A transcriptomic analysis reveals the adaptability of the growth and physiology of immature tassel to long-term soil water deficit in Zea mays L

Zou, W., Si, B., Han, X. and Jiang, H. 2012. The effect of long-term fertilization on soil water storage and water deficit in the Black Soil Zone in northeast China. Can. J. Soil Sci. 92: 439–448. The Black Soil Zone in northeast China is one of the most important areas of agricultural production in China and plays a crucial role in food supply. However, further improvement in crop yield hinges on effective management of soil water. There is a poor understanding of how different fertilization methods affect crop water use efficiency. The objective of this study was to examine the effect of different fertilization methods on soil water storage and deficit in Black soils. A long-term experiment was conducted at the National Field Research Station of Agro-ecosystems, at Hailun County, Heilongjiang province in northeastern China from 1999 to 2008. Three fertilizer treatments including no fertilizer (CK), inorganic fertilizer (NP) and inorganic fertilizer plus organic material (NPM) were tested. The results showed that soil water storage decreased in the order CK, NP, and NPM during the growing season and the differences in soil water storage in the active root zone (0–70 cm) and below the active root zone (70–130 cm) and soil water deficit were statistically significant among the three treatments. Due to the uneven temporal distribution of rainfall and crop water uptake, soil water content was very dynamic in all three treatments: The low soil water storage and resulting soil water deficit (defined as the monthly difference between potential evapotranspiration and soil available water storage) within the 0- to 70-cm soil profile were found in both June and July. Further, soil receiving NPM was more likely to have a soil water deficit, but less likely to have excessive water. A lower risk of excess water may result in deeper root penetration and increased water use at greater depth, and thus the water deficit under the NPM treatment may not be the limiting factor for crop production. Therefore, NPM seems a viable management practice for improving crop yields in the Black Soil Zone in northeast China, possibly due to higher soil organic carbon and nutrient supply and lower probability of excess water.

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A COMPARISON OF THE RESPONSES OF MATURE AND YOUNG CLONAL TEA TO DROUGHT

Experimental Agriculture ◽

10.1017/s001447970100309x ◽

2001 ◽

Vol 37 (3) ◽

pp. 391-402 ◽

Cited By ~ 10

Author(s):

D. J. Nixon ◽

P. J. Burgess ◽

B. N. K. Sanga ◽

M. K. V. Carr

Keyword(s):

Soil Water ◽

Water Deficit ◽

Fine Roots ◽

Dry Mass ◽

Soil Water Deficit ◽

Dry Matter Distribution ◽

Irrigated Crops ◽

Structural Roots ◽

Using Data

To assist commercial producers with optimizing the use of irrigation water, the responses to drought of mature and young tea (Camellia sinensis) crops (22 and 5 years after field planting respectively) were compared using data from two adjacent long-term irrigation experiments in southern Tanzania. Providing the maximum potential soil water deficit was below about 400–500 mm for mature, and 200–250 mm for young plants (clone 6/8), annual yields of dry tea from rainfed or partially irrigated crops were similar to those from the corresponding well-watered crops. At deficits greater than this, annual yields declined rapidly in young tea (up to 22 kg ha−1 mm−1) but relatively slowly in mature tea (up to 6.5 kg ha−1 mm−1). This apparent insensitivity of the mature crop to drought was principally due to compensation during the rains for yield lost in the dry season. Differences in dry matter distribution and shoot:root ratios contributed to these contrasting responses. Thus, the total above-ground dry mass of well-irrigated, mature plants was about twice that for young plants. Similarly, the total mass of structural roots (>1 mm diameter) to 3 m depth was four times greater in the mature crop than in the young crop and, for fine roots (<1 mm diameter), eight times greater. The corresponding shoot:root ratios (dry mass) were about 1:1 and 2:1 respectively. In addition, each unit area of leaf in the canopy of a mature plant had six times (by weight) more fine roots available to extract and supply water than did a young plant. These results show that young tea should be irrigated in preference to mature tea, especially where the maximum soil water deficit is likely to exceed 250 mm.

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