熱帶條件下多年生黑麥草水分脅迫閾值及Ks系數(shù)評(píng)估

Pessl植物生理生態(tài)系統(tǒng)：熱帶條件下多年生黑麥草水分脅迫閾值及Ks系數(shù)評(píng)估

Pessl植物生理生態(tài)監(jiān)測(cè)系統(tǒng)的全套監(jiān)測(cè)系統(tǒng)和在線平臺(tái)FieldClimate適用于所有氣候區(qū)，可用于各種行業(yè)和各種用途——從農(nóng)業(yè)到研究、水文、氣象、洪水警報(bào)等。iMetos植物生理生態(tài)監(jiān)測(cè)系統(tǒng)已經(jīng)成為一個(gè)全球品牌，使用持續(xù)時(shí)間更長(zhǎng)，性能更好，是通用的天氣監(jiān)測(cè)設(shè)備，具有早期識(shí)別和警報(bào)功能（有SMS手機(jī)提醒功能）；可以用來計(jì)劃、控制和管理復(fù)雜的獨(dú)立氣象過程。該監(jiān)測(cè)系統(tǒng)專為不同氣候區(qū)域的多種任務(wù)而設(shè)計(jì)。其可以安裝多達(dá)600個(gè)傳感器，如土壤和空氣濕度、溫度、降雨、風(fēng)速、風(fēng)向、葉片 濕度、總體輻射等傳感器。

摘要：多年生黑麥草(Lolium perenne) 是哥倫比亞赤道高地地區(qū)的主要牧草作物，因?yàn)樗�具有很高的營(yíng)養(yǎng)價(jià)值和生產(chǎn)牛奶和肉。本研究旨在確定可用土壤水分的相對(duì)消耗與多年生黑麥草冠層擴(kuò)張和關(guān)閉氣孔的Ks值之間的關(guān)系，并確定水分脅迫的閾值。實(shí)驗(yàn)在受控環(huán)境條件下的盆中進(jìn)行。這些花盆以完全隨機(jī)的方式排列。該實(shí)驗(yàn)包括五種處理——包括對(duì)照處理——土壤水分虧缺的處理，隨著作物周期的發(fā)展，這些處理逐漸增加了枯竭水平。這產(chǎn)生了一個(gè)生長(zhǎng)階段的各種條件。對(duì)于每個(gè)處理，進(jìn)行四次重復(fù) 生物質(zhì)生產(chǎn)受到水分脅迫的顯著影響。結(jié)果表明，Ks 的上限和下限分別為冠層擴(kuò)張（CE）的土壤中總有效水（TAW）耗竭水平（p）的 0.28 和 1.3，以及 0.25 和 1.1p TAW 氣孔關(guān)閉 (gs)。二次函數(shù)適用于 CE (R2 = 0.72) 和 CS (R2 = 0.73)；此外，具有正形狀因子（sf）的FAO-AquaCrop的Ks函數(shù)如下：sf = 11，CE為0.22，sf = 4.3，gs為RMSE 0.19。我們的研究結(jié)果表明，黑麥草對(duì)水分脅迫具有中等敏感性。糧農(nóng)組織的 Ks 函數(shù)與實(shí)驗(yàn)數(shù)據(jù)之間發(fā)現(xiàn)的差異要求使用模型，并根據(jù)每個(gè)案例調(diào)整參數(shù)。

試驗(yàn)期間不同處理的土壤體積含水量(%) 與種植后天數(shù)的關(guān)系
 

Water Stress Thresholds and Evaluation of Coefficient Ks for Perennial Ryegrass in Tropical Conditions

Abstract: Perennial ryegrass (Lolium perenne) is the predominant forage crop in the equatorial highland zones of Colombia due to its high nutritional value and versatility to produce both milk and meat. This study aimed to determine the relationship between the relative depletion of usable soil water and the Ks values of canopy expansion and closure stomatal of perennial ryegrass, as well as to identify the threshold values of water stress. The experiment was carried out in pots under a controlled environment condition. These pots were arranged in a completely randomized manner. The experiment consisted of five treatments—including control treatment—of water deficits in the soil that progressively increased the depletion level as the crop cycle developed. This generated a wide range of conditions in the growth stages. For each treatment, four repetitions were performed Biomass production was significantly affected by water stress. The results show that the upper and lower thresholds of Ks were 0.28 and 1.3 of the depletion level (p) of the total available water (TAW) in the soil for the expansion of the canopy (CE), and 0.25 and 1.1 p of the TAW for stomatal closure (gs). Quadratic functions were fitted for both the CE (R2 = 0.72) and CS (R2 = 0.73); moreover, the

Ks function of FAO-AquaCrop with positive shape factor (sf) was as follows: sf = 11, RMSE 0.22 for CE, and sf = 4.3, RMSE 0.19 for gs. Our results indicate that ryegrass is moderately sensitive to water stress. The differences found between the Ks function of FAO and the experimental data call for the need to use modeling with parameters adapted for each case.