轉作田玉米生育特性及肥培管理Ⅰ.子實收量之期作間和土壤間差異及有關因素

Characteristics of Corn Production in the Drained Paddies and Their Fertility Managements Ⅰ. Differences of Yield between Crop Seasons and Soils, and the Relevant Factors

連深(S. Lian) ； 王鐘和(C. H. Wang)

《中華農業研究》 37卷1期 (1988/03) Pp. 32-46

https://doi.org/10.29951/JARC.198803.0005

摘要

本試驗在臺中縣霧峰（本所）及雲林縣二崙比較臺農351號玉米在秋作和春作對氮肥用量和栽值密度之效應，及肥料深施的效果，以闡明高產之栽培條件，結果如下：
1.秋作由於營養生長期間短，一般吐絲期葉面積指數(LAI)不高；但多肥配合密值（71,000株／公頃）可有效提高LAI，而由於吐絲至成熟期間長，有利於乾物生產；故秋作之收量潛力高，可達8~9t/ha。反之，春作營養生長期間較長，LAI增大容易，但由於玉米抽穗適遇梅雨期，吐絲～成熟期間氣溫又高，玉米充實期間縮短，不利於乾物生產；故其收量水準顯著低於秋作(6t/ha)。
2.二崙試地土壤中無顯著限制因子，故其秋作玉米對氮施用量和栽值密度之效應均甚顯著；行株距70×20公分（71,400株／公頃）區產量顯著高於70×25公分（57,100株／公頃）區，而氮之需要量則爲150~200 kg/ha。玉米產量對氮肥用量和栽植密度具有顯著的連應；在高栽植密度及多氮的配合下可獲最高收量(8.9t/ha)。
3.霧峰之秋作收量水準顯著低於二崙（最高6.6t/ha）可以歸因於其玉米營養生長之不足及吐絲期～成熟期間葉片純同化率之低落。其表土物理性較差及磷肥力較低等係影響玉米營養生長之主要因素，而底土之密實性影響生育後期根部養分吸收則是玉米充實期間葉片同化能力低落致使純同化率低落之主要原因。肥料之深施（除了一部分起肥之淺施於種子旁外，餘基肥深施於深20~25公分處）可顯著促進吐絲期至成熟期間之養分吸收，提高此期間之葉片同化能力及乾物生產，顯著提高收量(7.5t/ha)。

並列摘要

N x spacing experiments were conducted at Wu-feng (TARI) and Erh-lun (about 30 Km south-west of TARI) to study the effects of levels of N and spacing (70×25 and 70×20cm) on dry matter production and yield of corn during 1983-1984 fall and 1984 spring crop seasons. In addition to the factors of N and spacing, the treatments at Wu-feng covered another factor, i. e., in-row subsoiling and deep placement of fertilizer versus conventional method of fertilization. The effects of the deep placement were further tested in the fall crops of 1984 and 1985. The results are as follows.
1. The vegetative growth period is far longer for the spring crop than for the fall crop. Consequently, the LAI (leaf area index) of the stand in spring is greater (about 4.3), even with a lower rate of N application. On the other hand, the duration of vegetative growth period is relatively short for the fall crop, and the LAI is small even with a high rate of N application. The combination of dense planting with high rate of N is required to attain higher LAIs.
In the spring crop, the silking stage occurs in the rainy weather in May, and lodging of plants is often serious, due to the height of plants and heavy rain. Mutual shading of leaves in the canopy is significant in the spring crop under heavy N application, while this is not so in the fall crop even with a high rate of N application and dense planting, due to the different plant type and better weather conditions. The period for ripening is longer in the fall crop than in the spring crop, due to lower air temperatures and consequently the dry matter production during ripening and yield are greater in the former than in the latter.
2. At the loction of Erh-lun where no obvious limiting factor of plant growth exists, the corn responds to both N and spacing significantly in the fall crop season; the maximum yield of 8.9t/ha was obtained under the dense planting (70×20 cm, i. e., 71,400 plants/ha) and heavy N application (150~200 kg/ha). The yields were very well correlated with the LAIs at silking, which were high with denser planting and heavier N application.
3. The yields of the fall crop t Wu-feng was far lower than those at Erh-lun, with a maximumn of 6.6t/ha. The low LAI and moreover the low NAR (Net Assimilation Rate) of the leaves during ripening stage were attributed to the low yield. The lower phosphate fertility as well as the poorer physical property of the soil compared to that of Erh-lun were at1ributed for the lower vegeative growth and LAI, whereas the lower nutrient uptake duri ng the ripening stage was attributed for the lower NAR of leaves during the same stage. The in-row subsoiling and deep placement of basal fertilizer promoted the nutrient uptake particularly N and P during the ripening stage resulting a higher NAR of leaves during the same stage and consequently a higher yield (7.5t/ ha).
4. The above results imply that both phosphate fertility and compactness of soil are the major factors affecting yield and both the close placement of starter fetilizer to the seeds and the banding of basal fetilizer in the subsoil are effective.