Rice yield and its relation to root growth and nutrient-use efficiency under SRI and conventional cultivation: an evaluation in Madagascar
Rice yield and its relation to root growth and nutrient-use efficiency under SRI and conventional cultivation: an evaluation in Madagascar
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DOI：
10.1007/s10333-010-0229-z
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发表时间：
2011-03-01
影响因子：
2.2
通讯作者：
Uphoff, Norman
中科院分区：
文献类型：
--
作者：
Barison, Joeli;Uphoff, Norman
虽然众所周知，植物生长和生产力源自遗传潜力 (G) 和环境因素 (E) 之间的相互作用，但提高水稻产量的努力通常是在假设传统水稻种植实践产生的标准 E 的情况下进行的。已经评估了基因型在持续淹没的稻田土壤中的表现，该土壤具有最佳的植物种群密度，并依靠无机肥料来提高产量。马达加斯加开发的水稻集约化系统 (SRI) 现已在亚洲大部分地区得到接受，该系统提出，通过不同的管理实践，可以提高 GxE 互动的生产力：通过精心移栽幼苗建立最佳稀疏种群、间歇性灌溉稻田、积极进行土壤通气并尽可能提高土壤有机质。本文评估了替代性水稻种植实践对粮食产量的影响，特别关注其对水稻根部生长和功能的影响，以及对相关养分利用效率的影响，这些效率可能有助于观察到的更高的粮食产量。在马达加斯加进行了现场实验和农场调查，以评估 SRI 实践与标准栽培方法的比较，考虑不同作物管理实践如何影响水稻植物遗传潜力的表达。在控制土壤和农民影响的情况下，采用 SRI 方法种植的水稻的平均产量是标准做法的两倍多（6.26 t ha(-1) 与 2.63 t ha(-1)）。最明显的表型差异是植物根系生长，通过根系拔丝阻力（RPR）进行评估，这是根系发育的总结指标。平均而言，拔除单株 SRI 植物需要 55.2 公斤的强力植物 (-1)，而拔除三株常规种植的植物丛则需要 20.7 公斤的山丘 (-1) 或 6.9 公斤的植物 (-1)。因此，SRI 植物的每株植物对连根拔起的抵抗力提高了 8 倍。直接测量证实，SRI 方法可诱导更大和更深的根系生长，这可能有助于增加整个作物周期中的养分吸收，而连续洪水下的根系较浅且根系功能持续时间较短。采用 SRI 方法种植的水稻植株比采用传统管理方式种植的水稻根吸收了更多的大量营养素，这反映在更高的 SRI 产量上。当根据养分吸收对谷物产量进行回归以评估养分利用效率时，与采用传统方法种植的植物相比，SRI 植物每吸收单位氮获得了更高的谷物产量。 SRI植物利用常量营养素的内部效率（IE）为N 69.2、P 347.2和K 69.7，而传统种植的植物中这三种常量营养素的IE分别为74.9、291.1和70.4。虽然 N 和 K 的 IE 没有观察到显着差异，但 P 的吸收明显更高，表明 SRI 植物更有效地利用 P 进行谷物生产。需要对这种关系进行更多研究，但这项研究表明，水稻植物结构和功能（特别是根部）的生产变化可以通过替代管理方法引起。
While plant growth and productivity are known to derive from the interaction between genetic potential (G) and environmental factors (E), efforts to improve rice production have usually proceeded assuming a standard E that is created by conventional rice-growing practices. Genotypes have been assessed for their performance in continuously flooded paddy soils, with optimally dense plant populations, with reliance on inorganic fertilization to raise yields. The System of Rice Intensification (SRI) developed in Madagascar and now becoming accepted in much of Asia proposes that GxE interactions can be made more productive with different management practices: optimally sparse populations, established with very young seedlings carefully transplanted, intermittent flooding of paddies, with active soil aeration and with soil organic matter enhanced as much as possible. This article evaluates the effects of alternative SRI cultural practices on grain yield with particular attention to their impact on the growth and functioning of rice plant roots and on associated nutrient-use efficiencies that could be contributing to the observed higher grain yields. On-station experiments and on-farm surveys were conducted in Madagascar to evaluate SRI practices in comparison with standard cultural methods, considering how rice plants' expression of their genetic potential was affected by different crop management practices. Controlling for both soil and farmer effects, rice plants cultivated with SRI methods produced average yields more than double those from standard practice (6.26 vs. 2.63 t ha(-1)). The most evident phenotypic difference was in plant root growth, assessed by root-pulling resistance (RPR), a summary measure of root system development. On average, uprooting single SRI plants required 55.2 kg of force plant(-1), while pulling up clumps of three conventionally grown plants required 20.7 kg hill(-1), or 6.9 kg plant(-1). SRI plants thus offered 8 times more resistance per plant to uprooting. Direct measurements confirmed that SRI methods induced both greater and deeper root growth, which could be contributing to increased nutrient uptake throughout the crop cycle, compared with the shallower rooting and shorter duration of root functioning under continuous flooding. Rice plants grown with SRI methods took up more macronutrients than did the roots of conventionally managed plants, which was reflected in the higher SRI yields. When grain yield was regressed on nutrient uptake to assess nutrient-use efficiency, SRI plants achieved higher grain yield per unit of N taken up, compared to plants grown with conventional methods. The internal efficiency (IE) of SRI plants in utilizing macronutrients was 69.2 for N, 347.2 for P, and 69.7 for K, while the IE in plants conventionally grown was 74.9, 291.1, and 70.4 for these three macronutrients, respectively. Although no significant differences in IE were observed for N and K, the uptake of P was significantly greater, indicating more efficient use of P by SRI plants for grain production. More research needs to be done on such relationships, but this study indicates that productive changes in the structure and functioning of rice plants, particularly their roots, can be induced by alternative management methods.