| The ridge and furrow rainfall harvesting(R) planting collecting runoff by the plastic mulched ridges is a useful method to improve soil water conditions and crop productivity in semiarid area of northwest China. In order to provide a theoretical basis for improving and developing ridge and furrow rainfall harvesting planting applied to irrigated farmland, and further extended this planting from semi-arid region to semi-humid region to cope with water scarcity, thus, we performed a field study to evaluate the influence of R planting supplement irrigation(RI) on water irrigation use, soil water content, maize eco-physiological characteristics, yield and maize water use efficiency(WUE) in a semiarid climate during2012–2014 with following eight treatments: irrigation during the trumpeting stage under R planting and traditional flat planting(R1/B1); irrigation both during the trumpeting and blooming stage under R planting and traditional flat planting(R2/B2); irrigation during the blooming stage under R planting and traditional flat planting(R3/B3); and without supplement irrigation under R planting and traditional flat planting(R0/B0), to evaluating the effects of deficiency irrigation combined with ridge and furrow rainwater harvesting planting on soil temperature and moisture in maize farmland and eco-physiological characteristics of maize, and the main obtained results are as follows:1. Soil moisture and temperature(1) In three consecutive experimental years(2012~2014), compared with corresponding BI treatments(BI: B1, B2, and B3), each RI treatments(RI: R1, R2, and R3) could significant increase the 0~200 cm soil water content and storage during the early stages of maize(seedling to trumpeting), especially in topsoil(0-60 cm), average increased by 10.40% and6.91%, respectively, and the increase increased with rainfall increasing. Due to the less irrigation amounts(only 50%) of R treatments than corresponding B treatments, after irrigation(blooming to harvesting stage), the soil water content and storage of RI treatments were all lower than corresponding BI treatments, but no significant differences.(2) In three consecutive years(2012~2014), our results found that the RI treatments could significant increase soil temperature(0-25 cm) compared with corresponding BItreatments during the all maize growth stage(seedling to harvesting stage), and the increase decreased with rainfall increasing. The high soil water content of irrigation treatments(RI and BI) after irrigation resulted in a lower soil temperature than no irrigation treatments(R0/B0).Comparison between irrigation treatments(RI and BI), the effects of supplement irrigation during trumpeting stage(R1/B1) or blooming stage(R3/B3) on soil temperature increasing were better than irrigation both during trumpeting and blooming stage(R2/B2).2. Soil nutrients and plant nutrients(1) In the 0-40 cm soil layer, the soil organic matter, total N, and available N contents of RI treatments were less than corresponding BI treatments, and decreased with the rainfall increasing; the soil available P and K contents of RI/BI treatments were higher than corresponding R0/B0 treatments, and the increase decreased with the soil depth, the effects of supplement irrigation during trumpeting stage(R1/B1) on available P is better than other irrigation treatments, and the effects of supplement irrigation both during trumpeting and blooming stage(R2/B2) on available K is best. During the 2012-2014, there were no significant effects of supplement irrigation on soil total P and K contents.(2) In each experimental year, the RI treatments could significant increase maize plants nutrients content compared with corresponding BI treatments, the total N, P and K of kernel average increased by 9.74%, 12.18%, and 24.83%, respectively, leaf average increased by14.26%, 37.07%, and 29.61%, and stalk average increased by 16.07%, 22.88%, and 20.94%.Compared with R0/B0, the RI/BI treatments could significant increase the maize plants nutrients content, and for the RI treatments, the effects of supplement irrigation during trumpeting stage(R1 and R2) is better than during blooming stage(R3), and for the B planting, irrigation both during trumpeting and blooming stage(B2) is better than others.(3) In three consecutive years(2012-2014), our results found that the supplement irrigation treatments could significant increase maize plant nutrient uptake compared with no supplement irrigation treatments, the order of nutrient uptake effects under RI treatments is R1>R2>R3, and the order of BI treatments is B2>B1>R3.3. Water consumption characteristics(1) In three consecutive years(2012-2014), the water consumption of maize increase with rainfall increasing. Compared with corresponding BI treatments, the RI treatments significant decreased the water consumption during the rainy year(2012 and 2013), average decreased by 6.79% and 8.44%, respectively, and increased by 9.51% in normal year(2014).In each experimental year, the water consumption under R2/R1 treatment was all higher than that under R3; and the B2 treatment was higher than that under B1 and B3.(2) Compared with corresponding BI treatments, the RI treatments could significantdecreased the water consumption of each maize growth stage; the water consumption of each growth stage under RI/BI treatments were all significantly higher than corresponding R0/B0 treatments, and supplement irrigation during trumpeting stage(R1/B1, R2/B2) were significantly higher than during blooming stage(R3/B3).(3) In the rainy year(2012 and 2013), the water consumption rate between each RI and BI treatments were no significant difference, but in the normal year(2014), the water consumption rate under each RI treatments were all significant higher than corresponding BI treatments. Comparison between irrigation treatments(RI/BI), the water consumption rate of supplement irrigation during trumpeting stage(R1/B1, R2/B2) were significantly higher than irrigation during blooming stage(R3/B3).