter, the differences in growth were substantial for each crop with highest biomass monitored with high mineral fertilizer use and lowest with the control. Biomass and economic yields at harvest were highest under high mineral fertilizer use and integrated soil–crop management practice, although the magnitude was crop‐specific. With the integrated soil–crop management practice and high mineral fertilizer use, N and P uptake by all crops was higher than for the un‐amended soil conditions. Inter‐seasonal changes in N uptake were higher for sorghum and cotton, but lower for maize. The highest agronomic efficiency and apparent recovery of N and P as well as positive N and P partial balances were obtained with the integrated soil–crop management practice for all three crops tested. The integrated soil–crop management strategy gave the highest yields and significantly improved N and P use efficiencies. The findings can contribute to formulating site and crop‐specific recommendations for sustainable agricultural practices in the Dry Savanna zone of West Africa.     

Widespread Deficiencies of Sulfur,Boron, and Zinc in Indian Semi-Arid Tropical Soils: On-Farm Crop Responses

On-farm studies were conducted during 2002–2004 to determine fertility status, including sulfur (S) and micronutrients, and crop response to fertilization on farmers' fields in the semi-arid zone of India. Nine hundred-twenty four soil samples taken from farmers' fields, spread in the three districts of Andhra Pradesh (India), were analyzed for soil chemical fertility parameters. Results showed that samples were low in organic carbon (C), total nitrogen (N), and low to moderate in extractable phosphorus (P), but adequate in available potassium (K). Analyses of soil samples for extractable S and micronutrients was most revealing and showed that 73–95% of the farmers' fields were deficient in S, 70–100% in boron (B), and 62–94% in zinc (Zn). On-farm trials conducted during three seasons (2002–2004) showed significant yield responses of maize, castor, groundnut, and mung bean to the applications of S, B, and Zn. The yield responses were larger when S, Zn, and B were applied along with N and P. Applications of S, B and Zn also significantly increased the uptake of N, P, K, S, B, and Zn in the crop biomass. Results show widespread deficiencies of S, B, and Zn under dryland agricultural conditions; results also show that the nutrient deficiencies can be diagnosed by soil testing. It was concluded that the drylands in the semi-arid regions of India were not only thirsty (water shortage), but also hungry (nutrient deficiencies).     

不同养分配比对高粱根系生长及养分吸收的影响

为探明高粱养分吸收和根系生长对氮、磷、钾胁迫的响应,通过长期定位试验,在高粱/玉米轮作条件下研究了不同养分配比NPK、PK、NK、NP、CK对高粱根系生长及养分吸收的影响。结果表明:与NPK相比,长期不施氮肥(PK)条件下高粱总根长增加18.29%,总根体积降低26.52%,且根系主要分布在0~10 cm土层,直径小于0.5 mm细根所占比例显著增加。不施磷肥(NK)显著抑制了高粱根系生长,总根长、总根表面积和总根体积分别降低24.03%、27.48%和41.29%。不施钾肥(NP)对细根生长有明显抑制作用。不施氮、磷、钾均降低高粱对相应养分的吸收和累积,不施氮促进了营养器官中氮和钾素向籽粒转运,不施磷或钾肥抑制了氮、磷及钾的转运。高粱对养分的吸收、积累和转运与根系形态有关,不同养分积累与运转与根系形态关系表现不尽相同:氮素、钾素积累和转运与根系形态具有较好的相关性,氮素的积累和转运与植株生物量和产量的相关性大于磷素和钾素。综上,高粱根系形态及养分吸收对氮、磷及钾胁迫响应不同,该研究可为不同养分瘠薄地高粱高效栽培提供理论依据。     

