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首页> 外文学位 >AGRONOMIC COMPARISONS BETWEEN PHOSPHATE ROCK AND SUPERPHOSPHATE IN SOILS OF THE CERRADO OF BRAZIL.
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AGRONOMIC COMPARISONS BETWEEN PHOSPHATE ROCK AND SUPERPHOSPHATE IN SOILS OF THE CERRADO OF BRAZIL.

机译：巴西塞拉多土壤中磷酸盐岩和超磷酸盐之间的农艺比较。

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摘要

The potential utilization of Patos de Minas phosphate rock (PR) for direct application to Cerrado soils was evaluated in field and laboratory experiments. In field studies, the effects of broadcast PR or ordinary superphosphate (OSP), with or without band-applied OSP, on the growth and yield of soybeans were studied on a Typic Acrustox in the Cerrado of Brazil during two consecutive crops. In laboratory studies, the dissolution patterns of North Carolina PR and Patos PR were compared in seven Cerrado soils during a 158-day incubation period.; Soybean yield maxima for two consecutive crops were higher with broadcast OSP than with broadcast PR. The low crop growth rates (CGR) and P accumulation rates (PAR) for plants receiving Patos PR indicated that this low reactivity source was unable to supply adequate P for optimal soybean growth. This observation was confirmed by the small increases in available soil P values. Estimates of critical P levels extracted by the Bray 1, Olsen, and anion resin methods were 11-15, 6-8, and 8-12 ppm P, respectively. The relationships between yield response and soil-test P values were identical for both sources of broadcast P. Although Bray 1 P levels at pH 4.4 were almost double the levels obtained at pH 4.8, increases in grain yield were not observed at this low pH, presumably because of Al toxicity.; Increasing the levels of available soil P increased the CGR and PAR throughout the growing season. Differences in CGR among the broadcast P treatments were evident at an earlier stage of growth with OSP than with PR.; Preplant band-applied OSP combined with either source of broadcast P improved initial growth and maintained CGR and PAR values superior to broadcast P alone during the first 70 days after planting. The band application of 44 kg P/ha combined with 176 kg P/ha of broadcast OSP provided yields equivalent to the maximum achieved with 352 kg P/ha as broadcast OSP, providing a reduction of 88 kg P/ha in the total P fertilizer application for two crops and decreased P costs by 25%. Yield increases due to band-applied P decreased with increasing soil-test P values.; The dissolution rate for Patos PR was approximately linear during the 158 days of incubation, as opposed to an exponential pattern for the North Carolina PR, indicative of an initially rapid release of P during the first 43 days of incubation. Inherent differences in the PR sources, namely the degree of isomorphous substitution of CO(,3) for PO(,4) in the apatite structure, were associated with these differing patterns of dissolution. Changes in Olsen-extractable P were found to be more indicative of the PR dissolution process than P extracted by an anion resin procedure. Maximum dissolution of the PR, when measured by increases in exchangeable Ca, occurred in soils with the highest P sorption capacity. The "Ci" modifier of the Fertility Capability Classification system was an effective criterion for separating soils with high and low levels of PR dissolution. Increases in exchangeable soil Ca during incubation ((DELTA)Ca) was a useful parameter for describing PR dissolution patterns.
机译：在野外和实验室实验中评估了帕托斯·德·米纳斯（Patos de Minas）磷酸盐岩（PR）直接应用于塞拉多土壤的潜在利用。在田间研究中，在巴西Cerrado的Typic Acrustox作物连续两次种植期间，研究了广播PR或普通过磷酸钙（OSP），无论有无带OSP施用，对大豆生长和产量的影响。在实验室研究中，比较了北卡罗莱纳州PR和Patos PR在158天的潜伏期中在7种Cerrado土壤中的溶解模式。播送OSP的两个连续作物的大豆单产最高值比播放PR的更高。接受Patos PR的植物的低作物生长速率（CGR）和磷积累速率（PAR）表明，这种低反应性源无法为大豆最佳生长提供充足的磷。可用土壤P值的少量增加证实了这一观察结果。用Bray 1，Olsen和阴离子树脂方法提取的临界P水平估计分别为11-15、6-8和8-12 ppmP。两种播种磷源的产量响应和土壤试验磷值之间的关系相同。尽管pH 4.4的Bray 1 P水平几乎是pH 4.8的水平的两倍，但在这种低pH下未观察到谷物产量的增加，大概是因为铝的毒性。在整个生长季节中，增加可用土壤P的水平会增加CGR和PAR。在OSP的生长较PR的生长早期，C广播的P处理之间的CGR差异明显。在播种后的前70天内，使用种植前带施肥的OSP与两种播种P的来源相结合，可改善初始生长，并保持CGR和PAR值优于单独播种P。播种44 kg P / ha结合176 kg P / ha的波段施用提供的产量等于播出OSP 352 kg P / ha的最高产量，使总磷肥减少88 kg P / ha申请两种作物，磷成本降低了25％。随土壤测试P值的增加，由于施带的P降低，产量增加。在培养的158天中，Patos PR的溶出速率大致呈线性，与北卡罗莱纳州的PR呈指数规律相反，这表明在培养的前43天中P最初迅速释放。 PR源的固有差异，即磷灰石结构中CO（，3）对PO（，4）同构取代的程度与这些不同的溶解模式有关。发现Olsen可萃取P的变化比阴离子树脂萃取的P更能反映PR的溶解过程。当通过交换性钙的增加来衡量时，PR的最大溶解发生在具有最高P吸附能力的土壤中。肥力分类系统的“ Ci”修饰剂是分离PR溶解度高和低的土壤的有效标准。孵育过程中可交换土壤Ca的增加（ΔCa）是描述PR溶解模式的有用参数。

著录项

  • 作者

    SMYTH, THOMAS JOT.;

  • 作者单位

    North Carolina State University.;

  • 授予单位 North Carolina State University.;
  • 学科 Agriculture Agronomy.; Geological Survey.
  • 学位 Ph.D.
  • 年度 1981
  • 页码 148 p.
  • 总页数 148
  • 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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