(4) In three consecutive years(2012-2014), the water consumption percentage of each growth stage under RI/BI treatments were all significantly higher than R0/B0 treatments, and the water consumption percentage of each supplement irrigation treatments were ranked in the order: R1/B1 > R2/B2 > R3/B3.4. Eco-physiological characteristics(1) In each experimental year, the RI treatments could significant increase leaf SPAD value compared with corresponding BI treatments during the each maize growth stage(trumpeting to filling stage). The leaf SPAD value with the three RI treatments were ranked in the order: R2>R1>R3, compared with R0, the RI treatments average increased by 11.94%(P< 0.05); the three BI treatments were ranked in the order: B2>B1>B3, and the BI treatments were higher than B0 by 12.72%(P < 0.05).(2) In three consecutive years(2012-2014), our results found that the RI treatments could significant(P < 0.05) increased the maize photosynthetic indexes compared with corresponding BI treatments. Compared with R0, the RI treatments could significant increase the net photosynthetic rate(Pn), stomatal conductance(Gs), and transpiration rate(Tr) of maize by 11.79%, 24.23%, and 22.94%, respectively, and R1 and R2 were better than R3. The BI treatments were significant higher than B0 in 2012 and 2014, average increased by 10.08%,15.95%, and 22.94%, respectively, and B2 were better than only B1 or B3.(3) Maize leaf chlorophyll fluorescence characteristics were sensitive to water stress, and decreased with rainfall increasing in three consecutive experimental years(2012-2014).Compared with corresponding BI treatments, the RI treatments could significant(P < 0.05)increased the maximal fluorescence level(Fm), the variable fluorescence(Fv), the maximal quantum yield of PSII photochemistry(Fv/Fm), and the potential activity of PSII(Fv/Fo) by7.66%, 12.19%, 5.47%, and 14.53%, respectively. And the effects of each supplement irrigation treatments on leaf chlorophyll fluorescence characteristics were ranked in the order:R1/B1 > R2/B2 > R3/B3.5. Yield and water use efficiency(1) Compared with corresponding BI treatments, the RI treatments could significant(P <0.05) increase the yield of maize in each experimental year during 2012-2014, and the increase decreased with rainfall increasing. The ear length, ear diameter, ear rows, 100-kernel weight, row numbers, and ear grains were increased by 3.53%, 6.23%, 4.74%, 10.01%, 1.40%,and 6.19%, respectively, and bare tip long was decreased by 9.30%. Comparison between irrigation RI/BI treatments, the effects of supplement irrigation during trumpeting stage(R1/B1, R2/B2) were better than irrigation during blooming stage(R3/B3).(2) In three consecutive years(2012-2014), our results found that the RI treatments could significant(P < 0.05) increase the maize economic yield compared with corresponding BI treatments, average increased by 29.51%, 7.49%, and 34.15% in 2012-2014, respectively, and the increase decreased with rainfall increasing. Compared with R0, the RI treatments average increased by 12.61%(P < 0.05), and supplement irrigation during trumpeting stage(R1/R2)were significantly higher than during blooming stage(R3); the three BI treatments was only significant increased by 16.12% in normal year(2014) compared with B0, and little decreased in rainy year(2012 and 2013), the increase of supplement irrigation during blooming stage(B3) was better than others(B1/B2).(3) In each experimental year, the water use efficiency(WUE) and precipitation use efficiency(PUE) of maize under each RI treatments were average increased by 27.09%(P <0.05) and 24.74%(P < 0.05) compared with corresponding BI treatments, respectively, and the RI and BI treatments were ranked in the order: R1 > R2 > R3 and B1 > B1 > B3,respectively. Compared with corresponding R0/B0, the WUE and PUE under RI treatments average increased by 10.46% and 10.65%, respectively, and the BI treatments only increased by 2.23% and 16.12%(P < 0.05) in normal year(2014). Comparison between RI/BI treatments, the effects of supplement irrigation were ranked in the order: R1/B1 > R2/B2 >R3/B3.(4) Compared with corresponding BI treatments, the RI treatments could significant(P <0.05) increase the irrigation water use efficiency(IWUE) of maize in each experimental year during 2012-2014, average increased by 1.6, 1.3, and 1.7 times, and the increase decreased with rainfall increasing. The effects of supplement irrigation on IWUE were ranked in the order: R1/B1 > R3/B3 > R2/B2.(5) Compared with corresponding BI treatments, the RI treatments could significant increase the irrigation water productivity(IWP) of maize in each experimental year during2012-2014, and the increase decreased with rainfall increasing. For the three RI treatments,the increase of supplement irrigation only during trumpeting stage(R1) was better than other two treatments(R2 and R3) in each experimental year; and for the three BI treatments, the IWP were present a negative value in rainy year(2012 and 2013), and the increase of supplement irrigation both during trumpeting and blooming stage(B2) was better than irrigation only during trumpeting(B1) or blooming stage(B3).6. Economic benefits(1) In three consecutive years(2012-2014), the RI treatments could significant(P < 0.05)increase the maize economic inputs compared with corresponding BI treatments, average increased by 26.09%, 9.61%, and 31.52% in 2012-2014, respectively, and the increase decreased with rainfall increasing. The RI/BI treatments could significantly higher than R0/B0. The increase effects of supplement irrigation on economic inputs were ranked in the order: R1/B1 > R2/B2 > R3/B3.(2) Compared with corresponding BI treatments, the RI treatments could significant(P <0.05) increase the net economic income in each experimental year during 2012-2014, average increased by 39.81%, 3.94%, and 59.92%, respectively. Comparison between RI/BI treatments, the increase of R1/B1 was better than others(R2/B2, R3/B3). |
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