Wang Xinbing, Zhou Baoyuan, Sun Xuefang, Yue Yang, Ma Wei, Zhao Ming
Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.
College of Agronomy and Biotechnology, China Agricultural University, Beijing, China.
PLoS One. 2015 Jun 22;10(6):e0129231. doi: 10.1371/journal.pone.0129231. eCollection 2015.
The spatial distribution of the root system through the soil profile has an impact on moisture and nutrient uptake by plants, affecting growth and productivity. The spatial distribution of the roots, soil moisture, and fertility are affected by tillage practices. The combination of high soil density and the presence of a soil plow pan typically impede the growth of maize (Zea mays L.).We investigated the spatial distribution coordination of the root system, soil moisture, and N status in response to different soil tillage treatments (NT: no-tillage, RT: rotary-tillage, SS: subsoiling) and the subsequent impact on maize yield, and identify yield-increasing mechanisms and optimal soil tillage management practices. Field experiments were conducted on the Huang-Huai-Hai plain in China during 2011 and 2012. The SS and RT treatments significantly reduced soil bulk density in the top 0-20 cm layer of the soil profile, while SS significantly decreased soil bulk density in the 20-30 cm layer. Soil moisture in the 20-50 cm profile layer was significantly higher for the SS treatment compared to the RT and NT treatment. In the 0-20 cm topsoil layer, the NT treatment had higher soil moisture than the SS and RT treatments. Root length density of the SS treatment was significantly greater than density of the RT and NT treatments, as soil depth increased. Soil moisture was reduced in the soil profile where root concentration was high. SS had greater soil moisture depletion and a more concentration root system than RT and NT in deep soil. Our results suggest that the SS treatment improved the spatial distribution of root density, soil moisture and N states, thereby promoting the absorption of soil moisture and reducing N leaching via the root system in the 20-50 cm layer of the profile. Within the context of the SS treatment, a root architecture densely distributed deep into the soil profile, played a pivotal role in plants' ability to access nutrients and water. An optimal combination of deeper deployment of roots and resource (water and N) availability was realized where the soil was prone to leaching. The correlation between the depletion of resources and distribution of patchy roots endorsed the SS tillage practice. It resulted in significantly greater post-silking biomass and grain yield compared to the RT and NT treatments, for summer maize on the Huang-Huai-Hai plain.
根系在土壤剖面中的空间分布会影响植物对水分和养分的吸收，进而影响生长和生产力。根系的空间分布、土壤水分和肥力会受到耕作方式的影响。土壤密度高和犁底层的存在通常会阻碍玉米（Zea mays L.）的生长。我们研究了不同土壤耕作处理（免耕：NT，旋耕：RT，深松：SS）下根系、土壤水分和氮素状况的空间分布协调性及其对玉米产量的后续影响，并确定增产机制和最佳土壤耕作管理措施。2011年和2012年在中国黄淮海平原进行了田间试验。深松和旋耕处理显著降低了土壤剖面0至20厘米表层的土壤容重，而深松显著降低了20至30厘米土层的土壤容重。与旋耕和免耕处理相比，深松处理在20至50厘米剖面层的土壤水分显著更高。在0至20厘米的表土层中，免耕处理的土壤水分高于深松和旋耕处理。随着土壤深度增加，深松处理的根长密度显著大于旋耕和免耕处理。根系集中的土壤剖面中土壤水分降低。在深层土壤中，深松比旋耕和免耕具有更大的土壤水分消耗和更集中的根系。我们的结果表明，深松处理改善了根密度、土壤水分和氮素状况的空间分布，从而促进了土壤水分吸收，并减少了剖面20至50厘米层中通过根系的氮素淋失。在深松处理的情况下，深入土壤剖面密集分布的根系结构在植物获取养分和水分的能力方面发挥了关键作用。在土壤易于淋失的地方实现了根系更深层分布与资源（水和氮）有效性的最佳组合。资源消耗与斑块状根系分布之间的相关性支持了深松耕作措施。对于黄淮海平原的夏玉米，与旋耕和免耕处理相比，深松处理显著提高了吐丝后的生物量和籽粒产量。
