Variation in grain yield, and nitrogen, phosphorus and potassium nutrition of irrigated rice cultivars grown at fertile and low-fertile soils
Variation in grain yield, and nitrogen, phosphorus and potassium nutrition of irrigated rice cultivars grown at fertile and low-fertile soils
复制标题
肥沃和低肥沃土壤灌溉水稻品种产量及氮、磷、钾营养的变异
作者：
D. Kekulandara;D. Sirisena;P. Bandaranayake;G. Samarasinghe;M. Wissuwa;L. Suriyagoda
背景和目的为肥沃土壤培育的水稻品种可能不是最适合养分有限环境的品种。因此，需要确定适合在低肥力土壤上维持生产力的水稻品种及其成功的适应机制。方法以斯里兰卡44个大面积种植的水稻品种为材料，在肥沃和低肥力地点分别进行了两个季节和五个季节的田间试验。在低肥力条件下，植株生物量和地上部N、P、K含量分别下降41%、54%、74%和36%，作物生育期延长12d。品种的籽粒干重(DW-g株−1)与籽粒N、P、K浓度在肥沃部位呈负相关(P <； 0.0 5)，只有在低肥力部位才与N呈负相关。低肥力部位的种子-P和K浓度分别达到最低和稳定浓度(分别为1.45g和1.61mgg−1)。无论土壤肥力状况如何，不同水稻品种的籽粒干重与地上部N、P、K含量(镁植株−1)及其积累速率(镁植株−1和日均−1)呈正相关。低肥力地区水稻品种的籽粒干重可用地上部P含量、籽粒P浓度和P收获指数进行回归分析(R2 = 0.74，P <达显著水平； 0.05)。Bw451、Bg379-2、H4、AT362、Ld408、Bg454、Bw400、AT353、Bg380、AT402、Bw452、Ld365和Bw453等品种在低肥力部位的籽粒干重高于其他品种。结论水稻品种对N、P、K的积累能力较强(mg株−1天−1)，作物历时越长，籽粒干重越高，而籽粒P、K浓度不是在磷限制严重的低肥力土壤上筛选优质水稻品种的良好指标。
Background and aimsRice cultivars bred for fertile soils may not be the best suited to nutrient limited environments. Therefore, rice cultivars suited to sustain productivity in low-fertile soils and their adaptive mechanisms for success need to be identified.MethodsField experiments were conducted in fertile and low-fertile sites for two and five seasons, respectively, using forty four widely grown rice cultivars in Sri Lanka. Growth and tissue nitrogen (N), phosphorus (P) and potassium (K) concentrations were measured.Key resultsPlant biomass and shoot- N, P and K contents were reduced by 41, 54, 74 and 36% under low soil fertility, respectively, while crop duration was extended by 12 days. Relationships between grain dry weight (DW- g plant−1) of a cultivar, and seed N, P and K concentrations were negative (P < 0.05) at the fertile site, and this was true only for N at the low-fertile site. Seed- P and K concentrations at the low-fertile site reached to minimum and stable concentrations (1.45 and 1.61 mg g−1, respectively). Irrespective of the soil fertility status, grain DW of rice cultivars was positively correlated with shoot N, P and K contents (mg plant−1) and their accumulation rates (mg plant−1 day−1). Moreover, grain DW of a rice cultivar at the low-fertile site could be explained by shoot P content, seed P concentration and P-harvest index through regression (R2 = 0.74, significant at P < 0.05). Cultivars; Bw451, Bg379–2, H4, At362, Ld408, Bg454, Bw400, At353, Bg380, At402, Bw452, Ld365, and Bw453 had higher grain DW than other cultivars at the low-fertile site.ConclusionRice cultivars with higher capacity to accumulate N, P and K (mg plant−1 day−1), and longer crop duration ensured higher grain DW while seed P and K concentrations are not good indicators to select promising rice cultivars to low-fertile soils with severe P limitation.