Abstract:As it significantly improves the physical and chemical characteristics of farmland plow layer soil, straw return is an efficient strategy to enhance soil fertility. To understand the effects of different straw return methods on soil fertility and maize growth, experiments were conducted from 2002 to 2010 in Pingliang Maize Breeding Experimental Station (PMBES) of Gansu Agricultural University. Soil chemical and physical characteristics, and maize plant root growth and yield were determined for three straw return treatments — 3-year straw return (H3, 2007—2010), 6-year straw return (H6, 2005—2010) and 9-year straw return (H9, 2002—2010) — and non-straw return used as the control (0-year straw return, CK). The results showed that soil contents of organic matter, total nitrogen, total phosphorus, alkali-hydrolysis N and available K in the 0~30 cm soil layer significantly improved with increasing years of straw return. Soil bulk density reduced significantly in the 20~50 cm soil layer with increasing years in the order of 9 < 6 < 3 < 0 years. Root weight density, total length and activity significantly improved with increasing years of maize straw return. Especially during later growth stage, maize root characteristics in deep soil exhibited significant differences among different straw return treatments. Root activity in the 40~60 cm soil layer in H9, H6 and H3 treatments were higher than in CK treatment by 54.8%, 29.1% and 16.3%, respectively. Root weight density and total length in H9 treatment increased respectively by 44.3% and 79.3% over CK. The root weight density and total length increased by 30.8% and 58.9% in H6, and by 18.8% and 47.7% in H3 treatments over CK, respectively. Under CK, maize root rapidly recession in the fields. Plant height, ear height of maize increased with increasing years of straw return. Ear height of H9, H6 and H3 was 11.1 cm, 5.3 cm and 0.7 cm higher than that of CK respectively. The maize yield improved with increasing years of straw return too. 100-seed weigh and yield of H9, H6, H3 increased by 17.4%, 10.2%, 7.5%, and 15.4%, 10.3%, 4.5%, respectively, over the CK. The findings suggested that straw return delayed root consenescence, enhanced root nutrient uptake at the later growth stage and increased maize yield.
全 文 :中国生态农业学报 2012年 3月 第 20卷 第 3期 Chinese Journal of Eco-Agriculture, Mar. 2012, 20(3): 291−296
长及根系活力水平等指标, 均表现出随着还田年限增加而增加的趋势。特别是生长后期较深土层的根系, 表现 不同处理间变化幅度差异显著的特点, 成熟期 40~60 cm 土层 H9、H6、H3 处理根系活力水平分别较对照高 54.76%、29.1%和 16.3%, H9根重密度、总根长分别较对照高 44.3%、79.3%, H6、H3处理根重密度分别较对 照增加 30.8%、18.8%, 根长增加 58.9%、47.7%, 而对照根系表现迅速衰退现象, 说明秸秆还田处理使成熟期 玉米根系衰退延迟, 有利于后期作物对养分的吸收和产量的形成。随秸秆还田年限增加, 玉米地上株高及穗位 高相应增加, H9、H6、H3穗位高分别较对照增加 11.1 cm、5.3 cm和 0.7 cm; 百粒重各处理较对照依次增加 17.4%、10.2%和 7.5%, H9处理产量较对照增产 15.4%以上, H6、H3分别较对照增产 10.3%和 4.5%, 表现随还 田年限增加显著增产的趋势。 