耕作与施肥对旱地玉米田土壤耗水量和水分利用效率的影响

Effect of tillage and fertilization on water use efficiency of maize in dryland conditions

为探究保护性耕作与施肥对渭北旱地春玉米田土壤耗水量和水分利用效率的影响,达到高效生产的目的。于2013—2015年在渭北旱塬实施了春玉米耕作与施肥田间试验,共设置6种耕作与施肥处理:翻耕+低肥(A1)、免耕+高肥(A2)、深松+平衡施肥(A3)、翻耕+无肥(B1)、免耕+无肥(B2)和深松+无肥(B3),测定了春玉米休闲期与生育时期0~200 cm土层土壤蓄水量和收获时籽粒产量。结果表明:1)保护性耕作能显著提高旱地玉米田土壤蓄水保墒能力。与传统翻耕处理B1相比,休闲期,B2和B3播前土壤蓄水量分别提高23.39 mm和27.73 mm(P<0.05);耕作处理区,B2和B3全生育期土壤蓄水量平均提高13.41 mm和15.70 mm;耕作施肥处理区,A2、A3土壤蓄水量较A1分别提高13.15 mm、19.54 mm。2)平衡施肥能有效提高玉米全生育期平均土壤蓄水量,与不施肥处理相比,全生育期土壤蓄水量平均提高6.79 mm(P<0.05)。3)保护性耕作与施肥能提高玉米籽粒产量与水分利用效率。耕作无肥处理区,与B1比较,B3处理产量提高212~576 kg×hm^(-2),水分利用效率提高0.83~2.21 kg×hm^(-2)×mm^(-1);耕作施肥处理区,A3产量与水分利用效率提高最为显著,产量较A1提高659~1 495 kg×hm^(-2),水分利用效率提高0.65~3.82 kg×hm^(-2)×mm^(-1)(P<0.05)。3种施肥方式下以氮、磷、钾平衡施肥产量与水分利用效率提高幅度最大。4)对耗水量与产量进行相关性分析发现,抽雄—灌浆生育阶段土壤耗水量与产量呈显著正相关,保护性耕作提高玉米生长初期土壤蓄水保墒能力,提高春玉米抽雄—灌浆期土壤水分,增加作物生长关键时期对水分的利用效率,利于玉米籽粒产量的提高。因此在渭北旱地春玉米田,深松与平衡施肥组合能提高春玉米产量与水分利用效率,是该地区玉米高效生产较为适宜的种植模式。

As crop production in rain-fed systems is highly dependent on natural rainfall,making full use of rainfall and increasing water use efficiency are the main modes of dryland farming.Spring maize is one of the main grain crops in Weibei drylands where the plowing induces greater soil water evaporation.Conventional tillage is conducive for high water use efficiency in dryland farming.A study on fertilization and tillage in a field experiment was conducted in Weibei highlands in2013-2015to determine the effects of tillage and fertilization on soil water consumption and water use efficiency of spring maize in Weibei drylands.A total of six treatments were processed in the experiment-conventional tillage with low fertilization(A1),no-tillage with high fertilization(A2),subsoiling with balanced fertilization(A3),conventional tillage without fertilization(B1),no-tillage without fertilization(B2)and subsoiling without fertilization(B3).Soil water moisture in the0?200cm layer during fallow period and maize growth stages was measured and also grain yield under different treatments measured.The results showed that:1)conservation tillage significantly improved soil water storage during fallow period.Compared with B1,B2and B3treatments increased oil water storage by23.39mm and27.73mm,respectively.2).Conservation tillage increased soil water storage during the growth stage.Compared with B1,B2and B3enhanced water storage in the0?200cm by13.41mm and15.70mm,respectively.Compared with A1,A2and A3improved soil water storage by13.15mm and19.54mm,respectively.During the experiment,balanced fertilization effectively improved average soil water storage for the whole growth period by6.79mm.3)Conservation tillage combination with fertilization increased grain yield and water use efficiency.Compared with B1treatment,B3improved grain yield by212?576kg?hm?2and increased water use efficiency(WUE)by0.83?2.21kg?hm?2?mm?1(P<0.05).Also compared with A1,A3treatment increased grain yield by659?1495kg?hm?2and WUE by0.65?3.82kg?hm?2?mm?1(P<0.05).Balanced fertilization had the highest grain yield and WUE.Compared with low and high fertilization,balanced fertilization increased grain yield by1268?2682kg?hm?2,and improved WUE by0.08?4.45kg?hm?2?mm?1(P<0.05).Correlation analysis showeda significant positive correlation between grain yield and soil water consumption during grain-filling stage.It was also noted that conservation tillage improved soil water storage in the early growth,increased soil water storage during tasseling?grain filling stage and promoted WUE at critical periods to increase grain yield.Thus,the combination of subsoiling with balanced fertilization was a suitable tillage system for enhancing grain yield and WUE in Weibei drylands.