施钾和秸秆还田对春玉米产量、养分吸收及土壤钾素平衡的影响

【目的】明确秸秆还田与施钾肥对玉米产量、养分吸收与利用以及土壤钾素平衡状况的影响,为东北地区玉米秸秆和钾肥资源合理利用提供科学依据。【方法】试验于2010~2012年在玉米主产区吉林省公主岭市朝阳坡镇大房身村开展,试验设氮磷肥（NP）、氮磷肥+秸秆还田（NP+St）、氮磷钾（NPK）、氮磷钾+秸秆还田（NPK+St）4个处理, 于每年玉米成熟期每处理小区取有代表性的玉米5株,分为秸秆和子粒两部分,测定地上部干物重,并测定其氮、 磷、 钾含量,收获时取中间四垄玉米按14%水分计产。试验前和小区玉米收获后采集020 cm土层土壤样品,测定土壤速效钾含量,计算钾素利用等相关参数,分析不同处理的春玉米产量、养分吸收及土壤钾素平衡状况。【结果】施钾肥和秸秆还田能提高玉米产量,与NP处理相比,NPK+St、NPK、NP+St处理玉米产量分别增加13.8%、 9.6%和3.8%。施钾肥和秸秆还田可提高玉米秸秆和子粒氮、磷、钾的吸收总量。与NP相比,NPK、NP+St 和 NPK+St处理氮的吸收总量提高9.4%~24.7%,磷提高12.2%~26.0%,钾提高6.9%~26.4%,其中NPK+St处理的养分吸收总量最高。秸秆还田结合施钾肥（NPK+St）有利于提高钾收获指数、化肥钾和秸秆钾的利用率,其钾收获指数,化肥钾农学效率、回收率、秸秆钾回收率均高于单施化学钾（NPK）和秸秆还田处理（NP+St）。其中钾收获指数分别提高5.5%和18.8%,化肥钾农学效率和回收率分别提高8.3%和1.1%,秸秆钾农学效率和回收率分别提高4.0%和0.7%。秸秆还田结合施用钾肥（NPK+St）土壤速效钾含量比NPK和NP+St提高1.9%~4.0%,其表现为NPK+StNP+StNPKNP。NPK+St、NPK、NP+St处理钾素实际盈亏率分别为15.0%、-51.1%和 -18.1%。【结论】秸秆还田结合施用钾肥不仅可以提高玉米产量、增加养分吸收总量,还有利于土壤钾素的收支平衡,提高土壤速效钾含量,对维持土壤钾素肥力的稳定具有重要的作用,可在当地农业生产中推广应用。     

传统耕作结合秸秆地膜双元覆盖是提高渭北旱塬春玉米产量和养分吸收的有效措施

  【目的】  在干旱半干旱地区,实现雨养农业作物持续增产的关键因素是提高作物养分利用效率。研究黄土高原旱作农业区长期不同耕作、覆盖措施对春玉米产量和养分吸收的影响,为黄土塬区可持续的农田管理提供参考。  【方法】  保护性耕作定位试验位于中国科学院黄土高原农业生态试验站,始于2003年。设有4个传统耕作和4个免耕处理,具体为传统耕作 (CT)、传统耕作+地膜覆盖 (CP)、传统耕作+秸秆覆盖 (CS)、传统耕作+地膜+秸秆覆盖 (CPS)、免耕 (NT)、免耕+地膜覆盖 (NP)、免耕+秸秆覆盖 (NS)、免耕+地膜+秸秆覆盖 (NPS)。调查分析了2007—2016年玉米产量和玉米养分吸收特性。  【结果】  4个传统耕作处理中,CP处理玉米籽粒平均产量比CT处理提高了24.4%,氮素和钾素养分利用效率最高;CS处理玉米平均生物产量比CT处理提高了39.4%,玉米茎秆养分吸收量最高,特别是总吸钾量提高了101.7%;CPS处理籽粒平均产量最高 (9381.6 kg/hm2),总吸氮量和吸磷量分别比CT处理提高了63.2%和123.7%。4个免耕处理中,NP处理籽粒平均产量比NT处理提高了25.8%,NS处理比NT处理降低了3.9%;CPS处理平均籽粒产量、生物产量、植株总吸氮量和总吸磷量最高。相同覆盖处理下,传统耕作的平均籽粒产量、生物产量、氮磷总吸收量均高于免耕。平水年地膜覆盖增产效果最好 (27.0%～37.4%),干旱年秸秆覆盖增产效果最好 (3.5%～8.5%),丰水年则以地膜秸秆双元覆盖增产效果最大 (31.6%～38.1%)。  【结论】  黄土高原旱地条件下,传统耕作对玉米的增产效果好于免耕。采用传统耕作结合地膜秸秆双元覆盖提高了玉米籽粒产量,增加了玉米地上部养分吸收量,在不同气候年份下对玉米增产效果均较好,且年际间变异幅度较小,是渭北旱塬增加玉米养分吸收,提高籽粒产量的最佳田间管理措施。     

