轮耕条件下土壤改良及春玉米增产增收效果研究

Effects of rotation tillage on soil improvement and increasing yield and benefit of spring maize

针对旱作区长期采用单一的土壤耕作方式造成的土壤结构变差及作物生长发育受限等问题,研究由免耕、深松及翻耕组成的不同轮作模式对干旱区春玉米土壤肥力及产量的影响具有重要生产意义。于2014—2016年在兰州市榆中县清水驿乡孟家山村玉米田开展连续免耕(NT)、连续深松(ST)、连续翻耕(PT)、深松、免耕及深松轮耕(ST/NT/ST)、免耕、免耕和深松轮耕(NT/NT/ST)、翻耕、免耕及翻耕轮耕(PT/NT/PT)、翻耕、免耕及深松轮耕(PT/NT/ST)和深松、翻耕及深松轮耕(ST/PT/ST) 8种耕作模式试验,测定8种耕作模式下的土壤孔隙度、土壤养分、干物质和玉米产量,并分析其经济效益。结果表明:在0～60 cm土层,随着土层的增加土壤孔隙度表现为先降后增,以20～40 cm土层的土壤孔隙度最低。5种轮耕措施较耕作前均能增加土壤孔隙度,以ST/PT/ST轮耕模式最优,其次为ST/NT/ST,较PT提高了1.24%、0.25%;土壤养分含量在0～20 cm土层均高于20～40 cm土层,其中,0～20 cm土层免耕与深松进行轮耕下土壤全氮、全磷含量较高,以ST/NT/ST全氮、磷含量最高,20～40 cm土层,对土壤全氮、全磷含量无显著影响,翻耕与深松轮作促进了速效氮、磷、钾的提高,以ST/PT/ST速效氮、磷、钾含量高,免耕土壤有机质含量较其它耕作方式低,其余土壤养分指标为表层富集,下层匮乏;轮耕模式较单一的耕作方式更能促进玉米干物质的累积,其中以ST/NT/ST与PT/NT/PT耕作下玉米干物质高,频繁的翻耕(PT)不利于玉米的生长; 3年产量相比,8种耕作模式中,ST/NT/ST处理下玉米产量显著高于其它处理(ST/NT/ST>NT/NT/ST>ST/PT/ST>ST>NT>PT/NT/ST> PT/NT/PT> PT)。较单一耕作(NT、ST、PT),ST/NT/ST处理下玉米产量提高了5. 97%、3. 56%、15.75%;且以ST/NT/ST经济效益最高。结论:深松、免耕及深松轮耕有利于改善耕层结构和提高土壤养分,增产增效显著,为旱作区春玉米农田适宜的轮耕模式。

A long-term practice of applying single soil tillage treatment harms soil structure,crop growth and development in arid area.Effects of different rotational tillage patterns combined with no-tillage,subsoiling and plow tillage on soil fertility and grain yield were explored in continuous cropping spring maize field in arid area.The experiments of NT(continuous no-tillage),ST(continuous subsoiling tillage),PT(continuous plow tillage),ST/NT/ST(subsoiling tillage in first year,no-tillage in the second year,subsoiling tillage in third year),NT/NT/ST(no-tillage in first year,no-tillage in the second year,subsoiling tillage in third year),PT/NT/PT(plow tillage in first year,no-tillage in the second year,plow tillage in third year),PT/NT/ST(plow tillage in first year,no-tillage in the second year,subsoiling tillage in third year),ST/PT/ST(subsoiling tillage in first year,plow tillage in the second year,subsoiling tillage in third year)were conducted in rainfed maize fields from 2014 to 2016.Different rotational tillage patterns on soil porosity,soil nutrients,dry matter and maize yield were measured.Economic benefits were analyzed.The results showed that,soil porosity(SP)decreased first and then increased in the soil depth 0~60 cm and the lowest occurred in the depth 20~40 cm.Rotational tillage could significantly increase SP and the highest was under ST/PT/ST,followed by ST/NT/ST.Comparing to PT,SBD increased under ST/PT/ST by 1.24%and 0.25%respectively.Soil nutrient content in the depth 0~20 cm soil was higher than that in the depth 20~40 cm soil.Rotational tillage with no tillage and subsoiling could increase content of soil total nitrogen and total phosphorus in 0~20 cm soil.The content of soil total nitrogen and total phosphorus were the highest under ST/NT/ST and tillage had no effect on the content of soil total nitrogen and total phosphorus in 20~40 cm soil.Rotational tillage with plow tillage and subsoiling could increase available nitrogen,phosphorus,and potassium in 0~40 cm.The content of soil available nitrogen,phosphorus,and potassium were the highest under ST/PT/ST.Soil organic matter content was the lowest under NT,and NT increased soil nutrient content in top soil.Comparing to NT,ST and PT,rotational tillage could improve the dry matter accumulacation.ST/NT/ST and PT/NT/PT could enhance dry matter accumulation.PT was not conducive to the growth of maize.ST/NT/ST was the best(ST/NT/ST>NT/NT/ST>ST/PT/ST>ST>NT>PT/NT/ST>PT/NT/PT>PT)after the spring maize grain yield and economic benefit of 8 rotational tillage patterns in 3 years were evaluated comprehensively.Comparing to NT,ST and PT,the average annual yields of 3 years under ST/NT/ST was increased by 5.97%,3.56%and 15.75%respectively.Rotational tillage of subsoiling tillage,no-tillage and subsoiling tillage(ST/NT/ST)improved good tilth soil structure,also increased soil nutrient contents,could effectively increase the yield and decrease production costs.It was suggested the ST/NT/ST was a more appropriate rotational tillage pattern for the continuous cropping spring maize field in arid area.