关键词 玉米 秸秆还田年限 耕层 土壤性状 根系特性 产量 中图分类号: S143-57 文献标识码: A 文章编号: 1671-3990(2012)03-0291-06 Effects of continuous straw return to soil on maize growth and soil chemical and physical characteristics MU Ping1,2, ZHANG En-He2, WANG Han-Ning2, FANG Yong-Feng2 (1. Gansu Provincial Key Laboratory of Aridland Crop Sciences, Lanzhou 730070, China; 2. College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China) Abstract As it significantly improves the physical and chemical characteristics of farmland plow layer soil, straw return is an efficient strategy to enhance soil fertility. To understand the effects of different straw return methods on soil fertility and maize growth, experiments were conducted from 2002 to 2010 in Pingliang Maize Breeding Experimental Station (PMBES) of Gansu Agricultural University. Soil chemical and physical characteristics, and maize plant root growth and yield were deter- mined for three straw return treatments — 3-year straw return (H3, 2007—2010), 6-year straw return (H6, 2005—2010) and 9-year straw return (H9, 2002—2010) — and non-straw return used as the control (0-year straw return, CK). The results showed that soil contents of organic matter, total nitrogen, total phosphorus, alkali-hydrolysis N and available K in the 0~30 cm soil layer significantly improved with increasing years of straw return. Soil bulk density reduced significantly in the 20~50 cm soil layer with increasing years in the order of 9 < 6 < 3 < 0 years. Root weight density, total length and activity signifi- cantly improved with increasing years of maize straw return. Especially during later growth stage, maize root characteristics in 292 中国生态农业学报 2012 第 20卷
deep soil exhibited significant differences among different straw return treatments. Root activity in the 40~60 cm soil layer in H9, H6 and H3 treatments were higher than in CK treatment by 54.8%, 29.1% and 16.3%, respectively. Root weight density and total length in H9 treatment increased respectively by 44.3% and 79.3% over CK. The root weight density and total length increased by 30.8% and 58.9% in H6, and by 18.8% and 47.7% in H3 treatments over CK, respectively. Under CK, maize root rapidly recession in the fields. Plant height, ear height of maize increased with increasing years of straw return. Ear height of H9, H6 and H3 was 11.1 cm, 5.3 cm and 0.7 cm higher than that of CK respectively. The maize yield improved with increasing years of straw return too. 100-seed weigh and yield of H9, H6, H3 increased by 17.4%, 10.2%, 7.5%, and 15.4%, 10.3%, 4.5%, respectively, over the CK. The findings suggested that straw return delayed root consenescence, enhanced root nutrient uptake at the later growth stage and increased maize yield. Key words Maize, Straw return year, Arable layer, Soil characteristics, Root characteristics, Yield (Received May 19, 2011; accepted Sep. 2, 2011) 秸秆还田能够改善土壤结构和理化性状, 提高 土壤保水保肥能力, 优化农田生态环境, 是一项重 要的生物养地培肥地力的措施, 因而受到国内外众 多学者的普遍关注[1−3]。李贵桐等[4]研究秸秆还田对 土壤氮素转化的影响时发现 , 秸秆在腐解过程中 , 能够促进土壤微粒的团聚, 有效改善土壤结构及土 壤理化性状, 持续提高土壤肥力; 邹聪明等[5]研究表 明, 秸秆覆盖栽培模式下, 玉米苗期根长、根表面积 及根系活力较对照显著增加; 霍竹等[6]研究发现, 秸 秆还田可一定程度上延缓玉米叶片衰老, 促进夏玉 米干物质由茎秆向籽粒的转运。而有关不同年限连 续全量玉米秸秆还田背景下, 玉米地上及地下物质 生长发育及相关生理特性影响的研究尚少见报道。 甘肃陇东黄土高原土层深厚, 降雨充沛, 是北 方重要的夏玉米产区, 由于常年玉米连作和化肥大 量施用 , 造成耕层土壤板结 , 肥力水平下降 , 不利 于玉米持续发展。近年来该区大力推广以全量玉米 秸秆还田为主的农田生物培肥措施, 旨在降低化肥 投入水平, 发展循环农业。在此背景下, 本试验针对 4 种不同年限玉米秸秆还田处理, 以其耕层土壤理 化性状、不同生育时期玉米根系发育状况、根系生 长相关生理指标以及玉米产量性状为对象, 研究长 期全量玉米秸秆还田措施对土壤理化性状及玉米植 株地下部和地上部生长发育的影响, 为合理指导秸 秆还田提供参考。 