保水剂与秸秆深施对砂质潮土水肥状况及小麦产量的影响

保水剂与秸秆深施对砂质潮土培肥效应的研究,为中低产田砂质潮土的改良提供科学合理的依据。于典型的砂质潮土区设置了五种不同的田间处理方式:秸秆翻埋还田(TS)、秸秆深施(DS)、秸秆与保水剂深施(DS+W)、保水剂深施(DW)和不处理对照(CK)。比较分析了小麦生育期不同土层中水分、有机质、速效氮以及小麦产量。研究结果表明:(1)与CK相比,从孕穗期到灌浆期,秸秆与保水剂的施用均使0~80 cm土层的含水量有所提高,且DS+W与DW均显著提高了60~80 cm土层水分,其中在孕穗期两处理水分含量分别是CK的3倍和2倍,灌浆期为CK的2倍和1.5倍。(2)与CK相比,其余各处理均显著提高了小麦产量(P<0.05),TS、DS和DS+W分别增产了30.7%、27.3%和48.9%。(3)与CK相比,TS、DS、DS+W和DW的水分利用效率显著增加,分别增加了0.63、0.57 0.93和0.29 kg m~(-3)。(4)与CK相比,20~80 cm土层中,深埋处理DS、DS+W、DW均提高了土壤中有机质含量,DS+W处理下土壤有机质含量与其他处理之间差异显著(P<0.05)。(5)与CK相比,TS和DS处理能够有效的提高各土层中硝态氮含量,保水剂的施用在40~80 cm土层中对土壤硝态氮未见显著影响。(6)各处理间单茎小麦各器官干物质积累量大小为:DS+W>DS>TS>DW>CK,且从不同器官的干物质积累量的比例来看,TS、DS、DS+W处理下的籽粒所占比重较CK的籽粒所占比重有所增加,茎+叶所占比例相应减少,植株干物质的积累逐渐向籽粒偏斜。(7)从小麦产量与土壤水分和硝态氮含量的相关分析结果来看,土壤水分主要在小麦灌浆期影响小麦产量,且是砂质潮土中影响小麦产量的最主要因素。综上所述,保水剂与秸秆的施用均能不同程度的改善砂质潮土的理化性状,提高农作物产量,以保水剂与秸秆的配合深施对砂质潮土的改良效果最佳。

Effect of Water Retaining Agent and Straw Applications on Water and Fertilizer Status and Wheat Yield in Sandy Chao Soil

This study investigated the effect of water retaining agent and straw applications on soil fertility,which would provide scientific and rational basis for the improvement of sandy Chao Soil in middle and low yield fields.A field experiment was carried out in a typical sandy Chao Soil area:traditional straw returning (TS),deep application of straw (DS),deep application of straw combined with water retaining agent (DS+W),deep application of water retaining agent (DW) and control (CK).The contents of soil moisture,organic matter,available nitrogen in different soil layers and wheat yield were analyzed and compared.The results showed that:(1) Compared with CK,soil moisture was significantly increased by 3 times and 2 times at booting stage and by 2 times and 1.5 times at the filling period,respectively,in the treatments of DS+W and DW at 60-80 cm soil depth;(2) The treatments of TS,DS,and DS+W significantly increased wheat yield,respectively,by 30.7％,27.3％ and 48.9％ compared with CK;(3) The water use efficiency was significantly larger 0.93,0.63,0.57 and 0.29 kg m-3,respectively,in the treatments of DS+W,TS,DS,and DW than in CK treatment;(4) Compared with CK treatment,DS,DS+W,and DW treatments significantly increased the content of soil organic matter in 20-80 cm soil layer,and significant difference (P ＜ 0.05) was found between DS+W and other treatments;(5) Compared with CK treatment,TS and DS treatments effectively enhanced the content of nitrate nitrogen in each soil layer,and water retaining agent application did not significantly influence the content of soil nitrate nitrogen in 40-80 cm soil layer;(6) The dry matter accumulation per stem in different organs of wheat decreased as follow:DS+W ＞ DS ＞ TS ＞ DW ＞ CK.The proportion of dry matter accumulation of grain in total was raised and that of stem + leaf decreased in TS,DS,DS+W treatments compared with CK treatment,which indicated the dry matter tended to accumulate in grain;(7) From the correlation analysis between wheat yield and soil water content and nitrate nitrogen content,soil moisture affected wheat yield mainly in wheat grain filling stage,and it was the most important factor affecting wheat yield in sandy Chao Soil.In conclusion,the deep application of water retaining agent combined with straw could effectively improve the physicochemical properties of sandy Chao Soil and increase crop yield.