长期不同施肥方式对砷在典型壤质潮土及作物中累积的影响

本文研究了长期(1989—2009年)不同施肥方式对砷在黄淮海地区典型壤质潮土及作物中累积的影响。田间试验设置7个处理:有机肥(OM)、OM+无机化肥氮磷钾(NPK)、NPK、NP、PK、NK和不施肥(CK),OM+NPK处理为有机肥和无机化肥氮磷钾各施一半。结果显示,长期不同施肥方式下砷在表层(0~20 cm)及亚表层(20~40 cm)土壤中的含量均有明显累积,但含量较低(<25 mg.kg 1),对农田生态环境安全的影响较小。土壤中砷的累积主要与灌溉及沉降有关,受施肥方式的影响相对较小。磷肥中砷的含量明显高于氮肥、钾肥及有机肥,磷肥的长期施用促进了砷在PK处理土壤中的累积,但在作物产量较高的情况下,对其在土壤中累积趋势的影响较小,而有机肥的添加则会减缓这种累积趋势。砷在小麦和玉米两种典型作物组织中的含量分布表现为:根系>茎叶>籽粒,其中籽粒中砷的含量显著低于根系及国家食品安全相关标准。经过长期不同方式的施肥处理,砷在小麦组织中的含量表现为:PK>OM>OM+NPK>NPK>NP>NK>CK,与土壤中有效磷含量的变化基本一致,并间接受到土壤有机质的影响。在OM、OM+NPK、NPK和NP施肥处理下,土壤有机质含量及作物产量均较高,土壤有机质含量的提高促进了砷在小麦体内的富集,但对其在玉米根系中含量的影响不明显;玉米生长期较短且产量较高,对砷的需求量较大,土壤中有效态砷含量的不足抑制了其在玉米根系中的分布,但玉米通过加强组织对砷的转移能力提高了其在茎叶中的含量。     

Fractions of Iron in Soil under a Long-Term Experiment and Their Contribution to Iron Availability and Uptake by Maize–Wheat Cropping Sequence

Soil and plant samples were collected from an ongoing long-term experiment (LTE) at the Indian Agricultural Research Institute farm, New Delhi, to study the distribution of various fractions of iron (Fe) and their contribution to availability and plant uptake in a maize–wheat sequence. The optimum dose-based treatments adopted for the study were nitrogen (N), nitrogen–phosphorus (NP), nitrogen–phosphorus–potassium (NPK), NPK + farmyard manure (FYM), NPK+ zinc (Zn), and control (no fertilizer or manure). Different fractions of Fe in the soil were sequentially extracted using different extractants. Diethylenetriaminepentaacetic acid (DTPA)–extractable Fe did not differ significantly among the treatments as a result of continuous cropping for more than three decades. The overall mean total iron (Fe) content varied from 2.36 to 2.61% under different treatments. Residual Fe constitutes a major portion of total Fe in all four layers of soil. The Fe associated with easily reducible Mn and organic matter contributed directly to DTPA-extractable Fe both in pre-maize and post-wheat soil. Residual Fe contributed directly to uptake Fe by maize and wheat crops.     

水肥条件对小麦、玉米N、P、K吸收的影响

水、N是影响作物N、P、K吸收的重要因素。通过对 6个水分等级和 5个N肥等级相互搭配的研究结果表明 ,高水、高N处理不利于小麦N吸收 ,而玉米是耐肥作物 ,相同灌水条件下 ,玉米的吸N量随施N量的增加而增加。在低灌水条件下 (W 0、W 1处理 ) ,玉米子粒吸N量很低 ,变幅为 0～17.3kg/hm2,并且不受施N量的影响 ;而小麦子粒吸N量仍达 36.6～154.2kg/hm2。小麦与玉米吸P量的变化趋势与吸N量的变化趋势非常接近。但是 ,作物的吸K量随灌水量增加有明显增加的趋势 ,在玉米上表现尤其明显 ,并且作物的吸K量主要存在于茎秆中 ,因此 ,在当地推广和宣传秸秆还田很有必要     

Enhanced nutrient and rainwater use efficiency in maize and soybean with secondary and micronutrient amendments in the rainfed semi-arid tropics

