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Xinjiang Agricultural University (2013)

Regulation Effect of Straw Mulching on Soil Water Salt Distribution and Cotton Growth under Drip Irirgation in Arid Region

张金珠; Zhang Jin Zhu

Titre : Regulation Effect of Straw Mulching on Soil Water Salt Distribution and Cotton Growth under Drip Irirgation in Arid Region

Auteur : 张金珠; Zhang Jin Zhu

Grade : Doctoral Dissertation 2013

Université : Xinjiang Agricultural University

Résumé
In order to explore the effect of straw mulching on soil water salt distribution in cotton growth andyield under drip irrigation in North Xinjiang.2009-2012with wheat straw as the material, the effect ofdifferent quantity of straw mulching, straw mulching position and straw length on soil profile water-saltdistribution in the case of soil column one-dimensional vertical infiltration and evaporation werecomparatively studied through soil column experiments in lab. Meanwhile combining four years test-pitexperiments, the effect of surface coverage, coverage below the surface30cm and no coverage on cottongrowth, root system and yield under drip irrigation respectively in the condition of nonsaline alkali soilsand saline-alkali soil on was studied. Motion process of soil moisture and temperature under straw mulchhas been simulated using HYDRUS. The main conclusions are as follows.(1)Ponding infiltration moist soil moisture in the treatment of no coverage and surface coveragegradually Reduce, from top to bottom, from saturated water content to initial value. Both cumulativeinfiltration and wetting front in one-dimensional vertical infiltration increase with the time. At thebeginning of infiltration, cumulative infiltration and wetting front increase rapidly. But its increasing trendgradually become slow over time and continue. The model of no cover one-dimensional vertical waterinfiltration is built.(2)Deep straw mulching which can block infiltration flow make infiltration flow detained in the soilabove straw mezzanine and it also has the permeability reduction which make infiltration water’s andinfiltration front’s wetting velocity reduced. Meanwhile it also affects salinity and ion migration. Salinityrises gradually from top to bottom. After infiltration, change rule of Cl-and change rule of total salinity isthe same in profile. Sensitivity of HCO3-to the straw interlining is stronger than SO42-.(3)Straw mulching has a significant effect on soil temperature field. Straw layer can stop or absorb partof heat energy at any position. The bigger surface cover, more slowly profile temperature changes and thebigger temperature difference than no cover. In the treatment of, temperature variation characteristics is thesame with no cover in the rage of0-40cm and heat transfer performance of straw laminated is greater thanthe surface coverage. The temperatures of the treatment of surface coverage are all lower than coveragebelow the surface20cm in the rage of0-20cm. In the0-40h, the temperatures of the treatment of coveragebelow the surface20cm are all lower than surface coverage in the rage of20-40cm. But endothermic effectof the treatment of coverage below the surface20cm reduces after40h and temperature rise rate is higherthan the treatment of surface coverage in the rage of entire depth. The general function of the soiltemperature with the depth and time is fitted.(4)Straw mulching shows significant influence on soil water distribution. And the location of strawmulching has a remarkable effect on the distribution of soil moisture content after the evaporation ofone-dimensional soil column. Straw coating can effectively restrain water loss from evaporation. The morethe surface of straw mulching quantity is, the stronger inhibition on the surface and the upper evaporationof soil moisture content is. Straw mulching of5cm length and12000kg/hm2or more could inhibit theevaporation loss by52.21%or much better. Soil moisture content of the treatment of surface coverage ishigher than coverage below the surface20cm in0-20cm, and coverage below the surface20cm is higherthan the surface coverage in20-40cm. The more the straw mulching quantity is, the more obvious thephenomenon is. Variance analysis shows that straw mulching quantity under the condition of surfacecoverage influences cumulative evaporation, averaging moisture content of0-15cm and averaging a saltcontent of0-15cm most significantly.When the straw cover is20cm, it only has the biggest influence on theaveraging moisture content of0-15cm.

Mots clés : straw mulch; drip; cotton; water and salt distribution; root density; production; temperature; aridregion;

Présentation (CNKI)

Page publiée le 30 mars 2014, mise à jour le 30 septembre 2017