旱地小麦产量差异与栽培、施肥及主要土壤肥力因素的关系

Yield Variation of Winter Wheat and Its Relation to Cultivation,Fertilization,and Main Soil Fertility Factors

【目的】针对中国西北旱地小麦低产田块多、分布范围广、农户地块间产量差异大的问题,探索影响旱地小麦产量的关键因素,为缩小产量差异,普遍提高旱地小麦产量提供理论依据。【方法】对分布在中国西北黄土高原地区的山西、陕西、甘肃旱地小麦主产区的180个农户麦田0—100 cm土壤和小麦植株的取样分析,结合对农户施肥情况的实地调查,研究了旱地小麦产量差异与栽培、施肥及主要土壤肥力因素的关系。【结果】山西、陕西和甘肃冬小麦产量分别介于2 529—8 419、1 344—8 073和2 984—7 145 kg·hm-2。覆膜栽培的小麦产量较传统栽培提高9.4%。传统栽培的高产组产量较中低产组分别高37.5%和77.2%,覆膜栽培分别高25.4%和66.2%。传统栽培高产组的平均施氮量比中低产组分别高44.4%和74.4%,覆膜栽培分别高9.9%和13.5%;传统栽培高产组施磷量比中低产组平均提高31.1%,覆膜栽培提高35.4%;但传统栽培高产组的施钾量却比低产组低62.1%,覆膜栽培高产组比低产组高96.0%。传统栽培不同产量水平间0—100 cm土壤有机质含量没有显著差异,覆膜栽培0—20 cm土壤有机质含量高产组比低产组显著高20.8%。传统栽培40—80 cm土壤全氮存在显著差异,其中40—60 cm土层高产组比中、低产组分别高出7.5%和18.6%;覆膜栽培0—60 cm土层全氮存在显著差异,其中0—20 cm土层高产比中、低产组分别高出3.2%和14.2%。传统栽培土壤矿质氮无显著差异,覆膜栽培80—100 cm土层高产比低产组高1.6倍。传统栽培0—40 cm土层速效磷含量存在显著差异,其中高产组0—20 cm土层比中、低产组分别高74.3%和86.9%;覆膜栽培土壤速效磷含量没有显著差异。传统栽培40—60 cm土壤速效钾含量高产组比中、低产组显著高22.5%和16.0%,覆膜栽培土壤速效钾没有显著差异。土壤p H在不同产量水平和栽培模式间亦无显著差异。【结论】引起产量变异的主要原因有栽培模式、氮磷钾肥用量、土壤有机质以及速效磷含量。因此,缩小西北旱地农户间产量差异、实现小麦增产的关键在于加强旱地麦田水分管理,采用保水栽培;适当提高传统栽培小麦中低产田块的氮磷肥用量、控制钾肥用量,在稳定覆膜栽培小麦中低产田块氮肥的基础上,适当提高磷钾肥用量;加强旱地麦田有机培肥,在提高土壤有机质含量、蓄水保墒和氮素供应能力的同时,提升传统栽培小麦中低产田土壤的有效磷供应能力,以达到通过促进小麦生长,提高籽粒产量的目的。

【Objective】In drylands of northwestern China,we have a serious problem in winter wheat production such as huge amount of and widely distributed low-yielding fields and remarkable yield variations among land parcels of farmers,therefore,it is of great importance to explore the key factors affecting the yield for the purpose of closing the yield variations and increasing the average yield levels of winter wheat universally.【Method】A survey on 180 farmers＇ fertilizer application in winter wheat production with the collection and analysis of their 0-100 cm deep soil samples in the corresponding fields was carried out in Shanxi,Shaanxi and Gansu provinces,the typical dryland wheat producing areas of the Loess Plateau in Northwest China,to study the relationship between the dryland wheat yield variations and cultivation,fertilization,as well as the main soil fertility factors.【Result】Observed winter wheat yields in the three provinces were in the ranges of 2 529-8 419,1 344-8 073 and 2 984-7 145 kg·hm-2,respectively.Compared with traditional cultivation,the wheat yield under plastic film mulching cultivation increased by 9.4%.Under traditional cultivation,the average yield of the high-yielding farmer group was respectively 37.5% and 77.2% higher than that of the middleand low-yielding groups,and the corresponding average yield differences were 25.4% and 66.2% under plastic film mulching cultivation.For fertilizer application,under traditional cultivation the average nitrogen（N） rate in the high-yielding group was respectively 44.4% and 74.4% higher than that in the middle-and low-yielding groups,and it was also 9.9% and 13.5% higher in the high-yielding group than that in the middle-and low-yielding groups under plastic film mulching cultivation.Average phosphorus（P） rate in the high-yielding group was 31.1% higher than the average rate of the middle-and low-yielding groups under traditional cultivation,and it was correspondingly 35.4% higher under plastic film mulching cultivation.Under traditional cultivation the average potassium（K） rate in the high-yielding group was 62.1% lower than that of the low-yielding group,but it was 96% higher in the high-yielding group than that of the low-yielding group under plastic film mulching cultivation.For soil fertility factors,no significant difference was observed in the organic matter content in 0-100 cm soil layers among yield levels in traditional cultivation,but it was 20.8% higher in 0-20 cm soil layers of the high-yielding group than that in low-yielding group under plastic film mulching cultivation.Significant differences were found in the soil total nitrogen in 40-80 cm depth under traditional cultivation,of which that in 40-60 cm soil depth was 7.5% and 18.6% higher in the high-yielding group than in the middle-and low-yielding groups,and under plastic film mulching cultivation,total N was significantly different in 0-60 cm soil layers,of which that in 0-20 cm soil layers was 3.2% and 14.2% higher in the high-yielding group than in the middle-and low-yielding groups,respectively.The mineral nitrogen showed no significant difference among yield groups under traditional cultivation,but that in 80-100 cm soil layers of the high-yielding group was 1.6 times higher than that of the low-yielding group under plastic film mulching cultivation.The available P in 0-40 cm soil layers was significantly different among yield groups in traditional cultivation,and that in the high-yielding group was 74.3% and 86.9% higher than that in the middle-and low-yielding group,respectively,but no significant difference was found in the available soil P under plastic film mulching cultivation.Under traditional cultivation,the available soil K in the high-yielding group was 37.5% and 77.2% higher than that in the middle-and low-yielding groups,respectively,and that was not significantly different among yield levels under plastic film mulching cultivation.Soil p H showed no significant difference at different yield levels and among cultivations.【Conclusion】Main causes for yield variation were found to be the differences in cultivation,fertilizer application rates,and soil fertility factors as soil organic matter content and available P level.Therefore,in northwest drylands,keys to narrow the farmers＇ winter wheat yield variations and increase its levels are to strengthen the management of soil water and employ water retention cultivations,reasonably increase N and P fertilizer input,control K fertilizer use in the middle-and low-yielding fields under traditional cultivation,increase P and K fertilizer application apart from stabilization of N input in the middle-and low-yielding fields under plastic film mulching cultivation,strengthen organic fertilizer application to increases soil organic matter content,water holding capacity and nitrogen supply capacity,and meanwhile enhance soil available P supply capacity in the middle-and low-yielding fields especially under the traditional cultivation,in order to realize the purpose of promoting wheat growth and increasing their grain yield in drylands.