In view of widespread deficiencies, a long-term experiment was started at the International Crops Research Institute for the Semi-Arid Tropics, Patancheru, India in 2007 to identify economically efficient application strategy (full or 50% dose every or every second year) of sulphur (S) (30 kg ha^?1), boron (B) (0.5 kg ha^?1) and zinc (Zn) (10 kg ha^?1). During the fourth year in 2010, balanced fertilization through adding S, B and Zn increased maize grain yield by 13–52% and soybean yield by 16–28% compared to nitrogen (N) and phosphorus (P) fertilization alone. Balanced nutrition increased N and P uptake, utilization and use efficiency for grain yield and harvest index indicating improved grain nutritional quality. The N, P plus 50% of S, B and Zn application every year recorded highest crop yields and N and P efficiencies indices and increased rainwater use efficiency with a benefit:cost ratio of 11.9 for maize and 4.14 for soybean. This study showed the importance of a deficient secondary nutrient S and micronutrients B, Zn in improving N and P use efficiency while enhancing economic food production.     

不同轮作体系土壤残留硒锌对小麦产量与营养品质的影响

采用盆栽试验,通过玉米-小麦和大豆-小麦轮作,探讨了不同种植模式中,土壤残留硒锌对小麦产量与营养品质的影响。结果表明,土壤中残留硒锌对小麦生物量和产量的影响与作物轮作体系有关。玉米-小麦轮作,土壤残留硒锌并没有表现出增加小麦产量的趋势,而大豆-小麦轮作,土壤残留硒锌对小麦生物量和产量呈增加趋势。土壤残留硒锌可改变作物体内元素组成。玉米-小麦轮作,土壤残留硒锌有利于小麦籽粒对氮、钾、硫、钙、铁、锌、硒、铜元素的吸收累积。大豆-小麦轮作,土壤残留硒锌促进小麦对钾、硫、镁、铁、锌、硒、铜、锰、硼的吸收,而氮、磷、钙吸收减少。     

Residual phosphorus and management strategy for grain sorghum on a vertisol

Abstract

Fertilizer phosphorus (P) use on Vertisols of the semi‐arid zone in India is becoming more common, so it is important that for developing P management strategies the residual value of P is allowed. Little information is available on this aspect for crops such as sorghum under rainfed cropping. A field experiment was conducted for three years to study the response of sorghum to fertilizer P (0, 10, 20, and 40 kg P ha^‐1) in the absence and presence of P residues from the preceding year on a Vertisol (Typic Pellustert), low in extractable P (0.4 mg kg^‐1 soil Olsen‐P). Despite the variable rainfall received during the cropping season (June‐September), P applied in the previous season had strong residual effects. Sorghum yield and P uptake in treatments in which P was applied at 20 or 40 kg P ha^‐1 once in two years was at par with or higher than in treatments in which 10 kg or 20 kg P ha^‐1 was added every year. Ninety percent relative grain yield was achieved at about 20 kg ha^‐1 of fresh P and the results presented show that application of 40 kg P ha^‐1 once in two years can satisfactorily meet the P requirement of sorghum on the Vertisol.     

