秸秆还田方式与播种深度对夏直播花生土壤物理性状与出苗特性的影响

Effects of straw returning methods and sowing depth on soil physical properties and emergence characteristics of summer peanut

为探讨播种深度及不同小麦秸秆还田方式下对土壤物理性状、花生下胚轴生长动态以及出苗率的影响,通过设置小麦-花生周年定位试验,花生季采用裂区试验设计,主区为小麦秸秆还田方式,包括翻耕还田(P)、旋耕还田(R)、免耕覆盖(N);裂区为花生品种,试验选用大粒花生品种山花108(B)与小粒花生品种山花106(S);裂裂区为播种深度,2021年设置3 cm(3)、5 cm(5)、9 cm(9)、15 cm(15),2022年设置3 cm(3)、6 cm(6)、9 cm(9)。结果表明,翻耕还田和旋耕还田提高了土壤温度,但降低了土壤含水量;免耕覆盖处理显著增加了6 cm以下土层的土壤紧实度;相同秸秆还田方式下,两品种均表现为适当浅播(播深3 cm和6 cm)显著提高了出苗率,深播(播深>9 cm)处理增加了下胚轴伸长速率,提高了子叶脂肪酶活性,降低了子叶干重、子叶中蔗糖与可溶性糖的含量,与PB3相比,PB6和PB9子叶可溶性糖和蔗糖含量分别下降19.72%和39.43%和14.15%和40.23%;与PS3相比,PS6、PS9子叶可溶性糖和蔗糖含量分别下降10.08%、24.84%和20.04%、37.08%,说明深播增加了出苗过程中子叶养分消耗;相同播种深度下,翻耕还田和旋耕还田的籽粒产量显著高于免耕覆盖;增加播种深度,各秸秆还田方式下单位面积株数以及单株结果数均显著降低,与PB6相比,PB3和PB9处理荚果产量分别降低7.47%和14.94%;与PS3相比,PS6和PS9处理荚果产量分别降低11.66%和24.03%。因此,秸秆翻耕还田处理有利于改善土壤结构,缩短花生出苗时间,提高出苗率以及花生荚果产量,在此条件下大粒型花生与小粒型花生的适宜播深分别为5~6 cm与3 cm。

To explore the effects of sowing depth and different wheat straw returning methods on soil physical properties,peanut hypocotyl growth dynamics and seedling emergence rate,a wheat-peanut annual positioning experiment was conducted.Peanut season was designed with a split-plot experiment.The main area was wheat straw returning methods,including moldboard plow tillage with wheat residue returning(P),rotary tillage with wheat residue returning(R),no tillage with wheat residue mulching(N).The split area was peanut varieties,which were large-seed peanut variety Shanhua 108(B)and small-seed peanut variety Shanhua 106(S).The split zone was the sowing depth,with 3 cm(3),5 cm(5),9 cm(9),15 cm(15)in 2021 and 3 cm(3),6 cm(6),9 cm(9)in 2022.The results showed that moldboard plow tillage and rotary tillage increased soil temperature,but decreased soil water content.The no tillage with wheat residue mulching treatment significantly increased the soil compactness of soil layer below 6 cm.Under the same straw returning method,both varieties showed that the appropriate shallow sowing(sowing depth of 3 cm,6 cm)significantly increased the emergence rate,deep sowing(sowing depth>9 cm)increased hypocotyl elongation rate,increased cotyledon lipase activity,and decreased cotyledon dry weight,sucrose and soluble sugar content in cotyledons.Compared with PB3,the contents of soluble sugar and sucrose in cotyledons of PB6 and PB9 decreased by 19.72%,39.43%and 14.15%,40.23%,respectively.Compared with PS3,the contents of soluble sugar and sucrose in cotyledons of PS6 and PS9 decreased by 10.08%,24.84%and 20.04%,37.08%,respectively,indicating that deep sowing increased the nutrient consumption of cotyledons during seedling emergence.The grain yield of tillage and rotary tillage was significantly higher than that of no-tillage.With the increase of sowing depth,the number of plants per unit area and the number of pods per plant decreased significantly under different straw returning methods.Compared with PB6,the pod yield of PB3 and PB9 decreased by 7.47%and 14.94%,respectively.Compared with PS3,the pod yield of PS6 and PS9 decreased by 11.66%and 24.03%,respectively.Therefore,moldboard plow tillage with wheat residue returning treatment was conducive to improving soil structure,shortening peanut emergence time,increasing emergence rate and peanut pod yield.Under this condition,the suitable sowing depth of large-grain peanut varieties and small-small peanut varieties was 5-6 cm and 3 cm,respectively.