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Rotation and nitrogen management impact of no-till dryland agroecosystems.

机译：免耕旱地农业生态系统的轮作和氮素管理影响。

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摘要

Dryland no-till management allows increased soil water storage efficiency and production potential. Greater production, will increase crop N requirements. Changes in soil N processes under no-till greatly impact crop N management. Two sites were used in eastern Colorado (1) Sterling (Weld loam, Aridic Argiustoll) and (2) Stratton (Keith clay loam, Pachic Argiustoll). The objectives were (1) determine N requirements of wheat (Triticum aestivum L.)-fallow (WF) and wheat-corn (Zea mays L.)-fallow (WCF) rotations, (2) compare production and N-use-efficiency of N source, placement and timing methods (NSP) for crops within these rotations, (3) determine core numbers needed per experimental unit and the effect of core placement and ion exchange capacity on soil net N mineralization via the ion exchange resin/soil core method (IER/SCM), and (4) examine the impact of increasing cropping intensity and previous applied N rates on in situ soil net N mineralization.; Wheat yields did not decrease as cropping intensity increased at adequate N rates. Wheat yield response to N rate was greater in WCF vs. WF. Yield increases from 68 to 101 kg N ha{dollar}sp{lcub}-1{rcub}{dollar} were not large enough to warrant the higher rate. Annual production of grain biomass per kg of total N uptake in WCF was 80% more than WF at comparable N rates. Average annual grain yields were affected by NSP treatments, but differences were small.; The IER/SCM can be successfully adapted to measure in situ soil net N mineralization in dryland no-till agroecosystems. Placement of cores relative to old corn rows affected mineralization, therefore random placement is recommended. Statistical evaluation of this procedure revealed that a precision of 1.5 mg kg{dollar}sp{lcub}-1{rcub}{dollar} and an alpha level of 0.20 required 5 cores/experimental unit.; Increased cropping intensity decreased total net N mineralization by one-half (22 kg ha{dollar}sp{lcub}-1{rcub}{dollar} in WCF vs. 43 kg ha{dollar}sp{lcub}-1{rcub}{dollar} in WF) due to higher residue levels. Increasing N rate from previously applied fertilizer increased average net daily and total net N mineralization. For every 1 kg ha{dollar}sp{lcub}-1{rcub}{dollar} of previous annually applied N, 0.20 kg ha{dollar}sp{lcub}-1{rcub}{dollar} of total N are mineralized.
机译：旱地免耕管理可以提高土壤蓄水效率和生产潜力。产量增加，将增加作物对氮的需求。免耕条件下土壤氮素过程的变化极大地影响了作物氮素的管理。在科罗拉多州东部使用了两个站点（1）斯特林（Weld壤土，Aridic Argiustoll）和（2）斯特拉顿（Keith粘土壤土，Pachic Argiustoll）。目的是（1）确定小麦（Triticum aestivum L.）-休耕（WF）和小麦-玉米（Zea mays L.）-休耕（WCF）轮作的氮素需求；（2）比较产量和氮利用效率轮换中作物的氮源，放置和定时方法（NSP）的数量，（3）确定每个实验单位所需的核心数量，以及核心位置和离子交换容量对通过离子交换树脂/土壤核心进行的土壤净氮矿化的影响（IER / SCM）方法，以及（4）研究增加耕种强度和先前施用的氮肥比例对土壤原位净氮矿化的影响。随着氮肥水平的提高，小麦单产并未降低。 WCF与WF相比，小麦产量对氮素含量的响应更大。产量从68 kg N ha {dollar} sp {lcub} -1 {rcub} {dollar}增加到不足以保证更高的收成。在可比的氮肥施用量下，WCF中每公斤N吸收的谷物生物量的年产量比WF高80％。 NSP处理会影响年均谷物单产，但差异很小。 IER / SCM可以成功地用于测量旱地免耕农业生态系统中的原位土壤净氮矿化度。相对于旧玉米行的玉米芯放置会影响矿化作用，因此建议随机放置。该程序的统计评估表明，精确度为1.5 mg kg {dol} sp {lcub} -1 {rcub} {dol}，α水平为0.20，需要5个核心/实验单位。种植强度的增加使WCF中的总净氮矿化减少了一半（22 kg ha {dolb} -1 {rcub} {rcub} {dollar），而43 kg ha {dollar} sp {lcub} -1 {rcub} {WF}中的{dollar}是由于较高的残留量。以前施用的肥料增加的氮含量增加了平均日净氮和总净氮矿化量。以前每年施用的N每增加1 kg ha {dollar} sp {lcub} -1 {rcub} {dollar}，就会矿化总N的0.20 kg ha {dollar} sp {lcub} -1 {rcub} {dollar}。

著录项

  • 作者

    Kolberg, Robert L.;

  • 作者单位

    Colorado State University.;

  • 授予单位 Colorado State University.;
  • 学科 Agriculture Agronomy.
  • 学位 Ph.D.
  • 年度 1996
  • 页码 88 p.
  • 总页数 88
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 农学（农艺学）;
  • 关键词

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