| In order to establish the suitable row spacing configuration of cotton machine-harvesting under different irrigation quotas,’Zhongmian 619’was used as the test material,and the two-factor split-plot experiment design was used.Three different irrigation quotas were set in the main area of irrigation quota:W1:4 200m~3/hm~2、W2:5 100 m~3/hm~2、W3:6 000 m~3/hm~2.The row spacing configuration was used as the auxiliary area.Two kinds of row spacing configuration modes under the same density were set:P1:width 2.05 m,row spacing 76 cm,plant spacing 5.5 cm,P1:(66+10)cm machine-harvesting mode.Line spacing 66 cm,plant spacing 10 cm.The differences of water consumption characteristics and physiological characteristics of cotton under different irrigation quotas and row spacing configurations were studied to explore the effects of filmless drip irrigation on the growth and yield of cotton,and provide theoretical basis for efficient and high-quality cultivation techniques of cotton under filmless drip irrigation in southern Xinjiang.The main research results are as follows:1、0～50 cm soil layer is soil moisture active layer,soil moisture change increases with the increase of irrigation quota,decreases with the increase of row spacing,P1W3 treatment of soil moisture change in each soil layer than other treatments.The variation law of soil bulk density and field capacity was consistent with that of soil moisture content,which was W3>W2>W1,P1>P2.The effect of irrigation quota on evaporation was W3>W2>W1.The soil water consumption was W3>W2>W1 under the same row spacing configuration,and P1>P2 under the same irrigation quota.The total water consumption of P1W3was 773.78 mm,and the stage water consumption was affected by the double factors of yield and total water consumption.The highest water consumption of P2W3 was 253.79 mm,and the lowest water consumption of P1W1 was 1 490.39 mm.With the increase of irrigation quota and row spacing,the water consumption showed a rising trend,and the maximum water consumption was at the peak of flowering and boll,indicating that this was the key period for cotton growth and development.2.Flowering and boll stage is the key period of cotton growth and development without film drip irrigation.At this time,the photosynthetic potential,leaf area index and leaf area per plant reached the maximum.The maximum photosynthetic potential was 117.35 under PIW3 treatment,and the minimum was 75.48 under P2W1 treatment.The maximum leaf area index was 4.48 in P2W2 treatment and 3.40 in P1W1treatment;the maximum leaf area of P2W3 treatment was 1 240.57 cm2,and the minimum leaf area of P1W1 treatment was 898.74 cm2,showing significant difference.Under different water treatments at flowering and bolling stages,the original and first-order derivative spectral reflectances increased with time.With the increase of irrigation quota,the extreme values of single leaf“s”‘green peak’,absorption valley and red edge position continued to migrate to the treatment with higher irrigation quota,and the single leaf water content also increased.With the increase of row spacing,the red-edge extreme values of the original and first-order derivative spectral reflectance under each treatment were biased towards the P2 row spacing treatment in the flowering and flowering periods.The single leaf moisture content and spectral reflectance of P2W3 were higher than other treatments.With the advancement of growth process,the content of protective enzymes was P2>P1 under the same irrigation quota;under the same row spacing configuration,the content of protective enzymes(SOD,CAT,POD)in cotton increased first and then decreased with the increase of irrigation quota.MDA content increased with the growth period,and the protective enzyme content of P2W3was the highest in the combined treatment.3.The plant height and leaf number of cotton under drip irrigation without plastic film increased with the increase of irrigation quota,and the plant height of each treatment was significantly positively correlated with stem diameter and fruit branch number.Stem diameter was significantly positively correlated with internode number of main stem and fruit branch number;the internode number of main stem was positively correlated with the number of fruit branches.Dry matter accumulation per plant showed a slow-fast-slow’S’growth trend.With the increase of irrigation quota and row spacing,the dry matter accumulation per plant and plant nutrient content of each treatment gradually increased.From the point of view of dry matter accumulation and distribution,the dry matter accumulation of vegetative organs of each treatment showed a trend of first increase and then decrease.The dry matter accumulation of reproductive organs increased rapidly at flowering and boll stage and then tended to be gentle.The fastest growth was P2W3 treatment.Nutrient content of vegetative and reproductive organs showed N>P>K,and the highest nutrient content of P2W3 was significantly different from other treatments.4.Single boll weight and boll number per plant increased with the increase of irrigation quota.Under the same irrigation quota,single boll weight,boll number per plant,seed cotton yield,lint yield and lint percentage of P2 line spacing were higher than those of P1 line spacing;the boll number per unit area was higher in low and medium water treatment than in P1 row spacing,and lower in high water treatment than in P1.The seed cotton yield increased with the increase of irrigation quota and row spacing.The seed cotton yield of P2 row spacing was higher than that of P1 row spacing.The water treatments under P2 row spacing configuration performed well after grey correlation analysis.In summary,under the irrigation quota of 6 000 m~2/hm~2,‘Zhong mian 619’selected the row spacing configuration of 76 equal row spacing to increase yield significantly.Under the irrigation quota of 5 100m~2/hm~2,(66+10)row spacing seed cotton and lint cotton increased yield significantly.Under the irrigation quota of 4 200 m~2/hm~2,the yield of 76 equal row spacing seed cotton was significantly. |
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