1 材料与方法 1.1 试验地概况 试验区位于甘肃农业大学平凉玉米育种站, 该 站位于东经 106°25′, 北纬 35°24′, 海拔 1 170 m, 年 均降水量 550~650 mm, ≥10 ℃年积温 2 862.8 ℃, 年均气温 9.4 ℃。试验地土壤为黄绵土, 土质绵软, 土 层深厚, 质地均匀。2001年秸秆还田处理前, 0~40 cm 土层土壤有机质含量 10.85 g·kg−1, 容重 1.26 g·cm−3, pH 8.73, 全氮、全磷含量分别为 0.86 g·kg−1、1.76 g·kg−1, 速效氮、速效磷、速效钾含量分别为 55.37 mg·kg−1、15.8 mg·kg−1和 203.35 mg·kg−1。试验区为 传统黄土高原中晚熟夏玉米区域, 玉米连作栽培 1 年 1熟。 1.2 试验设计 试验自 2002 年开始, 共设 4 个处理: 未秸秆还 田(H0, CK)、全量玉米秸秆(9 800 kg·hm−2)粉碎连续 还田 3 年(H3, 2007—2010 年)、连续还田 6 年(H6, 2005—2010年)和连续还田 9年(H9, 2002—2010年)。 每年玉米果穗收获后进行秸秆还田, 冬前结合整地 将玉米秸秆粉碎后全部覆盖地表, 春季播种前浅耕 作业翻埋入土。小区面积 150 m2, 随机区组排列, 重 复 3次。2002—2010年参试玉米品种为“富农 1号”, 宽窄行种植, 宽行行距 0.6 m, 窄行行距 0.4 m, 行长 10 m, 种植密度 5.25万株·hm−2。各处理均施 N 150 kg·hm−2(尿素), P2O5 150 kg·hm−2(过磷酸钙)。试验地 位于泾河灌区, 每年于玉米拔节期、开花期补灌 2 次, 灌水量保持 1 000 m3·hm−2, 样品采集及数据测 定于 2010年玉米生长季进行。 1.3 样品采集与测定 1.3.1 土样采集 于 2009 年 10 月玉米收获后各小区田间 S 型采 样, 先除去土样表面的枯叶和秸秆, 再用内径为 5 cm的土钻在各小区分层取 0~20 cm、20~40 cm的土 样, 每个样品均为多点采集混合而成, 然后用四分 法取出足够的样品, 拣出石砾和根系后, 室内风干 过 1 mm筛。 1.3.2 土壤容重及理化指标测定 采用环刀法测定土壤容重, 先挖出 70 cm 深土 壤剖面, 按剖面层次 0~10 cm、10~20 cm、20~30 cm、 30~40 cm、40~50 cm、50~60 cm分层采样, 重复 3 次, 计算平均值。土壤有机质、全氮、速效氮、速 效磷、速效钾均依据土壤农业化学分析方法测定[7]。 1.3.3 根系生长及生理特性测定 于2010年玉米生长的拔节期、吐丝期、成熟期3 第 3期 慕 平等: 不同年限全量玉米秸秆还田对玉米生长发育及土壤理化性状的影响 293
表 1 不同年限秸秆还田 0~30 cm耕层土壤养分含量变化 Table 1 Nutrient contents of 0~30 cm soil layer under different treatments of straw return years 处理 Treatment 有机质 Organic matter (g·kg−1) 全氮 Total N (g·kg−1) 速效氮 Alkali-hydrolysis N (mg·kg−1) 全磷 Total P (g·kg−1) 速效磷 Available P (mg·kg−1) 速效钾 Available K (mg·kg−1) H9 15.84a 1.36a 68.27a 0.85a 15.55a 205.42a H6 13.58b 1.32a 61.36b 0.83a 15.21b 198.08a H3 8.82c 1.07b 52.24c 0.77b 15.43ab 197.46a H0 7.79c 0.78c 49.89d 0.63c 15.20b 142.39b 同列不同小写字母表示处理间差异达 5%显著水平, 表 4同。H9、H6、H3、H0 表示秸秆还田 9年、6年、3年和无秸秆还田 4种处理, 下 同。Different small letters in same column mean significant difference at 5% level, the same as the table 4. H9, H6 and H3 mean straw return for 9, 6, and 3 years, and N0 means none straw return. The same below.
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图 1 不同年限秸秆还田 0~60 cm土层土壤容重变化 Fig. 1 Soil bulk density in 0~60 cm soil layers under different treatments of straw return years
25–114 [8] 刘晶淼, 安顺清, 廖荣伟, 等. 玉米根系在土壤剖面中的分 布研究[J]. 中国生态农业学报, 2009, 17(3): 517–521 [9] 白宝璋, 金锦子, 白崧, 等. 玉米根系活力 TTC 测定法的 改良[J]. 玉米科学, 1994, 2(4): 44–47 [10] 李秧秧 , 刘文兆 . 土壤水分与氮肥对玉米根系生长的影响 [J]. 中国生态农业学报, 2001, 9(1): 13–15 [11] Bengough A G, Young I M. Root elongation of seedling peas through layered soil of different penetration resistances[J]. Plant and Soil, 1993, 149(1): 129–139 [12] Goodman A M, Ennos A R. The effects of soil bulk density on the morphology and anchorage mechanics of the root systems of sunflower and maize[J]. Annals of Botany, 1999, 83(3): 293–302 [13] 李潮海, 李胜利, 王群, 等. 下层土壤容重对玉米根系生长 及吸收活力的影响 [J]. 中国农业科学 , 2005, 38(8): 1706–1711 [14] Coelho E L, Or D. Root distribution and water uptake patterns of corn under surface and subsurface drip irrigation[J]. Plant and Soil, 1999, 206(2): 123–136 [15] 刘义国, 林琪, 王月福, 等. 秸秆还田与氮肥耦合对冬小麦 光合特性及产量形成的影响[J]. 中国生态农业学报, 2007, 15(1): 42–44 [16] 罗珠珠, 黄高宝, 张仁陟, 等. 长期保护性耕作对黄土高原 旱地土壤肥力质量的影响 [J]. 中国生态农业学报 , 2010, 18(3): 458–464 [17] 杨景成, 韩兴国, 黄建辉, 等. 土壤有机质对农田管理措施 的动态响应[J]. 生态学报, 2003, 23(4): 787–796