摘要:

Concern over the pollution potential of nitrogen (N) fertilisers has prompted studies of the utilisation efficiency of applied N by crops. This study was conducted to determine the efficiency of N usage by bell pepper(Capsicum annuumL.) grown with plastic mulch and trickle irrigation, and to define a rate of applied N which is equal to uptake by the crop. The relationships between applied N (0, 70, 140, 210, and 280 kg/ha), nutrient uptake, and yield for spring and autumn bell pepper crops grown on a major soil type (Tropeptic Eutrustox) in the Bundaberg region of subtropical Australia were investigated. Maximum dry weight yield of fruit, leaves, roots, and stems corresponded with N210to N280for both spring and autumn crops. In addition, maximum fresh weight of marketable fruit corresponded with N210to N280for both seasons. Nitrogen uptake was equal to the applied rate at N140. Plant uptake of elements increased with applied N and, at N280, were ranked as follows: K> N> Ca> Mg > S > P. Fruit accumulated the greatest proportion of K, N, and P (40 to 64%, 40 to 64%, 49 to 76%, respectively), and only a comparatively small amount of Ca (6 to 7%). The efficiency of fruit production from absorbed applied N declined with increasing N rate. District standard rates of P, N, K, and S application exceeded uptake by plants grown at an equivalent N rate (differences of 68 and 65 kg P, 57 and 52 kg N, 32 and 24 kg K, and 19 and 24 kg S for spring and autumn, respectively). Because of the importance of pepper yield as a determinant in economic outcome and the relatively low cost of fertiliser N, application rates in excess of Ni40 are likely to continue by district growers in an attempt to maximise yield.

ISSN:0190-4167    

DOI:10.1080/01904169309364521

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Seven potassium (K) rates (0, 50, 150, 350, 450, 550, and 650 kg K/ha) were used to determine the optimum rate of K for turf‐type perennial ryegrass during the winter based on turf growth, quality, and winter hardiness. Turf density, color, growth, and winter hardiness were increased as the rate of K application increased up to 350 kg K/ha. However, there were no beneficial effects of K application beyond that rate. Potassium content of the whole plant was 1.72% of the dry matter at the 350 kg K/ha rate. Calcium and Mg contents of the plant were reduced as the result of K application, and a reduction in growth and K content was detected at the higher K application rates. It is suggested that the optimum K rate for perennial ryegrass is about 350 kg K/ha under our experimental conditions in the winter, and that the K content should be about 1.72% of dry weight of whole plant.

ISSN:0190-4167    

DOI:10.1080/01904169309364522

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0190-4167    

DOI:10.1080/01904169309364510

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor