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Shi X.,China Agricultural University | Li F.,China Agricultural University | Yan B.,Institute of Agricultural science of Rikaze District | He D.,Institute of Agricultural science of Rikaze District | And 2 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2015

Highland barley is the main food crop in high altitude cold region of Tibet. Effects of water deficit levels at different growth stages on the water use efficiency and yield of spring highland barley (Hordeum vulgare) were studied by barrel cultivated experiments. Experimental treatments included full irrigation treatment (two controlled lower limits on soil moisture content and straw mulching) as well as four water deficit levels (mild, moderate, severe and extreme deficits) in the whole growth period and five different growth stages, respectively, and the total treatments were 27. Experimental results showed that the harvest index, grain yield and water use efficiency of spring highland barley in the treatment with the water controlled lower limit of 75% of field capacity (FC) were greater than those of 80% FC treatment, and straw mulching treatment resulted in the largest grain yield and crop water use efficiency in all experimental treatments under full irrigation condition. Under the condition of various water deficit levels in the whole growth period, the grain yield of spring highland barley was smaller than that of full irrigation treatment, and it was decreased significantly with the increase of water deficit level. Water deficit from mild to severe levels obtained larger harvest index and crop water use efficiency, but extreme deficiency on water supply resulted in the lowest grain yield, harvest index and crop water use efficiency under various water deficit treatments in the whole growth period. The grain yield and crop water use efficiency under water deficit treatments at different growth stages of spring highland barley were basically decreased with the increase of water deficit level except the treatment with water deficit at ripening stage, and the effect of water deficit at jointing, tillering and filling stages on grain yield was greater than that at other growth stages. Straw mulching or water deficit with mild to severe levels in the whole growth period of spring highland barley can improve crop water use efficiency, and their effects in practice are deserved to be paid more attentions. ©, 2015, Chinese Society of Agricultural Machinery. All right reserved.


Shi X.,China Agricultural University | Li F.,China Agricultural University | Pubu D.,Institute of Agricultural science of Rikaze District | Gao J.,Institute of Agricultural science of Rikaze District | And 2 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2016

Soil temperature influences crop growth and its grain formation in high altitude cold region. Field plot experiments were conducted in order to investigate the effects of straw mulching on tillage soil temperature and the grain yield of spring highland barley in high altitude cold region of Tibet, China. Four experimental treatments, including straw mulching application rates of 0 (control), 5000 (M1), 10000 (M2), and 15000 kg/hm2 (M3), were designed. The results showed that straw mulching on soil surface could adjust soil temperature significantly. Compared with the control treatment, average daily soil temperature was lowered by 2.8~3.9℃ at seedling stage but it was raised by 0.4~1.8℃ at other growth stages of spring highland barley after straw mulching application. Straw mulching significantly reduced plant height (2.29%~16.53%) and dry matter weight (3.98%~25.93%) at seedling and jointing stages, but it increased plant height and dry matter weight by 3.12%~10.31% and 2.17%~18.26% at the filling and mature stages of spring highland barley, respectively, and it significantly decreased root mass density in 0~20 cm soil layer, but it was increased in other soil depths. Straw mulching significantly increased the thousand seed weight (4.65%~13.95%) and grain yield (4.30%~13.50%) of spring highland barley. To a certain extent, straw mulching also lowered the spike length and the grain number in each spike of spring highland barley. Generally, there was no significantly statistical difference among different straw mulching application rates (M1~M3) in soil temperature, but significant differences existed among M1~M3 in the growth parameters (except ear length and seeds per ear) of spring highland barley. Straw mulching is advantageous to the thriving growth of seedlings and the increase of grain yield of spring highland barley. © 2016, Chinese Society of Agricultural Machinery. All right reserved.


Shi X.,China Agricultural University | Li F.,China Agricultural University | Yan B.,Institute of Agricultural science of Rikaze District | He D.,Institute of Agricultural science of Rikaze District | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2016

It is very important to improve water use efficiency for the development of water-saving agriculture in high altitude semi-arid cold region of Tibet. In order to obtain a suitable lower control limit of soil moisture content for irrigation and set up water-saving irrigation regime, the responses of spring highland barley to water deficit level in various growth stages were investigated by a field experiment under straw mulching condition in 2014.Experimental treatments included full irrigation treatment in whole growth period (control) and water deficit treatments that exerted in seedling, jointing, heading, filling, and mature stages respectively. The lower control limit of soil moisture content was 75% of soil field capacity in full irrigation treatment. In water deficit treatments, the lower control limit of soil moisture content was 65% (slight water deficit) and 55% (heavy water deficit) of soil field capacity in the growth stage that water deficit was imposed, and that in the other growth stages was 75% of the soil field capacity. The upper control limit of soil moisture content for irrigation was soil field capacity for all the experimental treatments. The results showed that water deficit treatments in various growth stages significantly decreased water consumption amount and daily water consumption intensity of spring highland barley (P<0.05), and the degree of decrease increased with the increased water deficit level. Mean water consumption intensity all over the whole growth period was 4.9 mm/d with a maximum value of 7.3 mm/d that occurred at heading stage under full irrigation treatment, and the water consumption intensity was 4.0-4.6 mm/d under various water deficit treatments. The effect of water deficit treatment imposed in the filling stage of spring highland barley on crop water consumption amount was biggest and that of water deficit treatment in the heading stage was second in all water deficit treatments. Compared with full irrigation treatment, the water consumption amount of spring highland barley was decreased by 56.4-68.0, 82.1-124.7, 36.0-71.3, 142.2-175.9, and 43.6-48.2 mm, respectively, for the water deficit treatments exerted in seedling, jointing, heading, filling, and mature stages. Water deficit did not significantly affect the ear length, seeds per ear, thousand seed weight, harvest index, and grain yield of spring highland barley. Under the experimental conditions, water deficit treatments exerted in various growth stages did not significantly result in the reduction of grain yield, but water use efficiency was increased by 10.5% and water-saving percentage was 11.7% on average. Water deficit treatment imposed in the filling stage of spring highland barley resulted in a highest water use efficiency of 1.77-1.84 kg/m3 and a biggest water-saving percentage of 19.6%-24.2% in all experimental treatments. In a word, when the lower limit of soil moisture content was controlled at 55% of soil field capacity, water deficit did not significantly affect the yield and its components of spring highland barley, and meanwhile a high water-saving percentage was obtained. This indicates that spring highland barley has a great water-saving potential and possibility if straw mulching management measure is adopted in the high altitude semi-arid cold region of Tibet. The effects of water deficit treatments in multiple growth stages on the growth of spring highland barley need to be studied further. © 2016, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.

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