安徽省县域麦稻玉米秸秆时空分异特征与还田养分输入量测算

安徽省是国家重要商品粮生产基地,作为农业大省其粮食作物秸秆产量居于全国前列。明晰全省产粮大县主要粮食作物秸秆理论资源量和可收集资源量时空分布特征,并准确测算秸秆就地还田对土壤养分输入的贡献,可为秸秆全量化差异化利用策略优化及秸秆还田情景下的农田养分平衡调控提供决策依据。研究表明,2011-2019年安徽省产粮大县三大粮食作物秸秆资源总量呈现出稳步增长的态势,而不同作物秸秆产量年际变化趋势各异：小麦秸秆先升后稳,水稻秸秆波动不大,玉米秸秆逐年递增。2019年安徽省产粮大县三大粮食作物秸秆理论资源量为3 878万t,其中小麦、水稻和玉米秸秆所占比例分别为47.3%、36.3%和16.4%。淮北区为小麦和玉米秸秆资源集中分布区,占比分别为73.0%和88.3%,水稻秸秆主要产自江淮区（41.7%）、皖西区（21.3%）及沿江区（19.7%）。主要粮食作物秸秆资源总量分布表现为淮北区（52.5%）?江淮区（24.3%）?皖西区（10.5%）?沿江区（9.1%）?皖南区（3.6%）。2019年全省产粮大县小麦、水稻和玉米秸秆可收集资源量分别为1 338万、1 041万和542万t,淮北区单位播种面积小麦和玉米秸秆可收集资源量分别为4 505～6 310和4 171～5 395 kg/hm2,江淮区、皖西区和沿江区单位播种面积水稻秸秆可收集资源量分别为4 487～5 326、4 570～5 028和4 329～5 778 kg/hm2。2019年安徽省产粮大县三大粮食作物秸秆氮（N）、磷（P2O5）和钾（K2O）养分资源总量分别为25.3万、10.9万和90.1万t。在秸秆就地全量还田情景下,小麦玉米主产区（淮北区）小麦秸秆还田的氮（N）、磷（P2O5）和钾（K2O）养分输入量分别为35.8～50.1、14.1～19.8和139.8～195.8 kg/hm2,玉米秸秆还田的养分输入量分别为42.7～55.2、16.9～21.8和93.4～120.9 kg/hm2;水稻主产区（江淮区、皖西区和沿江区）水稻秸秆还田的养分输入量分别为38.0～50.8、18.8～25.0和151.6～202.3 kg/hm2。研究结果对进一步提升安徽省产粮大县秸秆资源综合利用效率及推动农业绿色高质量发展具有重要的现实意义。     

秸秆覆盖方式和施氮量对河套灌区夏玉米氮利用及产量影响

为探究夏玉米氮素转运利用规律、产量及土壤NO3－-N含量分布对秸秆覆盖方式和施氮量的响应,在河套灌区开展2a不同秸秆覆盖方式（秸秆表覆B处理、秸秆深埋S处理）和不同施氮水平（不施氮N0、低氮N1、中氮N2、高氮N3）的田间试验,以传统耕作模式为对照（CK处理）。结果表明：在0～100 cm土层,各处理NO3－-N含量随施氮量增加而增大,成熟期B和CK处理随土层加深呈先减后增趋势,而S处理呈先增后减趋势;B处理提高0～20 cm土层NO3－-N含量,而S处理提高20～40 cm土层NO3－-N含量（P<0.05）;秸秆覆盖可减少0～100 cm土层NO3－-N累积损失量,且显著提高氮肥利用率及夏玉米氮素转运量对籽粒产量的贡献率,SN2处理效果较佳。相比CK处理,成熟期的SN2处理2 a平均NO3－-N累积损失量降低39.6%,氮肥利用率较提高28.5%,夏玉米氮素转运量对籽粒产量的贡献率提高32.1%,增产9.3%。综合分析,秸秆深埋配施中氮效果较佳,可实现河套灌区夏玉米提效增产的目标,并减少深层土壤NO3－-N累积损失量,为优化河套灌区夏玉米耕作施氮模式和缓解农业面源污染提供参考。     

Preliminary studies on triticale,wheat, barley,and rye responses to lime and N.

Abstract

The lime and N requirements for triticale (X Triticosecale Wittmack) have not been established because of the relatively short history of the crop. This study was designed to evaluate the effects of lime and high N rates on triticale, wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and rye (Secale cereale L.) on Dickson silt loam (Typic Paleudult) and Decatur silty clay loam (Rhodic Paleudult) in 1974–1976. The soils had pH values of 4.9 and 5.5 with no lime and 5.4 and 5.8, respectively, when limed as recommended. The fertilizer rates were 112, 140, and 170 kg N/ha. Yields and N, P, K, Ca, Mg, Mn, Fe, Al, Zn, Cu, and B were determined in straw and grain. Liming the Dickson soil increased the straw yields of barley at 112 kg N/ha and grain yields of the cultivars generally at the 170 kg N/ha rate. Liming the Decatur soil did not have consistent effects on straw yields but increased the grain yields of the wheat and rye cultivars. Increasing N rate increased the straw yields of wheat on Dickson but decreased the grain yields of barley in the same soil with no lime. Nitrogen fertilization did not have consistent effects on the Decatur soil. The N, P, K, Ca, Mg, and Mn compositions suggested that more differences occured at the species level than at the cultivar level.